Abstract
1, 3, 6, 8-Tetramethy1-2, 4, 5, 7 (1H, 3H, 6H, 8H) pyrimido [5, 4-g] pteridinetetrone (I) is the common product which has frequently been observed during the reactions using 6-amino-1, 3-dimethyl-5-nitrosouracil and 5, 6-diamino-1, 3-dimethyluracil. The identity of the products with I has been established in following reactions:(a) the condensation of the monohydrochloride of 5, 6-diamino-1, 3-dimethyluracil with 1, 3-dimethylalloxan in aqueous solution, (b) the action of 2N sulfuric acid or hydrochloric acid on 5, 6-diamino-1, 3-dimethyluracil or its monoacetyl derivative, (c) the reaction of 6-amino-1, 3-dimethyl-5-nitrosouracil with 1, 3-dimethylbarbituric acid, and (d) the thermal and acid induced reaction of 6-amino-1, 3-dimethy1-5-nitrosouracil. Furthermore I has often been obtained as a byproduct in the purine and pteridine syntheses from 5, 6-diamino-1, 3-dimethyluracil and 6-amino-1, 3-dimethy1-5-nitrosouracil.
