Patent US3576854A successfully refreshed from Google Patents.
US3576854A
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US
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Method of optically resolving racemic bases and optically active n-(1-phenylethyl)-carbamyl carboxylic acids for use in said method
Assignee: Bracco SpA
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Filing: 1969-02-25
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Granted: 1971-04-27
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Expires: 1989-02-25
Abstract
Abstract THE OPTICALLY ACTIVE FORMS OF ACIDS OF THE FORMULA PHENYL-CH(-CH3)-NH-CO-A-COOH WHEREIN A IS A SINGLE CARBON-TO-CARBON BOND, A RADICAL OF THE FORMULA -(CH2)N- (N BEING AN INTEGER BETWEEN 1 AND 4), THE RADICAL -CH=CH-, OR PHENYLENE ARE READILY AVAILABLE FROM INEXPENSIVE STARTING MATERIALS AND WELL SUITED FOR FORMING DISASTEREOISOMERS WITH RACEMIC BASES. THE DIASTEREOISOMERS MAY BE FRACTIONATED BY CRYSTALLIZATION IN A CONVENTIONAL MANNER AND DECOMPOSED TO ISOLATE THE OPTICALLY ACTIVE FORMS OF THE BASE. THE ACID IS RECOVERED IN GOOD YIELD.
Inventors
- 👤 Ernst Felder
- 👤 Davide Pitre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 05:38
CPC Classifications
C; C07; C07C; C07C233/00
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) | 1974-04-26 | 1974-10-26 | 1975-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-26 | 1978-10-26 | 1979-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-26 | 1982-10-26 | 1983-04-27 | $7700.00 | Window Closed / Lapsed |