Process for the separation of isomeric cyclopropane-carboxylic acids
US4599444A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 17, 1984 |
| Grant date | Jul 8, 1986 |
| Priority date | — |
| Expiry date | Feb 17, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/487
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a new process for separating the four stereoisomers of the cyclopropanecarboxylic acids of the formula ##STR1## wherein R stands for a methyl group or a halogen atom. The process comprises PA0 reacting a salt formed with an alkali hydroxide or an alkali carbonate of dl-cis-trans-2,2-dimethyl-3-(2,2-disubstituted vinyl)-cyclopropanecarboxylic acids containing the isomers in any ratio or the pure dl-cis and dl-trans-2,2-dimethyl-3-(2,2-disubstituted vinyl)-cyclopropanecarboxylic acids prepared therefrom by the means of a selective dissolution with aromatic and aliphatic hydrocarbon solvents (suitably with benzene, extraction petroleum ether, n-hexane) with N-benzyl-2-aminobutanol enantiomers or with the hydrochlorides thereof in an aqueous medium or aqueous acetone medium, obtaining the crystalline diastereomeric salt from the solution by filtration, decomposing said salt by using a mineral acid, then separating the thus obtained optically active cyclopropanecarboxylic acid PA0 and obtaining the other isomer or other mixture of isomers from the filtrate of the said diastereomeric salt similarly after acidifying by a mineral acid, if desired, purifying the sai…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.