C. Hongo, R. Yoshioka, Masanori Tohyama
May 1, 1984
Citations
0
Influential Citations
8
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
The chemical synthesis of isoleucine leads to a mixture of DL-isoleucine and DL-alloisoleucine. The preparation of DL-isoleucine from the mixture was studied. When the mixture was reacted with 1,5-naphthalenedisulfonic acid in water, DL-isoleucine formed the less soluble 1,5-naphthalenedisulfonate and could be separated in the form of the salt from the mixture. The soluble DL-alloisoleucine salt was easily epimerized by heating in acetic acid in the presence of salicylaldehyde and free isoleucine mixture. Asymmetric transformation between the two diastereoisomeric racemates was carried out by the simultaneous combination of the fractional crystallization of the less soluble DL-isoleucine salt and the epimerization of the soluble DL-alloisoleucine salt. DL-Isoleucine salt was obtained in a yield of up to 95% from a DL-isoleucine–DL-alloisoleucine mixture or even from DL-alloisoleucine.