1: 1.) NaH / 1.) DMF, oil, 2-5 deg C, 15 min, 2.) DMF, oil, 2-5 deg C, 2 h 2: 97 percent / 20percent HBr / acetic acid / 1 h / Ambient temperature 3: 85.6 percent / dimethylformamide / 3.5 h / Ambient temperature View Scheme

1: 94.8 percent / 30percent HBr / acetic acid / 1.5 h / Ambient temperature 2: 89.3 percent / hexamethylphosphoric acid triamide / 3 h / Ambient temperature View Scheme

1: 1.) NaH / 1.) DMF, oil, 2-5 deg C, 15 min, 2.) DMF, oil, 2-5 deg C, 2 h 2: 97 percent / 20percent HBr / acetic acid / 1 h / Ambient temperature 3: 47.4 percent / dimethylformamide / 3.5 h / Ambient temperature View Scheme

1: 1.) NaH / 1.) DMF, oil, 2-5 deg C, 15 min, 2.) DMF, oil, 2-5 deg C, 2 h 2: 97 percent / 20percent HBr / acetic acid / 1 h / Ambient temperature 3: 92 percent / dimethylformamide / 3.5 h / Ambient temperature View Scheme

1: 1.) NaH / 1.) DMF, oil, 2-5 deg C, 15 min, 2.) DMF, oil, 2-5 deg C, 2 h 2: 97 percent / 20percent HBr / acetic acid / 1 h / Ambient temperature 3: 45.5 percent / dimethylformamide / 3.5 h / Ambient temperature View Scheme

1: 1.) NaH / 1.) DMF, oil, 2-5 deg C, 15 min, 2.) DMF, oil, 2-5 deg C, 2 h 2: 97 percent / 20percent HBr / acetic acid / 1 h / Ambient temperature 3: 85.3 percent / dimethylformamide / 3.5 h / Ambient temperature View Scheme

1: 1.) NaH / 1.) DMF, oil, 2-5 deg C, 15 min, 2.) DMF, oil, 2-5 deg C, 2 h 2: 97 percent / 20percent HBr / acetic acid / 1 h / Ambient temperature 3: 93.5 percent / dimethylformamide / 3 h / Ambient temperature 4: 90 percent / NH2NH2*H2O / ethanol / 0.5 h / Heating View Scheme

1: 1.) NaH / 1.) DMF, oil, 2-5 deg C, 15 min, 2.) DMF, oil, 2-5 deg C, 2 h 2: 97 percent / 20percent HBr / acetic acid / 1 h / Ambient temperature 3: 89 percent / hexamethylphosphoric acid triamide / 5 h 4: 91.5 percent / KI / acetone / 1 h / Heating 5: 100 percent / ethanol; CHCl3; methanol / 3 h / Ambient temperature View Scheme

1: 1.) NaH / 1.) DMF, oil, 2-5 deg C, 15 min, 2.) DMF, oil, 2-5 deg C, 2 h 2: 97 percent / 20percent HBr / acetic acid / 1 h / Ambient temperature 3: 89 percent / hexamethylphosphoric acid triamide / 5 h 4: 91.5 percent / KI / acetone / 1 h / Heating 5: 88.9 percent / ethanol; CHCl3; methanol / 3 h / Ambient temperature View Scheme

1: 1.) NaH / 1.) DMF, oil, 2-5 deg C, 15 min, 2.) DMF, oil, 2-5 deg C, 2 h 2: 97 percent / 20percent HBr / acetic acid / 1 h / Ambient temperature 3: 89 percent / hexamethylphosphoric acid triamide / 5 h 4: 91.5 percent / KI / acetone / 1 h / Heating 5: 84.7 percent / ethanol; CHCl3; methanol / 3 h / Ambient temperature View Scheme