Reactions of 3-phenyl-1,2,4-triazine with some C-nucleophiles

Dimedone is added at C(5) of 3-phenyl-1,2,4-triazine to give stable dihydro derivative. Its reaction with 1-aryl-3-methylpyrazol-5- ones proceeds with fragmentation affording 1,1,2,2-tetrakispyrazolylethane and amidrazone derivatives.