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:
Mar. 08, 2005
Filed:
Oct. 08, 2001
Flavio Villani, Parma, IT;
Antonio Nardi, Paderno Dugnano, IT;
Annibale Salvi, Milan, IT;
Giovanna Falabella, Milan, IT;
Flavio Villani, Parma, IT;
Antonio Nardi, Paderno Dugnano, IT;
Annibale Salvi, Milan, IT;
Giovanna Falabella, Milan, IT;
Laboratorio Chimico Internazionale S.p.A., Milan, IT;
Abstract
Process for the synthesis of R(+)α-lipoic acid comprising the following stages: a) Salifying of racemic 6,8-halo-octanoic acid with S(−)α-methylbenzylamine; b) separation by filtration of the crystallized diastereoisomeric salt of R(+)6,8-di-halo-octanoic acid-S(−)α-methylbenzylamine; c) purification by re-crystallization of the diastereoisomeric salt of R(+)6,8-di-halo-octanoic acid-S(−)α-methylbenzylamine; (d) separation of the diastereoisomeric salt to obtain R(+)6,8-di-halo-octanoic acid by reation of said salt with strong mineral acids in an aqueous solution with a dilution between 2 and 10% by weight; e) esterification of R(+)6,8-di-halo-octanoic acid to obtain the corresponding alkyl ester; f) reaction of the alkyl ester of R(+)6,8-di-halo-octanoic acid in an organic solvent with an aqueous solution of alkali disulfide in presence of a compound for phase transfer catalysis; g) hydolysis of the ester of R(+)α-lipoic acid.