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The question of whether student evaluations can be biased is a critical one for those using them, whether for formative or summative purposes. If student evaluations reflect more than an instructor’s actual teaching ability, such as how attractive the professor is, this information must be taken into account when such evaluations are used. Given the important role student evaluations play in many academic employment decisions--such as hiring, promotion, tenure, salary, and awards--it is vital to understand potential sources of bias (see McCarthy, this volume). In this chapter, we will examine potential biasing factors involving the professor--such as gender, race/ethnicity, attractiveness, and age-as well as the course, such as course difficulty and expected grade. | It is well established that students' evaluative ratings of instruction correlate positively with expected course grades. The authors identify 4 additional data patterns that, collectively, discriminate among 5 theories of the grades-ratings correlation. The presence of all 4 of these markers in student ratings data (obtained at University of Washington) was most consistent with the theory that the grades-ratings correlation is due to an unwanted influence of instructors'grading leniency on ratings. This conclusion just@es use of a statistical correction-illustrated here with actual ratings data-to remove the unwanted inflation of ratings produced by lenient grading. Additional research can projtably seek other inappropriate influences on ratings to identify more opportunities for validity-enhancing adjustments. | Blunt trauma abdomen rarely leads to gastrointestinal injury in children and isolated gastric rupture is even rarer presentation. We are reporting a case of isolated gastric rupture after fall from height in a three year old male child. | eng_Latn | 14,700 |
Mental illness in the criminal justice system is one of the most important and underserved public health challenges in psychiatry today, but few general psychiatry residency programs offer clinical education in correctional psychiatry. Developing such rotations might seem intimidating to educational leaders unfamiliar with the criminal justice system, but a variety of potential solutions exist for residency programs to offer this increasingly important clinical training. | OBJECTIVE ::: The Accreditation Council on Graduate Medical Education (ACGME) requires that general psychiatry residency training programs provide trainees with exposure to forensic psychiatry. Limited information is available on how to develop a core curriculum in forensic psychiatry for general psychiatry residents and few articles have been published on the topic. ::: ::: ::: METHODS ::: The objective of this article is to provide an overview of forensic psychiatry topics likely to be of benefit to general psychiatry residents. ::: ::: ::: RESULTS ::: The article is intended to be a springboard for future development of forensic curricula suitable for residents rather than a blueprint for an educational program. ::: ::: ::: CONCLUSION ::: Although most general psychiatry residents will not specialize in forensic psychiatry, a working knowledge of basic concepts in forensic psychiatry should be considered an important component of general psychiatry education. | Blunt trauma abdomen rarely leads to gastrointestinal injury in children and isolated gastric rupture is even rarer presentation. We are reporting a case of isolated gastric rupture after fall from height in a three year old male child. | eng_Latn | 14,701 |
Sickle cell disease: imaging of cerebrovascular complications. | This case is reported because of the unusual blood findings, no duplicate of which I have ever seen described. Whether the blood picture represents merely a freakish poikilocytosis or is dependent on some peculiar physical or chemical condition of the blood, or is characteristic of some particular disease, I cannot at present answer. I report some details that may seem non-essential, thinking that if a similar blood condition is found in some other case a comparison of clinical conditions may help in solving the problem. | This article, as published in issue 2 of European Psychiatry, lacked necessary corrections due to a production error. The publisher regrets the mistake. ::: ::: ::: In the Methods section, the following studies and checklists should have been capitalized: ::: ::: ::: Study of Twin Adults: Genes and Environment (STAGE) ::: ::: ::: Women, Co-occurring Disorders, and Violence Study (WCDVS) ::: ::: ::: Life Stressor Checklist-Revised (LSC-R) ::: ::: ::: Obsessive-Compulsive Inventory-Revised (OCI-R) ::: ::: ::: ::: ::: The title of Table 1 should have read: Sample characteristics and gender differences in OCS severity, depression severity and stressful life events (SLEs). ::: ::: The abbreviations DZ: dizygotic, and SD: standard deviation are here corrected. ::: ::: In Tables 2 and 3: the R2 value was mistakenly noted as r. | eng_Latn | 14,702 |
Valve replacement in the young patient with rheumatic heart disease | The Starr-Edwards ball valve prosthesis remains the device of choice, although other valves have been implanted. The overall hospital mortality rate was 9.6% in the mitral valve, 3.5% in the aortic valve, and 4.2% in the double valve replacement groups. Actuarial survival at 10, 15, and 20 years was 78.4% (±3.3%), 70.0% (±5.8%), and 59.3% (±11.1%), respectively, for patients with mitral valve replacement. The rates for aortic valve replacement were 85.9% (±4.6%) at 10 and 15 years and 72.7% (12.8) at 20 years. In the double valve replacement group the survival rates after 5 and 10 years were 79.9% (±5.1%). The incidence of thromboembolism was 0.41, 0.59, and 1.04 per 100 patient-years for the mitral, aortic, and double-valve prostheses respectively | Since the introduction of thyroid sonography as a routine method for thyroid investigation sonographically determined volumes are being increasingly used for comparative studies concerning the incidence of goitre. The main purpose of this paper is to establish mean values in seven to eleven years old children with sufficient iodine supply as evaluated by urine iodine excretion. Thus it was possible to fix standard mean values to be applied also in non endemic areas. The average thyroid volume of seven to eleven years old subjects was established to be 4.89 +/- 1.83 ml. Additionally the significance of palpatory findings in this age group was compared with sonographic values. The palpation alone especially in the age mentioned is mostly unsuitable in order to differentiate between normals and early goitre development. Consequently sonography is essential in epidemiological studies of goitre incidence. | eng_Latn | 14,703 |
Paediatric pancreaticobiliary endoscopy: a 21-year experience from a tertiary hepatobiliary centre and systematic literature review | Background ::: In adults ERCP and endoscopic ultrasound (EUS) are standard methods of evaluating and treating many hepatopancreaticobiliary (HPB) conditions. HPB disease is being diagnosed with increasing frequency in children but information about role of ERCP and EUS and their outcomes in this population remain limited. Therefore the aims of this study were to describe the paediatric ERCP and EUS experience from a large tertiary referral HPB centre, and to systematically compare outcomes with those of other published series. | BACKGROUND ::: Trauma is a global public health problem that claimed 5.1 million lives in 1990. Twenty percent of these deaths occurred days to weeks after injury and were due to sepsis or organ failure. Therapies to improve survival outcome after injury are limited by our inability to accurately stratify trauma patients at risk for these complications. In this review, the challenge of predicting post-traumatic complications is presented. There is potential for plasma DNA in diagnosis, prediction and monitoring non-traumatic disease. ::: ::: ::: CONCLUSIONS ::: The mechanisms and clearance of plasma DNA have a potential role as a predictor in trauma. | eng_Latn | 14,704 |
Sepsis and hypothermia in the newborn infant: value of gastric aspirate examination. | Bacteriologic examination of blood, urine, CSF, and gastric aspirate was performed in 88 babies admitted with hypothermia (rectal temperature less than 35 degrees C) during the neonatal period. Infection was common in infants older than 3 days (late-onset hypothermia). In 36 of the 44 (81.8%) infected babies, the gastric aspirate was abnormal, whereas it was abnormal in only three of the 23 (13%) not infected. Infection was much less common in babies younger than 3 days (early-onset hypothermia), and in these the gastric aspirate was mostly normal. Two babies had RDS-like symptoms, and streptococci were cultured from the gastric aspirate. Examination of the gastric aspirate is a quick, efficient method of diagnosing severe infection, not only immediately after birth but throughout the neonatal period. | This is the 32nd installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at: http://www.erad.org/page/CCIP_TOC | eng_Latn | 14,705 |
[The immune status of children with extrahepatic portal hypertension following splenectomy]. | The purpose of the work was to study the immune status and some nonspecific defense factors in children with extrarenal portal hypertension after splenectomy. Seventy-one children were examined. It was found that the T-lymphocyte count before and in the early periods after the operation in children with extrahepatic portal hypertension did not differ from that in the control group. At the same time, the changes in serum immunoglobulins depended on the stage of the examination. Study of other links of immunity also revealed the time course of changes in their values. | BACKGROUND ::: Trauma is a global public health problem that claimed 5.1 million lives in 1990. Twenty percent of these deaths occurred days to weeks after injury and were due to sepsis or organ failure. Therapies to improve survival outcome after injury are limited by our inability to accurately stratify trauma patients at risk for these complications. In this review, the challenge of predicting post-traumatic complications is presented. There is potential for plasma DNA in diagnosis, prediction and monitoring non-traumatic disease. ::: ::: ::: CONCLUSIONS ::: The mechanisms and clearance of plasma DNA have a potential role as a predictor in trauma. | eng_Latn | 14,706 |
Gallium uptake in a paraplegic patient with bilateral lower extremity fat necrosis. | A case of soft tissue gallium uptake in a paraplegic patient with biopsy-proven fat necrosis of both lower extremities is presented. Superficial bilateral lower extremity uptake has not been previously reported in the imaging literature, nor has fat necrosis in this unusual distribution been reported in the spinal cord population. | BACKGROUND ::: Trauma is a global public health problem that claimed 5.1 million lives in 1990. Twenty percent of these deaths occurred days to weeks after injury and were due to sepsis or organ failure. Therapies to improve survival outcome after injury are limited by our inability to accurately stratify trauma patients at risk for these complications. In this review, the challenge of predicting post-traumatic complications is presented. There is potential for plasma DNA in diagnosis, prediction and monitoring non-traumatic disease. ::: ::: ::: CONCLUSIONS ::: The mechanisms and clearance of plasma DNA have a potential role as a predictor in trauma. | eng_Latn | 14,707 |
define rupture | Definition of 'rupture'. rupture (rÊptÊÉʳ ) A rupture is a severe injury in which an internal part of your body tears or bursts open, especially the part between the bowels and the abdomen. If a person or animal ruptures a part of their body or if it ruptures, it tears or bursts open. His stomach might rupture from all the acid. | Dear Ibenkel, Myocardial [heart muscle] rupture is a clinical entity that happens after an acute myocardial infarction [aka heart attack with loss of tissue blood supply due to blocks in blood vessels supplying the heart muscles]. | eng_Latn | 14,708 |
Crystal structure of (3E,5E)-3,5-bis(3-nitrobenzylidene)-1-((4-(trifluoromethyl)phenyl)sulfonyl)piperidin-4-one — dichloromethane (2/1), C53H38Cl2F6N6O14S2 | The Essential Medicinal Chemistry of Curcumin | Experimental and theoretical studies of 4-[(4-methyl-5-phenyl- 4H1,2,4-triazol-3-yl)sulfanyl]benzene-1,2-dicarbonitrile | eng_Latn | 14,709 |
Quinolizidinyl derivatives of iminodibenzyl and phenothiazine as multidrug resistance modulators in ovarian cancer cells | Synthesis and antimicrobial assessment of new substituted 10H-phenothiazines, their sulfone derivatives, and ribofuranosides | Efficient one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives promoted by niobium pentachloride | eng_Latn | 14,710 |
REACTIONS OF 2,3-DIARYL-1-METHYL-4,5-DIHYDROIMIDAZOLIUM IODIDES WITH NUCLEOPHILIC REAGENTS | ABSTRACT 2,3-Diaryl imidazolium salts, represented by 1 and 2, reacted with 2-ethanolamine or ethylenediamine to produce 2-aryl oxazolines or imidazolines 5–8 respectively. Their hydrolysis resulted in ring-opened ethylenediamine derivatives 9 and 10. The reduction of 1 and 2 produced partially reduced imidazolidines 11, 12 and 11 reacted further with tryptamine to provide 2,3,4,9-tetrahydro-1-phenyl 1H-pyrido[3,4-b]indole, 13. In all these reactions one-carbon units were successfully transferred to the nucleophilic acceptors, which mimic the one-carbon unit transfer function for tetrahydrofolate coenzymes. | A ring-expanded bryostatin analogue was synthesized by utilizing a Ru-catalyzed tandem tetrahydropyran formation, a Pd-catalyzed tandem dihydropyran formation, and a ring-closing metathesis (RCM) as key steps. The analogue possesses potent antitumor activity against the NCI-ADR cancer cell line with an IC50 of 123 nM. | yue_Hant | 14,711 |
The Self-Association of Antibiotic Actinocyl-bis(3-dimethylaminopropylamine) in Aqueous Solution: A 1H NMR Analysis | Spectroscopic and Calorimetric Approach to Understand the Molecular Basis of Self-Association of Aureolic Acid Antibiotic, Chromomycin A3 | General Intermediates for the Synthesis of 6-C-Alkylated DMDP-Related Natural Products | eng_Latn | 14,712 |
Synthesis and characterization of new coordination polymers generated from bent bis(cyanophenyl)oxadiazole ligands and Ag(I) salts. | Crystal structure of tetra(2,3'-dipyridylamine)cobalt(II) diperchlorate methanol disolvate, [Co(C10H9N3)4](ClO4)2 · 2CH3OH | Absence of CCR8 does not impair the response to ovalbumin-induced allergic airway disease. | eng_Latn | 14,713 |
Bis(1,4-di-tert-butyl-1,4-diazabutadiene)gallium is not a gallium(II) compound | Cationic cluster formation versus disproportionation of low-valent indium and gallium complexes of 2,2'-bipyridine | Synthesis and characterisation of Co(II), Ni(II), Zn(II) and Cd(II) complexes with 5-bromo-N,N′-bis-(salicylidene)-o-tolidine | eng_Latn | 14,714 |
Dinuclear Molecular Model with Axial Asymmetry | Nuclear Reactions with Heavy Ions | Recent Advances in the Catalytic Asymmetric Reactions of Oxaziridines | eng_Latn | 14,715 |
Lyotropic Behavior of Diruthenium(II,III) Alkoxybenzoates in Dodecane | Fastener effect on magnetic properties of chain compounds of dinuclear ruthenium carboxylates | Efficient one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives promoted by niobium pentachloride | eng_Latn | 14,716 |
One-pot synthesis of substituted 2,2'-bipyrroles. A straightforward route to aryl porphycenes. | Synthesis of Multi-Substituted Pyrrole Derivatives Through [3+2] Cycloaddition with Tosylmethyl Isocyanides (TosMICs) and Electron-Deficient Compounds | Constant delay enumeration with FPT-preprocessing for conjunctive queries of bounded submodular width | eng_Latn | 14,717 |
A novel one-pot synthesis of annulated 2,2′-bipyridine ligands by inverse electron demand Diels–Alder reaction of 5,5′-bi-1,2,4-triazines | Conformational preferences of thiacrown ethers containing a 5,5′-bi-1,2,4-triazine subunit: X-ray analysis and DFT calculations | 5-HT3 receptor ligands lack modulatory influence on acetycholine release in rat entorhinal cortex | eng_Latn | 14,718 |
Syntheses of N-Alkyl-N-(α-acetoxyalkyl) nitrosamines, Model Compounds for metabolically Activated N, N-Dialkylnitrosamines | Cross-linkable Nitrosamines with a Chloroalkyl Group as Candidates for Anticancer Lead Compounds | Platelet Activation Is Not Involved in Acceleration of the Coagulation System in Acute Cardioembolic Stroke With Nonvalvular Atrial Fibrillation | eng_Latn | 14,719 |
Expedient synthesis of novel antibacterial hydrazono-4-thiazolidinones under catalysis of a natural-based binary ionic liquid | Synthesis and Hypnotic Activity of New 4-Thiazolidinone and 2-Thioxo-4,5-imidazolidinedione Derivatives | Sulfated chitosan as tear substitute with no antimicrobial activity. | eng_Latn | 14,720 |
Synthesis, characterization and in silico designing of diethyl-3-methyl-5-(6-methyl-2-thioxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxamido) thiophene-2,4-dicarboxylate derivative as anti-proliferative and anti-microbial agents. | Comparative efficacy of new antibacterial compounds against Yersinia entrolitica | 19F-NMR Diastereotopic Signals in Two N-CHF2 Derivatives of (4S,7R)-7,8,8-Trimethyl-4,5,6,7-tetrahydro-4,7-methano-2H-indazole † | eng_Latn | 14,721 |
Vibrational band intensities of the CN group in aliphatic nitriles | Synthesis and Biological Activity of Some New Pyrazoline and Pyrrolo[3,4-c]pyrazole-4,6-dione Derivatives: Reaction of Nitrilimines with Some Dipolarophiles | Mounting evidence against the role of ICC in neurotransmission to smooth muscle in the gut | eng_Latn | 14,722 |
Catalytic asymmetric umpolung reactions of imines | Control of chemoselectivity in asymmetric tandem reactions: Direct synthesis of chiral amines bearing nonadjacent stereocenters | Total synthesis of (+)-gelsemine via an organocatalytic Diels–Alder approach | eng_Latn | 14,723 |
Absolute Configuration of Phorboxazoles A and B from the Marine Sponge Phorbas sp. 1. Macrolide and Hemiketal Rings | Synthesis of the phorboxazoles—potent, architecturally novel marine natural products | Phospho-MED1-enhanced UBE2C locus looping drives castration-resistant prostate cancer growth. | eng_Latn | 14,724 |
Crystal structure of diaquabis(μ-4-carboxy-2-ethyl-1H-imidazole- 5-carboxylato-κ3N3,O4:O5)calcium(II), Ca(H2O)2(C7H7N2O4)2 | Isolation of the first ferromagnetically coupled Mn(III/IV) complex. | Absence of CCR8 does not impair the response to ovalbumin-induced allergic airway disease. | eng_Latn | 14,725 |
Non Solvent Reaction: Ammonium Acetate Catalyzed Highly Convenient Preparation of Trans-Cinnamic Acids | Green Chemistry – Aspects for the Knoevenagel Reaction | Histone acetyltransferase inhibitors block neuroblastoma cell growth in vivo | eng_Latn | 14,726 |
