1
Emiko Shinohara, Katsumi Sugiyama, Masanao Ozaki, Keizo Matsuda: Process for producing .alpha.-L-aspartyl-L-phenylalanine methyl ester or its hydrohalide. Ajinomoto Co, Oblon Fisher Spivak McClelland & Maier, January 6, 1987: US04634790 (13 worldwide citation)

A process for producing .alpha.-L-aspartyl-L-phenylalanine methyl ester or its hydrohalide, which comprises subjecting 3-benzyl-6-carboxymethyl-2,5-diketopiperazine to partial hydrolysis with a strong acid in a solvent mixture of methanol and water.


2
Yoichi Ozawa, Shinichi Kishimoto, Emiko Shinohara, Tadashi Takemoto, Chikahiko Eguchi: Method of preparing methyl ester and its hydrochloride. Ajinomoto Co, Oblon Fisher Spivak McClelland & Maier, October 21, 1986: US04618695 (2 worldwide citation)

A method of preparing .alpha.-L-phenylalanine methyl ester and its hydrochloride, which comprises dissolving .alpha.-L-aspartyl-L-phenylalanine .beta.-methyl ester in a methanol/hydrochloric acid mixture solvent which contains, when hydrochloric acid is expressed in terms of concentrated hydrochlori ...


3
Yoichi Ozawa, Shinichi Kishimoto, Emiko Shinohara, Tadashi Takemoto, Chikahiko Eguchi: Method of preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester and its hydrochloride. Ajinomoto Co, Oblon Fisher Spivak McClelland & Maier, August 19, 1986: US04606854 (1 worldwide citation)

A method for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester and its hydrochloride which comprises dissolving .alpha.-L-aspartyl-L-phenylalanine dimethyl ester in a mixture of 0-10% (v/v) methanol, 8-55% (v/v) of concentrated hydrochloric acid, and water (remainder) to a concentration of 0 ...