Abstract This communication reports on the investigation of a new recyclization conversion of a pyrimidine ring, which can be referred to as C [BOND] C recyclization. In this reaction the nucleophile cleaves the pyrimidine ring at the N (3)-C (4) bond, and following rotation around the single C (5)-C (6) bond the new cyclization takes place. This type of recyclization has general applicability, and takes place upon alkali treatment of substituted 4-methyl-5- ...