GB2039894A - Resolution of DL-cis and DL-trans chrysanthemic acid. - Google Patents
Resolution of DL-cis and DL-trans chrysanthemic acid. Download PDFInfo
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- GB2039894A GB2039894A GB7942284A GB7942284A GB2039894A GB 2039894 A GB2039894 A GB 2039894A GB 7942284 A GB7942284 A GB 7942284A GB 7942284 A GB7942284 A GB 7942284A GB 2039894 A GB2039894 A GB 2039894A
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- Prior art keywords
- acid
- cis
- chrysanthemic acid
- trans
- salt
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- XLOPRKKSAJMMEW-SFYZADRCSA-N (+)-trans-chrysanthemic acid Chemical compound CC(C)=C[C@@H]1[C@@H](C(O)=O)C1(C)C XLOPRKKSAJMMEW-SFYZADRCSA-N 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 claims abstract description 27
- FMCGSUUBYTWNDP-ONGXEEELSA-N (1R,2S)-2-(dimethylamino)-1-phenyl-1-propanol Chemical class CN(C)[C@@H](C)[C@H](O)C1=CC=CC=C1 FMCGSUUBYTWNDP-ONGXEEELSA-N 0.000 claims abstract description 23
- FMCGSUUBYTWNDP-MWLCHTKSSA-N (1s,2r)-2-(dimethylamino)-1-phenylpropan-1-ol Chemical compound CN(C)[C@H](C)[C@@H](O)C1=CC=CC=C1 FMCGSUUBYTWNDP-MWLCHTKSSA-N 0.000 claims abstract description 23
- XLOPRKKSAJMMEW-JGVFFNPUSA-N (-)-trans-chrysanthemic acid Chemical compound CC(C)=C[C@H]1[C@H](C(O)=O)C1(C)C XLOPRKKSAJMMEW-JGVFFNPUSA-N 0.000 claims abstract description 20
- 150000003839 salts Chemical class 0.000 claims abstract description 17
- 238000005903 acid hydrolysis reaction Methods 0.000 claims abstract description 15
- 239000003960 organic solvent Substances 0.000 claims abstract description 13
- 239000002253 acid Substances 0.000 claims abstract description 11
- KWGRBVOPPLSCSI-WPRPVWTQSA-N (-)-ephedrine Chemical compound CN[C@@H](C)[C@H](O)C1=CC=CC=C1 KWGRBVOPPLSCSI-WPRPVWTQSA-N 0.000 claims abstract description 5
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Natural products CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 32
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 20
- ZAFNJMIOTHYJRJ-UHFFFAOYSA-N Diisopropyl ether Chemical group CC(C)OC(C)C ZAFNJMIOTHYJRJ-UHFFFAOYSA-N 0.000 claims description 18
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical group CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 18
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 15
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 10
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 8
- XLOPRKKSAJMMEW-UHFFFAOYSA-N chrysanthemic acid Chemical compound CC(C)=CC1C(C(O)=O)C1(C)C XLOPRKKSAJMMEW-UHFFFAOYSA-N 0.000 claims description 5
- 238000002425 crystallisation Methods 0.000 claims description 2
- 125000003944 tolyl group Chemical group 0.000 claims 1
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 28
- 239000000203 mixture Substances 0.000 description 12
- 238000002360 preparation method Methods 0.000 description 7
- 239000012074 organic phase Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- FMCGSUUBYTWNDP-UHFFFAOYSA-N N-Methylephedrine Natural products CN(C)C(C)C(O)C1=CC=CC=C1 FMCGSUUBYTWNDP-UHFFFAOYSA-N 0.000 description 5
- 239000008346 aqueous phase Substances 0.000 description 5
- 229940073569 n-methylephedrine Drugs 0.000 description 5
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 238000004821 distillation Methods 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 239000011541 reaction mixture Substances 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- LOUPRKONTZGTKE-WZBLMQSHSA-N Quinine Chemical compound C([C@H]([C@H](C1)C=C)C2)C[N@@]1[C@@H]2[C@H](O)C1=CC=NC2=CC=C(OC)C=C21 LOUPRKONTZGTKE-WZBLMQSHSA-N 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 235000001258 Cinchona calisaya Nutrition 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- LOUPRKONTZGTKE-UHFFFAOYSA-N cinchonine Natural products C1C(C(C2)C=C)CCN2C1C(O)C1=CC=NC2=CC=C(OC)C=C21 LOUPRKONTZGTKE-UHFFFAOYSA-N 0.000 description 1
- 230000002301 combined effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229960002179 ephedrine Drugs 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 230000000749 insecticidal effect Effects 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229960000948 quinine Drugs 0.000 description 1
- 239000011369 resultant mixture Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A process for resolving DL-cis or DL-trans chrysanthemic acid which comprises reacting the said acid with L or D N-methyl-ephedrine in an organic solvent, separating the L N-methyl- ephedrine salt of D-cis or D-trans chrysanthemic acid or the D N-methyl- ephedrine salt of L-cis or L-trans chrysanthemic acid thus crystallised and subjecting the said salt to acid hydrolysis whereby the desired D-cis or D-trans chrysanthemic acid or L-cis or L-trans chrysanthemic acid is obtained.
