2-Chloromethyl-8-methyl-3-nitro-4H-pyrido[1,2-a]pyrimidin-4-one was shown t
o react with various nitronate or malonate anions under mild conditions to
give potentially bioactive nitro-4H-pyrido[1,2-a]pyrimidin-4-ones. Extensio
n to other anions centred on S or O atom allows to generalize this syntheti
c procedure.