Treatment of the readily available 6-amino-5-nitrosopyrimidines with a
slight excess of iodobenzene diacetate or N-iodosuccinimide in anhydr
ous DMF containing three equivalents of lithium hydride at ambient tem
perature resulted in the smooth and versatile formation of the corresp
onding furazano[3,4-d]pyrimidines, which are useful intermediates for
the preparation of biologically interesting fused pyrimidines.