variety of 2-methylpyrimidin-4(3 H)-ones promoted by chlorotrimethylsilane was investigated. A simple and flexible general procedure for the synthesis of a series of fused pyrido[1,2- A]pyrimidin-4-ones is proposed. A set of functionally and structurally diverse pyrido[1,2- A]pyrimidin-4-ones were obtained in high yields.