Catalytic, enantioselective hydroacylations of N-allylindole-2-carboxaldehydes and N-allylpyrrole-2-carboxaldehydes are reported. In contrast to many alkene hydroacylations that form six-membered rings, these annulative processes occur in the absence of ancillary functionality to stabilize the acylrhodium(III) hydride intermediate. The intramolecular hydroacylation reactions generate 7,8-dihydropyrido[1,2-a]indol-9(6H)ones and 6,7-dihydroindolizin-8(5H)-ones in moderate to high yields with excellent enantioselectivities. | Density functional theory (DFT) was used to study the cobalt(I)-catalyzed enantioselective intramolecular hydroacylation of ketones and alkenes. All intermediates and transition states were fully optimized at the M06/6-31G(d,p) level (LANL2DZ(f) for Co). The results demonstrated that the ketone and alkene present different reactivities in the enantioselective hydroacylation. In ketone hydroacylation catalyzed by the cobalt(I)–(R,R)-Ph-BPE complex, reaction channel “a” to (R)-phthalide was more favorable than channel “b” to (S)-phthalide. Hydrogen migration was both the rate-determining and chirality-limiting step, and this step was endothermic. In alkene hydroacylation catalyzed by the cobalt(I)–(R,R)-BDPP complex, reaction channel “c” leading to the formation of (S)-indanone was the most favorable, both thermodynamically and kinetically. Reductive elimination was the rate-determining step, but the chirality-limiting step was hydrogen migration, which occurred easily. The results also indicated that the alkene hydroacylation leading to (S)-indanone formation was more energetically favorable than the ketone hydroacylation that gave (R)-phthalide, both thermodynamically and kinetically. | A convenient, fast and environmentally benign procedure for the synthesis of a new series of highly functionalized N-alkylated pyridines as privileged medicinal scaffolds was developed via a unique three-component reaction of easily available aromatic as well as heteroaromatic aldehydes, N-alkyl-2-cyanoacetamides and malononitrile in EtOH in the presence of K2CO3 as a base promoter under microwave irradiation. The presented tandem process is presumed to proceed via Knoevenagel condensation, Michael addition, intramolecular cyclization, autoxidation and subsequent aromatization. Particularly valuable features of this protocol, including high product yields, mild conditions, atom-efficiency, simple execution, short reaction times and easy purification make it a highly efficient and promising synthetic strategy to prepare substituted pyridine nuclei. The proposed mechanism of this novel one-pot reaction and structure elucidation of the products are discussed. | eng_Latn | 14,727 |
1H-imidazol[1,2-a]indeno[2,1-e]pyridine-6(5H)-ones derivatives were synthesized in a one-pot four-component condensation of corresponding aldehydes, 1,3-indandione, diamine, and nitro ketene dithioacetal using KAl(SO4)2·12H2O (alum) as nontoxic, reusable, inexpensive and easily available catalyst in good to excellent yields. This green protocol provides a powerful entry into fused polycyclic structures related to bioactive heterocycles. | 2-Alkyl and 2-aryl-3-(phenylamino)quinazolin-4(3H)-ones 4a–h were synthesized in a one-pot three-component condensation of an isatoic anhydride 1a–h, ethyl or methyl ortho ester and phenylhydrazine in the presence of KAl(SO4)2·12H2O (alum) as a nontoxic, reusable, inexpensive and easily available catalyst. The synthesis was conducted under microwave irradiation or classical heating. Products 4a and 4b show good antimicrobial activities. | A combination of indomethacin and diflunisal, a new salicylic acid derivative, when given to rats, gave a greater reduction in the size of permanganate induced granulomas and less gastric irritation, than either drug given alone. | eng_Latn | 14,728 |
Antibacterial activity of 1,1′-methylenedipyrazole (AM1), 1-hydroxymethylpyrazole (SAM1), 1,1′-methylenediimidazole (AM2), and 1-hydroxymethylimidazole (SAM2) has been tested against reference and clinical strains by both difusimetric and broth dilution methods. Overall, the minimal inhibitory concentrations of tested compounds ranged from 180 to 270 μg/ml, while the minimal bactericidal concentrations were between 360 and 720 μg/ml. Comparative assessment with phenol and formaldehyde shows that AM1, AM2, SAM1, and SAM2 have moderate to good antibacterial activity. | The reaction of imidazole and imidazole derivatives with formaldehyde can be demonstrated with NMR techniques. The results show that only one nitrogen of the imidazole ring reacts to form a N -hydroxymethyl derivative in alkaline solution. Under acidic conditions both nitrogen positions can support N -hydroxymethyl derivatives. This reaction represents a useful tool for the further investigation of enzyme mechanisms involving the imidazole nucleus. | A new energetic salt, hydrazinium 5-nitro-3-dinitromethyl-2H-pyrazole, was synthesized using 1-nitro-3-trinitromethylpyrazole and hydrazine as raw materials and fully characterized by IR and NMR spectroscopy, elemental analysis, and X-ray crystallography. The isomerization of N-nitropyrazole in the reaction condition was first reported and the possible mechanism was explained by the density functional theory method. The salt has good density, high positive enthalpy of formation superior to those of the RDX and HMX, and good detonation properties comparable to those of RDX. By denitration and isomerization reactions, the salt gains a better thermal stability and lower sensitivity toward impact and friction compared with its parent compound. Based on an overall energetic evaluation, the salt has a promising future as an alternative explosive. The research also contributes to the synthesis and application of polynitro-substituted N-heterocyclic compounds as energetic materials. | eng_Latn | 14,729 |
Biotransformation of the H-1 antagonist terfenadine to its desalkyl and hydroxy metabolites was studied in vitro using microsomal preparations of human liver. These metabolic reactions are presumed to be mediated by Cytochrome P450-3A isoforms. The azole antifungal agent ketoconazole was a highly po | Biotransformation of phenacetin via O-deethylation to acetaminophen, an index reaction reflecting activity of Cytochrome P450-1A2, was studied in microsomal preparations from a series of human livers. Acetaminophen formation was consistent with a double Michaelis-Menten system, with low-Km (mean Km1 = 68 μM) and high-Km (mean Km2 = 7691 μM) components. The low-Km enzyme accounted for an average of 96% of estimated intrinsic clearance, and was predicted to contribute more than 50% of net reaction velocity at phenacetin concentrations less than 2000 μM. Among index inhibitor probes, α-naphthoflavone was a highly potent inhibitor of the low-Km enzyme (Ki1 = 0.013 μM); furafylline also was a moderately active inhibitor (Ki1 = 4.4 μM), but its inhibiting potency was increased by preincubation with microsomes. Ketoconazole was a relatively weak inhibitor (Ki1 = 32 μM); quinidine and cimetidine showed minimal inhibiting activity. Among six selective serotonin reuptake inhibitor (SSRI) antidepressants, fluvoxamine was a potent inhibitor of 1A2 (mean Ki1 = 0.24 μM). The other SSRIs were more than tenfold less potent. Mean Ki1 values were: fluoxetine, 4.4 μM; norfluoxetine, 15.9 μM; sertraline, 8.8 μM; desmethylsertraline, 9.5μM; paroxetine, 5.5 μM. The antidepressant nefazodone and four of its metabolites (meta-chloro-phenylpiperazine, two hydroxylated derivatives, and a triazoledione) were very weak inhibitors of P450-1A2. Venlafaxine and its O- and N-desmethyl metabolites showed minimal inhibitory activity. | A new energetic salt, hydrazinium 5-nitro-3-dinitromethyl-2H-pyrazole, was synthesized using 1-nitro-3-trinitromethylpyrazole and hydrazine as raw materials and fully characterized by IR and NMR spectroscopy, elemental analysis, and X-ray crystallography. The isomerization of N-nitropyrazole in the reaction condition was first reported and the possible mechanism was explained by the density functional theory method. The salt has good density, high positive enthalpy of formation superior to those of the RDX and HMX, and good detonation properties comparable to those of RDX. By denitration and isomerization reactions, the salt gains a better thermal stability and lower sensitivity toward impact and friction compared with its parent compound. Based on an overall energetic evaluation, the salt has a promising future as an alternative explosive. The research also contributes to the synthesis and application of polynitro-substituted N-heterocyclic compounds as energetic materials. | eng_Latn | 14,730 |
The reaction allows a new and mild access to a number of fused pyridines and the enantioselective synthesis of axially chiral pyridones is possible. | [2 + 2 + 2] cycloaddition of a 1,2-bis(propiolyl)benzene derivative with terminal and internal alkynes takes place in the presence of [Ir(cod)Cl]2 (cod = 1,5-cyclooctadiene) combined with bis(diphenylphosphino)ethane (DPPE) to give anthraquinones in 42% to 93% yields with a simple experimental procedure. A fluorenone derivative can also be synthesized by iridium-catalyzed [2 + 2 + 2] cycloaddition of a benzene-linked ketodiyne with an internal alkyne to give a 94% yield. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 14,731 |
[Co III (L1) 2 ] (NO 3 ) 1 , Co 3 II ( L2 ) 2 ( C 5 H 5 N ) 6 · 2 ( ClO 4 ) n 2 (where L1 = (3-carboxysalicylidene)-(2-hydroxyaminoethylamine), L2 = (3-carboxysalicylidene)-phenylmethylamine) were synthesized and characterized by elemental analysis, single crystal X-ray diffraction and tested for inhibitive enzymatic activity on Jack Bean Urease(jbU). 1 is a mononuclear complex and the center cobalt atom is chelated by donors of N 4 O 2 possessing a well defined octahedral configuration, and 2 contains two environmentally different cobalt centers, by the μ 2 carboxyl groups bridging the repeat units extending into a one-dimension configuration. Both of the mononuclear neutral molecules 1 and polymeric (1D chain) 2 are future connected via huge inter- and intra-molecular O-H⋯O and C–H⋯O bonds exhibiting a network structure. The enzymatic activity study indicated that the two complexes are showed potent inhibitions against jb U, with IC 50 20.31 ± 0.53 μM of 1 and 22.24 ± 0.67 μM of 2 , which are about 2 times more than 42.12 ± 0.08 μM of acetohydroxamic acid as positive reference. | 2-[6-(Morpholin-4-yl)pyridin-3-ylamino]acetohydrazide (4) was obtained starting from 6-morpholin-4-ylpyridin-3-amine (2) via the formation of ester (3) and then converted to the corresponding Schiff bases (5, 6) with the reaction with aromatic aldehydes. The carbothioamide (9), obtained from the reaction of hydrazide with phenylisothiocyanate, was converted to the corresponding 1,2,4-triazole (11) and 1,3,4-thiadiazole (12) derivatives by the treatment with NaOH or H2SO4, respectively. The cyclocondenzation of 9 with 4-chlorophenacyl bromide or ethyl bromoacetate produced the corresponding 1,3-thiazole (10) or 1,3-thiazolidine derivatives (13), respectively. Antimicrobial and antiurease activities of newly synthesized compounds were investigated. Some of them were found to be active on M. smegmatis, and they displayed activity toward C. albicans and S. cerevisiae in high concentration. Compound 10 proved to be the most potent showing an enzyme inhibition activity with an IC50 = 2.37 ± 0.19 μM. | Two sodium complexes, [(mu(3)-MDBP)Na-2(THF)(2)](2)[(mu(3)-OCH2CH2OCH3)Na](2) (1) and [(mu(1)-MDBP)Na(mu(2)-H2O)(THF)](2)(THF)(2) (2) have been synthesized and structurally characterized. Experimental results show that complex 1 initiates efficiently the ring opening polymerization of L-lactide in a controlled fashion, yielding polymers with narrow polydispersity indexes in a wide range of monomer-to-initiator ratios. (c) 2013 Elsevier B.V. All rights reserved. | eng_Latn | 14,732 |
Two novel benzohydroxamate complexes of anticancer active Pt(II)–diamine moieties have been synthesised in which Pt–C bonds are present in the dinuclear structures. The complexes, [{Pt(en)}2(µ-bha)]ClO4·H2O (en = ethane-1,2-diamine) and [{Pt(R,R-chxn)}2(µ-bha)]NO3·2H2O (chxn = cyclohexane-1,2-diamine), have two platinum centres that are bridged through the bha ligand via ::: (O,O) and (C,N) coordination modes, the latter mode occurring through deprotonation of the ortho carbon of the phenyl ring. The cytotoxicities of the complexes were tested against a panel of cell lines based on the A2780 ovarian cancer cell line and revealed that both dinuclear complexes were less active than their corresponding dichloro parent complexes. It is likely that they act in a similar manner to the parent complexes, but with the cytotoxicity mediated by factors influencing cellular uptake, such as the charge and lipophilicity of the compounds. | In the square-planar cycloplatinated complex of R–phenylethylamine, both additional substituents, an anionic iodo and a neutral donor ligand, have been replaced by chelating ethylenediamine. A very pronounced trans influence is observed in the cationic product complex: Two significantly different bond distances to the chelating ligand are found, the longer in trans geometry to the coordinated carbon atom. The positive charge of the monocationic complex is balanced by an uncoordinated iodide. This target solid crystallizes with four independent cations and anions in the unit cell; pairs of complex cations related by pseudo-inversion are stabilized by T stacking. Classical N–H···I hydrogen bonds lead to a layer structure in the (0 1 0) plane. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 14,733 |
Discovery of 2,4,6-trisubstituted N-arylsulfonyl piperidines as gamma-secretase inhibitors. | Microwave-assisted synthesis of new sulfonyl hydrazones, screening of biological activities and investigation of structure–activity relationship | 5-HT3 receptor ligands lack modulatory influence on acetycholine release in rat entorhinal cortex | eng_Latn | 14,734 |
The Microdetermination of Amines with 2,4-Dinitrofluorobenzene. | Studies on the selective fungitoxicity of aliphatic amines | A comparison between observed and DFT calculations on structure of 5-(4-chlorophenyl)-2-amino-1,3,4-thiadiazole | eng_Latn | 14,735 |
Five-membered rings, with more than two heteroatoms and fused carbocyclic derivatives | Bis(1,3,4-thiadiazolo)-1,3,5-triazinium halides 4.1 Syntheses of azole-substituted guanidines and bis(azolyl)alkanes | Transition metal-free one-pot synthesis of nitrogen-containing heterocycles | eng_Latn | 14,736 |
ON THE LOCAL SPECTRAL PROPERTIES OF WEIGHTED SHIFT OPERATORS | An introduction to local spectral theory | Transition metal-free one-pot synthesis of nitrogen-containing heterocycles | yue_Hant | 14,737 |
Synthesis of novel 1,2,3-triazole-linked beta-lactam-bile acid conjugates 17-24 using 1,3-dipolar cycloaddition reaction of azido beta-lactam and terminal alkyne of bile acids in the presence of Cu(I) catalyst (click chemistry) have been realized. These molecules were evaluated in vitro for their antifungal and antibacterial activities. Most of the compounds exhibited significant antifungal and moderate antibacterial activity against all the tested strains. | Betulin derivatives containing a 1,2,3-triazole ring possess a wide spectrum of biological activities, including antiviral, anticancer, and antibacterial activity. A series of novel triazoles were prepared by the 1,3-dipolar cycloaddition reaction between the alkyne derivatives of betulin and organic azides. The chemical structures of the obtained compounds were defined by ¹H and 13C NMR, IR, and high-resolution mass spectrometry (HR-MS) analysis. The target triazoles were screened for their antiviral activity against DNA and RNA viruses. The cytotoxic activity of the obtained compounds 5a-k and 6a-h was determined using five human cancer cell lines (T47D, MCF-7, SNB-19, Colo-829, and C-32) by a WST-1 assay. The bistriazole 6b displayed a promising IC50 value (0.05 μM) against the human ductal carcinoma T47D (500-fold higher potency than cisplatin). The microdilution method was applied for an evaluation of the antimicrobial activity of all of the compounds. The triazole 5e containing a 3'-deoxythymidine-5'-yl moiety exhibited antibacterial activity against two gram-negative bacteria vz. Klebsiellapneumoniae and Escherichia coli (minimal inhibitory concentration (MIC) range of 0.95-1.95 μM). | MLL1 regulates circadian promoters by depositing H3K4 trimethyl marks, whose levels are also modulated by the NAD+-dependent deacetylase SIRT1. SIRT1 is now shown to promote circadian deacetylation of MLL1, thus affecting MLL1's methyltransferase activity. | eng_Latn | 14,738 |
Some chiral sodium alkoxides can be used as catalysts in the asymmetric Michael reaction as exemplified by the 1,4-addition of an achiral NiII complex of the Schiff base derived from glycine andN-(2-pyridylcarbonyl)-o-aminobenzophenone (1) to methyl methacrylate (2) or methyl acrylate (14). The products of the reaction of1 with2,viz., the corresponding diastereomeric complexes of 4-methylglutamic acid, are formed in dissimilar amounts (de 26–85%); theee value for the major diastereomer (2S,4R)-3a is 28%. After recrystallization, the enantiomeric purity of complex3a increases toee>85%. Acidcatalyzed hydrolysis of the enantiomerically enriched complex3a affords (2S,4R)-4-methylglutamic acid (ee>85%). The complex of glutamic acid15 resulting from the reaction of1 with14 is formed with anee of 45%. After recrystallization, the enantiomeric purities of complex15 and glutamic acid increase toee>90%. | The major goal of this review is a critical discussion of the literature data on asymmetric synthesis of α-amino acids via Michael addition reactions involving Ni(II)-complexes of amino acids. The material covered is divided into two conceptually different groups dealing with applications of: (a) Ni(II)-complexes of glycine as C-nucleophiles and (b) Ni(II)-complexes of dehydroalanine as Michael acceptors. The first group is significantly larger and consequently subdivided into four chapters based on the source of stereocontrolling element. Thus, a chiral auxiliary can be used as a part of nucleophilic glycine Ni(II) complex, Michael acceptor or both, leading to the conditions of matching vs. mismatching stereochemical preferences. The particular focus of the review is made on the practical aspects of the methodology under discussion and mechanistic considerations. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 14,739 |
