A convergent microwave assisted synthesis of 4-amino-N-(4-oxo-2- substituted-4H-quinazolin-3-yl)benzenesulfonamide derivatives

Abstract

An optimization of Grimmel's method under microwave irradiation is reported here for the first time to synthesize 4-amino-N-(4-oxo-2-substituted-4H- quinazolin-3-yl)benzenesulfonamide derivatives. The method was successfully applied for the synthesis of 2-alkyl and 2-aryl substituted derivatives. However, unexpected results were obtained when the same protocol was applied for 2-styryl-substituted quinazolinones. 2-Styrylquinazolinone derivatives were then synthesized via benzoxazinones under microwave irradiation. Subsequently, the effect of various bases (e.g. Et3N, NMM, DMAP, DIPEA) on the efficiency of cyclization to quinazolinone was investigated. The use of microwave irradiation allows significant rate enhancements and better yields compared to conventional conditions. © ARKAT-USA, Inc.