Synthesis of (s)-3-(2-thienylthio) butyric acid and analogs
CA 2218654 C · Owner: Brown, Lynn May · Inventors: Sohar, Paul; Mathre, David J.; Brown, Lynn May
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention is concerned with an improved process for the synthesis of and intermediate en route to 5,6-dihydro-(s)-4-(ethylamino)-(s)-6-methyl-4hthieno2,3-bthiopyran-2-sulfonamide 7,7-dioxide and related compounds. The instant process reduces the reaction time for the synthesis of the key intermediate from 3 to 4 days to from about 2 to about 4 hours while retaining the high enantiomeric purity of the product.
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 April 22, 1996 and granted September 17, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 22, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 22, 2018.
- 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.