Facile synthesis of highly functionalized aromatic novel 3-(2,4-substituted diaryl- 2H-chromen-3-yl)-5-phenylisoxazole derivatives

Abstract

An efficient approach has been described for the synthesis of substituted diaryl aromatic flava none-isoxazole (7a-m) hybrids through simple and practical methodology. The synthetic strategy involves formation of substituted diaryl flavanone aldoxime intermediates (5a-k) from substituted flavanone -3- aldehydes (4a-k). This is followed by [3+2] cycloaddition of in situ generated nitrile oxides with aryl acetylenes using sodium hypochlorite oxidant in THF in absence of light, to furnish the functionalized isoxazoles with excellent yields (85-90%).