The synthesis of ethyl 2‐[(2,2‐dibenzoyl)ethenyl]amino‐3‐dimethyl‐aminopropenoate and its application to the synthesis of fused 3‐aminopyran‐2‐ones and 3‐aminoazolo‐ and ‐azinopyrimidin‐4(4 H )‐ones

Ethyl 2‐[(2,2‐dibenzoyl)ethenyl]amino‐3‐dimethylaminopropenoate ( 3 ) was prepared from dibenzoylmethane ( 1 ) in two steps, and used as a reagent for preparation of fused substituted 3‐aminopyranones 12–15 in over 90% yield, quinolizin‐4‐one 16 in over 79% yield, and fused pyrimidin‐4‐ones 17–19 in 40–50% yield. Deprotection of (2,2‐dibenzoyl)ethenyl group with either diethylamine or hydrazine hydrate produced free amino compounds 20, 21 and 22 in 35%, 91% and 71% yield, respectively.