The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 06, 2009
Filed:
Feb. 04, 2003
Koki Yamashita, Osaka, JP;
Toshihiro Takeda, Takasago, JP;
Yasuyoshi Ueda, Himeji, JP;
Kaneka Corporation, Osaka, JP;
Abstract
The invention provides processes for producing efficiently optically active 2-halogenocarboxylic acids useful in the preparation of drugs or the like and salts thereof with amines. Specifically, an optically active 2-halogenocarboxylic acid is produced by halogenating an optically active amino acid in water in the presence of a hydrophobic organic solvent and nitrous acid with the configuration retained and with the racemization inhibited through the removal of 2-hydroxy-bromocarboxylic acid formed as a by-product; the obtained optically active 2-halogenocarboxylic acid is transferred to an aqueous phase by converting it into a salt thereof with a base, followed by the removal of the organic phase; and the optically active 2-halogenocarboxylic acid is transferred again to an organic solvent phase, followed by the removal of the aqueous phase, whereby an optically active 2-halogenocarboxylic acid is obtained through the removal of a halogen component. Further, a high-quality salt of an optically active 2-halogenocarboxylic acid with an amine can be obtained by a crystallization method wherein the amine is added over the period of ½ hour or longer either continuously or in portions and/or wherein the crystallization solvent consists of a hydrophobic organic solvent and a hydrophilic organic solvent.