A new synthesis of thiazolo[3,2‐a] pyrimidinones

Abstract
5H‐Thiazolo[3,2‐a]pyrimidin‐5‐ones (V) have been prepared by S‐alkylation of 6‐methyl‐2‐thiouracil (Ib) with bromoacetone or bromoacetophenone followed by cyclization in sulfuric acid. By the same series of reactions, 2‐thiouracil (Ia) gave rise to 7H‐thiazolo[3,2‐a]pyrimidin‐7‐ones (VI). The properties and structures of the intermediates and products are discussed.