SYNTHESIS OF N-(2-PYRIDYL)CYANOACETAMIDES AND 4-AMINO-2H-PYRIDO-[1,2-A]PYRIMIDIN-2-ONES FROM ETHYL CYANOACETATE AND 2-AMINOPYRIDINE

The reaction of 2-aminopyridine and 2-aminopicolines with ethyl cyanoacetate under high pressures results in the formation of 4-amino-4H-pyrido[1,2-a]pyrimidin-2-ones. Depending on the structure of the initial pyridine base, heating of a mixture of the above reagents under low vacuum gives either the same products or their isomeric N-(2-pyridyl)cyanoacetamideBARs. The mutual transformations of the synthesized isomers were studied; it was found that cyanoacetamides are readily cyclized by the action of an alcoholic solution of HCl into pyrido[1,2-a]pyrimidin-2-ones, while the latter, during sublimation or heating in DMSO, undergo opening of the pyrimidine ring.