Patent US2581889A successfully refreshed from Google Patents.
US2581889A
Expired / Lapsed
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Method of preparing pyrimidopyrazines
Assignee: SmithKline Beecham Corp
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Filing: 1949-07-06
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Granted: 1952-01-08
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Expires: 1969-07-06
Abstract
No abstract record available.
Inventors
- 👤 Timmis Geoffrey Millward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:04
CPC Classifications
C; C07; C07D; C07D475/00; C07D475/02; C07D475/06; C07D475/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
13 words
THE PROCESS OF PREPARING PYRIMIDOPYRAZINE DERIVATIVES OF THE TYPE REPRESENTED BY THE FORMULA
Claim 2
Dependent Claim
13 words
THE PROCESS OF PREPARING PYRIMIDOPYRAZINE DERIVATIVES OF THE TYPE REPRESENTED BY THE FORMULA
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) | 1955-01-07 | 1955-07-09 | 1956-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-01-07 | 1959-07-09 | 1960-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-01-07 | 1963-07-09 | 1964-01-08 | $7700.00 | Window Closed / Lapsed |