Synthesis of new 4-amino-substituted 7-iminopyrido[2,3-d]pyrimidines

The reaction of 4,6-dichloropyrimidine-5-carbaldehyde with cyanomethyltriphenylphosphonium chloride gave (2 Е )-3-(4,6-dichloropyrimidin-5-yl)acrylonitrile, which was further used for the preparation of 4,6-diamino-substituted pyrimidinylacrylonitrile derivatives, capable of intramolecular cyclization with the formation of new 4-amino-substituted 7-iminopyrido[2,3- d ]pyrimidines. Performing the reaction with 4-amino-6-chloropyrimidine-5-carbaldehyde led to 7-amino-4-chloropyrido[2,3- d ]pyrimidine, a promising intermediate for the synthesis of pyrido[2,3- d ]pyrimidine-4,7-diamines.