1: 1.) 48percent aq. HBr, aq. NaNO2, 2.) 48percent aq. HBr, CuBr / 2.) reflux, 30 min 2: 57 percent / dimethylformamide / 4 h / Heating View Scheme

1: 34 percent / N-bromosuccinimide / dimethylformamide / 24 h / Ambient temperature 2: 1.) 48percent aq. HBr, aq. NaNO2, 2.) 48percent aq. HBr, CuBr / 2.) reflux, 30 min 3: 57 percent / dimethylformamide / 4 h / Heating View Scheme

in N,N-dimethyl-formamide 4 h; Heating;

pyridine