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US4243594A
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Process for the 13-deoxygenation of a 3,13-dehydroxy-gibberellin
Assignee: Imperial Chemical Industries Ltd
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Filing: 1978-11-27
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Granted: 1981-01-06
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Expires: 1998-11-27
Abstract
Abstract 13-Hydroxy gibberellins are dehydroxylated by esterifying the 13-hydroxy group with a sulphonic, carboxylic or thiocarboxylic acid or esterifiable derivative thereof and then reducing the 13-ester group with a tri-alkyltin hydride which is a selective reagent so that it is possible to remove a 13-hydroxy group in a gibberellin containing further hydroxy groups and/or lactone bridges. GA3 can be converted to GA7 by this process.
Inventors
- 👤 Michael H. Beale
- 👤 Jake MacMillan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:21
CPC Classifications
C; C07; C07D; C07D307/00; C07D307/77; C07D307/93
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
138 words
A process for the 13-deoxygenation of a 3,13-dihydroxy-gibberellin which comprises esterifying the 13-hydroxy group in a 3,13-dihydroxy gibberellin by reaction with a sulphonic acid or a carboxylic acid or a thiocarboxylic acid or an esterifiable derivative of one of said acids to form a 13-ester and then treating the 13-ester with a trialkyltin hydride in the presence of a free-radical initiator to reduce the 13-ester and form a 13-deoxygenated gibberellin, provided that when the esterifiable derivative is the acid chloride, the 6-carboxy group of the 3,13-dihydroxy gibberellin, which is converted to the corresponding acid chloride, is reinstated by treatment with an alkali, and further provided that the 3-hydroxy group and any further hydroxy group in the gibberellin is protected by a protecting group before esterification of the 13-hydroxy group, and each protecting group is removed after the 13-deoxygenation.
Claim 2
Dependent Claim
138 words
A process for the 13-deoxygenation of a 3,13-dihydroxy-gibberellin which comprises esterifying the 13-hydroxy group in a 3,13-dihydroxy gibberellin by reaction with a sulphonic acid or a carboxylic acid or a thiocarboxylic acid or an esterifiable derivative of one of said acids to form a 13-ester and then treating the 13-ester with a trialkyltin hydride in the presence of a free-radical initiator to reduce the 13-ester and form a 13-deoxygenated gibberellin, provided that when the esterifiable derivative is the acid chloride, the 6-carboxy group of the 3,13-dihydroxy gibberellin, which is converted to the corresponding acid chloride, is reinstated by treatment with an alkali, and further provided that the 3-hydroxy group and any further hydroxy group in the gibberellin is protected by a protecting group before esterification of the 13-hydroxy group, and each protecting group is removed after the 13-deoxygenation.
Claim 3
Dependent Claim
25 words
A process according to claim 1 wherein the 3,13-dihydroxy gibberellin is reacted with an alkylsulphonyl chloride or an aryl sulphonyl chloride or benzoic acid chloride.
Claim 4
Dependent Claim
15 words
A process according to claim 1 or 2 wherein the trialkyltin hydride is tri-n-butyltin hydride.
Claim 5
Dependent Claim
21 words
A process according to claim 3 wherein the 13-ester is refluxed in an inert organic diluent in the presence of α-azo-isobutyronitrile.
Claim 6
Dependent Claim
15 words
A process according to claim 1 wherein the 3-hydroxy group is an allylic hydroxy group.
Claim 7
Dependent Claim
13 words
A process according to claim 1 wherein the 3,13-dihydroxy gibberellin has 4,10-lactone bridge.
Claim 8
Dependent Claim
21 words
A process according to claim 1 wherein the 3,13-dihydroxy gibberellin is GA 3 and the 13-deoxygenated gibberellin is GA 7 .
Claim 9
Dependent Claim
72 words
A process according to claim 9 wherein GA 3 is treated with an acetylating agent to form a 3β-acetoxy-GA 3 , the 3β-acetoxy GA 3 is treated with mesyl chloride to form 3β-acetoxy-13-mesyloxy-GA 3 , the 3β-acetoxy-13-mesyloxy-GA 3 is treated with tri-n-butyltin hydride in the presence of α-azo-isobutyronitrile to form 3β-acetoxy-13-deoxy GA 3 and the 3β-acetoxy-13-deoxy-GA 3 is treated with alkali to deacetylate the 3β-acetoxy-13-deoxy GA 3 to form GA 7 .
References Cited (Backward Citations)
GB892777A
Cited
US4088658A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-06 | 1984-07-07 | 1985-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-06 | 1988-07-07 | 1989-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-06 | 1992-07-07 | 1993-01-06 | $7700.00 | Window Closed / Lapsed |