Pyrimidones. <b>2</b>. Synthesis and reactions of 2‐chloropyrimidines

Abstract

Abstract The treatment of 1‐alkyl‐5‐aryl and 1‐alkyl‐4,5‐diaryl‐2‐(1 H )pyrimidones with phosphorus oxychloride and phosphorus pentachloride resulted in chlorination and dealkylation to furnish 2‐chloro‐5‐aryl (or 4,5‐diaryl)‐pyrimidines. These chlorpyrimidines were reacted with a variety of nitrogen, oxygen, sulfur, and carbon nucleophiles to produce the corresponding 2‐substituted pyrimidines. In the case of phenyllithium, attack occurred at the 4‐position of the pyrimidine ring yielding 11 . Triazolopyrimidine 9 was synthesized via the treatment of 2d with hydrazine followed by reaction with triethyl orthoformate.