hydrogen bromide; dimethyl sulfoxide in water T=55°C;

1: 51 percent / ethanol; H2O / 6 h, RT; 60 deg C, 2 h 2: 2.) Br2 / 1.) 1,2-dichlorobenzene, 180 deg C, 15 h; 2.) CHCl3, -60 deg C View Scheme