Patent US3567725A successfully refreshed from Google Patents.
US3567725A
Expired / Lapsed
US
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Process for preparation of 1h-imidazo-(4,5-b)pyrazin-2-ones
Assignee: Merck and Co Inc
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Filing: 1968-11-20
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Granted: 1971-03-02
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Expires: 1988-11-20
Abstract
Abstract A PROCESS IS DESCRIBED FOR THE PREPARATION OF 5-AMINO(OR SUBSTITUTED AMINO) - 6 - CHLORO - 1H - IMIDAZO(4,5-B)PYRAZIN-2-ONES WHICH COMPRISES HEATING A 3 - AMINO - 5AMINO (OR SUBSTITUTED AMINO)-6-CHLOROPYRAZINOYLAMINIMIDE EITHER IN A SUITABLE SOLVENT OR AS A SOLID UNTIL REARRANGEMENT AND RING CLOSURE IS COMPLETE. THE PRODUCTS HAVE UTILITY AS ANTIHYPERTENSIVE AGENTS.
Inventors
- 👤 Edward J J Grabowski
- 👤 Edward W Tristram
- 👤 Roger J Tull
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:16
CPC Classifications
C; C07; C07D; C07D487/00; C07D487/02; C07D487/04; C07D241/00; C07D241/02; C07D241/10; C07D241/14; C07D241/24; C07D241/26
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |