Pyrimidine Derivatives and Related Compounds. XLIII. Studies on the Mechanism of the Ring Transformation of 6-Chloro-1, 3-oxazine-2, 4-diones to Barbituric Acids

Abstract

The mechanism of the ring transformation of 6-chloro-1, 3-oxazine-2, 4-diones (1) into barbituric acids (2) in the presence of primary aliphatic amines was studied. It has been elucidated that the mechanism involves initial attack on the 2-position of 1 by an amine and subsequent intramolecular cyclization of the ureide intermediate (5).