Investigation of a new method for the synthesis of isocytosine

Pyrimidine and quinazolines as pyrimidine-condensed derivatives, which are founded in the structure of some drugs and alkaloids, have an important value in synthetic chemistry area. In this work, we aimed to investigate a novel methodology for the strain forward synthesis of some quinazoline derivatives based on isocytosine. The proposed method base on the Cascade reactions of β-dicarbonyl compounds containing an 2-cyanophenyl group with cyanamide. In this reactions, DBU were used in organic base. Two novel 1H-pyrimido[1,2-a]quinazoline-1-ones derivatives were prepared with this methods. In addition, some dicarbonyl analogues were directly transformed to 4-aminoquinolin-2(1H)-one structures unaffected by cyanamide. One 5-Acyl-2-aminopyrimidin-4-one and nine 1H-pyrimido[1,2-a]quinazoline-1-one derivatives were prepared with this new metod. 1H and 13C NMR, IR, HRMS data of the synthesized products are corresponded to proposed structures of the compounds.