The antibiotic lock technique involves filling the catheter lumen with an antibiotic solution and allowing it to dwell for sufficient time to sterilize the infected device. However, antifungal therapy for treating catheter-related fungal infection in this setting is unknown. In this study, the effectiveness of the commercially available antifungal drugs, which are commonly used in candidemia, were assessed in an in vitro antibiotic lock model. Amphotericin B, caspofungin, fluconazole, itraconazole, and voriconazole were used as lock solutions against catheters infected with slime-forming Candida albicans and Candida parapsilosis. Infected catheters were exposed to each of the antifungal lock solution (300-, 500- and 1,000-fold MIC) for 1, 3, 5, and 7 days. The presence of the remaining Candida in the catheter was evaluated quantitatively. Among the antifungal agents, amphotericin B and caspofungin lock solutions decreased the yeast colony count significantly from baseline starting on the first day of treatment (P 105 at the end of the study. In summary, amphotericin B and caspofungin appear to have unique activities against Candida-infected catheters. It seems that one of these drugs may permit the retention of an affected intravascular catheter by sterilizing it in a few days. | Catheter-related bloodstream infection (C-RBSI) is one of the most frequent nosocomial infections. It is associated with high rates of morbidity and mortality. Candida spp. is the third most common cause of C-RBSI after coagulase-negative staphylococci and Staphylococcus aureus and is responsible for approximately 8% of episodes. The main cause of catheter-related candidemia is the ability of some Candida strains-mainly C. albicans and C. parapsilosis-to produce biofilms. Many in vitro and in vivo models have been designed to assess the activity of antifungal drugs against Candida biofilms. Echinocandins have proven to be the most active antifungal drugs. Potential options in situations where the catheter cannot be removed include the combination of systemic and lock antifungal therapy. However, well-designed and -executed clinical trials must be performed before firm recommendations can be issued. | This Account describes our achievements toward the development of a new class of platinum(II) complexes with interesting photophysical properties. The general motif of a strongly donating N-heterocyclic carbene with a cyclometalating phenyl group attached to the nitrogen atom together with β-diketonate based counterligands enabled us to synthesize a new class of phosphorescent emitters for use in organic light-emitting diodes (OLEDs). This Account is divided into sections and introduces imidazolium based as well as triazolium based structures and discusses the effects of structural changes on the photophysical properties. Starting from the basic methylated (substituted) phenylimidalium presursors, we initially extended the π-system of the phenyl ring to the dibenzofuran ligand, its regioisomer, and thio-derivative. As the substituents of the β-diketonate ligands turned out to have a strong influence on the photophysical properties (higher quantum yields as well as shorter decay times) a series of dibenzofuranyl-3-methylimidazol as well as diphenylbenzimidazol platinum complexes were synthesized to investigate the different steric and electronic effects, which are described in a separate section. The next section of the Account then describes other extensions of the π-system. Exchange of the methyl group against a phenyl ring, as well as the extension of the π-system in the backbone of the NHC-ligand lead to a significant improvement of the photophysical properties, which reached a maximum for the diphenylbenzimidazole (DPBIC) system. Further extension of the π-system to the diphenylnaphthylimidazol then lead to a unfavorable long decay time. The effect of substitution is discussed for cyano groups, which change the electronic situation and lead to highly emissive complexes. We are currently working on studying the effect of other substituents on the photophysical properties, as well as the introduction of additional heteroatoms into the general motif. Our initial work in that area had been on 1,2,4-triazole complexes. For the basic phenyl/methyl substituted system, two different isomers are accessible, the 4-phenyl-4H-1,2,4-triazoles as well as the 1-phenyl-1H-1,2,4 triazoles. It was interesting to note that the photophysical properties of the corresponding complexes are strongly dependent on the substituent R of the β-diketonate ligand. For R = methyl, the properties are significantly different, while we found almost identical photophysical results for R = mesityl for both 1,2,4-triazole isomers. The last section describes the synthesis of bimetallic complexes. To investigate whether it is possible to cyclometalate twice into the same phenyl ring, we synthesized dicationic NHC precursors from para- and meta-disubstituted bis(imidazole)benzenes. The bimetallic complexes show interesting photophysical properties with quantum yields of up to 93%. All experimental work was accompanied by quantum chemical calculations, which turned out to be very useful for the prediction of the emission wavelengths as well as the interpretation of the emissive states of the platinum complexes. | eng_Latn | 14,740 |
Amminecobalt(III) compounds with a coordinated primary alkyl group (ethyl, n -propyl, n -butyl, 2-phenylethyl, 3-aminopropyl) have been prepared using monoalkylhydrazines as alkylating agents. The identities have been established using solution 1 H and 13 C NMR spectroscopy and elemental analysis. The pentaammine(alkyl)cobalt(III) cations decompose in neutral aqueous solution to give alkyl radicals. | Alkyl xanthines underwent ::: selective homolytic aromatic substitution at C-8 position with alkyl groups of ::: pentaamminecobalt(III) complex. In this process of synthesis, we used monoalkyl ::: hydrazines as the radical source in aqueous ammonia solution. Evidence supporting ::: coordination of the alkyl hydrazine to pentaamminecobalt(III) complex by ::: radical trapping was in good agreement with literature. The products were ::: characterized using GC-MS and 1H, 14N and 59Co ::: NMR spectroscopy. | 2-Aminobenzoic acids or 4-aminobenzoic acid react with dimethyl acetylenedicarboxylate/triphenylphosphine in less than 20 min at 15–25°C to produce new organic phosphorus compounds in good to excellent yields. The conversion occurs with selective N- over O-alkylation of the amino group and isolation of the products is accomplished simply by filtration. | eng_Latn | 14,741 |
To investigate stereospecificity and the mechanism of activation of the histamine H3-receptor, a series of 2-(R and S)-amino-3-(1H-imidazol-4(5)-yl)propyl ether derivatives were synthesized. In these compounds, the structures of the well-known antagonist iodoproxyfan and the full agonists R- or S-(alpha)-methylhistamine were combined in one molecule. The obtained "hybrid" molecules were tested for H3-receptor affinity on rat cerebral cortex. Some selected compounds were further screened for H3-receptor functional activity with GTPgamma[35S] autoradiography studies using rat brain tissue sections. The affinity of all the synthesized compounds (-log Ki = 5.9-7.9) was lower than that found for iodoproxyfan or two of its analogues; however, the compounds showed stereospecificity. The S-configuration of the series of 2-amino-3-(1H-imidazol-4(5)-yl)propyl ether derivatives, which resembles the stereochemistry of R-(alpha)-methylhistamine, was more favorable. Incorporation of an amino group in the propyl chain of iodoproxyfan and analogues did not alter the antagonistic behavior for compounds with an aromatic side chain. However, when also the aromatic moiety was replaced by a cyclohexyl group, the compounds behaved as agonists. This indicates that an interaction between the side chain amino group and the H3-receptor protein is involved in H3-receptor activation. The 2-(S)-amino-3-(1H-imidazol-4(5)-yl)propyl cyclohexylmethyl ether (23) has H3-receptor agonistic properties with high affinity for the histamine H3-receptor (-log Ki = 7.9 +/- 0.2) and might serve as a useful tool for further studies concerning drug design and receptor-ligand interactions. | A series of 2-alkylthio-1-[4-(1-benzyl-2-ethyl-4-nitro-1H- -imidazol-5-yl)-piperazin-1-yl]ethanones (3-9) and alkyl-[4-(1-benzyl-2-ethyl-4-nitro-1H-imidazol-5-yl)-piperazin-1-yl)ketones (11-20) as well as the indole analogue 22 were synthesized from 4-nitro-5-piperazinyl imidazole derivative 1, with the aim to develop newly non-nucleoside reverse transcriptase inhibitors (NNRTIs). The newly synthesized compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. Compound 4 showed inhibition of HIV-1 (EC50 0.45 microg mL-1) and HIV-2 (0.50 microg mL-1), while 11 showed inhibition of HIV-1 (EC50 2.48 microg mL-1, SI = 4). | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 14,742 |
The diversity of products in the reaction of diethyl azodicarboxylate (DEAD)/diisopropyl azodicarboxylate (DIAD) and activated acetylenes with PIII compounds bearing oxygen or nitrogen substituents is discussed. New findings that are useful in understanding the nature of intermediates involved in the Mitsunobu reaction are highlighted. X-ray structures of two new compounds (2-t-Bu-4-MeC6H3O)P (μ-N-t-Bu)2P+[(NH-t-Bu)N[(CO2]-i-Pr)(HNCO2-i-Pr)]](Cl-)(2-t-Bu-4-MeC6H3OH)(23)and [CH2(6-t-Bu-4-Me-C6H2O)2P(O)C(CO2Me)C-(CO2Me)CClNC(O)Cl] (33) are also reported. The structure of23 is close to one of the intermediates proposed in the Mitsunobu reaction. | The control of reactivity to achieve specific syntheses is one of the overarching goals of organic chemistry.[...] | The chemistry of the 5,7-dihydro-6H-pyrrolo[2,3-d]pyrimidin-6-one (1,3-diazaoxindole) compound family, possessing a drug-like scaffold, is unexplored. In this study, the alkylation reactions of N(7)-unsubstituted 5-isopropyl-1,3-diazaoxindoles bearing various substituents at the C(2) position have been investigated. The starting compounds were synthesized from the C(5)-unsubstituted parent compounds by condensation with acetone and subsequent catalytic reduction of the 5-isopropylidene moiety. Alkylation of the thus obtained 5-isopropyl derivatives with methyl iodide or benzyl bromide in the presence of a large excess of sodium hydroxide led to 5,7-disubstituted derivatives. Use of butyllithium as the base rendered alkylation in the C(5) position possible with reasonable selectivity, without affecting the N(7) atom. During the study on the alkylation reactions, some interesting by-products were also isolated and characterized. | eng_Latn | 14,743 |
Plasmodium falciparum causes approximately 1 million deaths annually. However, increasing resistance imposes a continuous threat to existing drug therapies. We previously reported a number of potent and selective triazolopyrimidine-based inhibitors of P. falciparum dihydroorotate dehydrogenase that inhibit parasite in vitro growth with similar activity. Lead optimization of this series led to the recent identification of a preclinical candidate, showing good activity against P. falciparum in mice. As part of a backup program around this scaffold, we explored heteroatom rearrangement and substitution in the triazolopyrimidine ring and have identified several other ring configurations that are active as PfDHODH inhibitors. The imidazo[1,2-a]pyrimidines were shown to bind somewhat more potently than the triazolopyrimidines depending on the nature of the amino aniline substitution. DSM151, the best candidate in this series, binds with 4-fold better affinity (PfDHODH IC(50) = 0.077 μM) than the equivalent triazolopyrimidine and suppresses parasites in vivo in the Plasmodium berghei model. | Background ::: Chagas disease, caused by the parasite Trypanosoma cruzi, is a neglected tropical disease that causes severe human health problems. To develop a new chemotherapeutic agent for the treatment of Chagas disease, we predicted a pharmacophore model for T. cruzi dihydroorotate dehydrogenase (TcDHODH) by fragment molecular orbital (FMO) calculation for orotate, oxonate, and 43 orotate derivatives. | A unique synthetic approach to 3-hydroxy-4-substituted picolinonitriles is achieved via gold(I)-catalyzed cyclization of 4-propargylaminoisoxazoles and subsequent N-O bond cleavage of isoxazolopyridines under mild reaction conditions in a stepwise and one-pot fashion. | eng_Latn | 14,744 |
1,4-Bis[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]-1,4-dimethyl-2-tetrazene (12a), 1,4-bis[1-isopropoxycarbonylmethyl-1H-tetrazol-5-yl]-1,4-dimethyl-2-tetrazene (12b), and 1,4-bis[1-carboxymethyl-1H-tetrazol-5-yl]-1,4-dimethyl-2-tetrazene (13) have been synthesized as new nitrogen-rich compounds. The tetrazenes were obtained by oxidation of the corresponding tetrazolylhydrazines using bromine. Moreover, a new method to prepare tetrazolylhydrazines in high yield using 5-bromotetrazoles has been developed. 12a, 12b, and 13 were characterized using vibrational spectroscopy (IR, Raman), mass spectrometry, and multinuclear NMR spectroscopy. The crystal structures of 12a, 12b, and 13 were determined using single crystal X-ray diffraction. Furthermore, the energetic properties of 12a, 12b, and 13 have been investigated using DSC and bomb calorimetric measurements. The sensitivity data toward impact and friction has been determined using BAM methods. | A series of derivatives of N, N'-azobis(1,2,4-triazole) substituted by -N₃, -NF₂, -NO₂, and -NH₂ groups was studied using the density functional theory method. To reveal the orbital interactions clearly and interpret the stability of the title compounds, natural bonding orbital (NBO) analysis was carried out. Strong p-π and π-π conjugation interactions exist in molecules. Substituent effects on the geometrical and electronic structures, aromaticity of the triazole ring, electronic sensitivity, impact sensitivity, thermal stability, density, solid state heat of formation [ΔH(f)(s)], detonation velocity (D), detonation pressure (P), and specific impulse (I(s)) were investigated. Substituent groups have significant and differing effects on performance. -N₃, -NF₂, and -NO₂ groups are very helpful for enhancing D and P, but the case is different for the -NH₂ group. The order of the contribution of various groups to P and D is -NF₂> -NO₂ > -N₃ > -NH₂. -NF₂ brings the highest D and P, but the lowest I(s). -NO₂ results in the secondary highest D and P and the best electronic stability.-N₃ gives relatively low D, P and stability, but the highest ΔH(f)(s) and I(s). -NH₂ leads to the lowest D and P, while giving the best impact and thermal stabilities. Therefore, it is necessary to consider various aspects comprehensively according to the practical requirements for each compound designed. Taking both detonation performance and sensitivity into consideration, introducing -NH₂ and -N₃ into N, N'-azobis(1, 2, 4-triazole) may be a good choice for designing high-energy density materials. | We have found that Zn2+ prevented lysis of unfertilized sea urchin eggs, and the eggs retained the ability to form fertilization membranes and to divide. SDS polyacrylamide gel electrophoresis showed that proteolysis of several proteins accompanied egg lysis, but Zn2+ inhibited this proteolysis. Therefore, Zn2+ blocks protease activity directly or indirectly and thereby prolongs the longevity of unfertilized sea urchin eggs. | eng_Latn | 14,745 |
A number of mono- or diaminoalkylated indeno[1,2-c]isoquinolin-5,11-diones analogs of 1 were synthesized and evaluated for their DNA binding affinities, topoisomerase inhibition properties and antiproliferative activities against human cancer cell lines (HL60). Impact of the side chain connected to the aromatic D ring and to the N6 lactam position on the biological profile will be discussed. | Sulfur and nitrogen mustards are very toxic, yet versatile organic molecules with numerous applications. Herein, we report on a synthesis of a new class of green compounds, i.e., half-mustard and iprit carbonates, that result in new, unexplored, and safe molecules. Their chemical behavior with several nucleophiles and their reaction kinetics have been investigated. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 14,746 |
The present study provides an efficient strategy for the preparation of novel N-substituted-4-methyl-quinolin-1(2H)-one derivatives via two-step Ugi/Heck reaction. The procedure is based on the Ugi coupling between 2-bromoanilines, various aromatic aldehydes, vinylacetic acid, and isocyanides, and then intramolecular Heck reaction, which leads to the formation of the title compounds in good yields. | 2-Chloro-3-formyl quinoline has been applied as an aldehyde moiety in the Groebke-Blackburn-Bienaymé multi-component reaction with isocyanides, 2-aminoazines, and 2-aminoazole to afford the desired adducts which are amenable for further cyclization on the basis of Ullmann-type coupling. The copper iodide-mediated intramolecular C-N bond formation in the second step gave an easy access to a series of imidazo[4[Formula: see text],5[Formula: see text]:4,5]pyrrolo[2,3-b]quinoline derivatives in moderate to good yields. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 14,747 |
A series of new N-[(benzo)thiazol-2-yl]-2/3-[3,4-dihydroisoquinolin-2(1H)-yl]ethan/propanamide derivatives was synthesized and characterized by 1H, 13C NMR and IR spectroscopy and mass-spectrometry. A single crystal X-ray study of N-(1,3-benzothiazol-2-yl)-2-[3,4-dihydroisoquinolin-2(1H)-yl]ethanamide is reported to determine its conformational feature. The investigated compounds were found to be active in psychotropic in vivo, anti-inflammatory in vivo and cytotoxicity in vitro screening. They possess marked sedative action, reveal high anti-inflammatory activity, have selective cytotoxic effects and NO-induction ability concerning tumour cell lines. Some of the compounds synthesized demonstrate antimicrobial action. An attempt was made to correlate the biological results with their structural characteristics and physicochemical parameters. Some specific combinations of types of activities for the synthesized compounds have been revealed. | A series of 8- and 11-substituted hybrids of oxoisoaporphine–tetrahydroisoquinoline have been designed and synthesized. The new derivatives strongly suppressed NO and iNOS production and modulated the production of cytokines by decreasing TNF-α and IL-1β formation in lipopolysaccharide-activated BV-2 microglia and RAW 264.7 macrophages. Meanwhile, incubation of these derivatives with SH-SY5Y cells that were transfected with human APP containing the Swedish mutations significantly decreased the secretion of Aβ42. Moreover, these hybrids could strongly inhibit the activity of acetylcholinesterase and butyrylcholinesterase. Further investigations in vivo indicated that the 8-substituted hybrid 3b significantly delayed paralysis caused by Aβ1–42 toxicity in GMC101. In sum, these new hybrids could target multiple pathogenetic factors in Alzheimer’s disease and merit further investigation. | Cyanide-resistant respiration was induced in the yeast, Hansenula anomala in the presence of cyanide or antimycin A, which blocks the electron transport after ubiquinone. The de novo protein synthesis in cytosol and oxygen were deduced to be involved in this induction process. The period required for the induction varied during the growth stage, suggesting that involvement of additional physiological factor(s) in this induction process. The organism could multiply in the presence of antimycin A by developing cyanide-resistant respiration despite a decreased growth rate. | eng_Latn | 14,748 |
