barium dihydroxide in methanol T=0°C; 0.5 h;

1: 94 percent / pyridine / 18 h / Ambient temperature 2: 68 percent / Zn(Cu) couple / diethyl ether / 6 h / Heating 3: 63 percent / Zn, AcOH / pyridine / 40 deg C, 2 h, then 70 deg C, 2 h 4: 85 percent / Ba(OH)2 / methanol / 0.5 h / 0 °C View Scheme

1: 68 percent / Zn(Cu) couple / diethyl ether / 6 h / Heating 2: 63 percent / Zn, AcOH / pyridine / 40 deg C, 2 h, then 70 deg C, 2 h 3: 85 percent / Ba(OH)2 / methanol / 0.5 h / 0 °C View Scheme

1: 63 percent / Zn, AcOH / pyridine / 40 deg C, 2 h, then 70 deg C, 2 h 2: 85 percent / Ba(OH)2 / methanol / 0.5 h / 0 °C View Scheme