1: 76 percent / Br2 / acetic acid / 0.5 h / Ambient temperature 2: 79 percent / CuI, Na / dimethylformamide / 2 h / Heating 3: 90 percent / HCOONH4*5H2O / 10percent Pd-C / methanol / 15 h / Heating View Scheme

ammonium formate; palladium on activated charcoal in methanol 4.5 h; Heating;