Synthesis of Coumarins by Nucleophilic Denitrocyclization Reaction
2-propanedioic acids(2a-c) were denitrocyclized to coumarins (3a-c) by heating in quinoline in the presence of copper powder. 2-(4-Methoxiphenyl)-3-(2-nitrophenyl)-(Z)-2-propenoic acids (6a,b,d,e) were also similarly denitrocycli