Synthesis and evaluation of 3-cyano-4-imino-2-methylthio-4H-pyrido[1,2-a]pyrimidine derivatives as potent antioxidant agents

The bis (methylthio) methylene malononitrile (1) on treatment with 2-amino pyridine (2) in N,N-dimethyl formamide (DMF) and anhydrous potassium carbonate, gives 3-cyano-4-imino-2-(methylthio)-4H-pyrido[1,2-a]pyrimidine (3). The latter were further reacted with selected N-, O- and C-nucleophiles such as aryl amines, hetryl amines, substituted phenols and compounds containing active methylene groups.