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US3190896A
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Selective ketalization of polyketo-5alpha-androstanes and 3-dimethyl ketals produced thereby
Assignee: GD Searle LLC
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Filing: 1963-03-01
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Granted: 1965-06-22
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Expires: 1983-03-01
Abstract
No abstract record available.
Inventors
- 👤 Walter R Benn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:17
CPC Classifications
C; C07; C07J; C07J5/00; C07J1/00; C07J75/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
58 words
A PROCESS FOR THE SELECTIVE KETALIZATION OF THE 3-KETO GROUP OF A KA-ANDROSTAN-3-ONE POSSESSIG AN ADDITIONAL KETO FUNCTION IN AT LEAST ONE OF THE 6- AND 17-POSITIONS AND LACKING SUBSTITUTION BY LARGE GROUPS AT THE 2 AND/OR 4 POSITIONS, WHICH COMPRISES CONTACTING THAT 5A-ANDROSTAN3-ONE WITH METHANOL IN THE PRESENCE OF AN ACID CATALYST, THUS AFFORDING THE 3-DIMETHYL KETAL.
Claim 2
Dependent Claim
58 words
A PROCESS FOR THE SELECTIVE KETALIZATION OF THE 3-KETO GROUP OF A KA-ANDROSTAN-3-ONE POSSESSIG AN ADDITIONAL KETO FUNCTION IN AT LEAST ONE OF THE 6- AND 17-POSITIONS AND LACKING SUBSTITUTION BY LARGE GROUPS AT THE 2 AND/OR 4 POSITIONS, WHICH COMPRISES CONTACTING THAT 5A-ANDROSTAN3-ONE WITH METHANOL IN THE PRESENCE OF AN ACID CATALYST, THUS AFFORDING THE 3-DIMETHYL KETAL.
References Cited (Backward Citations)
US2927921A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-06-21 | 1968-12-21 | 1969-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-06-21 | 1972-12-21 | 1973-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-06-21 | 1976-12-21 | 1977-06-22 | $7700.00 | Window Closed / Lapsed |