Process for the preparation of optically and chemically highly pure (R)- or (S)-&agr;-hydroxycarboxylic acids
US6781012B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 2001 |
| Grant date | Aug 24, 2004 |
| Priority date | — |
| Expiry date | Apr 16, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/43
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Process for the preparation of optically highly pure (R)- and (S)-&agr;-hydroxycarboxylic acids, in which either isolated, impure (R)- and (S)-&agr;-hydroxycarboxylic acids prepared by acidic hydrolysis of the (R)- and (S)- cyanohydrins obtained by enzyme-catalyzed addition of a cyanide group donor to the corresponding aldehydes or ketones are recrystallized in an aromatic hydrocarbon, optionally in the presence of a cosolvent, and optically highly pure (R)- and (S)-&agr;-hydroxycarboxylic acids having an optical purity of over 98%ee are obtained or the hydrolysis solution obtained by acidic hydrolysis of the (R)- and (S)-cyanohydrins is treated directly with an aromatic hydrocarbon, optionally in combination with a cosolvent, and is then extracted at hydrolysis temperature, whereupon after cooling of the organic phase the corresponding chemically and optically highly pure (R)- and (S)-&agr;-hydroxycarboxylic acids having an optical purity of over 98%ee crystallize out.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.