反应详情

A solution of Boc2O (1.3 g, 6.1 mmol) and ethyl 3-amino-2-(4-chloro-3-fluorobenzyl)propanoate (1.6 g, 6.1 mmol) in DCM (10 mL) was stirred overnight. The mixture was concentrated in vacuo and chromatographed (SiO2) using DCM as eluent to give ethyl 3-(tert-butoxycarbonylamino)-2-(4-chloro-3-fluorobenzyl)propanoate. LiOH—H2O (0.26 g, 6.1 mmol) in H2O (7 mL) was added to a solution of ethyl 3-(tert-butoxycarbonylamino)-2-(4-chloro-3-fluorobenzyl)propanoate (0.55 g, 1.5 mmol) in THF/MeOH (7/7 mL) and stirred overnight. The mixture was concentrated in vacuo, acidifed to a pH of 1 with 1.0N HCl, and extracted with DCM. The DCM extracts were dried (Na2SO4), filtered, and concentrated in vacuo. The crude material was chromatographed (SiO2) using 10% MeOH/DCM as eluent to give 3-(tert-butoxycarbonylamino)-2-(4-chloro-3-fluorobenzyl)propanoic acid (0.5 g). LCMS (APCI+) [M−Boc+H]+ 232.0; Rf: 2.09 min.

1. concentrationThe mixture was concentrated in vacuo
2. extractionextracted with DCM
3. dry with materialThe DCM extracts were dried (Na2SO4)
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customThe crude material was chromatographed (SiO2)