bromine; acetic anhydride T=12 - 15°C; 2 h;

potassium fluoride in N,N-dimethyl-formamide T=110°C;

potassium fluoride in N,N-dimethyl-formamide T=110 - 120°C; 0.666667 h;

potassium carbonate in dichloromethane; N,N-dimethyl-formamide T=105°C; 6 h;

1: 98.5 percent / Amberlyst 15E / benzene / 18 h / Heating 2: potassium carbonate / dimethylformamide / 12 h / 70 °C 3: hydrochloric acid / methanol; H2O / 2 h / 20 °C 4: 98 percent / 1,3-dibromo-5,5-dimethylhydantoin / CHCl3 / 24 h / 20 °C 5: 84 percent / potassium fluoride / dimethylformamide / 110 °C View Scheme

1: 98 percent / 1,3-dibromo-5,5-dimethylhydantoin / CHCl3 / 24 h / 20 °C 2: 84 percent / potassium fluoride / dimethylformamide / 110 °C View Scheme

1: 100 percent / sulfuric acid / 6 h / Heating 2: 98.5 percent / Amberlyst 15E / benzene / 18 h / Heating 3: potassium carbonate / dimethylformamide / 12 h / 70 °C 4: hydrochloric acid / methanol; H2O / 2 h / 20 °C 5: 98 percent / 1,3-dibromo-5,5-dimethylhydantoin / CHCl3 / 24 h / 20 °C 6: 84 percent / potassium fluoride / dimethylformamide / 110 °C View Scheme

1: 74 percent / Br2, CH2Br2 / 1,2-dichloro-ethane / 5 h 2: 56 percent / conc H2SO4 / 8 h / Heating 3: 73 percent / KF / dimethylformamide / 0.67 h / 110 - 120 °C View Scheme

1: 56 percent / conc H2SO4 / 8 h / Heating 2: 73 percent / KF / dimethylformamide / 0.67 h / 110 - 120 °C View Scheme

1: potassium carbonate / dimethylformamide / 12 h / 70 °C 2: hydrochloric acid / methanol; H2O / 2 h / 20 °C 3: 98 percent / 1,3-dibromo-5,5-dimethylhydantoin / CHCl3 / 24 h / 20 °C 4: 84 percent / potassium fluoride / dimethylformamide / 110 °C View Scheme