Single crystal X-ray structures of monoazo disperse dyes comprising thiadiazolyl based diazo component and m-aminoacetanilide based coupling component were analysed and compared with a thiazolyl based monoazo disperse dye. It has been found that contrary to the earlier findings intramolecular hydrogen bonding between the β-nitrogen of the azo linkage and o-acetylamino substituent on the coupler is not the exclusive factor for the observed brightness of such dyes. An unequivocal evidence of the non-existence of such interaction has been presented. | This study focuses on the preparation, single crystal X-ray diffraction, characterization, and optical properties of some anthraquinone-based dyes. The anthraquinone-based antimicrobial dye N-{2-[(9,10-dioxo-9,10-dihydroanthracen-1-yl)amino]-2-oxoethyl}-N,N-dimethylbutan-1-aminium chloride monohydrate (III) was obtained from 1-aminoanthraquinone (I) via 2-chloro-N-(9,10-dioxo-9,10-dihydroanthracen-1-yl)acetamide (II) using known preparation and characterization methods. Single crystal X-ray diffraction analysis of III revealed a monoclinic system, space group P21/n, Z = 4. Photoluminescence properties of anthraquinone dyes I–III were also investigated. These dyes gave an intense emission (λmax = 341 nm) upon the irradiation by UV light and showed photoluminescence quantum yields of 73 %, 66 %, and 61 % with long excited-state lifetimes of 6.87 ns, 6.14 ns, and 5.69 ns, respectively. These anthraquinone dyes are of interest as an organic light emitting material for electroluminescent devices. | A versatile and practical “on-water” protocol was newly developed to synthesize quinazolinones using o-bromobenzonitrile as a novel starting material. Studies have found that air as well as water plays an important role in synthesis of quinazolinones. Further investigation indicated that dihydroquinazolinones can be prepared with this protocol under the protection of N2. The protocol can be extended to other substrates and various quinazolinones and dihydroquinazolinones were obtained. o-Bromobenzamide, o-aminobenzonitrile, and o-aminobenzamide were also evaluated as starting materials, and the results further proved the versatility of this protocol, especially towards dihydroquinazolinones. | eng_Latn | 14,749 |
In an attempt to find a new class of heterocyclic bio-active agents, a series of novel 3-(1-phenyl-4-((2-(4-arylthiazol-2-yl)hydrazono)methyl)-1H-pyrazol-3-yl)-2H-chromen-2-one derivatives (5a–l) have been synthesized efficiently both quantitatively and qualitatively via a three-component one-pot manner by Hantzsch condensation. Structures of all the newly synthesized compounds were established by their spectral data and elemental analyses, and they were evaluated for their in vitro antimicrobial and antioxidant activities. Among the tested compounds (5a–l), the derivatives 5k, 5h and 5a have displayed broad spectrum antibacterial activity, whereas the compounds 5b and 5f were found to be potent antifungal agents. Antioxidant activity results revealed that compounds 5a, 5b and 5i exhibited higher radical scavenging ability than the positive control drug Trolax. Further, molecular docking of synthesized compounds (5a–l) into the binding site of the crystal structure of E. coli MurB enzyme (PDB Id: 1MBT), a key enzyme in peptidoglycan biosynthesis, was performed to gain a comprehensive understanding of the plausible binding modes and also to compare the theoretical and experimental results of these compounds. Docking results revealed that the docking scores and H-bonding interactions of the ligands are in good agreement with the in vitro results and also indicated that compounds 5k, 5h and 5a have considerable binding energies and greater affinity towards the active site of MurB enzyme. Thus, they can be further optimized and developed as lead compounds. | As a part of our endeavor toward the synthesis of a new class of biologically potent heterocyclic hybrids, a series of newly fused thiazolo[2,3-b]pyrimidinones bearing a pyrazolylcoumarin moiety (6a–p) were synthesized in acceptable yields. Anticipated structures of all titled compounds were in agreement with spectral and analytical (C, H and N) analyses. The compounds were screened for in vitro antibacterial activity against both G+ and G− bacterial strains and antiproliferative activity against K562 (chronic myelogenous leukemia), MCF-7 (breast cancer), MDA-MB-231 (breast cancer), COLO 205 (colorectal adenocarcinoma), HepG2 (hepatocellular carcinoma) cell lines. Further, potent antibacterial compounds were subjected to molecular docking studies in order to gain insight into their plausible binding modes and mechanism of action against MurB. The modeling results were in agreement with the experimental data. | ABSTRACTUNC-45A is an ubiquitously expressed protein highly conserved throughout evolution. Most of what we currently know about UNC-45A pertains to its role as a regulator of the actomyosin system... | eng_Latn | 14,750 |
Three series of azole piperazine derivatives that mimic dicyclotyrosine (cYY), the natural substrate of the essential Mycobacterium tuberculosis cytochrome P450 CYP121A1, were prepared and evaluated for binding affinity and inhibitory activity (MIC) against M. tuberculosis. Series A replaces one phenol group of cYY with a C3-imidazole moiety, series B includes a keto group on the hydrocarbon chain preceding the series A imidazole, whilst series C explores replacing the keto group of the piperidone ring of cYY with a CH2-imidazole or CH2-triazole moiety to enhance binding interaction with the heme of CYP121A1. The series displayed moderate to weak type II binding affinity for CYP121A1, with the exception of series B 10a, which displayed mixed type I binding. Of the three series, series C imidazole derivatives showed the best, although modest, inhibitory activity against M. tuberculosis (17d MIC = 12.5 μg/mL, 17a 50 μg/mL). Crystal structures were determined for CYP121A1 bound to series A compounds 6a and 6b that show the imidazole groups positioned directly above the haem iron with binding between the haem iron and imidazole nitrogen of both compounds at a distance of 2.2 Å. A model generated from a 1.5 Å crystal structure of CYP121A1 in complex with compound 10a showed different binding modes in agreement with the heterogeneous binding observed. Although the crystal structures of 6a and 6b would indicate binding with CYP121A1, the binding assays themselves did not allow confirmation of CYP121A1 as the target. | The rise in multidrug resistant (MDR) cases of tuberculosis (TB) has led to the need for the development of TB drugs with different mechanisms of action. The genome sequence of Mycobacterium tuberculosis ( Mtb ) revealed twenty different genes coding for cytochrome P450s. CYP121A1 catalyzes a C C crosslinking reaction of dicyclotyrosine (cYY) producing mycocyclosin and current research suggests that either mycocyclosin is essential or the overproduction of cYY is toxic to Mtb . A series of 1,4-dibenzyl-2-imidazol-1-yl-methylpiperazine derivatives were designed and synthesised as cYY mimics. The derivatives substituted in the 4-position of the phenyl rings with halides or alkyl group showed promising antimycobacterial activity (MIC 6.25 μg/mL), with the more lipophilic branched alkyl derivatives displaying optimal binding affinity with CYP121A1 ( i Pr K D = 1.6 μM; t Bu K D = 1.2 μM). Computational studies revealed two possible binding modes within the CYP121A1 active site both of which would effectively block cYY from binding. | This article contains data that relate to the study carried out in the work of Marcus et al. (2018) [1]. Data represent an information about pharmacophore analysis of imidazo[1,2-a]benzimidazole and pyrimido[1,2-a]benzimidazole derivatives and results of construction of the relationship between intraocular pressure (IOP) lowering activity and hypotensive activity of imidazo[1,2-a]benzimidazole and pyrimido[1,2-a]benzimidazole derivatives using a multilayer perceptron artificial neural network. In particular, they include the ones listed in this article: 1) table of all pharmacophores of imidazo[1,2-a]benzimidazole and pyrimido[1,2-a]benzimidazole derivatives that showed IOP lowering activity; 2) table of all pharmacophores of the compounds that showed absence of IOP lowering activity; 3) table of initial data for artificial neural network analysis of relationship between IOP activity and hypotensive activity of this chemical series; 4) graphical representation of the best neural network model of this dependence; 5) original txt-file of results of pharmacophore analysis; 6) xls-file of initial data for neural network modeling; 7) original stw-file of results of neural network modeling; 8) original xml-file of the best neural network model of dependence between IOP lowering activity and hypotensive activity of these azole derivatives. The data may be useful for researchers interested in designing new drug substances and will contribute to understanding of the mechanisms of IOP lowering activity. | eng_Latn | 14,751 |
We have investigated the inhibitory effect of N2O on NH3 formation by purified component proteins from Klebsiella pneumoniae and have confirmed that the inhibition is competitive with respect to N2 and that N2O is reduced to N2, which in turn is further reduced to NH3. In addition, we have shown that N2O is unable to support HD formation from D2 and H2O. N2-supported HD formation from D2 and H2O was found to be inhibited by N2O. In contrast to N2, N2O was found to suppress nitrogenase-mediated H2 evolution completely at infinitely high pN2O. H2 was found to inhibit N2O-supported NH3 production but not N2O-supported N2 production. The steady-state kinetics of N2O reduction showed a good fit to Michaelis-Menten kinetics with a Km for N2O of 5 mM at 30 degrees C, corresponding to 24 kPa of N2O. A model is proposed that fits the observed results. | N2 O is a potent greenhouse gas, but also a potent electron acceptor. In search of thermodynamically favourable - yet undescribed - metabolic pathways involving N2 O reduction, we set up a continuous microbial enrichment, inoculated with activated sludge, fed with N2 O as the sole electron acceptor and acetate as an electron donor. A nitrogen-free mineral medium was used with the intention of creating a selective pressure towards organisms that would use N2 O directly as source of nitrogen for cell synthesis. Instead, we obtained a culture dominated by microorganisms of the Rhodocyclaceae family growing by N2 O reduction to N2 coupled to N2 fixation. Biomass yields of this culture were 40% lower than those of a previously reported culture grown under comparable conditions but with an NH4+-amended medium, as expected from the extra energy expense of N2 fixation. Interestingly, we found no significant difference in yields whether N2 O or acetate was the growth-limiting substrate in the chemostat in contrast to the study with NH4+-amended medium, in which biomass yields were roughly 30% lower during acetate limiting conditions. | A series of derivatives of N, N'-azobis(1,2,4-triazole) substituted by -N₃, -NF₂, -NO₂, and -NH₂ groups was studied using the density functional theory method. To reveal the orbital interactions clearly and interpret the stability of the title compounds, natural bonding orbital (NBO) analysis was carried out. Strong p-π and π-π conjugation interactions exist in molecules. Substituent effects on the geometrical and electronic structures, aromaticity of the triazole ring, electronic sensitivity, impact sensitivity, thermal stability, density, solid state heat of formation [ΔH(f)(s)], detonation velocity (D), detonation pressure (P), and specific impulse (I(s)) were investigated. Substituent groups have significant and differing effects on performance. -N₃, -NF₂, and -NO₂ groups are very helpful for enhancing D and P, but the case is different for the -NH₂ group. The order of the contribution of various groups to P and D is -NF₂> -NO₂ > -N₃ > -NH₂. -NF₂ brings the highest D and P, but the lowest I(s). -NO₂ results in the secondary highest D and P and the best electronic stability.-N₃ gives relatively low D, P and stability, but the highest ΔH(f)(s) and I(s). -NH₂ leads to the lowest D and P, while giving the best impact and thermal stabilities. Therefore, it is necessary to consider various aspects comprehensively according to the practical requirements for each compound designed. Taking both detonation performance and sensitivity into consideration, introducing -NH₂ and -N₃ into N, N'-azobis(1, 2, 4-triazole) may be a good choice for designing high-energy density materials. | eng_Latn | 14,752 |
A novel 2-amino-4-(8-quinolinol-5-yl)-1- (p-tolyl)-pyrrole-3-cabonitrile (2) was obtained by the reaction of 2-[2-bromo-1-(8-hydroxyquinolin-5-yl)-ethylidene]-malononitrile (1) with p-toluidene. The new synthon compound (2) could be annelated to the corresponding pyrrolo[2,3-d]pyrimidines (4, 6, 7, 26-28), triazolo[1,5-c]pyrrolo[3,2-e]pyrimidines (10, 29, 30), pyrrolo[2,3-c]pyrazoles (11-15), pyrrolo[1,2-a]pyrrolo[3,2-e] pyrimidine (17) and imidazo[1,2-c]pyrrolo[3,2-e]pyrimidines (18-25) via the reaction with some reagents such as acetic anhydride, formamide, triethyl orthoformate, hydrazine hydrate, hydroxylamine, ethylenediamine, carbon disulfide and phosphorus oxychloride. Chemical and spectroscopic evidences for the structures of these compounds are presented. The antifungal and antibacterial activity of the newly synthesized comounds were evaluated.�⨀�⨀ᢑ�⨀ကᢑ�⨀?麆Ѐက䂑�⨀䂑�⨀ | A series of novel pyrrolo[2,3-d]pyrimidine and fused pyrrolo[2,3-d]pyrimidine derivatives were synthesized and their structures were characterized by elemental analysis, 1H NMR, IR, and mass spectroscopy. Their in vivo anti-inflammatory activities were evaluated, and the results indicated that some of the title compounds compounds showed significant activities. These compounds are 2b ((7-(4-Methoxyphenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-hydrazine), 7b (4-(2-(Benzyl)hydrazinyl)-7-(4-methoxyphenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d] pyrimidine), 7d (4-(2-(Benzyl)hydrazinyl)-7-(4-methoxyphenyl)-5-phenyl-7H-pyrrolo[2,3-d]pyrimidine), and 9b (4-(3,5-Dimethyl-4H-pyrazol-1-yl)-7-(4-Methoxyphenyl)-5,6-diphenyl-4,7dihydro-3H-pyrrolo[2,3-d]pyrimidine). | Transfusion-dependent patients such as those suffering from β-thalassaemia develop a fatal secondary haemosiderosis and consequently a selective iron chelator must be used to relieve such iron overload. 3- Hydroxypyridin-4-ones are selective for iron(III) under most biological conditions, but unlike desferrioxamine, are efficiently absorbed when administered orally. In this study, the synthesis and determination of partition coefficients (Kpart) of a range of 1-substituted-2-ethyl-3-hydroxypyridin-4-ones, as orally active iron chelators, are described. All of the 1-substituted-2-ethyl-3-hydroxypyridin-4-ones were synthesized via a three step synthetic pathway. The commercially available 2-ethyl-3-hydroxypyran-4-one (ethyl maltol) was benzylated in aqueous methanol. The reaction product of the benzylated ethyl maltol with an excess of the suitable primary aryl amines was heated in a thick-walled sealed glass tube at 150-160 oC to give 1-aryl-2-ethyl-3-benzyloxypyridin-4-one derivatives which were isolated as the free-bases. Removal of the benzyl group under acidic conditions was performed by catalytic hydrogenation to yield the bidentate chelators as HCl salt in good yield. In this work, final following compounds of 1-phenyl-2-ethyl-3- hydroxypyridin-4-one, 1-(4-methylphenyl)-2-ethyl-3-hydroxypyridin-4-one, 1-(4-methoxylphenyl)-2-ethyl- 3-hydroxypyridin-4-one, and 1-(4-nitrophenyl)-2-ethyl-3-hydroxypyridin-4-one were synthesized. Identifcation and structural elucidation of ligands were achieved by 1HNMR, IR, elemental analysis, mass spectra and through physical experiments. The Kpart values of the compounds were also determined in an aqueous/octanol system using an automated continuous flow method (a filter probe method). | eng_Latn | 14,753 |
Reaction of indole-3-carboxaldehydes 4 with hydrazine derivatives and different substituted acid hydrazides afforded the corresponding hydrazine derivatives 5a-c and acid hydrazide derivatives 7-11 respectively. Condensation of indole-3-carboxaldehydes 4 with phenacyl bromide and thiourea gives 1,3-thiazol-2-amine derivative 18. On the other hand, reaction 4 with 3-acetylchromene-2-one afforded chalcone derivative 19. Compound 4 undergoing Knoevenagel condensation with cyanoacetamide, ethyl cyanoacetate, benzimidazol-2-ylacetonitrile, rhodanine-3-acetic acid, 2,3-dihydropyrimidin-4-one derivative and 2,4-dihydropyrazol-3-one afforded the compounds 20a,b, 22, 23, 27 and 28 respectively. The structure of the newly synthesized compounds has been confirmed by elemental analysis and spectra data. The antimicrobial activities of the some newly synthesized compounds were measured and showed that most of them have high activities | The main aim of the present study was to synthesize new leads with potential antimicrobial and antioxidant activities. As a part of systematic investigation of synthesis and biological activity, some new indole compounds 3a–c and 4a–c were prepared and screened for their antimicrobial and antioxidant activities. The antimicrobial evaluation of newly synthesized compounds was carried out by cup-plate method. Antimicrobial activity results revealed that compound 4a showed promising activity against bacteria Staphylococcus aureus, Klebsiella pneumonia, and Pseudomonas aeruginosa and exhibited maximum inhibition against Aspergillus niger, Aspergillus oryzae, Aspergillus terreus, and Aspergillus flavus. The antioxidant activity was performed by three methods, namely, radical scavenging activity (RSA), ferric ions (Fe | The reactions of substituted furo[3,2-b]pyrrole-5-carboxhydrazides 1 with 5-arylfuran-2-carboxaldehydes 2, 4,5-disubstituted furan-2-carboxaldehydes 3 and thiophene-2-carboxaldehyde 4 has been studied. The advantage of microwave irradiation on some of these reactions was reflected in the reduced reaction time and increased yields. Reactions of 1 with 4-substituted 1,3-oxazol-5(4H)-ones 11 led to diacylhydrazines 13 or to imidazole derivatives 14 depending on the temperature. 1,2,4-Triazole-3-thione 17 was synthesized by two-step reaction of 1 with phenylisothiocyanate and subsequent base-catalyzed cyclization of thiosemicarbazide 16. The effects of hydrazones 5–10 on inhibition of photosynthetic electron transport in spinach chloroplasts and chlorophyll content in the antialgal suspensions of Chlorella vulgaris were investigated. | eng_Latn | 14,754 |
This review article describes the synthesis and coordination chemistry of three types of thiophenol-based heterodonor ligands containing tertiary phosphine and/or arsine groups in combination with sulfur. Phenylthio(diphenyl)phosphine and -arsine ligands, EPh 2 (SPh) (E = P, As), incorporate an E–S bond in their structures. Upon reaction with different metal carbonyls, metal-mediated cleavage of the E–S bonds of these ligands has been observed, leading to a variety of sulfur- and phosphorus- or arsenic-containing metallacycles. The structurally isomeric phosphino- and arsinoarylthiols HSC 6 H 4 -2-EPh 2 ( ESH ) combine a phosphine or arsine centre with a thiol functionality, which is usually deprotonated on coordination. These compounds have been shown to be very versatile ligands that form stable complexes with a wide range of transition metals. The heterotopic ligand 1-Ph 2 AsSC 6 H 4 -2-PPh 2 ( P,SAs ) not only combines the properties of phenylthio(diphenyl)arsine and 2-diphenylphosphanylbenzenethiol by incorporating all three donor atoms in its structure, but also allows the effect of the PPh 2 group in the ortho position on the cleavage of the As–S bond to be studied. | A series of [Cu(N,N)(P,P)]+, [Cu(N,N)(P,S)]+, [Cu(N,N)2]+ and [Cu(P,S)2]+ complexes incorporating the ligands 2,2′-bipyridine, 1,10-phenanthroline, 1,2-bis(diphenylphosphino)ethane, bis(2-(diphenylphosphino)phenyl)ether (1), 2-diphenylphosphinothioanisole (3) and 2-methyl-6′-phenyl-2,2′-bipyridine (4) has been synthesized and structurally characterized. We have assessed the degree of distortion of two bidentate ligands away from an ideal tetrahedral arrangement about the copper(I) ion using the White model. The greatest distortion along a pathway towards square planar coordination is observed in [Cu(4)2][PF6] and is a result of intra-cation π-stacking between phenyl and bpy domains. Each of the complexes which contain the P,S-chelating ligand 3 exhibits significant ‘rocking’ or ‘wagging’ distortions which are associated with intra-cation CHmethyl⋯π interactions. The extent of this distortion can also be assessed using a less rigorous approach by measuring the S–Cu–X and P–Cu–X angles where the S and P atoms belong to ligand 3, and X is the midpoint of the backbone of the second ligand. [Cu(3)2][PF6] and [Cu(1)(3)][PF6] exhibit embraces between the phenyl substituents that result in the copper(I) ion being sterically protected, and the room temperature 1H NMR solution spectrum of [Cu(1)(3)][PF6] reveals hindered rotation of the phenyl rings of ligand. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 14,755 |
