Processes for preparing thioxanthone and derivatives thereof
CA 2253272 C · Owner: Eubanks, John Robert Ira · Inventors: Farmer, Alan Daniel; Haydel, Diana Boney; Bearson, Amy Lisa
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for preparing thioxanthone and derivatives thereof is disclosed. In the process, an aromatic compound, such as cumene is, reacted with thiosalicylic acid (TSA) or dithiosalicylic acid (DTSA) in the presence of sulfuric acid. The reaction mixture which includes, thioxanthone or a derivative thereof is thereafter distilled under reduced pressure to recover the thioxanthone compound.
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 28, 1997 and granted April 24, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 28, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 28, 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.
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.