A novel synthesis of N1-(substituted)-pyrimido[5,4-e]-1,2,4-triazine-5,7(1H,6H)-diones

A new synthesis of N1-(substituted)-pyrimido[5,4-e]-1,2,4-triazine-5,7(1H,6H)-diones, which are analogues of the natural product toxoflavin, is reported. Condensation of preformed alkyl or aryl hydrazones with 6-chloro-3-methyl-5-nitrouracil efficiently provides pyrimidotriazinediones in a three-step process that broadens the scope of R1 substituents.