A highly diastereoselective Lewis acid (BF3·Et2O or TiCl4) induced [3+2] cycloaddition of substituted and unsubstituted indoles with 2-arylcyclopropyl ketones/diesters yielding cyclopenta[b]indoles in high yields is reported. This methodology has also been extended to tetrahydrocarbazole, cyclopenta[b]- and cyclohepta[b]indoles affording tetracyclic propellane type frameworks in modest yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) | Methyl indolenines (4a-c) and(5a-c) were prepared in high yield by a Fischer indole synthesis reaction of o,m-tolylhydrazine hydrochlorides (1a-b) with isopropyl methyl ketone (2) and 2-methylcyclohexanone (3) in acetic acid at room temperature. o,p- Nitrophenylhydrazines (1c-d) were reacted with 2-methylcyclohexanone (3) in acetic acid at reflux to give nitroindolenines (5d-e), while the attempted reactions of o,p-nitrohydrazines with isopropyl methyl ketone (2) in acetic acid were not successful. Compounds(1c-d) were reacted with isopropyl methyl ketone (2) in acetic acid/HCl to give 2,3,3-trimethyl-5-nitro-indolenine (4e) and 2,3,3-trimethyl-7-nitroindolenine (4d). | Pneumoperitoneum was observed in five patients with acute perforative appendicitis (APA). In each case this radiographic observation led to an incorrect diagnosis. Free intraperitoneal gas is found in a small number of patients with APA and has no apparent effect on the course or prognosis of the disease. | eng_Latn | 14,756 |
A number of 2-arylimino-3-aryl-4-thiazolidones and their 1,1-dioxides and 5-phenylazo derivatives have been prepared. The structure of these thiazolidones was confirmed by studying their hydrolysis products. Some of these thiazolidones were screened for their fungicidal activity against Aspergillus niger by agar-growth method and found to be more appropriately fungistatic and not fungicidal. | New functionalized terphenyl derivatives incorporating various heterocyclic rings are prepared by using 4,4′′-difluoro-5′-hydroxy-1,1′:3′,1′′-terphenyl-4′-carbohydrazide as a key intermediate derived from 4,4′-difluoro chalcone, a versatile synthone. All the derivatives are characterized by 1H NMR, IR, and mass spectral data. All the synthesized products are screened for their in vitro antimicrobial and antioxidant properties. The majority of the tested compounds exhibited significant antioxidant activity and some of them showed good antimicrobial activity. | The title compound, 2-(4-fluoro-3-nitrophenyl)-6-(4-methoxyphenyl)imidazo[2,1-b]-1,3,4-thiadiazole (3) was obtained by the condensation of 5-(4-fluoro-3-nitrophenyl)-[1,3,4]thiadiazol-2-ylamine (1) with 4-methoxyphenacyl bromide (2). The newly prepared imidazo[2,1-b]-1,3,4-thiadiazole derivative (3) was characterized by IR, 1H-NMR, 13C-NMR and LCMS spectral data. | eng_Latn | 14,757 |
Ring transformation of readily prepared (4-chloro-5H-1,2,3-dithiazol-5-ylidene)acetonitriles afford 3-haloisothiazole-5-carbonitriles in good to excellent yields. The transformation can be mediated using HBr (g), HCl (g) or BnEt3NCl. Mechanisms for the transformations are discussed, together with rationalizations for the formation of side products. Furthermore, single crystal X-ray structures are provided for (Z)-2-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)acetonitrile and (E)-2-bromo-2-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)acetonitrile confirming the stereochemistry of the exocyclic ethene bond. | Thermolysis of 4,4′-dichloro-, 4,4′-diaryl-, and 4,4′-di(thien-2-yl)-5,5′-bi(1,2,3-dithiazol-ylidenes) affords the respective 3,6-dichloro-, 3,6-diaryl- and 3,6-di(thien-2-yl)isothiazolo[5,4-d]-isothiazoles in low to high yields. The transformation of the 4,4′-diaryl- and 4,4′-di(thien-2-yl)-5,5′-bi(1,2,3-dithiazolylidenes) occurs at lower temperatures in the presence of the thiophiles triphenylphosphine or tetraethylammonium iodide. Optimized reaction conditions and a mechanistic rationale for the thiophile-mediated ring transformation are presented. | MLL1 regulates circadian promoters by depositing H3K4 trimethyl marks, whose levels are also modulated by the NAD+-dependent deacetylase SIRT1. SIRT1 is now shown to promote circadian deacetylation of MLL1, thus affecting MLL1's methyltransferase activity. | eng_Latn | 14,758 |
Recently we reported the reaction of 1,1-dimethyl-4-substituted semicarbazides with phosgene to occur with formation of several new heterocyclic ring systems. Here we report the reaction of several semicarbazides, thiosemicarbazides and related acyl substituted hydrazides with oxalyl chloride and malonyl chloride. These reactions occur with the formation of heterocyclic products which are oxadiazolinones, imidazolidinetriones, 2-thioxoimidazolindine-4,5-diones, and 2-thioxo-1,3-diazine-4,6-diones (2-thioxopyrimidine-4,6-diones). | A series of novel and highly active acetylcholinesterase and butyrylcholinesterase inhibitors derived from substituted benzothiazoles containing an imidazolidine-2,4,5-trione moiety were synthesized and characterized. The molecular structure of 1-(2,6-diisopropyl-phenyl)-3-[(1R)-1-(6-fluoro-1,3-benzothiazol-2-yl)ethyl]-imidazolidine-2,4,5-trione (3g) was determined by single-crystal X-ray diffraction. Both optical isomers are present as two independent molecules in the triclinic crystal system. The lipophilicity of the compounds was determined as the partition coefficient log Kow using the traditional shake-flask method. The in vitro inhibitory activity on acetylcholinesterase from electric eel and butyrylcholinesterase isolated from equine serum was determined. The inhibitory activity on acetylcholinesterase was significantly higher than that of the standard drug rivastigmine. The discussed compounds are also promising inhibitors of butyrylcholinesterase, as some of the prepared compounds inhibit butyrylcholinesterase better than the internal standards rivastigmine and galanthamine. The highest inhibitory activity (IC50 = 1.66 μmol/L) corresponds to the compound 1-(4-isopropylphenyl)-3-[(R)-1-(6-fluorobenzo[d]thiazol-2-yl)ethyl]imidazolidine-2,4,5-trione (3d). For all the studied compounds, the relationships between the lipophilicity and the chemical structure as well as their structure-activity relationships are discussed. | The reactions of substituted furo[3,2-b]pyrrole-5-carboxhydrazides 1 with 5-arylfuran-2-carboxaldehydes 2, 4,5-disubstituted furan-2-carboxaldehydes 3 and thiophene-2-carboxaldehyde 4 has been studied. The advantage of microwave irradiation on some of these reactions was reflected in the reduced reaction time and increased yields. Reactions of 1 with 4-substituted 1,3-oxazol-5(4H)-ones 11 led to diacylhydrazines 13 or to imidazole derivatives 14 depending on the temperature. 1,2,4-Triazole-3-thione 17 was synthesized by two-step reaction of 1 with phenylisothiocyanate and subsequent base-catalyzed cyclization of thiosemicarbazide 16. The effects of hydrazones 5–10 on inhibition of photosynthetic electron transport in spinach chloroplasts and chlorophyll content in the antialgal suspensions of Chlorella vulgaris were investigated. | eng_Latn | 14,759 |
The stoichiometric reactions of enamines prepared from aldehydes and diphenyl-prolinol silyl ethers (intermediates of numerous organocatalytic processes) with nitro olefins have been investigated. As reported in the last century for simple achiral and chiral enamines, the products are cyclobutanes (4 with monosubstituted nitro-ethenes), dihydro-oxazine N-oxide derivatives (5 with disubstituted nitro-ethenes), and nitro enamines derived from γ-nitro aldehydes (6, often formed after longer reaction times). The same types of products were shown to be formed, when the reactions were carried out with peptides H-Pro-Pro-Xaa-OMe that lack an acidic H-atom. Functionalized components such as alkoxy enamines, nitro-acrylates, acetamido-nitro-ethylene, or hydroxylated nitro olefins also form products carrying the diphenyl-prolinol silyl ether as a substituent. All of these products must be considered intermediates in the corresponding catalytic reactions; the investigation of their chemical properties provided useful hints about the rates, the conditions, the catalyst resting states or irreversible traps, and/or the limitations of the corresponding organocatalytic processes. High-level DFT and MP2 computations of the structures of alkoxy enamines and thermodynamic data of a cyclobutane dissociation are also described. Some results obtained with the stoichiometrically prepared intermediates are not compatible with previous mechanistic proposals and assumptions. | Chiral thioureas and squaramides are among the most prominent hydrogen-bond bifunctional organocatalysts now extensively used for various transformations, including aldol, Michael, Mannich and Diels-Alder reactions. More importantly, the experimental and computational study of the mode of activation has begun to attract considerable attention. Various experimental, spectroscopic and calculation methods are now frequently used, often as an integrated approach, to establish the reaction mechanism, the mode of activation or explain the stereochemical outcome of the reaction. This article comprises several case studies, sorted according to the method used in their study. The aim of this review is to give the investigators an overview of the methods currently utilized for mechanistic investigations in hydrogen-bonding organocatalysis. | Nitro substituted picolinonitriles, in particular 3-nitro-picolinonitrile, have been found to be useful as anti-bacterial and anti-fungal agents. | eng_Latn | 14,760 |
A novel Mn(II) complex with 1,3-Thiazolidine-2,4-dicarboxylic acid and 1,10 phenanthroline has been synthesized, and its FT-IR, FT-Raman and UV–vis spectra have been recorded. Density functional theory calculations with the HSEH1PBE/6–311++G(d,p) level have been used to determine optimized molecular geometry, harmonic vibrational frequencies, electronic transitions, infrared and Raman intensities and bonding features of [Mn(tda)(phen)] complex (tda = 1,3-Thiazolidine-2,4-dicarboxylic acid; Mn = Manganese (II); phen = 1,10 phenanthroline). The assignments of vibrational modes have been performed on the basis of the weightiness of internal coordinates contributing to the vibrational frequencies calculated by HSEH1PBE method. The calculated small energy gap between HOMO and LUMO energies shows that the charge transfer occurs within Mn(II) complex. Molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength have been investigated by the applying of natural bond orbital (NBO) analysis. DFT calculations have been also performed to investigate total static dipole moment (μ), the mean polarizability ( ), the anisotropy of the polarizability (Δα), the mean first-order hyperpolarizability ( ), and the mean second-order hyperpolarizability ( ) for Mn(II) complex. The obtained values show that Mn(II) complex is an excellent candidate to NLO materials. | Two new complexes, [M(4-CNB)2(DENA)2(H2O)2] (where M: Co and Mn, 4-CNB = 4-cyanobenzoate and DENA = N,N’-diethylnicotinamide), were synthesized and characterized using different techniques (elemental analysis, FT-IR Spectroscopy, single-crystal X-ray diffraction, and TGA/DTA analysis). Looking at the crystal structure of the complexes, the metal atoms are coordinated by two nitrogen atoms from two DENA ligands, two carboxyl oxygen atoms from two 4-cyanobenzoate anions, and two oxygen atoms from two water molecules, and the complexes have distorted octahedral geometry around the metal atom center. Both complexes were crystallized with the P-1 space group in the triclinic system. The linear absorption and emission features of the complexes were recorded by UV–Vis and fluorescence spectrophotometers, respectively. Linear absorption and emission results of the complexes showed that [Mn(4-CNB)2(DENA)2(H2O)2] complex can be used as optical filter below 400 nm wavelength when [Co(4-CNB)2(DENA)2(H2O)2] complex has a good application potential among the fluorescent materials, because of its high emission intensity. In addition, the Hirshfeld surfaces analyses of complexes have been investigated in detail. | An 11-month-old girl was admitted for a 2-month history of regression of motor milestones and lateralizing neurologic findings. Tests for hypercoagulability were all within normal limits except for a | eng_Latn | 14,761 |
The design and synthesis of a new class of p38alpha MAP kinase inhibitors based on 4-fluorobenzylpiperidine heterocyclic oxalyl amides are described. Many of these compounds showed low-nanomolar activities in p38alpha enzymatic and cell-based cytokine TNFalpha production inhibition assays. The optimal linkers between the piperidine and the oxalyl amide were found to be [6,5] fused ring heterocycles. Substituted indoles and azaindoles were favored structural motifs in the cellular assay. | This review article illustrates the growing use of azaindole derivatives as kinase inhibitors and their contribution to drug discovery and innovation. The different protein kinases which have served as targets and the known molecules which have emerged from medicinal chemistry and Fragment-Based Drug Discovery (FBDD) programs are presented. The various synthetic routes used to access these compounds and the chemical pathways leading to their synthesis are also discussed. An analysis of their mode of binding based on X-ray crystallography data gives structural insights for the design of more potent and selective inhibitors. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 14,762 |
The tetrahydropyridine (THP) ring system has received considerable focus due to its excellent ability to act as a pharmacophore. It is recognized as a major constituent in natural alkaloids. THP derivatives have been reported for a diverse range of biological activities. Recent synthetic works contain syntheses of monosubstituted, disubstituted, trisubstituted, highly functionalized, and condensed structures. In this review, we summarize the recent literature dealing with the bioactive nature of this important heterocycle. | N-Sulfinyl Compounds and Sulfur Diimides. Imino Dienophiles. Nitroso and Thionitroso Dienophiles. Carbonyl Dienophiles. Thiocarbonyl and Selenocarbonyl Dienophiles. Miscellaneous Dienophiles. Oxabutadienes. Thiabutadienes. Azabutadienes. Heteroaromatic Azadienes. Each chapter includes references. Index. | Background ::: Serum calcium (Ca) and inorganic phosphate (Pi) concentrations and calcium-phosphate product (CPP) levels are positively associated with worse outcomes in patients with chronic kidney disease, but there are few data for Pi or Ca and none for CPP in patients with chronic heart failure (CHF). | eng_Latn | 14,763 |
A concept for designing nontoxic enediyne-based antitumor drugs that was previously suggested (J. Am. Chem. Soc. 2000, 122, 8245) is converted into reality by merging amidines with the natural enediyne dynemicin A. The dynemicin−amidines (DADs) resulting from this combination are biologically not active because they form extremely labile singlet biradicals that can no longer abstract H from DNA. However, if protonated in the acidic environment of the tumor cell, they possess increased biological activity, as is reflected by a lowering of the activation enthalpy for the Bergman cyclization from 16.7 (dynemicin A) to 11−12 kcal/mol (DADs), kinetic stability of the singlet biradicals formed in the cyclization reaction, increased H abstraction ability of the singlet biradicals, and improved docking properties in the minor groove of the duplex 10-mer B-DNA sequence d(CTACTACTGG)·d(CCAGTAGTAG) throughout the triggering and Bergman reactions. The implications and the consequences of using DADs to exploit the dif... | Enediynes undergo a Bergman cyclization reaction to form the labile 1,4-didehy-drobenzene (p-benzyne) biradical. The energetics of this reaction and the related Schreiner–Pascal reaction as well as that of the Myers–Saito and Schmittel reactions of enyne-allenes are discussed on the basis of a variety of quantum chemical and available experimental results. The computational investigation of enediynes has been beneficial for both experimentalists and theoreticians because it has led to new synthetic challenges and new computational methodologies. The accurate description of biradicals has been one of the results of this mutual fertilization. Other results have been the computer-assisted drug design of new antitumor antibiotics based on the biological activity of natural enediynes, the investigation of hetero- and metallo-enediynes, the use of enediynes in chemical synthesis and materials science, or an understanding of catalyzed enediyne reactions. ::: ::: ::: ::: For further resources related to this article, please visit the WIREs website. | Over p-adic Nagata rings, formal p-divisible groups are classified by nilpotent displays according to T. Zink. We extend this result to arbitrary p-adic rings. The proof uses the Grothendieck–Illusie deformation theory of truncated p-divisible groups. | eng_Latn | 14,764 |
