USRE29588E
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of d-2-amino-1-butanol salts
Assignee: Wyeth Holdings LLC
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Filing: 1971-12-02
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Granted: 1978-03-21
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Expires: 1991-12-02
Abstract
Abstract A racemic mixture of dl-2-amino-1-butanol is resolved with separation of the d-2-amino-1-butanol by crystallizing as a salt with L(+)-tartaric acid from an essentially anhydrous solution in ethanol or methanol. The salt is decomposed with calcium hydroxide to yield the d-2-amino-1-butanol. Water may be added to the residual anhydrous solution to separate the l-2-amino-1-butanol. Other listed volatile solvents may be present in the anhydrous ethanol or methanol without inhibiting the sharp separation.
Inventors
- 👤 Imre Aurel Halmos
- 👤 Thomas Emory Ricketts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:34
CPC Classifications
C; C07; C07C; C07C215/00; C07C215/02; C07C215/04; C07C215/06; C07C215/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
60 words
The process of preparing the acid L-tartrate of d-2-amino-1-butanol comprising forming a solution of dl-2-amino-1-butanol in a solvent consisting essentially of an anhydrous lower alkanol selected from the group consisting of methanol and ethanol and not more than 1.0% water, adding thereto L-tartaric acid in at least about a one-half molar quantity, and separating the crystalline acid L-tartrate of d-2-amino-1-butanol.
Claim 2
Dependent Claim
60 words
The process of preparing the acid L-tartrate of d-2-amino-1-butanol comprising forming a solution of dl-2-amino-1-butanol in a solvent consisting essentially of an anhydrous lower alkanol selected from the group consisting of methanol and ethanol and not more than 1.0% water, adding thereto L-tartaric acid in at least about a one-half molar quantity, and separating the crystalline acid L-tartrate of d-2-amino-1-butanol.
Claim 3
Dependent Claim
13 words
The process of claim 1 in which the solvent is essentially anhydrous methanol.
Claim 4
Dependent Claim
13 words
The process of claim 1 in which the solvent is essentially anhydrous ethanol.
Claim 5
Dependent Claim
18 words
The process of claim 1 in which the solvent is essentially an anhydrous mixture of ethanol and methanol.
Claim 6
Dependent Claim
47 words
A process for separating d-2-amino-1-butanol from dl-2-amino-1-butanol comprising following the process of claim 1, then suspending the acid L-tartrate salt of d-2-amino-1-butanol in a water-containing solvent, adding an alkaline earth oxide or hydroxide, separating the alkaline earth L-tartrate and fractionally distilling the remaining layer to obtain d-2-amino-1-butanol.
Claim 7
Dependent Claim
17 words
The process of claim 5 in which the separation of the tartrate salt is conducted in water.
Claim 8
Dependent Claim
173 words
The process of claim 6 in which about a stoichiometric quantity of sulfuric acid and sufficient water to dissolve the L-tartaric acid is added to the alkaline earth L-tartrate, the calcium sulfate formed is separated out and free L-tartaric acid is recovered by evaporating off the water. .Iadd. 8. In the preparation of the (+)2,2'-(ethylenediimino) di-1-butanol dihydrochloride, the improvement comprising the process of preparing the acid L-tartrate of d-2-amino-1-butanol comprising forming a solution of dl-2-amino-1-butanol in a solvent consisting essentially of an anhydrous lower alkanol selected from the group consisting of methanol and ethanol and not more than 1.0% water, adding thereto L-tartaric acid in at least about a one-half molar quantity, and separating the crystalline acid L-tartrate of d-2-amino-1-butanol. .Iaddend. .Iadd. 9. In the process of preparing d-2-amino-1-butanol from dl-2-amino-1-butanol, the step which comprises separating d-2-amino-1-butanol (+) hydrogen tartrate from l-2-amino-1-butanol (+) hydrogen tartrate by fractional crystallization in anhydrous methyl alcohol in which the d-2-amino-1-butanol (+) hydrogen tartrate is comparatively insoluble and the anhydrous l-2-amino-1-butanol (+) hydrogen tartrate is very soluble. .Iaddend.
References Cited (Backward Citations)
US3116332A
Cited
US3401194A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-20 | 1981-09-19 | 1982-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-20 | 1985-09-19 | 1986-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-20 | 1989-09-19 | 1990-03-21 | $7700.00 | Window Closed / Lapsed |