An unexpected result in the condensation of 2-amino-6-bromo- pyridine with ethyl 4-chloroacetoacetate: Four dihalo-substituted pyrido[1,2-a]pyrimidin-4-ones as reaction products

Article abstract of DOI:10.1002/jhet.5570360438

We report here the condensation of 2-amino-6-bromopyridine with ethyl 4-chloroacetoacetate in polyphosphoric acid. In this reaction, a mixture of the four possible dihalo-4H-pyrido[1,2- a]pyrimidin-4-ones 1-4 was obtained.