US4236026A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of stereoisomeric vinylcyclopropanecarboxylic acids
Assignee: Bayer AG
•
Filing: 1978-12-15
•
Granted: 1980-11-25
•
Expires: 1998-12-15
Abstract
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 R 1 is hydrogen, alkyl with 1 to 4 carbon atoms or halogen, or R and R 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.
Inventors
- 👤 Klaus Naumann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:24
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/487
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
140 words
A process for the separation of cis- and trans-stereoisomers of a substituted vinylcyclopropanecarboxylic acid of the formula ##STR4## 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 R 1 is hydrogen, alkyl with 1 to 4 carbon atoms or halogen, or R and R 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 cis-isomer present thereby to form a salt precipitate enriched in one of the stereosiomers, separating the precipitate 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.
Claim 2
Dependent Claim
140 words
A process for the separation of cis- and trans-stereoisomers of a substituted vinylcyclopropanecarboxylic acid of the formula ##STR4## 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 R 1 is hydrogen, alkyl with 1 to 4 carbon atoms or halogen, or R and R 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 cis-isomer present thereby to form a salt precipitate enriched in one of the stereosiomers, separating the precipitate 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.
Claim 3
Dependent Claim
17 words
A process according to claim 1, wherein R and R 1 each is cholorine, bromine or methyl.
Claim 4
Dependent Claim
16 words
A process according to claim 1, wherein the amine salt is a salt of an arylalkylamine.
Claim 5
Dependent Claim
22 words
A process according to claim 3, wherein the amine salt is the hydrochloride of benzylamine, α-methylbenzylamine, phentylamine or amino-phenylacetic acid ethyl ester.
Claim 6
Dependent Claim
25 words
A process according to claim 1, wherein the weakly alkaline medium is maintained by an inorganic salt of a polybasic acid as a buffering agent.
Claim 7
Dependent Claim
20 words
A process according to claim 5, wherein the buffering agent is a salt of phosphoric acid or of carbonic acid.
Claim 8
Dependent Claim
21 words
A process according to claim 6, wherein the buffering agent is sodium carbonate, potassium carbonate, sodium bicarbonate or sodium hydrogen phosphate.
Claim 9
Dependent Claim
22 words
A process according to claim 1, wherein the strong acid is hydrochloric acid, sulphuric acid, formic acid, trichloracetic acid or trifluoracetic acid.
Claim 10
Dependent Claim
32 words
A process according to claim 1, wherein recrystallization is effected from an alkane with up to 8 carbon atoms, petroleum ether, cyclohexane, carbon tetrachloride, chlorofluoromethane, aqueous alcohol, a ketone or an ether.
Claim 11
Dependent Claim
75 words
A process according to claim 9, wherein R and R 1 each is chlorine or bromine, the amine salt is the hydrochloride of benzylamine, α-methylbenzylamine, phenethylamine or amino-phenylacetic acid ethyl ester, the weakly alkaline medium is maintained by sodium carbonate, potassium carbonate, sodium bicarbonate or sodium hydrogen phosphate as a buffering agent, and the strong acid is hydrochloric acid, sulphuric acid, formic acid, trichloracetic acid or trifluoracetic acid, the precipitate being enriched in the cis-stereoisomer.
References Cited (Backward Citations)
US3646118A
Cited
US3636093A
Cited
US3739019A
Cited
US3842125A
Cited
GB1446304A
Cited
DE2432951A1
Cited
DE2439177A1
Cited
US4002666A
Cited
DE2615159A1
Cited
US4118417A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-25 | 1984-05-26 | 1984-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-25 | 1988-05-26 | 1988-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-25 | 1992-05-26 | 1992-11-25 | $7700.00 | Window Closed / Lapsed |