Hydrochloric Acid → (R)-2-(methoxycarbonylamino)-3-phenylpropanoic acid

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Reaction Steps

A mixture of D-phenylalanine (I, 25.00 g, 0.151 mol) and sodium hydroxide (6.05 g, 0.151 mol) in water (170 ml) and tetrahydrofuran (225 ml) is cooled to −15°, and a mixture of methyl chloroformate (18.6 g, 0.197 mol) in tetrahydrofuran (50 ml) is added dropwise. When the one-half of the methyl chloroformate had been added, a mixture of sodium hydroxide (9.10 g, 0.227 mol) in water (20 ml) is added. When the addition is complete, the mixture is stirred at 25° for an additional 2 hours and acidified with hydrochloric acid (10%) to pH 2. The mixture is extracted twice with ether and the extracts are washed with saline and dried over magnesium sulfate. The solvent is removed under reduced pressure to give the title compound, NMR (CDCl3) 3.09, 3.19, 3.65, 4.66, 5.25, 7.15-7.31 and 8.22 δ; IR (thin film) 1726, 1498, 1455, 1448 and 1377 cm−1; MS calculated for C11H13NO4=224.0923, found=224.0921.

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