Methyl 2‐[bis(acetyl)ethenyl]aminopropenoate in the synthesis of heterocyclic systems

Methyl 2‐[bis(acetyl)ethenyl]aminopropenoate ( 4 ) was prepared in 3 steps from acetylacetone ( 1 ) via 4‐( N,N ‐dimethylamino)‐3‐acetylbut‐3‐en‐2‐one ( 2 ) and methyl N ‐[2,2‐bis(acetyl)ethenyl]glycinate ( 3 ). Compound 4 reacts with N ‐ and C ‐nucleophiles to give fused heterocyclic systems. Derivatives of pyrido[1,2‐ a ]pyrimidones 14–16 and thiazolo[3,2‐ a ]pyrimidones 17 and 18 were prepared from 2‐aminopyridines and 2‐aminothiazoles, respectively. With C ‐nucleophiles derivatives of pyrido[1,2‐ a ]‐pyridinone 19 and 2 H ‐1‐benzopyran‐2‐one 20–22 were prepared.