Chemistry of 5-oxodihydroisoxazoles. Part 17.1 Acylation of 5-oxodihydroisoxazoles
作者:Rolf H. Prager、Jason A. Smith、Ben Weber、Craig M. Williams
DOI:10.1039/a700133i
日期:——
2-Unsubstituted isoxazol-5(4H)-ones and
-5(2H)-ones may be acylated by acid chlorides,
anhydrides or carboxylic acids in the presence of carbodiimides, to give
O- and N-acylated products. The solvent, the presence
of base and the temperature are found to alter the product ratios
dramatically, but the substituents present at C-3 have the greatest
effect. Aliphatic acid anhydrides and chlorides generally react at
nitrogen, but aroyl halides give significant proportions of
O-acylated products. Limited success in converting
O-aroyl to N-aroyl isoxazolones is reported.
Synthesis, biological evaluation, and molecular modelling studies of potent human neutrophil elastase (HNE) inhibitors
作者:Maria Paola Giovannoni、Igor A. Schepetkin、Mark T. Quinn、Niccolò Cantini、Letizia Crocetti、Gabriella Guerrini、Antonella Iacovone、Paola Paoli、Patrizia Rossi、Gianluca Bartolucci、Marta Menicatti、Claudia Vergelli
DOI:10.1080/14756366.2018.1480615
日期:2018.1.1
both competitive HNE inhibitors. Molecularmodelling on 7d and 8d suggests for the latter a more crowded region about the site of the nucleophilic attack, which could explain its lowered activity. In addition molecular dynamics (MD) simulations showed that the isomer 8d appears more prone to form H-bond interactions which, however, keep the reactive sites quite distant for the attack by Ser195. By contrast
The tautomerism of heteroaromatic compounds with five-membered rings—I
作者:A.J. Boulton、A.R. Katritzky
DOI:10.1016/0040-4020(61)80097-5
日期:1961.1
Infra-red and ultra-violet spectra show that 3,4-dimethyl-5-hydroxyisoxazole exists in aqueous and chloroform solution, and in the solid phase in the OH form; and that 3-phenyl-, 4-bromo-3-phenyl-, and 4-methyl-3-phenyl-isoxazol-5-ones exist as mixtures of the CH and NH forms in solution, the proportion of the NH form increasing with the polarity of the solvent. The basicities of isoxazole and some