反应详情

A solution of N-[(phenylmethoxy)carbonyl]-L-homoserine [prepared as described in Example 6(a), 3.0 g., 11.85 mmol.] in dry dimethylformamide (65 ml.) was treated with [(1,1-dimethylethyl)dimethylsilyl chloride (10.72 g., 71.1 mmol.) and imidazole (9.65 g, 0.14 mol.) and stirred at room temperature under argon for 24 hours. The reaction mixture was diluted with methanol (207 ml.), stirred for another 24 hours at room temperature and then concentrated to a syrup. The residual syrup was dissolved in ethyl acetate (200 ml.), washed with 10% citric acid (2×75 ml) and brine, dried (anhydrous sodium sulfate), filtered, evaporated to dryness and dried in vacuo. The crude product mixture was chromatographed on a silica gel column (Merck), eluting the column with ethyl acetate:hexane (1:1) followed by ethyl acetate:acetic acid (99.5:0.5). The desired fractions were combined, concentrated and evaporated several times from toluene to give 3.56 g. of title compound as a waxy solid. TLC (ethyl acetate:acetic acid, 95:5) Rf =0.82.

1. stirringstirred for another 24 hours at room temperature
2. concentrationconcentrated to a syrup
3. dissolutionThe residual syrup was dissolved in ethyl acetate (200 ml.)
4. washwashed with 10% citric acid (2×75 ml) and brine
5. dry with materialdried (anhydrous sodium sulfate)
6. filtrationfiltered
7. customevaporated to dryness
8. customdried in vacuo
9. customThe crude product mixture was chromatographed on a silica gel column (Merck)
10. washeluting the column with ethyl acetate:hexane (1:1)
11. concentrationconcentrated
12. customevaporated several times from toluene
13. customto give 3.56 g