抄録
Reaction of hydrazobenzene (Ia) with diketene in the presence of triethylamine gave 1, 2-diphenyl-5-methyl-3-pyrazolone (IIIa) in 80% yield. Similarly, twelve kinds of symmetrical substituted hydrazobenzene derivatives, such as dimethylhydrazobenzenes (Ib, c, d), dichlorohydrazobenzenes (Ie, f, g), dimethoxyhydrazobenzenes (Ih, i, j), and diethoxyhydrazobenzenes (Ik, l, m) afforded the corresponding 1, 2-diaryl-5-methyl-3-pyrazolone derivatives (IIIb-m).
