反应详情

To a cooled (0° C.) solution of the compound of example 7 (2.47 g, 12.9 mmoles) in trifluoroacetic acid (53 ml) was added dropwise 2.53 ml of a 35% aqueous H2O2 solution. The reaction mixture was kept at 4° C. for two days in the refrigerator, whereby another 1.25 ml of the same H2O2 solution was added after 1 day. The solution was concentrated in vacuo. The residue was suspended in water and neutralized by the addition of a concentrated ammonia solution. Evaporation of the solvent in vacuo and purification of the residue by flash chromatography (silica, using a CH3OH/CH2Cl2 mixture (6:94) as the eluent) provided the title compound as a yellow powder (861 mg, yield: 32%). Mass spectrum data are as follows: m/z (%): 230 ([M+Na]+, 30), 208 ([M+H]+, 100), 180 [(M+H-ethene)+, 10].

1. concentrationThe solution was concentrated in vacuo
2. additionneutralized by the addition of a concentrated ammonia solution
3. customEvaporation of the solvent
4. customin vacuo and purification of the residue by flash chromatography (silica