Synthesis of Coumarins by Nucleophilic Denitrocyclization Reaction

Abstract

2- [(2-Nitrophenyl) methylene] propanedioic acids (2a-c) were denitrocyclized to coumarins (3a-c) by heating in quinoline in the presence of copper powder. 2- (4-Methoxyphenyl) -3- (2-nitrophenyl) - (Z) -2-propenoic acids (6a, b, d, e) were also similarly denitrocyclized to 3-substituted coumarins (7a, b, d, e).