Patent US4672109A successfully refreshed from Google Patents.
US4672109A
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Method for selective methylation of erythromycin A derivatives
Assignee: Taisho Pharmaceutical Co Ltd
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Filing: 1985-04-05
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Granted: 1987-06-09
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Expires: 2005-04-05
Abstract
Abstract A method for the selective methylation of a hydroxy group at the 6-position of an erythromycin A derivative which comprises converting an erythromycin A derivative into an erythromycin A 9-oxime derivative, and reacting the resulting ethythromycin A 9-oxime derivative with an methylating agent.
Inventors
- 👤 Yoshiaki Watanabe
- 👤 Shigeo Morimoto
- 👤 Masami Goi
- 👤 Morihiro Mitsukuchi
- 👤 Takashi Adachi
- 👤 Jozi Nakagami
- 👤 Toshifumi Asaka
- 👤 Tadashi Eguchi
- 👤 Kaoru Sota
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:11
CPC Classifications
C; C07; C07H; C07H17/00; C07H17/04; C07H17/08; A; A61; A61K; A61K31/00; A61K31/70
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
43 words
A process for the selective methylation of a hydroxy group at the 6-position of an erythromycin A derivative which comprises converting an erythromycin A derivative into an erythromycin A 9-oxime derivative, and reacting the resulting erythromycin A 9-oxime derivative with a methylating agent.
Claim 2
Dependent Claim
43 words
A process for the selective methylation of a hydroxy group at the 6-position of an erythromycin A derivative which comprises converting an erythromycin A derivative into an erythromycin A 9-oxime derivative, and reacting the resulting erythromycin A 9-oxime derivative with a methylating agent.
Claim 3
Dependent Claim
62 words
A process according to claim 1, wherein the erythromycin A derivative is an erythromicin A having no substituent group or having conventional substituent groups in place of (1) a hydrogen atom of the 2'-hydroxy group or (2) a methyl group of the 3'-dimethylamino group or (3) both a hydrogen atom of the 2'-hydroxy group and a methyl group of the 3'-dimethylamino group.
Claim 4
Dependent Claim
21 words
A process according to claim 1, wherein the methylation is carried out in a solvent in the presence of a base.
Claim 5
Dependent Claim
24 words
A process according to claim 1, wherein the methylating agent is methyl iodide, methyl bromide, methyl chloride, dimethyl sulfate, methyl p-toluenesulfonate or methyl methanesulfonate.
Claim 6
Dependent Claim
14 words
A process according to claim 3, wherein the solvent is a polar aprotic solvent.
Claim 7
Dependent Claim
40 words
A process according to claim 5, wherein the polar aprotic solvent is dimethyl sulfoxide, N,N-dimethylformamide, hexamethylphosphoric triamide, a mixture consisting of two or more of these solvents, or a mixture consisting of one of these solvents and tetrahydrofuran or 1,2-dimethoxyethane.
Claim 8
Dependent Claim
38 words
A process according to claim 3, wherein the base is potassium hydroxide, sodium hydroxide, sodium hydride, or potassium hydride and, 1.0 to 1.7 molar equivalents of the base are used per mole of the erythromycin A 9-oxime derivative.
Claim 9
Dependent Claim
88 words
A process according to claim 1, wherein when the erythromycin A derivative having no substituent group in place of a hydrogen atom of the 2'-hydroxy group and a methyl groups of the 3'-dimethylamino group was used as a starting material, (1) a hydrogen atom of the 2'-hydroxy group or (2) of a methyl group of the 3'-dimethylamino group or (3) both a hydrogen atom of the 2'-hydroxy group and a methyl group of the 3'-dimethylamino group should be substituted by a conventional substituent group prior to the methylation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-08 | 1990-12-08 | 1991-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-08 | 1994-12-08 | 1995-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-08 | 1998-12-08 | 1999-06-09 | $7700.00 | Window Closed / Lapsed |