反应详情

Potassium carbonate (33.0 g; 0.19 mol) is added to a solution of the product from Example 4 (32.15 g; 0.18 mol) in dioxane (1.0 l) and water (0.5 l). A solution of benzyl chloroformate (27.3 ml; 0.19 mol) in dioxane (0.2 l) is slowly added dropwise at room temperature. The solution is stirred at room temperature for 3.5 h and subsequently concentrated. The residue is taken up in dichloromethane (3.0 l) and extracted by shaking with water (1.0 l). The aqueous phase is re-extracted five times with dichloromethane. The organic phases are combined, dried (magnesium sulphate) and concentrated. Yield: 24.47 g (43%), pale yellow oil.

1. concentrationsubsequently concentrated
2. extractionextracted
3. stirringby shaking with water (1.0 l)
4. extractionThe aqueous phase is re-extracted five times with dichloromethane
5. dry with materialdried (magnesium sulphate)
6. concentrationconcentrated