Treatment of the sodium salt of 4-chloro-2-(methylthio)pyrrolo[2,3-d]pyrimidine (2) with (2-acetoxyethoxy)methyl bromide (3) has provided 4-chloro-2-(methylthio)-7[(2-acetoxyethoxy)methyl]pyrrolo[2,3- d]pyrimidine (4). Ammonolysis of 4 at room temperature gave 4-chloro-2-(methylthio)-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3- d]pyrimidine (5). However, ammonolysis of 5 at 130 degrees C furnished 4-amino-2-(methylthio)-7-[(2-hydroxyethoxy)methyl]-pyrrolo[2,3- d]pyrimidine (6), which on desulfurization with Raney Ni yielded 4-amino-7-[(2-hydroxyethoxy)-methyl]pyrrolo[2,3-d]pyrimidine (7) (acyclic analogue of tubercidin). The oxidation of 6 with m-chloroperbenzoic acid provided the sulfone derivative 8. A nucleophilic displacement of the 2-methylsulfonyl group from 8 with methoxide anion provided 4-amino-2-methoxy-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine (9). Demethylation of 9 with iodotrimethylsilane gave 4-amino-2-hydroxy-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine (10). Treatment of 2,4-dichloropyrrolo[2,3-d]pyrimidine (11) with 3 gave the protected acyclic compound 12, which on deacetylation and ammonolysis under controlled reaction conditions gave 2,4-dichloro-7-[(2-hydroxyethoxy)-methyl]pyrrolo[2,3-d]pyrimidine (13) and 4-amino-2-chloro-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3- d]pyrimidine (14), respectively. The condensation of 2-acetamido-4-chloropyrrolo[2,3-d]pyrimidine (15) with 3 gave the protected acyclic compound 16, which on concomitant deacetylation and ammonolysis with methanolic ammonia at an elevated temperature yielded 2,4-diamino-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine (17) in moderate yield. In tests involving human cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1), only slight activity and cytotoxicity were observed. The most active compounds (12 and 13) were slightly more active against HCMV than acyclovir, but both compounds were inactive against HSV-1. The activity against HCMV, however, was not well separated from cytotoxicity leading to the conclusion that these compounds did not merit further study. | 7-Deazapurine (pyrrolo[2,3-d]pyrimidine) nucleosides are important analogues of biogenic purine nucleosides with diverse biological activities. Replacement of the N7 atom with a carbon atom makes the five-membered ring more electron rich and brings a possibility of attaching additional substituents at the C7 position. This often leads to derivatives with increased base-pairing in DNA or RNA or better binding to enzymes. Several types of 7-deazapurine nucleosides with potent cytostatic or cytotoxic effects have been identified. The most promising are 7-hetaryl-7-deazaadenosines, which are activated in cancer cells by phosphorylation and get incorporated both to RNA (causing inhibition of proteosynthesis) and to DNA (causing DNA damage). Mechanism of action of other types of cytostatic nucleosides, 6-hetaryl-7-deazapurine and thieno-fused deazapurine ribonucleosides, is not yet known. Many 7-deazaadenosine derivatives are potent inhibitors of adenosine kinases. Many types of sugar-modified derivatives of 7-deazapurine nucleosides are also strong antivirals. Most important are 2'-C-methylribo- or 2'-C-methyl-2'-fluororibonucleosides with anti-HCV activities (several compounds underwent clinical trials). Some underexplored areas of potential interest are also outlined. | Transfusion-dependent patients such as those suffering from β-thalassaemia develop a fatal secondary haemosiderosis and consequently a selective iron chelator must be used to relieve such iron overload. 3- Hydroxypyridin-4-ones are selective for iron(III) under most biological conditions, but unlike desferrioxamine, are efficiently absorbed when administered orally. In this study, the synthesis and determination of partition coefficients (Kpart) of a range of 1-substituted-2-ethyl-3-hydroxypyridin-4-ones, as orally active iron chelators, are described. All of the 1-substituted-2-ethyl-3-hydroxypyridin-4-ones were synthesized via a three step synthetic pathway. The commercially available 2-ethyl-3-hydroxypyran-4-one (ethyl maltol) was benzylated in aqueous methanol. The reaction product of the benzylated ethyl maltol with an excess of the suitable primary aryl amines was heated in a thick-walled sealed glass tube at 150-160 oC to give 1-aryl-2-ethyl-3-benzyloxypyridin-4-one derivatives which were isolated as the free-bases. Removal of the benzyl group under acidic conditions was performed by catalytic hydrogenation to yield the bidentate chelators as HCl salt in good yield. In this work, final following compounds of 1-phenyl-2-ethyl-3- hydroxypyridin-4-one, 1-(4-methylphenyl)-2-ethyl-3-hydroxypyridin-4-one, 1-(4-methoxylphenyl)-2-ethyl- 3-hydroxypyridin-4-one, and 1-(4-nitrophenyl)-2-ethyl-3-hydroxypyridin-4-one were synthesized. Identifcation and structural elucidation of ligands were achieved by 1HNMR, IR, elemental analysis, mass spectra and through physical experiments. The Kpart values of the compounds were also determined in an aqueous/octanol system using an automated continuous flow method (a filter probe method). | eng_Latn | 14,765 |
Reaction of quinazoline (I) with 2-methylindole, pyrogallol, and 1-phenyl-3-methylpyrazol-5-one in the presence of acid led to the formation of C-4 adducts II, III, and V. Adduct IV was obtained by heating I with 1,3-dimethylbarbituric acid without acid catalysis. 1-Phenyl-3-methylpyrazol-5-one reacts with I without acid catalysis with the formation of dipyrazolylmethane VI. 4-Chloroquinazoline VIII reacts with 1-phenyl-3-methylpyrazol-5-one to yield 4-(1-phenyl-3-methyl-5-oxopyrazol-4-yl)quinazoline IX and dipyrazolylmethane VI. Heating VIII with 2-methylindole leads to formation of 4-(2-methylindol-3-yl)quinazoline X and tris(2-methylindol-3-yl)methane XI. The proposed structures were confirmed by NMR spectral data. | 4-Anilinoquinazolines have been widely studied as anticancer agents. Despite the widespread utility of this class of compounds, the reported syntheses of 4-anilinoquinazolines require multistep and low-yielding pathways. A novel strategy to prepare 4-anilinoquinazoline derivatives based on the cyclization of anthranilic acid is described. By using of dichloro anthranilic acid we could etherified the quinazoline ring in order to mimic the erlotinib structure as a tyrosine kinase inhibitor. Our new compounds contain different substitutions at the meta -positions of the quinazoline ring instead of the ortho -positions of erlotinib. We synthesized ten new 4-anilinoquinazoline derivatives (17-26) in only 4 steps with desirable yields. Key words: Synthesis, Erlotinib, Anilinoquinazolines, EGFR. | Transfusion-dependent patients such as those suffering from β-thalassaemia develop a fatal secondary haemosiderosis and consequently a selective iron chelator must be used to relieve such iron overload. 3- Hydroxypyridin-4-ones are selective for iron(III) under most biological conditions, but unlike desferrioxamine, are efficiently absorbed when administered orally. In this study, the synthesis and determination of partition coefficients (Kpart) of a range of 1-substituted-2-ethyl-3-hydroxypyridin-4-ones, as orally active iron chelators, are described. All of the 1-substituted-2-ethyl-3-hydroxypyridin-4-ones were synthesized via a three step synthetic pathway. The commercially available 2-ethyl-3-hydroxypyran-4-one (ethyl maltol) was benzylated in aqueous methanol. The reaction product of the benzylated ethyl maltol with an excess of the suitable primary aryl amines was heated in a thick-walled sealed glass tube at 150-160 oC to give 1-aryl-2-ethyl-3-benzyloxypyridin-4-one derivatives which were isolated as the free-bases. Removal of the benzyl group under acidic conditions was performed by catalytic hydrogenation to yield the bidentate chelators as HCl salt in good yield. In this work, final following compounds of 1-phenyl-2-ethyl-3- hydroxypyridin-4-one, 1-(4-methylphenyl)-2-ethyl-3-hydroxypyridin-4-one, 1-(4-methoxylphenyl)-2-ethyl- 3-hydroxypyridin-4-one, and 1-(4-nitrophenyl)-2-ethyl-3-hydroxypyridin-4-one were synthesized. Identifcation and structural elucidation of ligands were achieved by 1HNMR, IR, elemental analysis, mass spectra and through physical experiments. The Kpart values of the compounds were also determined in an aqueous/octanol system using an automated continuous flow method (a filter probe method). | eng_Latn | 14,766 |
By the use of a novel electrofluorescence method, estimates have been made of the geometry of binding to DNA of racemic mixtures of the anti-diol-epoxide derivatives of three polycyclic hydrocarbon carcinogens. These anti-configurations bind in a manner consistent with the planar diol-epoxide ring's being inclined at approximately 50 degrees to the DNA axis. This is true for the derivatives of benzo(a)pyrene, benz(a)anthracene and 3-methylcholanthrene. This binding is thus different from the regular intercalative interaction associated with the native hydrocarbons. As the (+ anti)-diol-epoxides are thought to be the initiatory compounds for carcinogenesis, the common binding characteristics for the three hydrocarbons may be significant in understanding the molecular interactions precursive to cancer. | The formation, stereostructure, and cellular reactions of the 7,8-diol-9,10-epoxide metabolites of the carcinogen benzo[a]pyrene have been examined after topical application of benzo[a]pyrene to the skin of mice. In this known target tissue, polymer adducts from diastereomeric diol epoxides, (+)-(7S, 8R, 9R, 10R) and (+)-(7R, 8S, 9R, 10R), were formed stereospecifically from their corresponding 7,8-dihydrodiols. Both diol epoxides bind with proteins, RNA, and DNA in vivo. For the nucleic acids, binding occurs preferentially at the 2-amino group of guanine in cellular RNA and DNA in vivo. Methods for establishing the structure of the cellular adducts as well as the possible biological implications of their formation are discussed. | The acid-promoted three-component reaction of o-aminophenol or 2-aminoethanol with dialkyl acetylenedicarboxylate and 3-phenacylideneoxindolines in refluxing acetonitrile afforded functionalized oxindolinyl-substituted benzo[b]pyrrolo[1,2-d][1,4]oxazine or pyrrolo-[2,1-c][1,4]oxazine derivatives in good yields. However, using o-phenylenediamine only resulted in oxindolinyl-substituted 3,4-dihydroquinoxaline derivatives. | eng_Latn | 14,767 |
In this report, we introduce a set of aggregation operators (AOs) to calculate global and local (group and atom type) molecular descriptors (MDs) as a generalization of the classical approach of molecular encoding using the sum of the atomic (or fragment) contributions. These AOs are implemented in a new and free software denominated MD-LOVIs ( ::: http://tomocomd.com/md-lovis ::: ), which allows for the calculation of MDs from atomic weights vector and LOVIs (local vertex invariants). This software was developed in Java programming language and employed the Chemical Development Kit (CDK) library for handling chemical structures and the calculation of atomic weights. An analysis of the complexities of the algorithms presented herein demonstrates that these aspects were efficiently implemented. The calculation speed experiments show that the MD-LOVIs software has satisfactory behavior when compared to software such as Padel, CDKDescriptor, DRAGON and Bluecal software. Shannon’s entropy (SE)-based variability studies demonstrate that MD-LOVIs yields indices with greater information content when compared to those of popular academic and commercial software. A principal component analysis reveals that our approach captures chemical information orthogonal to that codified by the DRAGON, Padel and Mold2 software, as a result of the several generalizations in MD-LOVIs not used in other programs. Lastly, three QSARs were built using multiple linear regression with genetic algorithms, and the statistical parameters of these models demonstrate that the MD-LOVIs indices obtained with AOs yield better performance than those obtained when the summation operator is used exclusively. Moreover, it is also revealed that the MD-LOVIs indices yield models with comparable to superior performance when compared to other QSAR methodologies reported in the literature, despite their simplicity. The studies performed herein collectively demonstrated that MD-LOVIs software generates indices as simple as possible, but not simpler and that use of AOs enhances the diversity of the chemical information codified, which consequently improves the performance of traditional MDs. | Preface. Forward. Introduction. The General Problem. What Is Structure? Aspects of Atom Level Description. Summary. A Look Ahead. The Electrotopological State. The Molecule as a Complex System. Atom Information Fields. The Intrinsic State of an Atom. The Graph Representation of a Molecule. The Atom Representation. The Intrinsic State Algorithm. Higher Quantum Level Atoms. Field Influences on the Intrinsic State. Sample Calculations. Influence of Structure change of E-State Values. Calculation Exercises. Summary. A Look Ahead. Significance and Interpretations of the E-State Indices. The Intrinsic State Values. Comparison of the E-State Values with Other Indices. The E-State Spectrum Significance. The E-State and Free Valence. Summary. A Look Ahead. Extended Forms of the E-State. Specific Consideration of Hydrogen. The E-State as a Three-Dimensional Field. Molecular Group Polarity Index. The Atom Type E-State Indices. Summary. A Look Ahead. Strategies for Use of the E-State. Experimental Design. Preliminary Data Analysis. Topological Superposition Strategy. Data Selection and Manipulation. Structure Data Input. Calculation of Tautomers and Equivalent Atoms. Consideration of Types of Indices. Use of Orthoganalization of a Set of Indices: Antagonism of Adrenalin by 2-Bromo-2-phenethylamines. Illustration of the Partial Least Squares Method: Flavone Derivatives as HIV-1 Integrase Inhibitors. Artificial Neural Networks: Solubility of HIV Reverse Transcriptase Inhibitors. Summary. A Look Ahead. Similarity and Database Applications. Introduction. Similarity. The E-State Information Field. Characterization of E-State Space. Functional Group Description in Parameter Space. The Quantitation of Molecular Fragments. Organization of Database Subsets. Diversity. Virtual Screening. Exercises. Summary. A Look Ahead. Structure-Activity Studies: Atom-Level Indices. The Structure-Activity Paradigm. Inhibition of Monoamine Oxidase by Hydrazides. Odor Threshold of Alkylpyrazines. Xanthine Inhibitors of Adenosine A1. Benzimidazoles as Flu Virus Inhibitors. The binding of Barbiturates to Cyclodextrin. Imidazole Inhibitors of Thromboxane Synthase. The Binding of Salicylamides. Summary. A Look Ahead. Structure-Activity Studies: Mixed Indices. Analyses With Mixed Indices. Reaction of the OH Radical with CFCs. 5-HT2 Binding of Phenylisopropylamines. Opiate Receptor Activity of Fentanyl-like compounds. E-State and Bimolecular Encounter Parameters. Dopamine Receptor Ligands. Carboquinones as Antileukemic Agents. Toxicity of Amide Herbicides. Aqueous Solubility of Drug Molecules Using Artificial Neural Networking. Direct QSAR Modeling of Percent Effect Data. Summary. A Look Ahead. Structure-Activity Studies: Atom Type Indices. Use of Atom Type Indices. Toxicity of Substituted Benzenes to Fathead Minnows. Boiling Point and Critical Temperature of a Set of Heterogeneous Compounds. Boiling Point of a Set of 372 Polychloroalkanes, Alcohols and Alkanes. Summary. A Look Ahead. Future Directions for E-State Studies. Group E-State Indices. An Iterative E-State. Higher Dimensional E-State Calculations. Parameterizing the Onium Group. Electrotopological State Index for Bonds and Bond Types. Summary. A Look Ahead. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 14,768 |
The design, synthesis, and pharmacological properties of a novel type of 4-(1,2,5,6-tetrahydro-1-alkyl-3-pyridinyl)-2-thiazolamine with dopaminergic properties are described. In particular, 4-(1,2,5,6-tetrahydro-1-propyl-3-pyridinyl)-2-thiazolamine (PD 118440) and its allyl analogue (PD 120697) have been identified as orally active dopamine (DA) agonists with pronounced central nervous system effects in tests | The synthetic utility of 3,3’-(3,4-dimethylthieno[2,3- b ]thiophene-2,5-diyl)bis (3-oxopropanenitrile) ( 1 ) in the synthesis of some novel bis-[1,3,4-thiadiazole] 6a–g and bis-thiazole 10 and 13 derivatives with thieno[2,3-b]thiophene moiety is reported. Antimicrobial evaluation of some selected examples from the synthesized products was carried out and showed promising results. Keywords: thieno[2,3- b ]thiophene; nucleophilic addition; hydrazonoyl halides; bis-thiadiazoles; bis-thiazoles; antimicrobial activity 1. Introduction Thiophene compounds are well known to exhibit various biological and medicinal activities such as BACE1 inhibitors [1], antitubercular [2], anti-depressant [3], anti-inflammatory [4], anti-HIV PR inhibitors [5], and anti-breast cancer activities [6]. In addition, thienothiophenes have potential applications in a wide variety of optical and electronic systems [7–9]. Furthermore, 1,3,4-thiadiazoles were recently reported as highly anti-inflammatory [10,11], and anticonvulsant agents [10,12]. | Twenty 5-alkyl-2-thiopyrimidine nucleosides were newly synthesized and examined for antiviral activities against herpes simplex virus (HSV), varicella-zoster virus (VZV) and human cytomegalovirus (HCMV). In this study, 2'-deoxy-5-alkyl-2-thiocytidine analogues had lower 50% effective concentration (EC50) values against HSV-1, and 2'-deoxy-5-alkyl-2-thiouridine analogues showed lower EC50 against VZV than their congeners of arabinoside form. Among the compounds examined, 2'-deoxy-5-ethyl and 5-propyl-2-thiocytidine (TN-53 and TN-54) were most potent and selective anti-HSV compounds. Their EC50s were 0.04 and 0.15 microM, and selectivity indexes were more than 7,215 and 1,849, respectively. On the other hand, 2'-deoxy-5-propyl-2-thiouridine (TN-51), 5-bromovinyl-2-thiouracil arabinoside (TN-65) and 5-styryl-2-thiouracil arabinoside (TN-67) were most potent and selective anti-VZV compounds. Their EC50s were 3.1, 3.8 and 2.6 pM for CaQu strain of VZV, respectively, and 2.1 to 3.0 times lower than that of acyclovir. All 2-thiopyrimidine nucleoside analogues did not show antiviral activities against thymidine kinase (TK) negative strains of HSV-1 and VZV. Only three 2-thiocytosine arabinoside compounds showed marginal anti-CMV activities (EC50s were 57-159 pM). All of the five alkyl-2-thio-pyrimidine nucleoside analogues examined were not cytotoxic to human lymphoblastoid cells (RPM18226) and human embryonic fibroblast cells (MRC-5) at 240 microM (100 microg/ml) or more. Regarding the structure-activity relationship of 5-alkyl-2-thiopyrimidine nucleoside analogues, the following remarks will be noted. Elongation of 5-alkyl chain (methyl to ethyl) of 2-thiocytosine in both deoxyribosyl and arabinosyl nucleosides increased anti-HSV-1 activity but not anti-VZV activity. Furthermore, elongation of the same chain (ethyl to propyl) of 2-thiodeoxyuridine increased anti-VZV activity whereas it did not in the case of 2-thiouracil arabinosides. | eng_Latn | 14,769 |
Two analogues, 6-(2-aminopropyl)-5-methoxy-2,3-dihydrobenzofuran and 6-(2-aminopropyl)-5-methoxy-2-methyl-2,3-dihydrobenzofuran, of the hallucinogenic agent 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) were synthesized and tested in the two-lever drug discrimination paradigm. In rats trained to discriminate saline from LSD tartrate (0.08 mg/kg), stimulus generalization occurred to both of the 2,3-dihydrobenzofuran analogues but at doses more than 10-fold higher than for DOM. A possible explanation for this dramatic attenuation of LSD-like activity could involve a highly directional electrophilic binding site on the receptor that cannot accept the orientation of the unshared electron pairs on the heterocyclic oxygen atom in the benzofurans. | Tetrahydrobenzodifuran functionalities were employed as conformationally restricted bioisosteres of the aromatic methoxy groups in prototypical hallucinogenic phenylalkylamines 1 and 2. Thus, a series of 8-substituted 1-(2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b']difuran-4-yl)-2-aminoal kanes (7a-e) were prepared and evaluated for activity in the two-lever drug discrimination paradigm in rats trained to discriminate saline from LSD tartrate (0.08 mg/kg) and for the ability to displace [3H]ketanserin from rat cortical homogenate 5-HT2A receptors and [3H]-8-OH-DPAT from rat hippocampal homogenate 5-HT1A receptors. In addition, 1-(8-bromo-2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b']difuran-4-yl)-2-am inopropane (7b), which was found to be extremely potent in the rat in vivo assays, was evaluated for its ability to compete with [125I]DOI and [3H]ketanserin binding to cells expressing cloned human 5-HT2A, 5-HT2B, and 5-HT2C receptors. All of the dihydrofuranyl compounds having a hydrophobic substituent para to the alkylamine side chain had activities in both the in vitro and in vivo assays that equaled or surpassed the activity of the analogous conformationally flexible parent compounds. For example, 7b substituted for LSD in the drug discrimination assay with an ED50 of 61 nmol/kg and had Kj values in the nanomolar to subnanomolar range for the displacement of radioligand from rat and human 5-HT2 receptors, making it one of the most potent hallucinogen-like phenylalkylamine derivatives reported to date. The results suggest that the dihydrofuran rings in these new analogues effectively model the active binding conformations of the methoxy groups of the parent compounds 1 and 2. In addition, the results provide information about the topography and relative orientation of residues involved in agonist binding in the serotonin 5-HT2 receptors. | 2-Aminobenzoic acids or 4-aminobenzoic acid react with dimethyl acetylenedicarboxylate/triphenylphosphine in less than 20 min at 15–25°C to produce new organic phosphorus compounds in good to excellent yields. The conversion occurs with selective N- over O-alkylation of the amino group and isolation of the products is accomplished simply by filtration. | eng_Latn | 14,770 |
