反应详情

A solution of 3.43 g of sodium hydrogen sulfite in 20 ml of water was added to 2.81 g of N-carbobenzoxy-L-leucinal, and the mixture was stirred for 14 hours under ice-cooling. A solution of 1.41 g of potassium cyanide in 50 ml of water and 200 ml of ethyl acetate were added successively to the reaction mixture. The ethyl acetate layer was washed with a saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate, and evaporated under reduced pressure to obtain 2.54 g of 3-carbobenzoxyamino-2-hydroxy-5-methylhexanenitrile. To 500 mg of the nitrile were added 20 ml of dioxane and 20 ml of concentrated hydrochloric acid, and the mixture was heated under reflux for 12 hours. The reaction mixture was evaporated under reduced pressure, and the residual crystals were purified by cation exchange column chromatography (eluent: a 2N aqueous NH4OH solution) to obtain 254 mg of (2RS, 3S)-3-amino-2-hydroxy-5-methylhexanoic acid as colorless crystals (a mixture ratio of 2R and 2S being about 7:3).

1. temperaturecooling
2. washThe ethyl acetate layer was washed with a saturated sodium chloride aqueous solution
3. dry with materialdried over anhydrous magnesium sulfate
4. customevaporated under reduced pressure