The permanganate oxidation of thymine

Abstract

1. Mild permanganate oxidation of thymine yielded cis-thymine glycol (cis-5,6-dihydroxy-5,6-dihydrothymine) and 5-hydroxy-5-methylbarbituric acid. Under certain reaction conditions, only these two compounds were the products of the reaction. 2. While cis-thymine glycol was resistant to hydrolysis at neutral pH, 5-hydroxy-5-methylbarbituric acid readily underwent hydrolysis to give methyltartronylurea. 3. In this oxidation reaction, 5-hydroxy-5-methylbarbituric acid, which is higher in the oxidation level than thymine glycol, is formed not via the thymine glycol but directly from thymine. 4. When the oxidation of thymine was carried out at an acidic pH, 5-hydroxy-5-methylbarbituric acid was predominantly produced, whereas thymine glycol was preferentially formed when the oxidation was performed at an alkaline pH. 5. The mechanism of the oxidation is discussed. © 1970.