Methyl 2‐benzoylamino‐3‐dimethylaminopropenoate in the synthesis of heterocyclic systems. The synthesis of benzoyl‐ amino substituted 7 H ‐pyrano[2,3‐ d ]pyrimidine, 1 H ,6 H ‐pyrano‐ [2,3‐ c ]pyrazole and 2 H ‐1‐benzopyran derivatives

Methyl 2‐benzoylamino‐3‐dimethylaminopropenoate (6) reacts with heterocyclic compounds containing an active methylene group or potential methylene group in the ring system, such as barbituric acid derivatives 1 and 2, pyrazolones 3 and 4, and resorcinol, in acetic acid to afford the corresponding benzoylamino substituted pyranopyrimidinones 7 and 8 , pyranopyrazolones 9 and 10 , and 2 H ‐1‐benzopyranone 11 . The method represents a novel procedure for the preparation of condensed pyranones.