Electrochemical reactions. Part XIII. Reduction of some styrylpyrazole derivatives
5-Phenyl-3-styrylpyrazole (E½–2·16 and –2·60 V versus s.c.e.) and 1,5-diphenyl-3-styrylpyrazole (E½–2·27. –2·44, and –2·85 V) in dimethylformamide give rise to polarographic waves, but radical anions were not detected as intermediates by cyclic voltammetry. Reduction of 5-phenyl-3-styrylpyrazole at the potential of the first wave afforded 5-phenyl-3-(2-phenylethyl)pyrazole. Reduction of 1,5-diphenyl-3-styrylpyrazole at a potential near the diffusion plateau of the second wave (this is not completely separated from the first wave) gave 1,5-diphenyl-3-(2-phenylethyl)-Δ2-pyrazoline.