Squarylium dyes
CA 2123991 A1 · Owner: Mcgowan, Donald A. · Inventors: Telfer, Stephen J.; Ramos, Socorro M.; Chu, Peter K.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Squarylium compounds of formula (I) (in which Q1 and Q2 are each a chromophoric group having an aromatic unsaturated system conjugated with the squarylium ring and such that in the compounds of formulae Q1CH2R1 and Q2CH2R2 the methylene hydrogens are active hydrogen; R1 and R2 are each independently a hydrogen atom or an aliphatic or cycloaliphatic group; and .OMEGA. is a group of the formula -NR3R4 or of the formula -CR5R6R7, wherein: R3 and R4 are each independently a hydrogen atom, or an acyl, aliphatic, cycloaliphatic aromatic or heterocyclic, group, subject to the proviso that one of R3 and R4 may be an amino, substituted amino group, or organosulfonyl group or, R3 and R4 together …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed November 20, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 20, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 20, 2014.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.