反应详情

tert-Butyl (2S)-2-(2-methoxy-2-oxoethyl)-1-pyrrolidinecarboxylate (8.35 g, 34.3 mmol) was dissolved in 150 mL MeOH. Aqueous NaOH (50 mL, 1 M) was added and the reaction mixture was allowed to stand overnight. After concentration in vacuo to ca. 100 mL, the solution was added to 300 mL water and extracted with ether (2×). The carboxylate solution was acidified to pH 2 with 12 N HCl and extracted with ether (2×). The aqueous layer was saturated with salt and extracted a third time with ether. The combined organic layers were washed with water, brine and dried over MgSO4. Filtration and concentration provided the title acid as a white solid (7.28 g, 31.7 mmol, 92.6%): 1H NMR (300 MHz, CDCl3, mixture of rotamers) δ 4.16 (bs, 1H), 3.37 (bs, 2H), 3.0–2.8 (bs, 1H), 2.36 (dd, J=9.3, 15.3 Hz, 1H), 2.2–2.0 (m, 1H), 1.9–1.7 (m, 4H), 1.48 (s, 9H) ppm.

1. concentrationAfter concentration in vacuo to ca. 100 mL
2. additionthe solution was added to 300 mL water
3. extractionextracted with ether (2×)
4. extractionextracted with ether (2×)
5. extractionextracted a third time with ether
6. washThe combined organic layers were washed with water, brine
7. dry with materialdried over MgSO4
8. filtrationFiltration and concentration