Method for preparing an optically pure benzofuran carboxylic acid and use thereof for preparing efaroxan
US5880296A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 10, 1997 |
| Grant date | Mar 9, 1999 |
| Priority date | — |
| Expiry date | Nov 10, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D307/85
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method for preparing an optically pure 2-ethyl-2,3-dihydrobenzofurancarboxylic acid of formula II wherein R is a hydrogen atom, halogen, lower alkyl, lower alkoxy or hydroxy is described. ##STR1## The method comprises separating the racemic mixture by selective crystallization with the suitable optically pure enantiomer of 2-phenylglycinol, in a suitable solvent, whereafter the optically pure, crystallized acid of formula II is isolated and recovered. The invention also provides the optically pure 2-ethyl-2,3-dihydro-benzofurancarboxylic acid derivative thus obtained and the use thereof for the preparation of an optically pure derivative of efaroxan.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.