FACILE SYNTHESIS AND NO-GENERATING PROPERTY OF 4H-[1,2,5]OXADIAZOLO[3,4-D]PYRIMIDINE-5,7-DIONE 1-OXIDES

4H-[1,2,5]Oxadiazolo[3,4-d]pyrimidine-5,7-oxides (2) are conveniently prepared in high yields by the oxidative intramolecular cyclization of 6-amino-5-nitro-H-1-pyrimidine-2,4-diones (1) employing iodosylbenzen e diacetate as an oxidant in the presence of lithium hydride. The gene ration of nitric oxide (NO) and NO-related species from 2 occurs in th e presence of thiols such as N-acetylcysteamine, cysteine, and glutath ione under physiological conditions. The evidence for the NO generatio n derives from mechanistic interpretations for the reaction of 2 with thiols and other chemical observations.