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US2646432A
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Method of preparing 2, 6-diketopurines
Assignee: Mallinckrodt Chemical Works
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Filing: 1947-01-13
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Granted: 1953-07-21
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Expires: 1967-01-13
Abstract
No abstract record available.
Inventors
- 👤 August H Homeyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 03:05
CPC Classifications
C; C07; C07D; C07D239/00; C07D239/02; C07D239/24; C07D239/28; C07D239/46; C07D239/52; C07D239/54; C07D239/545; C07D473/00; C07D473/02; C07D473/04; C07D473/06; C07D473/08
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
71 words
THE METHOD WHICH COMPRISES REACTING A 4-AMINO-5-NITROSOURACIL WITH HYDROGEN AT A TEMPERATURE NOT SUBSTANTIALLY IN EXCESS OF 85* C. AND IN THE PRESENCE OF A CATALYST SELECTED FROM THE GROUP CONSISTING OF NICKEL, PALLDIUM AND PLATINUM TO FORM A 4,5-DIAMINOURACIL, FORMYLATING THE PRODUCT BY REACTION WITH FORMIC ACID, AND CYCLIZING THE FORMYLATED COMPOUND WITH AN ALKALI TO FORM A PURINE, SAID FORMYLATION AND CYCLIZING BEING CARRIED OUT WITHOUT ISOLATION OF INTERMEDIATES.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-07-20 | 1957-01-19 | 1957-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-07-20 | 1961-01-19 | 1961-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-07-20 | 1965-01-19 | 1965-07-21 | $7700.00 | Window Closed / Lapsed |