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US3681400A
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Process for the preparation of salts of an optically active amine and d({31 )-{60 -azidophenylacetic acid
Assignee: Astra Lakemedel AB
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Filing: 1969-09-11
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Granted: 1972-08-01
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Expires: 1989-09-11
Abstract
Abstract A new process for the preparation of the 1-ephedrine salt of D()- Alpha -azidophenylacetic acid is prepared by reacting 1 mole of DL-azidophenylacetic acid with 0.6 mole of 1-ephedrine in a liquid reaction medium in the presence of a substance which increases the solubility of the slats of 1-ephedrine and the two optical isomers of Alpha -azidophenylacetic acid. A product of high optical purity is obtained in a single step.
Inventors
- 👤 Thore Oskar Verner Rydh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:07
CPC Classifications
C; C07; C07C; C07C247/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
152 words
A process for the preparation of the 1-ephedrine salt of D(-)- Alpha -azidophenylacetic acid by reaction between DL-azidophenylacetic acid in the form of the free acid or a salt thereof and 1-ephedrine or a salt thereof in a liquid reaction medium, in which process 1-ephedrine or a salt thereof is added in an amount of at most 0.6 mole/mole of DL- Alpha -azidophenylacetic acid, and to the liquid reaction medium a substance is added in an amount sufficient to increase the solubility of the salts of 1-ephedrine and the two optical isomers of Alpha -azidophenylacetic acid and thereby suppresses the precipitation of the 1-ephedrine salt of L(+)- Alpha -aziodophenylacetic acid and which substance is selected from the group consisting of lower alkanols, ethers, lower esters, polyalcohols, and thereafter the D(-)- Alpha -azidophenylacetic acid 1-ephedrine salt is selectively crystallized by the addition of seed crystals of said D(-)- Alpha -azidophenylacetic acid 1-ephedrine salt.
Claim 2
Dependent Claim
11 words
Process according to claim 2, wherein the reaction medium is water.
Claim 3
Dependent Claim
27 words
A process according to claim 2, wherein the reaction medium is selected from the class consisting of organic solvents which do not have unlimited solubility in water.
Claim 4
Dependent Claim
37 words
A process according to claim 2, wherein the solubilizing agent is added in an amount of at most 33 percent (weight/weight) and not less than 1 percent (weight/weight), calculated on the weight of the liquid reaction medium.
Claim 5
Dependent Claim
21 words
A process according to claim 3, wherein the solubilizing agent is selected from the group consisting of lower alkanols and glycerol.
Claim 6
Dependent Claim
17 words
A process according to claim 4, wherein the solvent is trichloroethylene and the solubilizing agent is isopropanol.
Claim 7
Dependent Claim
17 words
A process according to claim 4, wherein the solvent is benzene and the solubilizing agent is isopropanol.
Claim 8
Dependent Claim
17 words
A process according to claim 4, wherein the solvent is ligroin and the solubilizing agent is n-butanol.
Claim 9
Dependent Claim
15 words
A process according to claim 3, wherein a 1-ephedrine salt is used at the crystallization.
Claim 10
Dependent Claim
36 words
A process according to claim 2, wherein the DL- Alpha -azidophenylacetic acid which is used as starting material for the resolution of the racemate is added to the reaction solution in the form of a salt.
Claim 11
Dependent Claim
23 words
A process according to claim 2, wherein the resolution of the racemate is carried out at a temperature not higher than +60* C.
References Cited (Backward Citations)
US3461164A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |