Canadian application, no grantCanada
Naphthopyrans, compositions and articles containing them
CA 2255678 A1 · Owner: Bryson, Nathan · Inventors: Bryson, Nathan; Chan, You-Ping
Overview
Drawings and full text
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to photochromic compounds of general formula (I) in , which: R1-R8 represent various substituents characterized in that at least , two of the groups R3-R6 are C1-C6 alkoxy groups.
Read the whole patent
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 July 16, 1997. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended July 16, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 16, 2019.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJuly 16, 1997
GrantedNo grant recorded
Term endedJuly 16, 2017
Patent numberCA 2255678 A1
Classification (IPC)C07D311/92 +2 more
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.