Synthesis of Highly Functionalized Benzofuran-2-carboxamides by Ugi Four-Component Reaction and Microwave-Assisted Rap-Stoermer Reaction

摘要

A two-step, diversity-oriented synthesis of highly functionalized benzofuran-2-carboxamides has been developed. The Ugi four-component reaction of aromatic amines, isocyanides,2-bromobenzaldehyde, and 2-bromoacetic acid was used to provide a collection of N-aryl 2-bromoacetamides. The latter were then reacted with selected salicyladehydes in the presence of Cs_2CO_3 in ace-tonitrile under controlled microwave heating at 90-140 °C for 15-40 minutes to furnish the benzofuran-2-carboxamides in moderate to good yields.