Patent US3928328A successfully refreshed from Google Patents.
US3928328A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Schiff base and metal bisazomethine metal chelate
Assignee: EIDP Inc
•
Filing: 1974-12-20
•
Granted: 1975-12-23
•
Expires: 1994-12-20
Abstract
Abstract Novel Schiff bases are prepared by condensation of phenanthrene9,10-diamines with o-hydroxy aldehydes. The bases can be chelated with metals to form compounds useful as yellow pigments.
Inventors
- 👤 Pritam Singh Dhaliwal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:04
CPC Classifications
C; C07; C07F; C07F15/00; C07F15/04; C07F15/045; C07F1/00; C07F1/005; C07C; C07C2603/00; C07C2603/02; C07C2603/04; C07C2603/22; C07C2603/26
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
6 words
A SCHIFF BASE OF STRUCTURAL FORMULA:
Claim 2
Dependent Claim
6 words
A SCHIFF BASE OF STRUCTURAL FORMULA:
Claim 3
Dependent Claim
6 words
A metal chelate of structural formula:
Claim 4
Dependent Claim
6 words
A metal chelate of structural formula:
Claim 5
Dependent Claim
15 words
A metal chelate of claim 2 wherein Me is nickel and each R is hydrogen.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |