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Patent US5202449A successfully refreshed from Google Patents.
US5202449A
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Process for purifying 7-dimethylamino-6-demethyl-6-deoxytetracycline
Assignee: Nippon Kayaku Co Ltd
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Filing: 1991-08-27
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Granted: 1993-04-13
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Expires: 2011-08-27
Abstract
Abstract A process for purifying 7-dimenthylamino-6-demethyl-6-deoxytetracycline represented by the following formula, ##STR1## which comprises dissolving 7-dimethylamino-6-demethyl-6-deoxytetracycline or its hydrochloride having a lower purity in a mixed solvent of an alcohol and water by using hydrochloric acid and then adjusting the pH of the solution to 3.5 to 4.5 to recrystallize the hydrochloride having a higher purity.
Inventors
- 👤 Ryoichi Hasegawa
- 👤 Hiroaki Ohno
- 👤 Kazuaki Sano
- 👤 Yoshinori Saito
- 👤 Hiroaki Nishiyama
- 👤 Shin'ichi Umeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:21
CPC Classifications
C; C07; C07C; C07C231/00; C07C231/22; C07C231/24
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
71 words
A process for purifying 7-dimethylamino-6-demethyl-6-deoxytetracycline represented by the following formula (I) ##STR4## from impurities formed when said 7-dimethylamino-6-demethyl-6-deoxytetracycline is obtained by reductive dimethylation of 7-amino-6-demethyl-6-deoxytetracycline with formaldehyde, comprising dissolving 7-dimethyl-6-demethyl-6-deoxytetracycline or its hydrochloride having a lower purity in a mixed solvent of an alcohol and water by using hydrochloric acid and then adjusting the pH of the solution to 3.5 to 4.5 to recrystallize the hydrochloride salt having a higher purity.
Claim 2
Dependent Claim
71 words
A process for purifying 7-dimethylamino-6-demethyl-6-deoxytetracycline represented by the following formula (I) ##STR4## from impurities formed when said 7-dimethylamino-6-demethyl-6-deoxytetracycline is obtained by reductive dimethylation of 7-amino-6-demethyl-6-deoxytetracycline with formaldehyde, comprising dissolving 7-dimethyl-6-demethyl-6-deoxytetracycline or its hydrochloride having a lower purity in a mixed solvent of an alcohol and water by using hydrochloric acid and then adjusting the pH of the solution to 3.5 to 4.5 to recrystallize the hydrochloride salt having a higher purity.
Claim 3
Dependent Claim
11 words
A process according to claim 1, wherein an alcohol is methanol.
Claim 4
Dependent Claim
42 words
A process according to claim 1, wherein 7-dimethylamino-6-demethyl-6-deoxytetracycline or its hydrochloride salt is dissolved in a mixed solvent of methanol and water at a pH of 0.5 to 2.5 and then the pH of the solution is adjusted to 3.5 to 4.5.
References Cited (Backward Citations)
US4061676A
Cited
US4579686A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-04-12 | 1996-10-12 | 1997-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-12 | 2000-10-12 | 2001-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-12 | 2004-10-12 | 2005-04-13 | $7700.00 | Window Closed / Lapsed |