Fervenulin, preparation

To prepare fervenulin 4-oxides 12 or toxoflavine 4-oxides 146, it is convenient to use the reaction of l,3-dimethyl-2,4-dioxopyrimidin-6-yl hydrazone 147 or N-(3-methyl-2,4-dioxopyiimidin-6-yl) iV-methylhydrazone 148 with potassium nitrate in acetic acid [75CPB1885,76CPB338,76JCS(CC)658,82JHC1309,93CPB362]. Diethyl azodicarboxylate can be used instead of potassium nitrate [76JCS(P1 )713]. 

Very few compounds containing the 1,2,4-triazine moiety are found as natural materials, such as the pyrimido[5,4-c]-1,2,4-triazines, fervenulin (2),265 reumycin (3),265 toxoflavin (4) and MSD-92 (5).441 A large number of synthetic 1,2,4-triazines have biological activity and have been used for various purposes. Thus, 1,2,4-triazines can be considered as azapyrimidines and thus a large number of 6-azapyrimidine nucleotides and nucleosides have been prepared and their properties studied intensively, for example 6-azauracil (6), 6-azathymine(7), 6-azacytosine (8), 6-azauridine (9),442 and 6-azacytidine (10).443... 

---