Description
SPECIFICATION
Resolution of DL-cis and DL-trans chrysanthemic acid
This invention relates to a new process for resolving
DL-cis and DL-trans chrysanthemic acid.
Processes for resolving DL-trans chrysa nthem ic acid are already known, for example the process described by Campbell J.Sci.Food.Agr. 2, 421 (1951) as well as the processes described in French Patent
Specification No.1,536,458, French Patent of Addition Specification No. 92,748 and British Patent
Specification No. 1,178,423.
Processes for resolving DL-cis chrysanthemic acid have also been described for example by Campbell, J.Sci.Food.Agr. 421(1951) and by Okada Katsuhidi and Colleagues, Agr. Biol. Chem. 1973,37(10) 2235-40.
In general all these processes use relatively expensive reagents such as, for example, quinine or reagents which are not readily available commercially.
We have now found that the resolution of DL-cis and DL-trans chrysanthemic acids to give the resolved cis and trans chrysanthemic acids, intermediates well known as useful in the synthesis of esters having remarkable insecticidal activity, may be carried out with less expensive commercial reagents and solvents and under easily-industrialisable conditions.
Thus, according to the present invention there is provided a process for resolving DL-cis or DL-trans chrysanthemic acid, which comprises reacting the said acid with L or D N-methyl-ephedrine in an organic solvent, separating the L N-methylephedrine salt of D-cis or D-trans chrysanthemic acid or the D N-methyl-ephedrine salt of L-cis or L-trans chrysanthemic acid thus crystallised and subjecting the said salt to acid hydrolysis whereby the desired
D-cis or D-trans chrysanthemic acid or L-cis or
L-trans chrysanthemic acid is obtained.
According to one embodiment of the invention,
DL-cis chrysanthemic acid may be resolved by reactinq the said acid with L or D N-methylephedrine in an organic solvent and the L N-methylephedrine salt of D-cis chrysanthemic acid or the D
N-methyl ephedrine salt of L-cis chrysanthemic acid which crystallises is separated and subjected to acid hydrolysis to give D-cis chrysanthemic acid or L-cis chrysanthemic acid.
According to a preferred method of carrying out this embodiment of the invention, the organic solvent used in the salification reaction is, for example, toluene, ethyl acetate, acetone, isopropanol or, more preferably diisopropyl ether. the reaction mixture is conveniently heated, if need be to reflux, two obtain complete dissolution of the Nmethyl-ephedrine and then allowed to return slowly to ambient temperature. The mixture may then be cooled, if need be to e,g, -10 C, before separating the salt formed. The acid hydrolysis is conveniently carried out with hydrochloric acid in the presence of methylene chloride or diisopropyl ether.
According to a further embodiment of the invention DL-trans chrysanthemic acid may be resolved by reacting the said acid with L or D N-methylephedrine in an organic solvent and the L N-methylephedrine salt of D-trans chrysanthemic acid or the
D N-methyl-ephedrine salt of L-trans chrysanthemic acid which crystallises is separated and subjected acid hydrolysis to give D-trans chrysanthemic acid or
L-trans chrysanthemic acid.
According to a preferred method of carrying out this embodiment, the organic solvent used in the salification reaction is preferably diisopropyl ether or toluene; however, it is also possible to work in ethyl acetate.
The reaction mixture is conveniently warmed to 40-45"C to facilitate dissolution of the N-methyl ephedrine, then allowed to return slowly to ambient temperature and then cooled to 0 C.
Acid hydrolysis is preferably carried out with hydrochloric acid in the presence of diisopropyl ether or methylene chloride.
It will be appreciated that the N-methyl-ephedrine salt of chrysanthemic acid which does not crystallise may be obtained, if desired, by evaporation of the mother liquors to dryness, which salt may then also be subjected to acid hydrolysis to yield the corresponding D or L isomeric chrysanthemic acid.
The N-methyl-ephedrine used in the process according to the invention can, if desired, be recovered easily after the acid hydrolysis according to process known per se
The following non-limiting examples serve to illustrate the present invention.
EXAMPLE 1:
Preparation of 2,2-dimethyl-3S-(2'-methyl-1 propenyl)-cyclopropane-1 R-carboxylic acid or D-cis chrysanthemic acid, in toluene.
Stage A: L N-methyl-ephedrine salt of D-cis chrysanthemic acid.
Into 75 cm3 oftoluene are introduced 15 g of DL-cis chrysanthemic acid and at200C, 9 of L N-methyl-ephedrine are added thereto. The mixture obtained is taken to a temperature of 60"C, then allowed to cool, and maintained at 20"C for 48 hours.
The precipitate thus formed is isolated by extracting the liquid therefrom and washed with toluene. The L
N-methyl-ephedrine salt of D-cis chrysanthemic acid is obtained and used in the following stage without further purification.
Stage B: Obtaining D-cis chrysanthemic acid.
Into 19.5 cm3 of a 2N aqueous solution of hydrochloric acid are introduced 7.5 cm3 of diisopropyl ether, followed by the L N-methyl-ephedrine salt of D-cis chrysanthemic acid obtained in Stage A. The mixture obtained is agitated for 30 minutes. The organic phase is separated by decanting and the aqueous phase is washed with diisopropyl ether. The combined organic phases are washed with water and concentrated to dryness by distillation under reduced pressure. 4.5 g of D-cis chrysanthemic acid are obtained, [a3D =+65"5 (c = 2% dimethylformamide), containing about 94% of D-cis acid and 6% of
L-cis chrysanthemic acid.
Similarly, by the action of D N-methyl-ephedrine on DL-cis chrysanthemic acid, the D N-methyl ephedrine salt of L-cis chrysanthemic acid may be obtained, then L-cis chrysanthemic acid [a]D = -65's (c = 2%, dimethylformamide).
EXAMPLE 2:
Preparation of D-cis chrysanthemic acid in toluene.
StageA: L N-methyl ephedrine salt ofD-cis chrysanthemic acid.
50 g of DL-cis chrysanthemic acid in 125 cm3 of toluene and 53.3 g of L N-methyl-ephedrine are worked as indicated in Stage A of Example 1. After taking the reaction mixture to reflux it is allowed to cool 7 hours at 200C with slow agitation, then cooled afterwards over 4 hours to OOC. The solid material is separated and washed with toluene at 0 C.
Stage B: Obtaining D-cis chrysanthemic acid.
The salt obtained in Stage A above is dissolved in 100 cm3 of 2N hydrochloric acid and 100 cm3 of methylene chloride. The mixture obtained is agitated for 30 minutes at 200C. The organic phase is separated by decanting and washed with water. The aqueous phases is re-extracted with methylene chloride. The organic phases are combined and concentrated to dryness by distillation under reduced pressure. 20.5 g of D-cis chrysanthemic acid are obtained [a]D =+69 5 (c = 2% dimethylformamide), containing about 96.4% of D-cis acid and 3.6% of L-cis chrysanthemic acid.
EXAMPLE 3:
Preparation of D-cis chrysanthemic acid in ethyl acetate.
Stage A: L N-methyl-ephedrine salt of D-cis chrysanthemic acid.
The desired salt is obtained working as indicated in Stage A of Example 2, in 125 cm3 of ethyl acetate.
Stage B: Obtaining D-cis chrysanthemic acid.
Working as indicated in Stage B of Example 2, 17.6 g of D-cis chrysanthemic acid are obtained [a]D = +67 5 (c = 2% dimethylformamide), containing about 95% of D-cis acid and 5% of L-cis chrysanthemic acid.
EXAMPLE 4:
Preparation of D-cis chrysanthemic acid in acetone.
Stage A: L N-methyl-ephedrine salt of D-cis chrysanthemic acid.
The desired salt is obtained working as indicated in Stage A of Example 2, in 100 cm3 of acetone, with cooling and separation of the salt at 20"C.
Stage B: obtaining D-cis chrysanthemic acid.
Working as indicated in Stage B of Example 2, 14.8 g of D-cis chrysanthemic acid are obtained [aiD = +71 (c = 2% dimethylformamide), containing about 97.3% of D-cis acid and 2.7% of L-cis chrysanthemic acid.
EXAMPLE 5:
Preparation of D-cis chrysanthemic acid in isopropanol.
Stage A: L N-methyl-ephedrine salt of D-cis chrysanthemic acid.
The desired salt is obtained working as indicated in Stage A of Example 2, in 125 cm3 of isopropanol, with cooling and separation of the salt at -100C instead of 0 C Stage B: Obtaining D-cis chrysanthemic acid.
Working as indicated in Stage B of Example 2, 16 g of D-cis chrysanthemic acid are obtained [a]D = +69 (c = 2% dimethylformamide), containing about 96% of D-cis acid and 4% of L-cis chrysanthemic acid.
EXAMPLE 6:
Preparation of D-cis chrysanthemic acid in diisopropyl ether.
Stage A: L N-methyl-ephedrine salt ofD-cischrysanthemic acid.
The desired salt is obtained working as indicated in Stage A of Example 2, in 125 cm3 of diisopropyl ether with cooling and separation of the salt at 200C instead of 0 C.
Stage B: Obtaining D-cis chrysanthemic acid.
Working as indicated in Stage B of Example 2, 20.45 g of D-cis chrysanthemic acid are obtained [a]D = +73 5 (c = 2% dimethylformamide), containing 99% of D-cis chrysanthemic acid and 1% of L-cis chrysanthemic acid.
EXAMPLE 7:
Preparation of 2,2-dimethyl-3S-(2'-methyl-1 propenyl)--cyclopropane-1S-carboxylic acid or Ltrans chrysanthemic acid.
Stage A: D N-methyl-ephedrine salt of L-trans chrysanthemic acid.
Into 80 cm3 of diisopropyl ether are introduced 40 g of DL-trans chrysanthemic acid [[a]D =0 (c = 5% dimethylformide)], followed at 20"C, all at once, by 40.4 g of D N-methyl-ephedrine, [M.Pt. = 87"C, [a]D = +29 5(c = 4%, methanol)]. The resulant mixture is heated until complete dissolution takes place (obtained at about 40-45"C) then cooled steadily over about 3 hours to 20 C, initiating at about 35"C with 0.2 g of D N-methyl-ephedrine salt of L-trans chrysanthemic acid.The mixture is subsequently cooled steadily over 4 hours to 0 C and maintained for 1 hour at this temperature. The precipitate thus formed is separated, washed with diisopropyl ether at 0 C then dried under reduced pressure at 20do.
31.8 g of D N-methyl-ephedrine salt of L-trans chrysanthemic acid are obtained.
Stage B: Obtaining L-trans chrysanthemic acid.
Into a mixture of 41.6 cm3 of water,10.4 of or a 22 B6 aqueous solution of hydrochloric acid and 20 cm3 of diisopropyl ether are introduced, at 20 C, the 31.8 g of the D N-methyl-ephedrine salt of L-trans chrysanthemic acid obtained above. The mixture obtained is agitated for 30 minutes and then the pH is checked to ensure it is 1.5. If the pH is not 1.5 it is readjusted with an aqueous solution of hydrochloric acid. The resultant mixture is left to stand for 15 minutes. The aqueous phase is separated by decanting and extracted with diisopropyl ether. The ethereal phases are combined and washed with a mixture of water and hydrochloric acid, at pH 1.5-2.
The mixture obtained is agitated then the organic phase is separated from the aqueous phase by decanting. The organic phase is washed with water, the two final aqueous phases being extracted with diisopropyl ether. The ethereal phases are all com bined and washed four times with water, each washing being extracted with diisopropyl ether. The ethereal phases are combined and concentrated to dryness by distillation under reduced pressure. 14.4 g of L-trans chrysanthemic acid are obtained [a]D =-35 (c = 5%, dimethylformamide).
Acid index: 334 (theoretical 333).
The compound obtained contains about 96% of
L-trans chrysanthemic acid and 4% of D-trans chrysanthemic acid.
Similarly, by the action of L N-methyl-ephedrine on DL-trans chrysanthemic acid, the L N-methylephedrine salt of D-trans chrysanthemic acid is obtained then D-trans chrysanthemic acid [a]D = +35 (c = 5%, dimethylformamide).
