Patent US3553257A successfully refreshed from Google Patents.
US3553257A
Expired / Lapsed
US
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Preparation of d-2-amino-1-butanol salts
Assignee: Wyeth Holdings LLC
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Filing: 1966-09-16
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Granted: 1971-01-05
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Expires: 1986-09-16
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-2AMINO-1-BUTANOL. WATER MAY BE ADDED TO THE RESIDUAL ANHYDROUS SOLUTION TO SEPARATE THE 1-2-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
2026-11-02 21:24
CPC Classifications
C; C07; C07C; C07C215/00; C07C215/02; C07C215/04; C07C215/06; C07C215/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |