Recyclization of 2,2-Disubstituted 4(3H)-Oxo- and 4-Chloro-1,2-dihydropyrimidines to 4-Aminopyridine Derivatives

Article abstract of DOI:10.1007/BF00512825

The intramolecular cationotropic rearrangement of salts of two-ring 2,2-disubstituted 4-chloro-1,2-dihydropyrimidines to 4-aminopyrimidine derivatives was observed.Recyclization to 4-aminopyridines can take place in the reaction of two-ring 2,2-disubstituted 4(3H)-oxo-1,2-dihydropyrimidines with phosphorus oxychloride without isolation of the intermediate chloro derivatives.A probable mechanism that makes it possible to assert that the observed recyclization is a variant of the intramolecular cationotropic rearrangement that is characteristic for 2,2-dialkylsubstituted 1,2-dihydropyrimidines with functional substituents (for example, oxo or chloro) in the 4 position of the ring is discussed.