2-(Substituted phenyl)oxazolo[4,5-b]pyridines and 2-(substituted phenyl)oxazolo[5,4-b]pyridines as nonacidic antiinflammatory agents
作者:Robert L. Clark、Arsenio A. Pessolano、Bruce Witzel、Thomas Lanza、T. Y. Shen、C. Gordon Van Arman、Edwin A. Risley
DOI:10.1021/jm00209a014
日期:1978.11
Some 2-(substitutedphenyl)oxazolo[4,5-b]pyridines and 2-(substitutedphenyl)oxazolo[5,4-b]pyridines have good antiinflammatory and analgesic activity. A few possess activity comparable to phenylbutazone or indomethacin without producing the irritation in the gastrointestinal tract that acidic antiinflammatory compounds cause.
The present paper describes a silica-supported, perchloric-acid-catalyzed, efficient protocol for the synthesis of 2-(phenyl)oxazolo[4,5-b]pyridine derivatives. This strategy has high conversion, simple workup procedures, ambient conditions, short reaction times, and a reusable catalyst. Structures of the synthesized compounds have been established on the basis of elemental analysis and spectral data (IR, H-1 NMR, C-13 NMR, and mass spectrometry). Moreover, to investigate the mechanistic details of the reaction and to ascertain the regioselective outcome of the product, local nucleophilicity descriptors N-k at B3LYP/6-311G++(d, p) level were determined and analyzed.