Patent US3812157A successfully refreshed from Google Patents.
US3812157A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Benzopyran compounds
Assignee: WTA Inc
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Filing: 1972-03-31
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Granted: 1974-05-21
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Expires: 1992-03-31
Abstract
Abstract COLORLESS, BUT COLORABLE BENZOPYRAN COMPOUNDS ARE DISCLOSED, WHICH ARE REPRESENTED BY THE FORMULA: 2-(((R)2-PHENYL)-NH-),2-((R)2-PHENYL),(R)2-2H-CHROMENE OR 2-(((R)2-PHENYL)-NH-),2-((R)2-NAPHTH-1-YL),(R)2-2H- CHROMENE WHEREIN EACH R IS HYDROGEN, AN ALKYL RADICAL HAVING 1 TO 5 CARBON ATOMS, AN ALKOXY RADICAL HAVING 1 TO 5 CARBON ATOMS, A DIALKYLAMINO RADICAL WHEREIN EACH ALKYL RADICAL HAS 1 TO 5 CARBON ATOMS, AN AMINO RADICAL, A NITRO RADICAL OR A HALOGEN. THESE COMPOUNDS ARE USED IN PRESSURE-SENSITIVE RECORD MATERIAL AND IN MARK-FORMING MANIFOLD SYSTEMS.
Inventors
- 👤 C Lin
- 👤 A Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:36
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/124; B41M5/132; B41M5/136; C; C07; C07D; C07D311/00; C07D311/02; C07D311/04; C07D311/58; C07D311/60
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |