US3639427A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Novel 1 2 3 4-tetrahydro - (and 1 2 3 4 12 13-hexahydro) cyclopenta(c)(1)benzopyrans
Assignee: Arthur D Little Inc
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Filing: 1970-01-08
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Granted: 1972-02-01
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Expires: 1990-01-08
Abstract
Abstract NEW 1,2,3,4 - TETRAHYDROCYCLOPENTA(C)(1)BENZOPYRANS AND 1,2,3,4,12,13 - HEXAHYDROCYCLOPENTA(C)(1)BENZOPYRANS HAVING C.N.S. ACTIVITY.
Inventors
- 👤 Raj K Razdan
- 👤 Felix E Granchelli
- 👤 Harry G Pars
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:33
CPC Classifications
C; C07; C07D; C07D311/00; C07D311/02; C07D311/94
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) | 1975-01-31 | 1975-08-02 | 1976-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-31 | 1979-08-02 | 1980-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-31 | 1983-08-02 | 1984-02-01 | $7700.00 | Window Closed / Lapsed |