1: HBr gas / CH2Cl2 / 4 °C 2: CH2Cl2 / 168 h / Ambient temperature 3: NH3 / methanol / 24 h / Ambient temperature View Scheme

1: HBr gas / CH2Cl2 / 4 °C 2: CH2Cl2 / 168 h / Ambient temperature 3: NH3 / methanol / Ambient temperature 4: 1.) 75percent AcOH, 2.) NH3 / 1.) reflux, 48 h, 2.) MeOH, 24 h View Scheme

1: 30percent HBr / CH2Cl2; acetic acid / 1 h 2: 4A molecular sieves / CH2Cl2 / 15 h / Heating 3: 90 percent / NH3 / methanol / 84 h / 95 - 100 °C 4: 85 percent / imidazole / dimethylformamide / Ambient temperature 5: 0.029 g / (dimethylamido)pyridine / dimethylformamide; acetonitrile / 1.5 h / Ambient temperature 6: 71 percent / 2,2'-azobis(2-methylpropionitrile), tributyltin hydride / toluene / 0.5 h / Heating 7: 78 percent / 1 M tetrabutylammonium fluoride / tetrahydrofuran / 0.18 h / Ambient temperature View Scheme

1: HBr gas / CH2Cl2 / 4 °C 2: CH2Cl2 / 168 h / Ambient temperature 3: NH3 / methanol / Ambient temperature View Scheme