1: 1.) ethyl chloroformate, triethylamine; 2.) Ac2O, fum. HNO3; 3.) NaOH / 1.) THF, 0-5 deg C, 0.5 h; 2.) acetonitrile, -8 deg C, 1 h; 3.) MeOH, H2O, RT, 0.5 h 2: 1 N NaOH / 2 h / 50 °C 3: methanol / 1 h / 70 °C View Scheme

hydrogen bromide T=90°C; 9 h;

1: 88.7 percent / 40 percent (w/v) peracetic acid, AcOK / CH2Cl2 / 48 h / Ambient temperature 2: 90.4 percent / 20 percent (w/v) HCl / diethyl ether / 12 h / Ambient temperature 3: 1.53 g / K2CO3 / dimethylformamide / 2 h / Ambient temperature 4: 52.1 percent / 1 N NaOH / methanol / 1 h / Ambient temperature 5: 88.9 percent / 47 percent HBr / 9 h / 90 °C View Scheme

1: 52.1 percent / 1 N NaOH / methanol / 1 h / Ambient temperature 2: 88.9 percent / 47 percent HBr / 9 h / 90 °C View Scheme

1: 90.4 percent / 20 percent (w/v) HCl / diethyl ether / 12 h / Ambient temperature 2: 1.53 g / K2CO3 / dimethylformamide / 2 h / Ambient temperature 3: 52.1 percent / 1 N NaOH / methanol / 1 h / Ambient temperature 4: 88.9 percent / 47 percent HBr / 9 h / 90 °C View Scheme

1: 1.53 g / K2CO3 / dimethylformamide / 2 h / Ambient temperature 2: 52.1 percent / 1 N NaOH / methanol / 1 h / Ambient temperature 3: 88.9 percent / 47 percent HBr / 9 h / 90 °C View Scheme