反应详情

Typically, N-acetyl-D-phenylalanine is allowed to contact DL-phenylalanine methyl ester in a suitable solvent, e.g. methanol or water, to produce a crystalline salt of N-acetyl-D-phenylalanine and L-phenylalanine methyl ester. That salt is separated from the filtrate and decomposed with aqueous hydrochloric acid to afford N-acetyl-D-phenylalanine as a precipitate and L-phenylalanine methyl ester hydrochloride in solution. After filtering, the solvent in the filtrate is removed to afford the hydrochloride salt of L-phenylalanine methyl ester. Alternatively, the salt of N-acetyl-D-phenylalanine and L-phenylalanine methyl ester is dissolved in aqueous potassium carbonate and extracted with ether. The D-amide remains in the aqueous phase and the L-ester remains in the organic phase. After phase separation, the ethereal solution is acidified with hydrochloric acid-isopropanol to precipitate the hydrochloride salt of L-phenylalanine methyl ester.