反应详情

A solution of the keto-ester (5) (16.0 mg, 0.046 mmoles) in acetone (0.39 ml) and sodium hydroxide (0.118 M, 0.39 mls) is stirred at room temperature for 2.0 hours. The solution is diluted with water and extracted once with ethyl acetate. The aqueous phase is acidified to pH 3 with citric acid and extracted thrice with ethyl acetate. The ethyl acetate is washed with water and saline and dried over magnesium sulphate. Evaporation of the solvent affords the pure keto-acid (6). (14.7 mg, 100%) as a colourless gum. νmax (CHCl3): 1710, 1490 cm-1. τ(CHCl3): 2.8 (5H, multiplet, C6H5), ca 3.6 broad (D2O-exchangeable, COOH), 4.95 (1H multiplet, D2O-exchangeable, NH), 5.66 (1H, multiplet, CH), 6.86-7.65 (6H, complex, 3×CH2), 8.62 (9H, s, BOC--tBu).

1. extractionextracted once with ethyl acetate
2. extractionextracted thrice with ethyl acetate
3. washThe ethyl acetate is washed with water and saline
4. dry with materialdried over magnesium sulphate
5. customEvaporation of the solvent