Patent US2756229A successfully refreshed from Google Patents.
US2756229A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Xanthine derivatives
Assignee: —
•
Filing: —
•
Granted: 1956-07-24
•
Expires: 1973-07-24
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:32
CPC Classifications
C; C07; C07D; C07D473/00; C07D473/02; C07D473/04; C07D473/06; C07D473/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
7 words
XANTHINE DERIVATIVES CORRESPONDING TO THE GENERAL FORMULA:
Claim 2
Dependent Claim
7 words
XANTHINE DERIVATIVES CORRESPONDING TO THE GENERAL FORMULA:
References Cited (Backward Citations)
US2351843A
Cited
US2517410A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-07-24 | 1960-01-23 | 1960-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-07-24 | 1964-01-23 | 1964-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-07-24 | 1968-01-23 | 1968-07-24 | $7700.00 | Window Closed / Lapsed |