Novel process for the preparation of roflumilast
CA 2503290 C · Owner: Kohl, Bernhard · Inventors: Mueller, Bernd; Palosch, Walter; Kohl, Bernhard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to novel processes for the preparation of high-purity roflumilast. , The process involves reacting the anion of 4-amino-3,5-dichloropyridine (I) with an , activated derivative of 3-cyclopropylmethoxy-4-difluoromethoxybenzoic acid (II), characterized in that the molar ratio of the employed anion of 4-amino-3,5 dichloropyridine to the activated derivative of 3-cyclopropylmethoxy-4 difluoromethoxybenzoic acid is at least 1.5 and at most 3 preferably at least , 1.8 and at , most 2.7 particularly preferably at least 2 and at most 2.5 and very particularly preferably , 2.2.
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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 8, 2004 and granted December 4, 2012. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 8, 2024.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 8, 2026.
- 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.