Synthesis, Reactions and Spectral Properties of Ethyl Esters of 2-Cyano-3-(5-X-2-furyl)acrylic Acid

The reaction of 5-X-2-furaldehydes (X = C 6 H 5 , COOCH 3 , COOC 2 H 5 , C 6 H 5 O, C 6 H 5 S, CH 3 S, 4-Cl-C 6 H 4 S, CH 3 SO 2 , C 6 H 5 SO 2 , 4-Cl-C 6 H 4 SO 2 ) with ethyl cyanoacetate in dry ethanol catalyzed by sodium ethoxide yielded the corresponding ethyl 2-cyano-3-(5-X-2-furyl)acrylates. It was found that the reactions of these esters with cyanoacetophenone or ethyl acetoacetate do not afford the corresponding 4 H -pyran derivatives but that there proceeds the exchange of ethyl acetoacetate or of ethyl cyanoacetate for the cyanoacetophenone carbanion. The same course has been observed also for the reactions of these substrates with malononitrile.