反应详情

To a solution of 2(R)-(4-methoxybenzenesulfonylamino)-3-methylbutyric acid (40 g, 139.2 mmol) and cesium carbonate (85.7 g, 444 mmol) in dimethylformamide was added benzyl bromide (16.1 g, 135 mmol). The reaction mixture was stirred overnight. The dimethylformamide was removed on the rotoevaporator and the residue was dissolved in ethyl acetate (200 ml) and partitioned with an equal volume of water. The organic phase was collected and washed with an equal volume of brine. The aqueous phases were back extracted with ethyl acetate (2×150 ml), combined and dried over magnesium sulfate and condensed to provide 2(R)-(4-methoxybenzenesulfonylamino)-3-methylbutyric acid benzyl ester (42.6 g) as a white crystalline solid.

1. customThe dimethylformamide was removed on the rotoevaporator
2. dissolutionthe residue was dissolved in ethyl acetate (200 ml)
3. custompartitioned with an equal volume of water
4. customThe organic phase was collected
5. washwashed with an equal volume of brine
6. extractionThe aqueous phases were back extracted with ethyl acetate (2×150 ml)
7. dry with materialdried over magnesium sulfate and condensed