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 2H‐1‐benzopyran‐2‐one 20–22 were prepared.