Reaction of Ketone Enolates with 2,4-Dichloropyrimidine. A Novel Pyrimidine to Pyridine Interconversion

Article abstract of DOI:10.1021/jo00219a004

Treatment of 2,4-dichloropyrimidine (1) with a series of ketone potassium enolate in liquid NH3 results in a novel ring transformation leading to the formation of 6-(cyanamino)pyridines (8a-c).An S_N(ANRORC) mechanism initiated by nucleophilic addition of the enolate to C₆ of 1 is proposed.The pyrimidine-pyridine transformation involves displacement of the N₁-C₂-N₃ portion of pyrimidine with a C-C-N moiety, where the enolate contributes the C-C fragment while NH3 is shown, using 15N-labeled NH3, to be the N donor.