The reaction of 2-aminopyridine with some β-keto-esters in the presence of polyphosphoric acid ethyl ester
Abstract
Treatment of 2-aminopyridine with ethyl α-methylacetoacetate in the presence of polyphosphoric acid ethyl ester affords 2,3-dimethyl-4H-pyrido[1,2-a]pyrimidin-4-one and not 2,3-dimethyl-1,8-naphthyridone, as previously reported. This appears to be a general reaction for β-keto-esters with 2-aminopyridine in the presence of polyphosphoric acid ethyl ester.