1: 1.) NaH / 1.) 1,2-dimethoxy ethane, room temp., 1h, 2.) reflux 0.5h 2: 71 percent / bromine / CH2Cl2 / 0 °C 3: 52 percent / 1,5-diazabicyclo<4.3.0.>non-5-ene (DBN) / diethyl ether / 2 h 4: CF3COOH / H2O; tetrahydrofuran / var. pH; (2)H labelled comp. View Scheme

1: 44 percent / Br2 / CHCl3 / -65 °C 2: 2.) DBN / 1.) CCl4, 1 h, 2.) ether, room temperature, 10 h 3: 49 percent / aq. phosphate buffer / CHCl3 / 4 h / pH 6 4: 12 percent / carbonate/borate buffer / tetrahydrofuran; H2O / pH 10.0 View Scheme

dimethyl sulfoxide; trifluoroacetic anhydride in dichloromethane T=-65°C; 0.666667 h;

1: 88 percent / tert-butyl hydroperoxide, VO(acac)2 / benzene / 3 h / Heating 2: 70 percent / dimethyl sulfoxide, trifluoroacetic anhydride / CH2Cl2 / 0.67 h / -65 °C View Scheme

1: 1.) hydroxylamine sulfate, NaHCO3; 2.) 1,1'-carbonyldiimidazol / 1.) 10 deg C, 1 h, water and ether; 2.) CH2Cl2, room temp., overnight 2: 96 percent / Br2 / CH2Cl2; CHCl3 / 0.67 h / -70 °C 3: 42 percent / 1,4-diazabicyclo<4.3.0>non-5-ene / diethyl ether / 3 h / Ambient temperature View Scheme

1: 1.) hydroxylamine sulfate, NaHCO3; 2.) 1,1'-carbonyldiimidazol / 1.) 10 deg C, 1 h, water and ether; 2.) CH2Cl2, room temp., overnight 2: 96 percent / Br2 / CH2Cl2; CHCl3 / 0.67 h / -70 °C View Scheme

bromine in chloroform T=-65°C;

1: 44 percent / Br2 / CHCl3 / -65 °C 2: 2.) DBN / 1.) CCl4, 1 h, 2.) ether, room temperature, 10 h View Scheme

1: 44 percent / Br2 / CHCl3 / -65 °C 2: 2.) DBN / 1.) CCl4, 1 h, 2.) ether, room temperature, 10 h 3: 49 percent / aq. phosphate buffer / CHCl3 / 4 h / pH 6 View Scheme