Enantioselective synthesis of 5,6-dihydro-(s)-4-(ethylamino)-(s)-6-methyl-4h-thieno 2,3-b thiopyran-2-sulfonamide 7,7-dioxide and related compounds
CA 2119218 C · Owner: Mathre, David J. · Inventors: Blacklock, Thomas J.; Sohar, Paul; Mathre, David J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A key step in the synthesis of 5,6-dihydro-(S)-4- (ethylamino)-(S)-6-methyl-4H-thieno2,3-bthiopyran-2-sulfonamide 7,7-dioxide (dorzolamide) and related compounds is a Ritter reaction with an unexpected tendency to proceed with retention of chirality.
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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 March 16, 1994 and granted February 15, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 16, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 16, 2016.
- 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.