反应详情

A solution of the product from part (a) (1.02 g., 3.02 mmole) in methanol (6 ml.) is chilled (ice/methanol) and to it, under nitrogen, is added 1N sodium hydroxide (6.35 ml.) over 15 minutes. The mixture is stirred for 3 hours while warming to room temperature (TLC indicates incomplete reaction), and additional 1N sodium hydroxide (3.0 ml.) is added in one portion. After stirring for an additional 3 hours at room temperature, the mixture is concentrated to approximately 1/2 volume in vacuo, and the residue is partitioned between water (50 ml.) and ethyl acetate (30 ml.). The aqueous layer is washed with ethyl acetate (30 ml.), adjusted to a pH of about 2 with concentrated hydrochloric acid, and extracted again with ethyl acetate (3×20 ml.). These organic layers are pooled, washed with water and brine (30 ml. each), dried (Na2SO4), and concentrated in vacuo to yield 0.71 g. of (±)-3-[[2-(mercaptomethyl)-1-oxo- -phenylpropyl]amino]propanoic acid as a white solid; m.p. 76°-82°. TLC (silica gel, toluene/acetic acid; (4:1) Rf =0.37, minor spot at 0.07.

1. additionis added in one portion
2. stirringAfter stirring for an additional 3 hours at room temperature
3. concentrationthe mixture is concentrated to approximately 1/2 volume in vacuo
4. customthe residue is partitioned between water (50 ml.) and ethyl acetate (30 ml.)
5. washThe aqueous layer is washed with ethyl acetate (30 ml.)
6. extractionextracted again with ethyl acetate (3×20 ml.)
7. washwashed with water and brine (30 ml
8. dry with materialeach), dried (Na2SO4)
9. concentrationconcentrated in vacuo
10. customto yield 0.71 g