4-Aminotriazines proved difficult to prepare by reduction of substituted 4-nitrosotriazines because of the attendant reduction of the triazine ring and cleavage of the nitroso group. The reductions with hydrazine hydrate or tin (II) chloride involved cleavage of the nitroso group to provide 6-phenyl-3-thioxo-2, 3-dihydro-1, 2, 4-triazine-5 (4H)-one (III). Boiling with phenyl hydrazine resulted, along with cleavage of the nitroso group, in further hydrogenation of ...
