Photochemical Synthesis of Condensed Triazole N-Oxide

抄録

Photolysis of 1, 3-dimethyl-5-nitro-6-benzylidenemethylhydrazinouracil (IV) resulted in the formation of 1, 5, 7-trimethyl-3-phenyl-4, 6 (5H, 7H)-pyrazolo (3, 4-d) pyrimidinedione (V) and 3, 4, 6-trimethyl-5, 7 (4H, 6H)-triazolo (4, 5-d) pyrimidinedione 1-oxide (VI). Upon irradiation of 1, 3-dimethyl-5-nitro-6-acetophenylidenemethylhydrazinouracil (VIII), however, VI was obtained exclusively in excellent yield. On the basis of mechanistic consideration on these photocyclizations, a new photochemical synthesis of condensed 3-alkyltriazole 1-oxides was developed.