Methyl L-phenylalaninate hydrochloride → methyl (2S)-2-amino-3-cyclohexylpropanoate hydrochloride

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Reaction Steps

L-Phenylalanine, methyl ester, hydrochloride, 292 g (1.35 mol) in about 4 L of methanol is exposed to hydrogen gas in the presence of 10% Rhodium on carbon catalyst. After hydrogen uptake is complete, the catalyst is filtered and the filtrate concentrated under reduced pressure to a volume of about 500 ml. Diethyl ether, about 1 liter, is added to the thick slurry of crystals and the mixture filtered and washed with diethyl ether to afford 288.9 g of (S)-α-aminocyclohexanepropanoic acid, methyl ester, hydrochloride; mp 157°-159° C.; [α]D23 =+21.6° (c=1.09% methanol).

Provenance & Evidence