US3832375A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carbonic acid esters
Assignee: Astellas Pharma Inc
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Filing: 1972-08-09
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Granted: 1974-08-27
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Expires: 1992-08-09
Abstract
Abstract A PROCESS FOR ESTERIFYING ORGANIC CARBOXYLIC ACIDS WHICH COMPRISES REACTING AN ORGANIC CARBOXYLIC ACID WITH A CARBONIC ACID ESTER OF THE FORMULA: R-O-CO-O-N=C(-X)-Y WHEREIN R IS AN ORGANIC GROUP AND X AND Y ARE EACH A NEGATIVE GROUP IN THE PRESENCE OF A BASIC SUBSTANCE TO MAKE ESTERIFIED THE CARBOXYL GROUP IN THE ORGANIC CARBOXYLIC ACID. THE PROCESS IS ADVANTAGEOUS IN AFFORDING THE OBJECTIVE CARBOXYLIC ESTER IN A GOOD YIELD WITHIN A SHORT TIME BY A SIMPLE OPERATION UNDER A MILD REACTION CONDITION.
Inventors
- 👤 M Itoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:23
CPC Classifications
C; C07; C07D; C07D209/00; C07D209/02; C07D209/04; C07D209/10; C07D209/18; C07D209/20; C07C; C07C67/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-26 | 1978-02-25 | 1978-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-26 | 1982-02-25 | 1982-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-26 | 1986-02-25 | 1986-08-27 | $7700.00 | Window Closed / Lapsed |