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.) with heating and allowed to stand. To the solution was added a solution of diethyl 2-(4-methoxybenzyloxycarbonyloxyimino)malonate (1.0 g.) in tert-butyl alcohol (10 ml.) with stirring at room temperature and water (10 ml.) was added thereto, after which the mixture was 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, after which the mixture was 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, and the solvent was distilled off under reduced pressure to give N-(4-methoxybenzyloxycarbonyl)-L-phenylalanine (410 mg.), oil.

Provenance & Evidence