反应详情

To a solution of compound 4a (4.77 g, 15.9 mmol) in dry DMF (20 mL) and dry THF (20 mL) was added NBS (3.12 g, 17.5 mmol) in portions at 0° C. The mixture was stirred at rt overnight, diluted with EA, washed with water and brine, dried over Na2SO4, concentrated and purified by CC (PE/EA=1/0 to 15/1) to give compound 4b (4.2 g, 63%).

1. washwashed with water and brine
2. dry with materialdried over Na2SO4
3. concentrationconcentrated
4. custompurified by CC (PE/EA=1/0 to 15/1)