pyridine; bromine in chloroform T=20 - 24°C; 3.75 h;

pyridine; bromine in ammonia; acetic acid

1: 43 percent / CHCl3 / 1) after mixing slowly heated and refluxed 2 h, 2) standing overnight 2: 58 percent / hydrazine hydrate / methanol; CHCl3; H2O / 1) 45 deg C, 10 min, 2) 60 deg C, 1,5 h, 3) standing overnight 3: 13 percent / acetic acid / benzene; pyridine / 5.5 h / Heating 4: 86 percent / bromine, pyridine / CHCl3 / 3.75 h / 20 - 24 °C View Scheme

1: 58 percent / hydrazine hydrate / methanol; CHCl3; H2O / 1) 45 deg C, 10 min, 2) 60 deg C, 1,5 h, 3) standing overnight 2: 13 percent / acetic acid / benzene; pyridine / 5.5 h / Heating 3: 86 percent / bromine, pyridine / CHCl3 / 3.75 h / 20 - 24 °C View Scheme

1: 13 percent / acetic acid / benzene; pyridine / 5.5 h / Heating 2: 86 percent / bromine, pyridine / CHCl3 / 3.75 h / 20 - 24 °C View Scheme

1: 85 percent / P2S5 / pyridine / 2.5 h / 70 - 75 °C 2: 73 percent / hydrazine hydrate / methanol / 3.5 h / Ambient temperature 3: 99 percent / sulphuric acid / ethanol / 2 h / Heating View Scheme