A scarcity of stable n-type doping strategies compatible with facile processing has been a major impediment to the advancement of organic electronic devices. Localizing dopants near the cores of conductive molecules can lead to improved efficacy of doping. We and others recently showed the effectiveness of tethering dopants covalently to an electron-deficient aromatic molecule using trimethylammonium functionalization with hydroxide counterions linked to a perylene diimide core by alkyl spacers. In this work, we demonstrate that, contrary to previous hypotheses, the main driver responsible for the highly effective doping observed in thin films is the formation of tethered tertiary amine moieties during thin film processing. Furthermore, we demonstrate that tethered tertiary amine groups are powerful and general n-doping motifs for the successful generation of free electron carriers in the solid-state, not only when coupled to the perylene diimide molecular core, but also when linked with other small molecule systems including naphthalene diimide, diketopyrrolopyrrole, and fullerene derivatives. Our findings help expand a promising molecular design strategy for future enhancements of n-type organic electronic materials. | Perylene bisimides (PBIs) are one example of useful π-conjugated molecules that can be used in optoelectronic devices as n-type materials with strong visible light absorption. PBIs can self-assemble into a range of structures, but it is rare to be able to control the packing such that the same PBI can form either H-type or J-type aggregates. This is important because the conductivity pathways and optoelectronic properties are directly affected by this packing. Here, we show that we can control the packing of a single PBI functionalized with an amino acid by a subtle change in pH. Under one set of conditions, H-type aggregates form a gel when the pH is decreased. At a slightly different set of starting conditions, J-type aggregates are formed, but they cannot form a gel when the pH is lowered. We show that films formed from the self-assembled structures have very different photoconductive properties. | Yohimbine is a potent and relatively nonselective α 2 -adrenergic receptor (AR) antagonist. In an earlier report, we demonstrated that dimeric yohimbine analogs containing methylene and methylene-diglycine tethers were highly selective human α 2C -AR ligands. Little work has been done to examine the role of the tether group or the absence of the second yohimbine pharmacophore on selectivity for human α 2 -AR subtypes. The goal of our study was to determine the binding affinities and functional subtype selectivities of a series of tethered yohimbine ligands in the absence of the second pharmacophore. The profiles of pharmacological activity for the yohimbine analogs on the three human α 2 -AR subtypes expressed in Chinese hamster ovary cells were examined using receptor binding and cAMP inhibition assays. All of the tethered yohimbine analogs exhibited higher binding affinities at the α 2C - versus α 2A - and α 2B -AR subtypes. Notably, the benzyl carboxy alkyl amine and the carboxy alkyl amine analogs exhibited 43- and 1995-fold and 295- and 54-fold selectivities in binding to the α 2C - versus α 2A - and α 2B -ARs, respectively. Data from luciferase reporter gene assays confirmed the functional antagonist activities and selectivity profiles of selected compounds from the tethered series. The data demonstrate that the second pharmacophore may not be essential to obtain α 2C -AR subtype selectivity, previously observed with the dimers. Further changes in the nature of the tether will help in optimization of the structure-activity relationship to obtain potent and selective α 2C -AR ligands. These compounds may be used as pharmacological probes and in the treatment of human disorders. | eng_Latn | 14,771 |
The unique features of the pentafluorosulfanyl (SF 5 ) group have made it renowned as a “super trifluoromethyl (CF 3 )” group. Owing to the big success of CF 3 -containing heteroaromatic compounds in medicinal chemistry, agro-chemistry and material sciences, SF 5 -substituted heteroaromatic compounds have gained a lot of attention in very recent years as novel and potential candidates in these fields. However, the synthetic methodology for SF 5 -substituted heteroaromatic compounds is still highly limited. This digest highlights the recent, rapid, and significant advances made in the synthesis of SF 5 -heteroaromatics. | The activation of halogen bonding by the substitution of the pentafluoro-λ6-sulfanyl (SF5) group was studied using a series of SF5-substituted iodobenzenes. The simulated electrostatic potential values of SF5-substituted iodobenzenes, the ab initio molecular orbital calculations of intermolecular interactions of SF5-substituted iodobenzenes with pyridine, and the 13C-NMR titration experiments of SF5-substituted iodobenzenes in the presence of pyridine or tetra (n-butyl) ammonium chloride (TBAC) indicated the obvious activation of halogen bonding, although this was highly dependent on the position of SF5-substitution on the benzene ring. It was found that 3,5-bis-SF5-iodobenzene was the most effective halogen bond donor, followed by o-SF5-substituted iodobenzene, while the m- and p-SF5 substitutions did not activate the halogen bonding of iodobenzenes. The similar ortho-effect was also confirmed by studies using a series of nitro (NO2)-substituted iodobenzenes. These observations are in good agreement with the corresponding Mulliken charge of iodine. The 2:1 halogen bonding complex of 3,5-bis-SF5-iodobenzene and 1,4-diazabicyclo[2.2.2]octane (DABCO) was also confirmed. Since SF5-containing compounds have emerged as promising novel pharmaceutical and agrochemical candidates, the 3,5-bis-SF5-iodobenzene unit may be an attractive fragment of rational drug design capable of halogen bonding with biomolecules. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 14,772 |
X-Ray single-crystal crystallographic analysis of a series of Pd(II) pincer complexes with tridentate ligands comprising a secondary amine sandwiched by two thioether donors of general formula [PdX(RSC2H4N(H)C2H4SR)]X′·nH2O [X = X′ = Cl: R = Et, n = 1 (3); R = tBu, n = 1.5 (4), R = cychex, n = 2 (5); X = X′ = Br, R = iBu, n = 2 (6); X = Cl, X′ = NO3, R = iBu, n = 0 (7)] has been carried out at ambient or low temperature. All the cationic complexes with coordinated and uncoordinated halides (Cl or Br) invariably show hydrate aggregation and interaction with the halides to give water–halide cluster blends in the solid lattices. Extensive H-bonding is evident within these water-blends and between these clusters and the cations, giving different forms of hydrates that are dependent on the sulfur substituent and the halide. Complex 3 contains a water–chloride intercalating zigzag chain; 4 shows a wave-like water trimer–chloride; 5 (at 100 K) reveals a water–chloride tape-like structure formed from four disorder water molecules each with half occupancy; 6 (at 100 K) displays a step-like polymer blend formed by aggregation of water tetramers with orthogonal H-bonding interaction with bromides. No lattice hydration is evident when nitrate is the anion (viz. 7). | The crystal structures of two mononuclear Cu(II) NH2trz complexes [Cu(NH2trz)4(H2O)](AsF6)2 (I) and [Cu(NH2trz)4(H2O)](PF6)2 (II) as well as two coordination polymers [Cu(μ2-NH2trz)2Cl]Cl·H2O (III) and [Cu(μ2-NH2trz)2Cl] (SiF6)0.5·1.5H2O (IV) are presented. Cationic 1D chains with bridging bis-monodentate μ2-coordinated NH2trz and bridging μ2-coordinated chloride ligands are present in III and IV. In these coordination polymers, the Cu(II) ions are strongly antiferromagnetically coupled with J = -128.4 cm-1 for III and J = -143 cm-1 for IV (H = -JΣSiSi+1), due to the nature of the bridges between spin centers. Inter-chain interactions present in the crystal structures were taken into consideration, as well as g factors, which were determined experimentally, for the quantitative modeling of their magnetic properties. © 2013 by the authors; licensee MDPI, Basel, Switzerland. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 14,773 |
Combination of 1,3-bis(2,6-diisopropylphenyl)imidazolum-2-carboxylate (IPrCO2) with the Lewis acids MBPh4, where M = Li or Na, provided two separate complexes. The crystal structures of these complexes revealed that coordination to NaBPh4 yielded a dimeric species, yet coordination of IPrCO2 with LiBPh4 yielded a monomeric species. Combination of 1,3-bis(2,4,6-trimethylphenyl)imidazolum-2-carboxylate (IMesCO2) with LiBPh4 also afforded a dimeric species that was similar in global structure to that of the IPrCO2+NaBPh4 dimer. In all three cases, the cation of the organic salt was coordinated to the oxyanion of the zwitterionic carboxylate. Thermogravimetric analysis of the crystals demonstrated that decarboxylation occurred at lower temperatures than the decarboxylation temperature of the parent NHC·CO2 (NHC = N-heterocyclic carbene). Kinetic analysis of the transcarboxylation of IPrCO2 to acetophenone with NaBPh4 to yield sodium benzoylacetate was performed. First-order dependences were observed for IPrCO... | The present review covers organic transformations involved in the reduction of CO2 to chemical fuels. In particular, we focus on reactions of CO2 with organic molecules to yield carboxylic acid derivatives as a first step in CO2 reduction reaction sequences. These biomimetic initial steps create opportunities for tandem electrochemical/chemical reductions. We draw parallels between long-standing knowledge of CO2 reactivity from organic chemistry, organocatalysis, surface science and electrocatalysis. We point out some possible non-faradaic chemical reactions that may contribute to product distributions in the production of solar fuels from CO2. These reactions may be accelerated by thermal effects such as resistive heating and illumination. | Recently, the efficient chemical fixation of carbon dioxide (CO2) into high value chemicals without using noble metal catalysts has become extremely appealing from the viewpoint of sustainable chemistry. In this work, a one-pot three component reaction of propargylic alcohols, anines and CO2 that can proceed in an atom economy and environmentally benign manner by combination of CuI and tetrabutylphosphonium imidazol ([P4444][Im]) as a catalyst was described. Catalysis studies indicate that this catalytic system is an effective catalyst for the conversion of CO2 into oxazolidinones at room temperature and ambient pressure without any solvent. The results provide a useful way to design novel noble metal-free catalyst systems for the transformation of CO2 into other valuable compounds. | eng_Latn | 14,774 |
Quinqzoline based scaffolds holding thiosemicarbazide and styryl frame | Structural evolution of the quinqzoline as effective agents in the treatment of microbial infe ctions. Novel quinqzoline based thiosemicarbazide and styryl derivatives have been designed and synthesized. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, 1H NMR. spectral data. All the newly synthesized compounds were screened against various strains of bacterial and fungi.it has been observed that compounds gave significant co-relation. | Abstract A procedure for the asymmetric synthesis of 4-alkyl-1,2,3,4-tetrahydroisoquinolines is described. The key step in the synthetic route is a stereocontrolled metalloenamine alkylation using ( R )-(+)-phenylglycinol methyl ether as the chiral auxiliary. Subsequent N -methylation, hydrogenolysis and cyclization afforded the target heterocycles with enantiomeric excesses higher than 99%. | eng_Latn | 14,775 |
Novel Lewis Acid Promoted Reactions of Allylsilane Bearing Bulky Silyl Substituents and Aldehydes | Reported herein are two novel modes of reactions that were mediated by the proper choice of Lewis acid. Thus, by the influence of SnCl4, allyl-t-butyldimethylsilane reacted with aldehyde in 2:1 stoichiometry to afford a ketone derivative. In contrast, use of BF3•OEt2 led to the formation of a 1,3-dioxane derivative, which is a 1:2 adduct. | We report herein a stereoselective and straightforward methodology for the synthesis of new androgen receptor ligands with (anti)-agonistic activities. Oxygen-nitrogen replacement in bicalutamide-like structures paves the way to the disclosure of a new class of analogues, including cyclized/nitrogen-substituted derivatives, with promising antiandrogen (or anabolic) activity. | eng_Latn | 14,776 |
Syntheses,Properties and Crystal Structures of the Supramolecula Compound Formed by 4,4'-bipyridine | Two new compounds,[(DPA)·0.5(4,4′-bipy)](1) and [Cd(H2O)2·(4,4′-bipy)2]·2DSTA(2),have been synthesized with 4,4′-bipyridine been hydrothermally synthesized and structural characteristic is obtained by elemental analysis,X-ray diffraction,IR spectroscopy and single-crystal X-ray diffraction.The structure of the compound 1 exhibits two-dimensional networks through O-H…N and C-H…O bonds.In compound 2,the Cd(II) ion is six-coordinated with a regular octahedral coordination geometry.The research shows that this arrangement gives rise to a(4,4) connecting 2D topologic grid sheet with large rings of 16.112×17.535 in diagonal distances. | Abstract A convenient microwave-assisted methodology is developed for the generation of 5-chloro-3-(dimethylamino)pyrazin-2(1H)-ones. The method entails a chemoselective desulfitative removal of a phenylthioether bond upon DMF/H2O treatment in the presence of sodium carbonate, yielding the desired compounds in 73–96%. | eng_Latn | 14,777 |
Palladium-catalyzed synthesis of 4-aminophthalazin-1(2H)-ones by isocyanide insertion. | Palladium-catalyzed cross-coupling of a wide range of substituted o-(pseudo)halobenzoates and hydrazines with isocyanide insertion followed by lactamization efficiently affords 4-aminophthalazin-1(2H)-ones that are difficult to obtain regioselectively by classical methods. | Abstract Design and synthesis of some TSA inhibitors on novel molecular frameworks is described. This TSA analog design culminates in the preparation of the phosphonate 18 . | eng_Latn | 14,778 |
The isomerization of butenes over doped zinc oxides | Abstract The isomerization of butenes over cation-doped zinc oxides was investigated in order to elucidate the nature of the active sites and their catalytic behavior in the reaction. The effects of doping of zinc oxide with foreign cations, such as Ga 3+ , A1 3+ , and Li + , on the catalytic activity and the selectivity were observed. The results were discussed in terms of the acid-base character of -Zn-O- pair sites. It may be said conclusively that the nature of the active sites as well as the electronic structures of the semiconductor surface are modified in the presence of the foreign cations so that the relative stabilities of the intermediate complex on these sites are affected. | The benzimidazole exhibits widespread activities,and the benzimidazole nucleus is found in a variety of drugs.In this paper,we research a new and efficient synthetic method of 1,2-disubstituted benzimidazole.o-phenylenediamine and ketone form schiff bases having one free amine group with microwave,and then schiff bases condensed with different aldehydes to give five 1,2-substituted benzimidazoles.The mechanism of reaction involves 1,3 shift of negative hydrogen ion. | eng_Latn | 14,779 |
A study of solvent effects on the NMR shieldings of the two types of nitrogen atoms contained in diazole ring systems | Abstract The diazole ring systems, N-methyl derivatives of pyrazole and imidazole, show a clear differentiation between pyrrole and pyridine types of nitrogen atoms from the point of view of their solvent-induced nitrogen shielding variations. The largest effects on the nitrogen shieldings derive from hydrogen bonding from solvent to solute, which involve the lone pair electrons at the pyridine-type nitrogen atoms of the solute. These effects may be used to identify sites of hydrogen-bond accepters in the solute molecules. Solvent-polarity effects on the nitrogen shieldings suggest a significant charge migration from pyrrole- to pyridine-type nitrogen atoms in such systems. Solvaton calculations amply support this proposal by correctly predicting the observed directions and relative magnitudes of the nitrogen shielding variations as a function of solvent polarity. | Biaryl ethers were recently reported as potent NNRTIs. Herein, we disclose a detailed effort to modify the previously reported compound 1. We have designed and synthesized a series of novel pyrazole derivatives as a surrogate for pyrazolopyridine motif that were potent inhibitors of HIV-1 RT with nanomolar intrinsic activity on the WT and key mutant enzymes and potent antiviral activity in infected cells. | eng_Latn | 14,780 |
Synthesis of 2,2',6,6'-Tetranitro-4,4'-di(trifluoromethyl)-biphenyl | 2,2',6,6'-Tetranitro-4,4'-di (trifluoromethyl)-biphenyl was prepared from p-chloro trifluoromethylbenzene via nitration and Ullmann coupling reaction in an overal yield of 68%. The yield of the coupling reaction catalyzed by copper powder could be reached up to 93% under the condition of m (C6H2ClCF3N2O4)∶m(Cu)=1∶0.25 at 110℃ in toluene. | Thermal decarbonylation of furandione (III) gives an unsymmetrical bis(imidoyl)ketene (IV) which undergoes an unusual intramolecular cyclization in situ furnishing benzophenazinol derivative (V). | eng_Latn | 14,781 |
Synthesis of substituted 3-hydroxy-4-alkoxycarbonyl-2-azetidinones | Abstract A short chemical process is described for the synthesis of optically active 3-hydroxy-4-alkoxycarbonyl-2-azetidinones (β-lactams) from L-tartaric acid. | In the present investigation a series of some novel synthetic Chalcones (2a-d) and their heterocyclic analogs such as Isoxazolines (3a-d), Pyrimidines (4a-d), Pyrazolines (5a-d), Benzodiazepines (6a-d) and | eng_Latn | 14,782 |
