Synthetic Studies on 2-Pyrrolidinone Derivatives. III. : Syntheses of 2-Substituted-6-phenylpyrrolo[3, 4-d]pyrimidin-7-ones and Its 5-Methyl Analogs

Treatment of ethyl 1-phenyl-2, 3-dioxo-4-pyrrolidinecarboxylate (I) with excess urea afforded the corresponding 2, 4-dihydroxy-6-phenylpyrrolo[3, 4-d]pyrimidin-7-ones (II). Ethyl 3-amino-1-phenyl-2-oxo-4-pyrrolinecarboxylate (III), prepared by the Leucalt reaction of I with ammonium acetate, gave 2-amino(and 2-methyl)-4-hydroxy-6-phenylpyrrolo[3, 4-d]pyrimidin-7-ones (IV) and (V) by reaction with guanidine hydrochloride (and acetamidine hydrochloride) by the use of a base catalizer. Heating of IIIa in formamide gave a small amount of VI.