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US4182906A
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Racemization of optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acids
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1977-05-19
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Granted: 1980-01-08
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Expires: 1997-05-19
Abstract
Abstract A method for racemization of optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acids of the formula: <IMAGE> wherein R1 and R2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms, which comprises the step of contacting the corresponding acid halide with boron halide at a temperature of not more than 20 DEG C.
Inventors
- 👤 Gohu Suzukamo
- 👤 Tsuneyuki Nagase
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:17
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/487
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
100 words
A method for the racemization of an optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acid halide of the formula: ##STR4## wherein R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms and X is a halogen atom, which comprises contacting the acid halide with a boron halide as a catalyst at a temperature of 10° C. or less to permit the racemization to proceed until a trans-rich racemic mixture is obtained.
Claim 2
Independent Claim
100 words
A method for the racemization of an optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acid halide of the formula: ##STR4## wherein R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms and X is a halogen atom, which comprises contacting the acid halide with a boron halide as a catalyst at a temperature of 10° C. or less to permit the racemization to proceed until a trans-rich racemic mixture is obtained.
Claim 3
Dependent Claim
18 words
The method according to claim 1, wherein the boron halide is boron trichloride, boron tribromide or boron trifluoride.
Claim 4
Dependent Claim
13 words
The method according to claim 2, wherein the boron halide is boron trichloride.
Claim 5
Dependent Claim
27 words
The method according to claim 1, wherein the amount of the boron halide is about 1/2000 to 1/2 mole based on 1 mole of the acid halide.
Claim 6
Dependent Claim
15 words
The method according to claim 1, wherein the contact is effected in an inert solvent.
Claim 7
Dependent Claim
25 words
The method according to claim 5, wherein the inert solvent is an aromatic hydrocarbon or derivative thereof, an aliphatic hydrocarbon or a halogen-substituted aliphatic hydrocarbon.
Claim 8
Dependent Claim
21 words
The method according to claim 1, wherein the contact is effected at a temperature of from -70° C. to 10° C.
Claim 9
Dependent Claim
20 words
The method according to claim 1, wherein the contact is effected within a time of 0.1 minute to 3 hours.
Claim 10
Dependent Claim
14 words
The method according to claim 1, wherein the acid halide is an acid chloride.
Claim 11
Independent Claim
107 words
A method for the conversion of the racemic cis isomer or of a mixture of the racemic cis and trans isomers of a 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acid halide of the formula: ##STR5## wherein R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms and X is a halogen atom, into the corresponding racemic trans-rich isomer which comprises contacting the acid halide with a boron halide as a catalyst at a temperature of 10° C. or less.
Claim 12
Independent Claim
107 words
A method for the conversion of the racemic cis isomer or of a mixture of the racemic cis and trans isomers of a 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acid halide of the formula: ##STR5## wherein R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms and X is a halogen atom, into the corresponding racemic trans-rich isomer which comprises contacting the acid halide with a boron halide as a catalyst at a temperature of 10° C. or less.
Claim 13
Dependent Claim
12 words
The method of claim 10, wherein the boron halide is boron trichloride.
Claim 14
Dependent Claim
24 words
The method of claim 10, wherein the acid halide is contacted with said boron halide at a temperature of from -70° to 10° C.
Claim 15
Dependent Claim
122 words
In a method for the racemization of an optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acid of the formula: ##STR6## wherein R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms, wherein said acid is treated with a chlorinating or brominating agent to give the corresponding acid halide, and said acid halide is racemized and hydrolyzed to the corresponding acid, the improvement which comprises contacting said acid halide with a boron halide at a temperature of 10° C. or less to permit the racemization to proceed until a trans-rich racemic mixture is obtained.
Claim 16
Dependent Claim
122 words
In a method for the racemization of an optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acid of the formula: ##STR6## wherein R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms, wherein said acid is treated with a chlorinating or brominating agent to give the corresponding acid halide, and said acid halide is racemized and hydrolyzed to the corresponding acid, the improvement which comprises contacting said acid halide with a boron halide at a temperature of 10° C. or less to permit the racemization to proceed until a trans-rich racemic mixture is obtained.
Claim 17
Dependent Claim
12 words
The method of claim 13, wherein the boron halide is boron trichloride.
Claim 18
Dependent Claim
24 words
The method of claim 13, wherein the acid halide is contacted with said boron halide at a temperature of from -70° to 10° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-01-07 | 1983-07-09 | 1984-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-07 | 1987-07-09 | 1988-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-07 | 1991-07-09 | 1992-01-08 | $7700.00 | Window Closed / Lapsed |