US3853869A
Expired / Lapsed
US
⏱️ 0.0 years remaining
7-(1-ethyl-2-methylindol-3-yl) 7-(substituted)-5,7-dihydrofuro (3,4-b) pyrazin-5-one
Assignee: WTA Inc
•
Filing: 1973-04-19
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Granted: 1974-12-10
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Expires: 1993-04-19
Abstract
Abstract A novel chromogenic compound of normally colorless form is disclosed, having the structural formula: WHEREIN EACH X is WHEREIN EACH R is hydrogen, an alkyl radical having 1 to 4 carbon atoms, an alkoxy radical having 1 to 4 carbon atoms or a phenyl radical. These colorless, but colorable dyes are employed in pressure-sensitive record material and mark-forming manifold systems.
Inventors
- 👤 S Farber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:42
CPC Classifications
C; C07; C07D; C07D491/00; C07D491/02; C07D491/04; B; B41; B41M; B41M5/00; B41M5/124; B41M5/132; B41M5/136; B41M5/145; C09; C09B; C09B11/00; C09B11/04; C09B11/26
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
7 words
A CHROMOGENIC COMPOUND REPRESENTED BY THE FORMULA:
Claim 2
Dependent Claim
7 words
A CHROMOGENIC COMPOUND REPRESENTED BY THE FORMULA:
References Cited (Backward Citations)
US3647792A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |