pyridine; lithium carbonate; N-bromoacetamide in tetrahydrofuran; methanol; water

tetraethylammonium p-toluenesulfonate; acetic acid

bromine; calcium carbonate in tetrachloromethane; chloroform T=5°C; 0.5 h;

1: Br2, CaCO3 / CHCl3; CCl4 / 0.5 h / 5 °C 2: 72 percent / LiBr2, Li2CO3 / dimethylformamide / 0.5 h / Heating 3: 100 percent / N-bromosuccinimide, 2,2-azadiisobutyronitrile / CCl4 / 5 h / Heating 4: 62 percent / H2O / dioxane / 2.5 h / Heating View Scheme

1: Br2, CaCO3 / CHCl3; CCl4 / 0.5 h / 5 °C 2: 72 percent / LiBr2, Li2CO3 / dimethylformamide / 0.5 h / Heating 3: 100 percent / N-bromosuccinimide, 2,2-azadiisobutyronitrile / CCl4 / 5 h / Heating 4: 62 percent / H2O / dioxane / 2.5 h / Heating 5: 72 percent / conc. HCl / 4 h / Ambient temperature View Scheme