A Facile Synthesis of Polycyclic Pyrimidine Fluorophores via Inter- and Intramolecular Cyclization of Activated 2-Amino-3,6-disubstitued Pyrimidin-4-ones | An efficient synthesis and fluorescent properties of a new series of fused pyrimidine derivatives are described. Condensation of aminopyrimidine derivative 1 with acetophenone leads to olefinic pyrimidine 2, various addition-cyclization reactions of which give the corresponding bicyclic pyrimidines 4, 6, and 8. Cycloaddition reaction of pyrimidine 1 to benzoyl isothiocyanate gives thiourea derivative 9. Intramolecular cyclization of compound 9 with NaOH or Br2 produces pyrimidine derivatives 10 or 12, respectively. Heteroannulation of pyrimidine 1 with ninhydrin or α-carbonyl carboxylic acid 15 gives the tetracyclic pyrimidine 14 and diazepine derivative 18, respectively. Fluorescence properties of pyrimidine derivatives have been tested. | Disclosed is a medicated patch comprising 5-methyl-1-phenyl-2-(1H)-pyridone. Specifically disclosed is a medicated patch having a percutaneously absorbable preparation layer. The percutaneously absorbable preparation layer comprises 5-methyl-1-phenyl-2-(1H)-pyridone or a pharmaceutically acceptable salt thereof as an active ingredient, a dissolving agent and an aqueous base material (or a rubber-type base material), wherein the active ingredient is contained in an amount of 0.1 to 30 mass% relative to the total amount of the percutaneously absorbable preparation layer. | eng_Latn | 14,783 |
ChemInform Abstract: Stereoselective Bromocyclization of Allylated Aldoxime Ethers | Bromination of O-allylated aldoxime ethers having a trans substituted allyl group with Br(collidine)2PF6 induces an efficient diastereoselective cyclization to give 5-bromooxazine derivatives. | A new general one-pot preparative method for the synthesis of 1-aryl(hetaryl)-2,2-dichloroethenes from aldehydes was developed. The method involves successive conversions of the latter into hydrazones followed by treatment with carbon tetrachloride in the presence of copper(i) chloride. | eng_Latn | 14,784 |
Synthesis and antitumor activities of sinomenine derivatives on rings A and C | AbstractA series of new sinomenine derivatives were designed, synthesized, and evaluated in tumor inhibitory activity, such as human triple negative breast cancer cell line (MDA-MB-231), glioma cell line (A172), human lung cancer cell line (A549), human colon cancer cell line (HCT-8). The modifications were carried out on rings A and C of the sinomenine by esterificating on phenolic hydroxyl with good yields. The highlight of this work was that the synthetic procedures were concise and sinomenine derivatives demonstrated promising antitumor activities. | A domino approach to 2-imino-1,2-dihydroquinolines and 2-imino-thiochromenes from sulfonyl azides, alkynes, and 2-acyl anilines or the potassium salt of 2-mercapto-benzaldehyde has been developed. This one-pot method is efficient and versatile. | eng_Latn | 14,785 |
Facile synthesis of model indazolo〔2,1-c〕〔1,3,4〕benzotriazepine-5,13-diones | In basic media, 2-aminobenzoic acids (5) react with 2-[N -(l-carboxyphenyl)]hydrazonoyl chlorides (6, 7) (precursors of the reactive nitrile imine 1,3-dipolar species) to afford good yields of the corresponding 2-[N'-(l-carboxyphenyl-2-amino)hydrazino]benzoic acids (8a-d, 9a). The latter acyclic adducts, in the presence of 1,1'-carbonyldiimidazole (CDI), undergo two consecutive lactamizations involving both activated carboxyl groups and the suitably located hydrazino-NH partners, to deliver the respective indazolo[2,1-c]-[1,3,4]benzotriazepin- 5,13-diones (lOa-d, lla). Structural assignments for these novel tetracyclic products are based on analytical and spectral (IR, MS, NMR) data, and confirmed by single crystal X-ray structure determination for 10a. | The direct reductive amination of aldehydes using S-benzyl isothiouronium chloride as a recoverable organocatalyst for the activation of the imine intermediate through hydrogen bonding is described. A mild and operationally simple fragment coupling procedure was accomplished with a wide range of aldehydes as well as amines in good to excellent yields. In addition, the S-benzyl isothiouronium chloride catalyst was easily recovered by simple filtration and reused without any drop in its efficiency. | eng_Latn | 14,786 |
Clinical analysis of therapeutic effect of aminophylline on asthma patients with anti-high Airway | Objective To investigate the therapeutic:effect of aminophylline on asthma patients with anti - high airway. Methods 64 cases of asthma were given regular treatment of the drug aminophylline for 30 days,compare the improvement of the patients' airway situation.Results After treatment,Dmin,FEVl and PEFR were significantly higher than before (P 0.05 ).Conclusion Aminophylline can significantly reduce asthma airway hyperresponsiveness.It is worth clinical application. | The possibility has been studied of using anilines in the Hantzsch synthesis. It has been shown that, with the exception of those containing strong electron-accepting substituents, they take part in this reaction with the formation of 1-aryl-1,4-dihydropyridines. The reaction largely depends on the nature of the substituents in the aniline and in the benzaldehyde and is promoted by electron-accepting substituents in the aldehyde and electron-donating substituents in the amine. The mechanism of the reaction is discussed. A number of 1-benzyl-1,4-dihydropyridines have been synthesized. The UV, IR, and PMR spectra and the electro-oxidation of the compounds obtained have been studied. | eng_Latn | 14,787 |
Dess–Martin periodinane oxidative rearrangement for preparation of α-keto thioesters | A Dess-Martin Periodinane (DMP) mediated oxidative rearrangement reaction was uncovered. The reaction proceeds via oxidation of a β-hydroxy thioester to a β-keto thioester, followed by an α-hydroxylation and then further oxidation to form a vicinal thioester tricarbonyl. This product then rearranges, extruding CO2, to form an α-keto product. The mechanism of the rearrangement was elucidated using 13C labelling and analysis of the intermediates as well as the products of the reaction. This efficient process allows for easy preparation of α-keto thioesters which are potential intermediates in the synthesis of pharmaceutically important heterocyclic scaffolds such as quinoxalinones. | (57) Abstract: The present invention, as substance P antagonists, compounds of formula (I), these N- oxide forms, For these pharmaceutically may receive addition salts and their stereochemically isomeric forms in the above formula, n is 0, 1 or 2, m is 1 or 2, when m is 2, n is 1, p is 0, 1 or 2, = Q is = O or = NR Le is Het or HetC Kiruokishi, a C | eng_Latn | 14,788 |
SPECTROSCOPIC STUDIES: PART 5, THE SPECTRA AND STRUCTURE OF MONOHALOGENO-ACETONITRILES, | Abstract : The infra-red spectra of a closely related series of acetonitriles were obtained between 5,000 and 500/cm. An analysis of the fine-structure obtained for two fundamentals of fluoro-acetonitrile and of band contours in other cases shows that the molecules have the nitrile structure, XCH2 .CN (X = halogen) and not the alternative ketimine structure XCH = C = NH Frequency assignments were made and structural details deduced in each case. The spectroscopic data were used to calculate thermodynamic data for FCH2 .CN and C1CH2 .CN. (Author) | Abstract Asymmetric total synthesis of small ring macrolide stagonolide-E has been described in this communication. The main highlight of our synthetic strategy is the application of ME-DKR (metal enzyme combo dynamic kinetic resolution) reaction, asymmetric reduction with Noyori’s BINAL-H reagent system, stereoselective cross metathesis, and RCM (ring closing metathesis) reaction at a late stage enables us to achieve the synthesis of the target molecule in an efficient way. | yue_Hant | 14,789 |
Isoxazolopyrimidine-Based Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase with Antimalarial Activity | Malaria kills nearly 0.5 million people yearly and impacts the lives of those living in over 90 countries where it is endemic. The current treatment programs are threatened by increasing drug resistance. Dihydroorotate dehydrogenase (DHODH) is now clinically validated as a target for antimalarial drug discovery as a triazolopyrimidine class inhibitor (DSM265) is currently undergoing clinical development. We discovered a related isoxazolopyrimidine series in a phenotypic screen, later determining that it targeted DHODH. To determine if the isoxazolopyrimidines could yield a drug candidate, we initiated hit-to-lead medicinal chemistry. Several potent analogues were identified, including a compound that showed in vivo antimalarial activity. The isoxazolopyrimidines were more rapidly metabolized than their triazolopyrimidine counterparts, and the pharmacokinetic data were not consistent with the goal of a single-dose treatment for malaria. | Rotational isomeric state theory provides a relatively simple formalism for the evaluation of the persistence vector, a, for a chain that can be represented by a repeating sequence of independent virtual bonds. The numerical problem can be reduced to the computation of the averages of the elements in the transformation matrices, . This approach is applied for the evaluation of the limiting length of a for poly(benzobisorazole) and poly(benzobisthiazole) as the molecular weight becomes infinite. Some of the elements in can be assigned by symmetry arguments and the remaining nonzero elements are deduced from molecular dynamics theory. | eng_Latn | 14,790 |
A Simple and Efficient Method for the Reduction of Azo Compounds | Reduction of azo compounds using hydrazine hydrate as reducant without catalyst is described, which proceeded smoothly in mild condition and did not pollute the environment. | Information on dibenzylideneacetone complexes of transition metals is reviewed. Their methods of preparation, physicochemical and chemical properties, and also applications as reagents and catalysts are discussed. The bibliography includes 162 references. | eng_Latn | 14,791 |
A probable aziridine radical: mechanism of addition of aziridine to styrenes | Strong evidence of an aziridine radical in the sodium-catalysed addition of aziridine to styrenes has been obtained. | C 6 H 14 N 2 O 6 , M r =210. 19, tetragonal, P4 3 , a=4.938 (1), c=36.907 (8) A, V=899.93 A 3 , Z=4, D x =1.551 g cm -3 , λ(Cu Kα)=1.5418 A, μ=12.18 cm -3 , F(000)=448.0, T=295 K, final R=0.032 and wR=0.029 for 759 observed reflections. The sugar chain of L-mannonic acid hydrazide shows the expected all-trans conformation. The hydrogen-bond pattern includes a homodromic cycle with a special connectivity that is also realized in several other open-chain sugar derivatives with different chirality. The relationship between the dimensions of the crystal lattice and the occurrence of this special cycle is discussed | eng_Latn | 14,792 |
Synthesis and Bioevaluation of 4-((2/4-chloro-/2, 3-dichloro-/2/4-bromo-/2, 4-dinitro-/4-nitrophenyl) Anilinomethyl)-6-t-butyl-2H-1-benzopyran-2-ones | Synthesis of 4-[(2/4-chloro-/2,3-dichloro-/2/4-bromo-/2,4-dinitro-/4-nitrophenyl) anilinemethyl]6-t-butyl-2H-1-benzopyran-2-ones have been carried out. Synthesized compounds were characterized by 1 HNMR, IR and other physical and analytical data. All of the synthesized compounds were evaluated for their antifungal activity against Aspergillus awamori and Sclerotium rolfsii and antibacterial activity against a bacterium of Bacillus species in vitro at 10, 50, 100 and 200 µg/ml concentrations. Compounds 4-[(2-chlorophenyl)anilinomethyl]-6-t-butyl-2H-1-benzopyran-2-one(11) and 4-[(4chlorophenyl) anilinomethyl]-6-t-butyl-2H-1-benzopyran-2-one(12) exhibited good antifungal activity among tested compounds. Compound 4-[(2-bromophenyl) anilinomethyl]-6-t-butyl-2H-1-benzopyran2-one(14) showed significant antibacterial activity against the test bacterium. | Biaryl ethers were recently reported as potent NNRTIs. Herein, we disclose a detailed effort to modify the previously reported compound 1. We have designed and synthesized a series of novel pyrazole derivatives as a surrogate for pyrazolopyridine motif that were potent inhibitors of HIV-1 RT with nanomolar intrinsic activity on the WT and key mutant enzymes and potent antiviral activity in infected cells. | eng_Latn | 14,793 |
Fully ordered copolyhydrazides based upon bisacid A2 | The preparation of copolyhydrazides containing equimolar quantities of “bisacetyl A2” and terephthaloyl or isophthaloyl groups is described. The resulting copolymers were found to form clear colorless films which, when immersed in concentrated formic acid, softened but rehardened and turned white after subsequent immersion in water. The formic acid treatment did not bring about a morphological change from the amorphous to the crystalline state, but caused changes in the differential scanning calorimetry (DSC) traces which suggest that an α/β transformation had taken place. The possible nature of this transition is discussed. The results of tensile tests on cast film are given. | During the last eight years a number of aspects of ::: amide chemistry have been studied in the Chemistry ::: Department, University of Tasmania, under the direction ::: of Dr. J. B. Polya. Acylation of amides to diacylamines ::: was investigated, and satisfactory syntheses were developed ::: for unsymmetrical diacylamines (R1 ::: .CO.NH.CO.R2; R1≠R2 ). In some cases such diacylamines, through reacylation, ::: may form mixtures of the two corresponding ::: symmetrical diacylamines. Diacylamines react with hydrazines ::: to form 1:2:4-triazoles, which are convenient ::: derivatives indicating the structure of the diacylamine. ::: With a hydrazine R.NH.NH2 an unsymmetrical diacylamine ::: of the type indicated could form 1R-3R1 -5R2 - and ::: 1R-3R2 -5R1 -1:2:4-triazole. Proving the orientations of ::: the products from a number of diacylamines seemed a ::: promising way to investigate the mechanism of this triazole ::: synthesis. | eng_Latn | 14,794 |
X-ray diffraction examination of the molecular structure of guanazole (3,5-diamino-1h-1,2,4-triazole) | In the case of guanazole, five isomeric forms can exist. From the study of UV and IR spectra, amino-imine [i], diimine [2] and diamine [3] structures have been attributed to guanazole. According to the data of the quantum-chemical calculation of the heat of formation, the diamine asymmetric form is the most probable structure [4]. To unequivocally determine the structure of the guanazole molecule in the crystalline state, we carried out out an x-ray diffraction study. | A tetrasaccharide, corresponding to the heparan sulfate heparanase substrate, namely beta-D-GlcA(2S)-(1-->4)-alpha-D-GlcN(NS,6S)-(1-->4)-beta-D-GlcA-(1-->4)-alpha-D-GlcN(NS,6S)-OMe, was synthesized in a convergent manner via coupling of a pair of the disaccharide building blocks as a key step. | eng_Latn | 14,795 |
(2,2′-Bipyridine)dichlorogold(III) nitrate | The title compound, [AuCl2(C10H8N2)]NO3, is layered parallel to ((1) over bar 01) by pi-pi stacking. The individual {(1) over bar 01} layers are held together by extensive C-H...O and C-H...Cl hydrogen bonding. | Abstract The synthesis and utility of the novel axially chiral bis-urea ligand BINUREA are described. A complex of this urea ligand with ytterbium triflate and DBU can be used in the catalytic enantioselective Diels–Alder reaction of Danishefsky-type diene and electron-deficient olefins to give the adducts in good to excellent yield and enantiomeric excess (ee). | eng_Latn | 14,796 |
Paddlewheel 1,2,4-diazaphospholide dibismuthanes with very short bismuth–bismuth single bonds | One-electron oxidation of the 1,2,4-diazaphospholide anion [3,5-R2dp](-) by BiCl3 generated several remarkable paddlewheel dibismuthanes [L2(Bi-Bi)L2] (L = η(1),η(1)-3,5-R2dp, R = tBu, iPr, or Ph) with very short Bi-Bi single bond lengths (2.7964(4)-2.8873(3) Å). | Rotational isomeric state theory provides a relatively simple formalism for the evaluation of the persistence vector, a, for a chain that can be represented by a repeating sequence of independent virtual bonds. The numerical problem can be reduced to the computation of the averages of the elements in the transformation matrices, . This approach is applied for the evaluation of the limiting length of a for poly(benzobisorazole) and poly(benzobisthiazole) as the molecular weight becomes infinite. Some of the elements in can be assigned by symmetry arguments and the remaining nonzero elements are deduced from molecular dynamics theory. | eng_Latn | 14,797 |
Isolation and characterization of 2-alkylaminobenzo[b]furans. Evidence for competing O-arylation in Cu-catalyzed intramolecular amidation | 2-Alkylaminobenzo[b]furans were isolated and characterized by X-ray crystal structural analysis, for the first time, from the Cu-catalyzed intramolecular amidation of hindered secondary amides under controlled microwave heating. A mechanism was proposed to account for competing Cu-catalyzed intramolecular N- and O-arylation pathways, which were controlled by the bulkiness of substituents on the nitrogen atom of secondary amides. | (57) Abstract: The present invention claims the copper in an aqueous solution, a coordination compound, a method of depolymerization and / or modification of the peroxide lignin or lignin related compounds by the system. Copper coordination compound than 20% relative to the substrate in aqueous solution, is preferably applied in 0.001-5%. Coordination compounds, pyridine, histidyl-glycine, compounds containing phthalocyanine, acetonitrile, nitrogen, such as, compounds containing hydroxyl groups such as catechol, compounds such an ether like 18-crown-6, mercapto succinic acid compounds containing sulfur, such as, or compounds containing olefinic double bonds such as 1,3-cyclohexadiene. Peroxide hydrogen peroxide, organic peroxide, or to be added from outside as peracids, may also be produced in a solution containing lignin by reaction to produce a peroxide. | eng_Latn | 14,798 |
Antifibrinolytics in Subarachnoid Hemorrhage | Few conditions evince potential for disaster or cure as vividly as subarachnoid hemorrhage. If the patient survives the initial bleeding intact or with minor deficits, clipping of the aneurysm virtually eliminates the risk of recurrence. However, before something definite can be done, the patient faces the risk of rebleeding and later that of vasospasm. As Dr Adams documents, 20% of patients with subarachnoid hemorrhage will rebleed, half of them in the first 24 hours. Two thirds of those who rebleed die. The obvious solution is to operate before rebleeding or vasospasm can occur, a logical but unpopular approach because of the high perioperative complication rate of early intervention. Both Adams and Weir agree that the published evidence shows that in patients treated with antifibrinolytics, the advantages of decreased rebleeding rates are negated by the increase in ischemic complications and hydrocephalus. Dr Adams states that if the usual therapeutic lag | The investigations of recent progress in the fields of design and synthesis of supramolecular coordination compounds,as well as their applications,are reviewed in the text.As new potential functional materials, supramolecular coordination compounds containing thiosemicarbazide have been synthesized via molecular design and spontaneous assembly,and their composition-structure-nonlinearity relationships are discussed in this thesis.All the achievements for our research work have been carried out in order to design and synthesize new functional complex with novel structure effectively. | eng_Latn | 14,799 |
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