Condensation of 2-aminopyridine salts withβ-chlorovinyl aldehydes

2-Aminopyridine perchlorates react with-chlorovinyl aldehydes to give pyrido[1,2-a]-pyrimidinium salts, the structures of which were confirmed by PMR spectra. The reaction products form polymethine dyes through the methyl or methylene group in the position relative to the bridge nitrogen atom in the pyrimidine ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 242–244, February, 1973.