Hydrochloric Acid → Ethyl (2R)-2-(2,3,4-trifluoroanilino)propionate
Reaction equation
[F:1][C:2]1[C:13]([F:14])=[C:12]([F:15])[CH:11]=[CH:10][C:3]=1[NH:4][C@H:5]([CH3:9])[C:6]([OH:8])=[O:7].Cl.[CH2:17](O)[CH3:18]>>[F:1][C:2]1[C:13]([F:14])=[C:12]([F:15])[CH:11]=[CH:10][C:3]=1[NH:4][C@H:5]([CH3:9])[C:6]([O:8][CH2:17][CH3:18])=[O:7]Participants
4
Procedure
(2R)-2-(2,3,4-trifluoroanilino)propionic acid (219 mg; 99% ee) was dissolved in ethanol (2 ml) and hydrochloric acid (5 mol/l; 0.2 ml) was added thereto at room temperature. The liquid reaction mixture was heated under reflux for 6 hours and then the solvent was evaporated. To the obtained residue was added chloroform (10 ml). Next, the organic layer was washed with a saturated aqueous solution of sodium chloride and water and dried over anhydrous magnesium sulfate. After evaporating the solvent, the obtained residue was subjected to silica gel column chromatography (ethyl acetate-normal hexane=1:4) to give the title compound (245 mg) as a pale yellow oily substance. The optical purity of the product was 98% ee. The 1H-NMR and IR spectral data of this product was identical with those of the compound obtained in Example 7.