The D N-methyl-ephedrine salt of L-trans chrysanthemic acid used to initiate the crystallisation in
Stage A of Example 7 can be prepared in the following manner:
1.7 g of L-trans chrysanthemic acid, 1.8 g of D
N-methyl-ephedrine and 3.4 cm3 of toluene are admixed. The mixture obtained is warmed to 60"C then allowed to cool to 20"C over 3 hours under agitation. The mixture is then maintened at 20"C for 16 hours. The salt thus formed is separated and washed with toluene then dried. 1.7 g of the desired product are obtained.
Claims (15)
1. A process for resolving DL-cis or DL-trans chrysanthemic acid which comprises reacting the said acid with L or D N-methyl-ephedrine in an organic solvent, separating the L N-methylephedrine salt of D-cis or D-trans chrysanthemic acid or the D N-methyl-ephedrine salt of L-cis or L-trans chrysanthemic acid thus crystallised and subjecting the said salt to acid hydrolysis whereby the desired
D-cis or D-trans chrysanthemic acid or L-cis or
L-trans chrysanthemic acid is obtained.
2. A process as claimed in Claim 1 for resolving
DL-cis chrysanthemic acid which comprises reacting the said acid with L or D N-methyl-ephedrine in an organic solvent, separating the L N-methylephedrine salt of D-cis chrysanthemic acid or the D
N-methyl-ephedrine salt of L-cis chrysanthemic acid thus crystallised and subjecting the said salt to acid hydrolysis whereby the desired D-cis chrysanthemic acid or L-cis chrysanthemic acid is obtained.
3. A process as claimed in Claim 2 wherein the organic solvent is ethyl acetate, acetone or isopropanol.
4. A process as claimed in Claim 2 wherein the organic solvent is diisopropyl ether.
5. A process as claimed in Claim 2 wherein the organic solvent is toluene.
6. A process as claimed in any one of Claims 2 to 5 wherein acid hydrolysis is carried out with hydrochloric acid in the presence of diisopropyl ether.
7. A process as claimed in any one of Claims 2 to 5wherein acid hydrolysis is carried out with hydrochloric acid in the presence of methylene chloride.
8. A process as claimed in Claim 1 for resolving
DL-trans chrysanthemic acid which comprises reacting the said acid with L or D N-methyl-ephedrine in an organic solvent, separating the L N-methyl ephedrine salt of D-trans chrysanthemic acid or the
D N-methyl-ephedrine salt of L-trans chrysanthemic acid thus crystallised and subjecting the said salt to acid hydrolysis whereby the desired D-trans chrysanthemic acid or L-trans chrysanthemic acid is obtained.
9. A process as claimed in Claim 8 wherein the organic solvent is diisopropyl ether, toluene or ethyl acetate.
10. A process as claimed in Claim 8 or Claim 9 wherein acid hydrolysis is carried out with hydrochloric acid in the presence of diisopropyl ether.
11. A process as claimed in any preceding Claim wherein the mother liquors of crystallisation containing the N-methyl ephedrine salt of chrysanthemic acid which has not crystallised are evaporated to dryness and the salt thus obtained is subjected to acid hydrolysis to obtain the corresponding chrysanthemic acid.
12. A process for resolving DL-cis or DL-trans chrysanthemic acid as claimed in Claim 1 substantially as herein described.
13. A process for resolving DL-cis or DL-trans chrysanthemic acid substantially as herein described in any one of Examples 1 to 7.
14. A process for resolving DL-cis or DL-trans chrysanthemic acid substantially as herein described in Example 1 or Example 7.
15. D-cis, D-trans, L-cis or L-trans chrysanthemic acid whenever prepared by a resolution process as claimed in any one of Examples 1 to 14.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7942284A GB2039894B (en) | 1979-12-07 | 1979-12-07 | Resolution of dl-cis and dl-trans chrysanthemic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7942284A GB2039894B (en) | 1979-12-07 | 1979-12-07 | Resolution of dl-cis and dl-trans chrysanthemic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2039894A true GB2039894A (en) | 1980-08-20 |
| GB2039894B GB2039894B (en) | 1982-12-15 |
Family
ID=10509698
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7942284A Expired GB2039894B (en) | 1979-12-07 | 1979-12-07 | Resolution of dl-cis and dl-trans chrysanthemic acid |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2039894B (en) |
-
1979
- 1979-12-07 GB GB7942284A patent/GB2039894B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2039894B (en) | 1982-12-15 |
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| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19961207 |