Temperature-controlled synthesis of N-acyl anthranilamides and quinazoline-4ones via Pd-catalysed cascade consisting of isocyanide insertion

Abstract

A one step synthesis of functionlized N-acyl anthranilamide via Pd-catalyzed carboxamidation of o-halo substituted N-phenylamide consisting of isocyanide insertion followed by oxidation of the imine intermediate has been achived successfully. Furthermore, at elevated temprature (160oC) the Pd-catalyzed tandem reaction afforded functionlized quinazolin-4-one in a single step without the isolation of N-acyl anthranilamide and proceed through carboxamidation/de-t-butylation/cyclodehydration cascade. This work extends the application of isocyanide insertion chemistry for synthesizing diverse N-heterocycles by transition metal catalysed sequential reactions in a single step.