Separation of stereoisomeric vinylcyclopropanecarboxylic acids
US4236026A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 15, 1978 |
| Grant date | Nov 25, 1980 |
| Priority date | — |
| Expiry date | Dec 15, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/487
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for the separation of the cis- and trans-stereoisomers of a substituted vinylcyclopropanecarboxylic acid of the formula ##STR1## in which R is alkyl with 1 to 4 carbon atoms, halogen, phenyl or phenyl substituted by at least one of alkyl and halogen, and PA1 R.sup.1 is hydrogen, alkyl with 1 to 4 carbon atoms or halogen, or PA1 R and R.sup.1, together with the adjacent C atom, form a carbocyclic ring, comprising reacting the free vinylcyclopropanecarboxylic acid in a weakly alkaline aqueous solution with an amount of an amine salt corresponding to the proportion of the cis-isomer present thereby to form a salt precipitate enriched in one of the stereoisomers, separating the precipitant from the supernatant, separately reacting the precipitate and supernatant with a strong acid to liberate the isomeric vinylcyclopropanecarboxylic acid, and recrystallizing at least one of the stereoisomers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.