L-Phenylalanine → (2S)-2-[(4-methoxyphenyl)methoxycarbonylamino]-3-phenylpropanoic acid

Participants

Reaction Steps

L-Phenylalanine (330 mg.) and sodium bicarbonate (202 mg.) were dissolved in water (10 ml.) under heating and allowed to stand. A solution of diethyl 2-(4-methoxybenzyloxycarbonyloxyimino)malonate (1.0 g.) in tert-butyl alcohol (10 ml.) was added to the solution with stirring at room temperature and water (10 ml.) was added thereto. The mixture was then stirred for 2 hours at room temperature. The reaction mixture was brought to pH 9 by adding water (20 ml.) and a saturated sodium bicarbonate aqueous solution (10 ml.), and water (10 ml.) was added thereto. The resulting mixture was then washed twice with ethyl acetate (20 ml.). The aqueous layer was adjusted to pH 7 with a 10% citric acid aqueous solution, washed twice with ethyl acetate (30 ml.), adjusted to pH 3.5 with a 10% citric acid aqueous solution and extracted three times with ethyl acetate (30 ml.). The extract was washed with a sodium chloride aqueous solution and dried over magnesium sulfate. The solvent was distilled off under reduced pressure to give N-(4-methoxybenzyloxycarbonyl)-L-phenylalanine (410 mg.), oil.

Provenance & Evidence