US3557162A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of 17alpha-monoesters of 11beta,17alpha,21-trihydroxysteroids
Assignee: DSM Delft BV
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Filing: 1969-01-23
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Granted: 1971-01-19
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Expires: 1989-01-23
Abstract
Abstract 17A-MONOESTERS OF 11B,17A,21-TRIHYDROXYSTEROIDS ARE PREPARED BY SILYLATING THE 11B-HYDROXYL GROUP OF AN 11B, 17A-DIHYDROXY-21-ACLOXY STEROID TO A SILYLOXY GROUP, ESTERIFYING THE 17A-HYDROXYL GROUP, AND THEN REMOVING THE SILYL GROUP AT THE 11B POSITION AND THE ACYL GROUP AT THE 21 POSITION BY HUDROLYSIS OR ALCOHOLYSIS.
Inventors
- 👤 Jan Lens
- 👤 Arthur F Marx
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:10
CPC Classifications
A; A61; A61K; A61K31/00; A61K31/56; A61K31/57; A61K31/573; A61K31/565; C; C07; C07J; C07J5/00; F; F21; F21V; F21V17/00; F21V17/10; F21V17/20
Claims Analysis
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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) | 1974-01-18 | 1974-07-20 | 1975-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-18 | 1978-07-20 | 1979-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-18 | 1982-07-20 | 1983-01-19 | $7700.00 | Window Closed / Lapsed |