Studies on isocyanides : synthesis of tetrazolyl-isoindolinones via tandem Ugi four-component condensation/intramolecular amidation

Abstract The Ugi four-component condensation between methyl o -formylbenzoates 1 , anilines 2a – c , isocyanides 3 , and trimethylsilyl azide ( 4 ) afforded the expected Ugi adducts 5a – d , which were cyclized to the title compounds 6a – d upon treatment with sodium ethoxide in ethanol. Starting from aralkyl- or alkylamines 2d – g the Ugi adducts underwent a spontaneous cyclization to tetrazolyl-isoindolinones 6e – j .