Heterocyclic studies. Part I. Ring-opening of some 4-hydroxypteridine derivatives

Abstract

4-Hydroxypteridine and its C-methyl derivatives, without a 2-substituent, yielded 3-aminopyrazine-2-carboxylic acids readily when treated with alkali. When a 2-methyl group was present ring-opening was greatly retarded. Treatment of each pteridine with hydrazine gave a mixture of a 4,5-diaminopyrimidine and a 3-aminopyrazine-2-carbohydrazide, unless a 7-methyl group was present, in which case no pyrimidine derivative was formed. The positions of attack on the pteridine molecule by the reagents are discussed.