Synthesis of 9-Substituted 8-Phenyltheophyllines

Abstract

Various 9-substituted 8-phenyltheophyllines (III) were prepared in two steps starting from 5, 7-dimethyl-2-phenyloxazolo [5, 4-d] pyrimidine-4, 6 (5H, 7H)-dione (I). Thus, treatment of I with amines afforded 5-(N-substituted benzamidino)-1, 3-dimethylbarbituric acids (II). The reaction of II with thionyl chloride or phosphorus oxychloride gave III.