bromine; triphenylphosphine in dichloromethane T=0°C; 1 h;

trichloromonobromomethane T=10 - 15°C; 0.5 h;

1: oxalyl chloride / toluene / 20 °C 2: 2-mercaptopyridine N-oxide, sodium salt hydrate; 4-dimethylaminopyridine; bromotrichloromethane / Heating View Scheme

1: 1.) BuLi, 3.) toluene-p-sulfonic acid / 1) hexane; 2) THF, hexane, HMPA, room temperature, 10 h; 3) methanol, reflux, 3 h 2: 97 percent / Lindlar catalyst, quinoline, cyclohexene, H2 / 3 h 3: 97 percent / bromine-triphenylphosphine, Br2 / CH2Cl2 / 1 h / 0 °C View Scheme

1: 97 percent / Lindlar catalyst, quinoline, cyclohexene, H2 / 3 h 2: 97 percent / bromine-triphenylphosphine, Br2 / CH2Cl2 / 1 h / 0 °C View Scheme

4-(N,N-dimethlyamino)pyridine; trichloromonobromomethane; sodium salt hydrate; 2-mercaptopyridine-1-oxide Heating;

1: 100 percent / NaI / acetone / 2 h / Heating 2: 82 percent / DMSO, NaHCO3 / 0.25 h / 150 °C 3: 95 percent / Jones reagent / acetone / Ambient temperature View Scheme

triethylamine