Pyrimidine Derivatives and Related Compounds. XXIX. Photoreductive Cyclization of 5-Nitro-6-styryl (or anilino) uracil Derivatives to Pyrrolo [3, 2-d] pyrimidine and Alloxazine Derivatives

Abstract

Irradiation of 1, 3-dimethyl-5-nitro-6-styryluracils (1a-c) principally gave 1, 3-dimethyl-6-phenylpyrrolo [3, 2-d] pyrimidines (3a-c) in 8-16% yields. Irradiation of 6-anilino-5-nitrouracils (5a-c) gave alloxazines (6a, b) and isoalloxazine (6c) in 14-18% yields. These products were formed by photoreductive cyclization of a nitro group with an o-substituted styryl or anilino group.