| US 7,547,792 B2 | ||
| Process for purifying thioctic acid in water | ||
| Annibale Salvi, Milan (Italy); Antonio Nardi, Paderno Dugnano (Italy); and Giacomo Bruno, Caravaggio (Italy) | ||
| Assigned to Laboratorio Chimico Internazionale S.p.A., Milan (Italy) | ||
| Appl. No. 11/909,305 PCT Filed Mar. 21, 2006, PCT No. PCT/EP2006/060893 § 371(c)(1), (2), (4) Date Sep. 21, 2007, PCT Pub. No. WO2006/100229, PCT Pub. Date Sep. 28, 2006. |
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| Claims priority of application No. MI05A0466 (IT), filed on Mar. 22, 2005. | ||
| Prior Publication US 2008/0227990 A1, Sep. 18, 2008 | ||
| Int. Cl. C07D 339/02 (2006.01) | ||
| U.S. Cl. 549—39 | 9 Claims |
| 1. Process for purifying thioctic acid comprising the following steps:
a) dissolving the thioctic acid in an aqueous alkaline solution or alternatively dissolving a salt thereof and suitably adjusting
to an alkaline pH,
b) acidifying the solution derived from step (a) with an acid chosen from the class consisting of sulfuric acid, phosphoric
acid, methanesulfonic acid to a pH between 5.4 and 5.8,
c) isolating the thioctic acid precipitated in step (b) by filtration.
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