Patent Number: 6,310,242

Title: Process for preparing D-alloisoleucine and intermediates for preparation

Abstract: Disclosed are a novel process for preparing D-alloisoleucine and an improved process for epimerizing L-isoleucine to prepare D-alloisoleucine. In the former process, (2S, 3S)-tartaric acid derivative of formula I below; wherein R stands for a hydrogen atom, a C.sub.1 -C.sub.3 lower alkyl group, lower alkoxy group, chlorine atom, bromine atom and nitro group; and "n" is a number of 0, 1 and 2; is combined with an epimer mixture of L-isoleucine and D-alloisoleucine in a reaction medium to form a complex of D-alloisoleucine and the compound of formula I. The precipitated complex is decomposed by putting it in an alcohol to isolate D-alloisoleucine. In the latter process, L-isoleucine is suspended in an inert solvent which does not substantially dissolve amino acids, and epimerized in the presence of C.sub.1 -C.sub.5 saturated lower fatty acid and salicylaldehyde. ##STR1##

Inventors: Noda; Hirofumi (Tokyo, JP), Ohsaka; Koji (Tokyo, JP), Sakai; Kenichi (Tokyo, JP), Murakami; Hisamichi (Tokyo, JP)

Assignee: Yamakawa Chemical Industry Co., Ltd.

International Classification: C07C 229/08 (20060101); C07C 227/00 (20060101); C07C 227/36 (20060101); C07C 229/00 (20060101); C07C 227/34 (20060101); C07C 205/00 (); C07C 207/00 (); C07C 229/00 ()

Expiration Date: 10/30/2018