| 摘要 |
PURPOSE:To obtain the titled compound useful as sweetener, etc., in high efficiency, by desalting a solution containing alpha-L-aspartyl-L-phenylalanine methyl ester, its demethylated compound and inorganic salt with a reverse osmosis membrane and precipitating in an aqueous solution. CONSTITUTION:The objective compound can be obtained by (1) desalting and concentrating a mixed solution containing (A) a methyl ester of L-aspartic acid beta-carboxyl residue of alpha-L-aspartyl-L-phenylalanine methyl ester, (B) its demethylated compound (A/B is <=1.0 by weight) and (C) an inorganic salt [C/(A+B) is >=1.0 by weight] with a reverse osmosis membrane having an NaCl rejection of 30-80% until the ratio C/(A+B) reaches 0.3-1.0 by weight, (2) contacting the concentrated solution with an aqueous medium containing methanol and hydrochloric acid, (3) separating precipitated alpha-L-aspartyl-L- phenylalanine methyl ester hydrochloride and, if necessary, (4) neutralizing the product.
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