反应详情

A solution of dehydrated tetra-n-butylammonium fluoride in tetrahydrofuran, which is prepared from tetra-n-butylammonium fluoride trihydrate by drying at 55°-60°/0.1 mm and dissolving in 40 ml of tetrahydrofuran, is added dropwise at 0° to a solution of 1.426 g (3.38 mmol) of N-p-methoxybenzyl-N-tert.-butylsulphonylmethyl-2-(S)-bromo-3-hydroxypropionic acid amide in 6 ml of tetrahydrofuran. Activated molecular sieve (4 Å) is added to the reaction mixture and the whole is stirred for 2 hours at 0°. The molecular sieve is filtered off and washed with methylene chloride; 600 ml of ether and 75 ml of buffer solution having a pH of 8 are added to the combined filtrates. After drying over sodium sulphate and concentration by evaporation in vacuo, the crude product is obtained which is purified by chromatography over 50 g of silica gel using toluene:ethyl acetate (4:1) and (2:1).

1. customby drying at 55°-60°/0.1 mm
2. dissolutiondissolving in 40 ml of tetrahydrofuran
3. additionActivated molecular sieve (4 Å) is added to the reaction mixture
4. filtrationThe molecular sieve is filtered off
5. washwashed with methylene chloride
6. additionare added to the combined filtrates
7. dry with materialAfter drying over sodium sulphate and concentration by evaporation in vacuo