The oxidation of 5,6-diamino-1,3-dimethyl-2,4-dioxopyrimidine (H2ddd) by perrhenate (ReO4-) led to the formation of 1,3-dimethylalloxan, which condenses with unoxidized H2ddd to yield the product 1,3,6,8-tetramethylpyrimidopteridine-2,4,5,7-tetrone (tppt). The structure of tppt consists of a central pyrazine ring and two terminal pyrimidine rings in cis positions. The dihedral angles between the pyrazine and pyrimidine rings are 1.08° and 1.20°.
oxidation; diaminouracil; perrhenate; crystal structure
