Preparation of 3-methylquinoline-8-carboxylic acid
CA 2024865 C · Owner: Arbogast, Karlheinz · Inventors: Arbogast, Karlheinz; Hagen, Helmut; Dupuis, Jacques
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
3-Methylquinoline-8-carboxylic acid I, (see formula I) and derivatives thereof are prepared by reacting o-toluidine II or a derivative thereof (see formula II), with methacrolein III (see formula III) , in 70-90% strength by weight sulfuric acid in the presence of iodine or of an iodine compound, and oxidizing the resulting 3,8-dimethylquinoline IV or a derivative thereof, (see formula IV), with nitric acid in a solution containing sulfuric acid in the presence of vanadium ions, by a process in which in the sulfuric acid-containing reaction solution of the 3,8-dimethylquinoline IV, the byproducts of the reaction are first decomposed by oxidation, the resulting 3,8-dimethylquinoline …
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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 September 7, 1990 and granted May 8, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 7, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 7, 2012.
- 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
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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.