An unexpected result in the condensation of 2-amino-6-bromopyridine with ethyl 4-chloroacetoacetate: Four dihalo-substituted pyrido[1,2-a]pyrimidin-4-ones as reaction products

Simple and efficient protocol for synthesis of pyrido[1,2-a]pyrimidin-4-one derivatives over solid heteropolyacid catalysts

Aluminium exchnaged tungstophosphoric acid salts with Keggin structure (Al_xH_3−xPW₁₂O₄₀) were prepared and used as catalysts to synthesize pyrido[1,2-a]pyrimidines under mild reaction conditions.