Hydrochloric Acid → Methyl (2S)-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.[CH3:17]O>>[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][CH3:17])=[O:7]Participants
4
Procedure
(2S)-2-(2,3,4-trifluoroanilino)propionic acid (1.1 g; 99% ee) was dissolved in methanol (10 ml) and hydrochloric acid (5 mol/l; 1 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 (1.17 g) as an oily substance. The optical purity of the product was 99% ee. The 1H-NMR and IR spectral data of this product was identical with those of the compound obtained in Example 5.