US2731474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydroxytetrahydrocarbazoles
Assignee: Wyeth Holdings LLC
•
Filing: 1954-02-16
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Granted: 1956-01-17
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Expires: 1974-02-16
Abstract
No abstract record available.
Inventors
- 👤 Long Robert Sidney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:26
CPC Classifications
C; C07; C07C; C07C251/00; C07C251/72; C07C243/00; C07D; C07D209/00; C07D209/56; C07D209/80; C07D209/82; C07D209/88
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
130 words
A PROCESS OF PREPARING 2-HYDROXY-5,6,7,8-TETRAHYDROCARBAZOLE-3-CARBOXY-P-CHLORANILIDE FROM 4-AMINOSALICYLIC ACID WHICH COMPRISES (1) CONVERTING THE 4-AMINOSALISALICYLIC ACID INTO 4-HYDRAZINOSALICYLIC ACID BY DIAZOTIZING THE 4-AMINOSALICYLIC ACID AND REACTING THE DIAZO COMPOUND WITH SODIUM HYDROSULFITE IN AN AQUEOUS MEDIUM TO FORM 4-HYDRAZINOSALICYLIC ACID, (2) RECOVERING THE 4-HYDRAZINOSALICYLOC ACID SO OBTAINED, (3) CONCERTING THE 4-HYDRAZINOSALICYLIC ACID INTO THE CYCLOHEXANONE HYDRAZONE THEREOF BY REACTING SAID 4-HYDRAZINO-SALICYLIC ACID WITH CYCLOHEXANONE TO FORM SAID HYDRAZONE COMPOUND, (4) RECOVERING THE CYCLOHEXANONE-4-CARBOXY-3-HYDROXYPHENYLHYDRAZONE SO OBTAINED, (5) CONVERTING THE SAID HYDRAZONE COMPOUND INTO 2-HYDROXY-5,6,6,8-TETRAHYDROCARBAZOLE-3-CARBOXYLIC ACID BY HEATING SAID HYDRAZONE COMPOUND IN ACIDIC MEDIUM TO EFFECT REARRANGEMENT AND CYCLIZATION AND FORM 2-HYDROXY-5,6,7,8-TETRAHYDROCARBAZOLE-3-CARBOXYLIC ACID, (6) RECOVERING THE 2-HYDROXY5,6,7,8-TETRAHYDROCARBOAZOLE-3-CARBOXYLIC ACID SO OBTAINED, (7) CONVERTING THE 2-HYDROXY-5,6,7,8-TETRAHYDROCARBAZOLE-3-CARBOXYLIC ACID INTO THE P-CHLORANILIDE THEREOF BY REACTING SAID CARBOXYLIC ACID WITH P-CHLOR-ANILINE AND (8) RECOVERING THE 2-HYDROXY-5,6,7,8-TETRAHYDROCARBAZOLE-3CARBOXY-P-CHLORANILIDE SO OBTAINED.
Claim 2
Dependent Claim
130 words
A PROCESS OF PREPARING 2-HYDROXY-5,6,7,8-TETRAHYDROCARBAZOLE-3-CARBOXY-P-CHLORANILIDE FROM 4-AMINOSALICYLIC ACID WHICH COMPRISES (1) CONVERTING THE 4-AMINOSALISALICYLIC ACID INTO 4-HYDRAZINOSALICYLIC ACID BY DIAZOTIZING THE 4-AMINOSALICYLIC ACID AND REACTING THE DIAZO COMPOUND WITH SODIUM HYDROSULFITE IN AN AQUEOUS MEDIUM TO FORM 4-HYDRAZINOSALICYLIC ACID, (2) RECOVERING THE 4-HYDRAZINOSALICYLOC ACID SO OBTAINED, (3) CONCERTING THE 4-HYDRAZINOSALICYLIC ACID INTO THE CYCLOHEXANONE HYDRAZONE THEREOF BY REACTING SAID 4-HYDRAZINO-SALICYLIC ACID WITH CYCLOHEXANONE TO FORM SAID HYDRAZONE COMPOUND, (4) RECOVERING THE CYCLOHEXANONE-4-CARBOXY-3-HYDROXYPHENYLHYDRAZONE SO OBTAINED, (5) CONVERTING THE SAID HYDRAZONE COMPOUND INTO 2-HYDROXY-5,6,6,8-TETRAHYDROCARBAZOLE-3-CARBOXYLIC ACID BY HEATING SAID HYDRAZONE COMPOUND IN ACIDIC MEDIUM TO EFFECT REARRANGEMENT AND CYCLIZATION AND FORM 2-HYDROXY-5,6,7,8-TETRAHYDROCARBAZOLE-3-CARBOXYLIC ACID, (6) RECOVERING THE 2-HYDROXY5,6,7,8-TETRAHYDROCARBOAZOLE-3-CARBOXYLIC ACID SO OBTAINED, (7) CONVERTING THE 2-HYDROXY-5,6,7,8-TETRAHYDROCARBAZOLE-3-CARBOXYLIC ACID INTO THE P-CHLORANILIDE THEREOF BY REACTING SAID CARBOXYLIC ACID WITH P-CHLOR-ANILINE AND (8) RECOVERING THE 2-HYDROXY-5,6,7,8-TETRAHYDROCARBAZOLE-3CARBOXY-P-CHLORANILIDE SO OBTAINED.
References Cited (Backward Citations)
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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) | 1959-01-16 | 1959-07-18 | 1960-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-01-16 | 1963-07-18 | 1964-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-01-16 | 1967-07-18 | 1968-01-17 | $7700.00 | Window Closed / Lapsed |