title: New resolution technologies controlled by chiral discrimination mechanisms.
abstract: It is well known that optical resolution via crystallization is still a useful and practicalmethod for obtaining enantiomerically pure compounds for both laboratory experiment and industrial production,although it is a classical technique discovered nearly 160 years ago. In particular, diastereomericsalt formation using a resolving agent (diastereomer method) has been well applied in various fieldssuch as the pharmaceutical, agrochemical, and liquid crystal industries. Despite these affluent reportedand patented examples, unfortunately no concrete theory to determine an optimum resolution condition hasbeen devised, and only empirical procedures seem to provide a unique path in process development. Inthis chapter, three novel approaches for optical resolution via diastereomeric salt formation are presented:(1) chiral purity improvement by crystal habit modification with a tailored chiral additive; (2) a newapproach for finding a suitable resolving agent based on the space filler concept; and (3) chiralitycontrol by dielectrically controlled resolution.
authors.affiliation: R&D Division, Yamakawa Chemical Industry Co., Ltd., Kitaibaraki, 319-1541, Ibaraki, Japan, kenichi_sakai@tfc.toray.co.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sakai
authors.forename: Rumiko
authors.initials: R
authors.lastname: Sakurai
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nohira