反应详情

A solution of ethyl N-Boc-(R)-nipecotate-L-tartrate (24) (10.00 g, 32.5 mol) in 50 mL of dioxane and 50 mL of H2O was cooled in ice-water bath and NEt3 (9 mL) was added with stirring. Stirring and cooling were continued while di-tert-butyl dicarbonate (7.44 g, 1.05 eq.) was introduced. The mixture was warmed to room temperature and stirred for 4 h. 100 mL of Ethyl acetate and 20 mL of H2O were added to mixture. The aqueous layer was extracted with ethyl acetate (2×100 mL). The extracts were combined and washed with aqueous potassium carbonate (sat., 2×50 mL), aqueous HCl (5%, 2×50 mL), brine (50 mL), and dried over anhydrous sodium sulfate, filtered and evaporated to give ethyl N-Boc-(R)-nipecotate as a colorless oil 8.37 g (100%).

1. stirringStirring
2. temperaturecooling
3. additionwas introduced
4. stirringstirred for 4 h
5. extractionThe aqueous layer was extracted with ethyl acetate (2×100 mL)
6. washwashed with aqueous potassium carbonate (sat., 2×50 mL), aqueous HCl (5%, 2×50 mL), brine (50 mL)
7. dry with materialdried over anhydrous sodium sulfate
8. filtrationfiltered
9. customevaporated