Chemistry Articles

Purpose:
The purpose of this study was to prepare several 1,3-thaizolidin-4-ones bearing variously substituted diaryl ring at C-2 and N-3 positions and evaluate them for their anti-YFV activity.

Methods:
Several 1,3-thaizolidin-4-ones were prepared by reacting substituted benzaldehyde with equimolar amount of an appropriate substituted aromatic amine in the presence of an excess of mercaptoacetic acid in toluene utilizing microwave irradiation. The synthesized compounds were also evaluated for their inhibitory effects on the replication of YFV in green monkey kidney (Vero) cells (ATCC CCL81), by means of a cytopathic effect reduction assay. Results: The compound DS1 emerged as the most potent anti-YFV agent with EC50 of 6.9 µM and CC50 more than 100 µM making it more potent than ribavirin. Conclusion: 2,3-diaryl-1,3-thiazolidin-4-ones possess anti-YFV potency.

Abstract: PURPOSE: A series of N-Arylhydrazone derivatives of mefenamic acid (a known non-steroidal anti-inflammatory drug) were synthesized in order to obtain new compounds with potential analgesic and anti-inflammatory activity. METHODS: The structures of all synthesized compounds were confirmed by means of infrared, proton magnetic resonance and mass spectroscopy. All compounds were evaluated for their analgesic and anti-inflammatory activities by abdominal constriction test (writhing test) and carrageenan-induced rat paw edema test respectively. RESULTS: Most of the synthesized compounds induced significant reduction in the writhing response when compared to control. Among them, compounds 11, 12, 15, 16, 19, 20, and 21 were significantly more potent than mefenamic acid in the writhing test.

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Most fluorinated polymers are prepared by polymerizing fluorinated monomers. An alternative route--direct fluorination of a polymer--usually involves "chemically aggressive" reagents such as elemental fluorine. Assistant processor of chemistry Marc A. Hillmyer, graduate student Yu Ren, and chemistry professor Timothy P. Lodge of the University of Minnesota, Minneapolis, now have found a mild, selective, and quantitative route to a new class of fluorinated polymers using the reaction of difluorocarbene (:CF2) with model polydienes having well-defined molecular characteristics. A solution of the polydiene and the difluorocarbene precursor (hexafluoropropylene oxide) is heated to 185 °C for 18 hours. Thermolysis of the precursor generates :CF2, which adds to all the double bonds in the polydiene. To prevent free-radical reactions such as cross-linking, the researchers add a radical inhibitor.

Mechanistic studies of the enolization of 2-methylcyclohexanone mediated by lithium hexamethyldisilazide (LiHMDS; TMS2NLi) solvated by hindered dialkyl ethers (ROR¢) are described. Rate studies using in situ IR spectroscopy show that enolizations in the presence of i-Pr2O, 2,2,5,5- tetramethyltetrahydrofuran, and cineole proceed via dimer-based transition structures [(TMS2- NLi)2(ROR¢)(ketone)]‡. Comparing the relative solvation energies and the corresponding solventdependent activation energies shows that the highly substituted ethers accelerate the enolizations by sterically destabilizing the reactants and stabilizing the transition structures. Comparisons of hindered dialkyl ethers with their isostructural dialkylamines reveal that the considerably higher rates elicited by the amines derive from an analogous relative destabilization of the reactants and relative stabilization of the transition structures.

Thiazole synthase complexed with the sulfur carrier protein consists of a tetramer of ThiS/thiazole synthase heterodimers. ThiS is a 7.2 kDa protein with a ubiquitin-like fold, and thiazole synthase is a 26.9 kDa protein. The mechanism of the early steps catalyzed by thiazole synthase have been elucidated, and an imine between the DXP substrate and lysine 96 has been characterized. The thiazole synthase sequence is highly conserved in bacteria and shows similarity to thiamin phosphate synthase, a member of the flavin mononucleotide dependent oxidoreductase and phosphate binding (FMOP) superfamilies of ( )8 barrel enzymes.

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When the 1995 Nobel Prizes were announced last October, Paul J. Crutzen was o­n vacation in Spain with his wife, Terttu. So when journalists called at the Max Planck Institute for Chemistry in Mainz, Germany, where Crutzen is director of the Air Chemistry Division, they interviewed o­ne of his senior colleagues instead. When informed that Crutzen had won the Nobel Prize in Chemistry, the colleague replied: "What for?"

The question seemed to imply surprise that Crutzen had won the prize, according to Thomas E. Graedel, distinguished member of the technical staff at AT&T Bell Laboratories, Murray Hill, N.J., who tells the anecdote. "But what the colleague meant was: There are so many things that Crutzen could have been cited for - for example, his work o­n biomass burning, his work o­n defining the methane cycle in the atmosphere, or his work o­n defining the sulfur cycle in the stratosphere," says Graedel.

Metalation of Imines by Lithium Diisopropylamide Solvated by N,N,N',N'-Tetramethylethylenediamine: Evidence for Solvent-Free Open Dimer Reactive Intermediates Max P. Bernstein and David B.

Osnat Herzberg, Celia C. H. Chen, Sijiu Liu, Aleksandra Tempczyk, Andrew Howard, Min Wei, Dongmei Ye, and Debra Dunaway-Mariano
Biochemistry, December 19, 2001
10.1021/bi011799+ S0006-2960(02)05949-4
Copyright © 2001 American Chemical Society

2131. Treatment of (L)Mo(CO), (L = v2-pyridyl dimethylphosphinite) at 0 'C in diethyl ether with 1.1 equiv of lithium alkoxides (ROLi) derived from unsaturated alcohols affords (v3-PMe20R)Mo(CO), chelates. The reaction involves nucleophilic attack at the phosphorus with cleavage of the chelate bridge and subsequent rapid extrusion of the alkoxide of 2-hydroxypyridine. The procedure is illustrated by using a number of allylic, homoallylic, l o , 2', and 3' alkoxides. When the alkoxides contain asymmetric centers, disastereofacial coordination selectivities of 3 - 30: 1 are observed. A molecular structure determination of (q3-PMe20R)Mo(CO), (10; R = 1-phenylallyl) was effected. Crystals of (PMe20CPhCH=CH2)Mo(C0), belong to the centrosymmetric triclinic space group Pi with cell parameters a = 7.416 (1) A, b = 8.649 (1) A, c = 13.572 (2) A, a = 98.48 (l)', 0 = 94.08 (l)', y = 97.29 (l)', and Z = 2.

Neuronal nicotinic acetylcholine receptors (nAChR) are members of a supergene family of ion channels gated by neurotransmitters. They are pentameric oligomers composed of related glycoprotein subunits, each o­ne composed of ~500 amino acids and four transmembrane segments. About 210 amino acids at the N-terminus form the major extracellular domain.

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