Process for the preparation of polycyclic dyes
CA 2058890 A1 · Owner: Hughes, Nigel · Inventors: Patel, Prakash; Hall, Nigel; Hughes, Nigel
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract, Process For the Preparation of Polycyclic Dyes A process for the preparation of a polycyclic dye of the Formula (1):, formula I, by reacting a substituted acetic acid of the Formula (2): Formula 2, with a compound of the Formula (3): Formula 3, Abstract (cont'd) SMC 36118 and oxidation of the intermediate leuco compound to dehydrogenate the peripheral heterocyclic rings wherein, Y is an optionally substituted aromatic or heteroaromatic radical;, Ring A is unsubstituted or is substituted by from one to five groups; Z is -NR1R2;, R1 and R2 are each independently H or are independently selected from optionally substituted alkyl, alkenyl, cycloalkyl aralkyl, aryl and heteroaryl; or, …
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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 January 7, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 7, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 7, 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.