The Synthesis and Chlorination of Some Pyrimidin-4-ols Having 5-Nitrogen Functionality

Abstract

Syntheses of a number of pyrimidin-4-ols having 5-nitrogen functionality are described. Phosphorus oxychloride/diethylaniline chlorination of 6-amino-2-methylthio-5-nitropyrimidin-4-ol gave the corresponding 6-chloro derivative. However, 2-amino-6-methylthio-5-nitropyrimidin-4-ol failed to yield a 4-chloro derivative under the same conditions. Similar chlorination of 2,5-diaminopyrimidine-4,6-diol gave a poor yield of the 4,6-dichloro product but under these conditions 2-amino-5-benzoylaminopyrimidine-4,6-diol* gave 7-chloro-2-phenyloxazolo[5,4-d]pyrimidin-5-amine. 5-Acetylamino-2-methylthiopyrimidine-4,6-diol yielded 7-chloro-2- methyl-5-methylthiooxazolo[5,4-d] pyrimidine as the major product together with some 5-acetylamino-4,6-dichloro-2-methylthiopyrimidine under the same chlorination conditions.