US3557218A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polysubstituted dihydropyrenes
Assignee: Novartis Corp
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Filing: 1967-04-07
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Granted: 1971-01-19
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Expires: 1987-04-07
Abstract
Abstract PHOTOCHROMIC 1,3,6,8-TETRA(LOWER)ALKYL-15,16-DIMETHYL15,16 - DIHYDROPYRENES, 15,16-METHYLENE-15,16-DIHYDROPYRENES, 15,16-METHYLENE-15,16-DIHYDROPYRENES AND 1,3,6,8TETRA(LOWER)ALKYL-15,16-METHYLENE-15,16 - DIHYDROPYRENES SUBSTITUTED IN ONE OR BOTH OF THE 2-AND 7-POSITIONS BENZOYL, ALKANOYL, ALKANOYLOXY, CYANO, NITRO, ALKYL, A-HYDROXYALKYL, A-ACYLOXYALKYL, A-ISONITROSOALKYL, OR ACYLAMIDO GROUPS ARE PREPARED VIA SUBSTITUTION OF THE PARENT HYDROCARBON. A TYPICAL EMBODIMENT IS 2-ACETAMIDO-7-NITRO-1,3, 6,8,15,16-HEXAMETHYL-15,16-DIHYDROPYRENE.
Inventors
- 👤 Luther A R Hall
- 👤 John A Gurney
- 👤 Harris R Renfroe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:21
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/72; G03C1/73; C; C07; C07C; C07C13/00; C07C13/28; C07C13/32; C07C13/62; C07C13/66; C07C29/00; C07C29/132; C07C29/136; C07C29/14; C07C33/00; C07C33/05; C07C33/14; C07C37/00; C07C37/11; C07C37/115; C07C41/00; C07C41/01; C07C41/16; C07C41/18; C07C41/22; C07C41/30; C07C45/00; C07C45/27; C07C45/45; C07C45/46; C07C47/00; C07C47/38; C07C47/44; C07C47/445; C07C49/00; C07C49/527; C07C49/553; C12; C12C; C12C11/00; C12C11/02; C07C2603/00; C07C2603/02; C07C2603/04; C07C2603/30; C07C2603/34; C07C2603/38; C07C2603/40; C07C2603/42; C07C2603/50
Claims Analysis
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-18 | 1974-07-20 | 1975-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-18 | 1978-07-20 | 1979-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-18 | 1982-07-20 | 1983-01-19 | $7700.00 | Window Closed / Lapsed |