US4423209A
Expired / Lapsed
US
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Processes for the interconversion of avermectin compounds
Assignee: Merck and Co Inc
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Filing: 1982-02-26
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Granted: 1983-12-27
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Expires: 2002-02-26
Abstract
Abstract There is disclosed a process for converting avermectin compounds (formerly identified as C-076 compounds) of the A-type, into avermectin compounds of the B-type. The process is carried out on the naturally occuring avermectin compounds as well as on derivatives thereof. The process involves selectively cleaving the 5-methoxy group, converting it into the hydroxy group, through the intermediate 5-keto group.
Inventors
- 👤 Helmut H. Mrozik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:05
CPC Classifications
C; C07; C07H; C07H19/00; C07H19/01
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
137 words
A process for the preparation of a compound having the formula: ##STR5## wherein the broken line at the 22,23-position indicates a single or a double bond, provided that the double bond is present only when R 2 is iso-propyl or sec-butyl; R 1 is hydrogen or hydroxy, provided R 1 is hydroxy only when the broken line indicates a single bond; R 2 is methyl, ethyl, sec-butyl or isopropyl; and R is hydrogen, hydroxy. ##STR6## which comprises treating a compound having the formula: ##STR7## wherein R, R 1 and R 2 are as previously defined, with mercuric acetate and hydrolyzing the thus produced 3-acetoxy enol ether with a mild acid to produce a 5-keto compound having the formula: ##STR8## which is reduced with sodium borohydride, tri-t-butoxy aluminum hydride or lithium aluminum hydride to produce the desired compound.
Claim 2
Dependent Claim
137 words
A process for the preparation of a compound having the formula: ##STR5## wherein the broken line at the 22,23-position indicates a single or a double bond, provided that the double bond is present only when R 2 is iso-propyl or sec-butyl; R 1 is hydrogen or hydroxy, provided R 1 is hydroxy only when the broken line indicates a single bond; R 2 is methyl, ethyl, sec-butyl or isopropyl; and R is hydrogen, hydroxy. ##STR6## which comprises treating a compound having the formula: ##STR7## wherein R, R 1 and R 2 are as previously defined, with mercuric acetate and hydrolyzing the thus produced 3-acetoxy enol ether with a mild acid to produce a 5-keto compound having the formula: ##STR8## which is reduced with sodium borohydride, tri-t-butoxy aluminum hydride or lithium aluminum hydride to produce the desired compound.
Claim 3
Dependent Claim
29 words
The process of claim 1 wherein the hydrolysis step is carried out using oxalic acid or p-toluene sulfonic acid, and the reduction step is carried out using sodium borohydride.
Claim 4
Dependent Claim
56 words
The process of claim 2 wherein the mercuric acetate step is carried out at from 15° to 150° C. in an inert solvent; the hydrolysis step is carried out at from -10° to 25° C. in an inert solvent; and the reduction step is carried out at from -10° to 25° C. in an inert solvent.
Claim 5
Dependent Claim
56 words
The process of claim 3 wherein the mercuric acetate step is carried out at from 40°-115° C. in toluene, methylene chloride, tetrahydrofuran, or N,N-dimethylformamide; the hydrolysis step is carried out at about 15° C. in a lower alkanol; and the reduction step is carried out at from -15° to 15° C. in methanol, ethanol, or ether.
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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) | 1986-12-26 | 1987-06-27 | 1987-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-26 | 1991-06-27 | 1991-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-26 | 1995-06-27 | 1995-12-27 | $7700.00 | Window Closed / Lapsed |