Patent US4254273A successfully refreshed from Google Patents.
US4254273A
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Process for preparing esters of α-methyl-3,4-dihydroxyphenylalanine
Assignee: Merck and Co Inc
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Filing: 1979-08-06
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Granted: 1981-03-03
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Expires: 1999-08-06
Abstract
Abstract Improved process for preparing esters of α-methyl-3,4-dihydroxyphenylalanine having pharmaceutical activity via novel N-(tert-butoxycarbonyl) intermediates.
Inventors
- 👤 Burwell F. Powell
- 👤 Ralph F. Hirschmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:01
CPC Classifications
C; C07; C07D; C07D207/00; C07D207/02; C07D207/30; C07D207/34; C07D207/36; C07D207/40; C07D207/404; C07D317/00; C07D317/08; C07D317/44; C07D317/46; C07D317/48; C07D317/50; C07D317/60
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
52 words
A process for preparing the L-isomer of a compound of the formula ##STR6## which consists essentially of treating the L-isomer of the compound having the formula ##STR7## with a compound of the formula ##STR8## in a di-C 1-4 -alkylamide solvent in the presence of triethylamine wherein R 7 is 2,4,5-trichlorophenyl or pentafluorophenyl.
Claim 2
Dependent Claim
52 words
A process for preparing the L-isomer of a compound of the formula ##STR6## which consists essentially of treating the L-isomer of the compound having the formula ##STR7## with a compound of the formula ##STR8## in a di-C 1-4 -alkylamide solvent in the presence of triethylamine wherein R 7 is 2,4,5-trichlorophenyl or pentafluorophenyl.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein said di-C 1-4 -alkylamide is dimethylformamide.
Claim 4
Dependent Claim
10 words
The process of claim 2 wherein R 7 is pentafluorophenyl.
References Cited (Backward Citations)
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US3859331A
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US3839395A
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US3932375A
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US3829456A
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US4007173A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-02 | 1984-09-01 | 1985-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-02 | 1988-09-01 | 1989-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-02 | 1992-09-01 | 1993-03-03 | $7700.00 | Window Closed / Lapsed |