1: 68 percent / glac. AcOH / methanol / 4 h / Heating 2: dimethylformamide; H2O / 1) heating, 10 min, 2) r.t., overnight View Scheme

1: 60 percent / hydrazine hydrate / methanol / 8 h / Heating 2: 68 percent / glac. AcOH / methanol / 4 h / Heating 3: dimethylformamide; H2O / 1) heating, 10 min, 2) r.t., overnight View Scheme

in water; N,N-dimethyl-formamide 1) heating, 10 min, 2) r.t., overnight;