Improved process for the preparation of substituted hydroxyhydrocinnamate esters by removal of tin catalysts
CA 2260388 A1 · Owner: Ross, John Richard · Inventors: Ross, John Richard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention is directed to an improved process for the preparation of a compound, of formula (I), (see fig. I) wherein R is alkyl, n is 0 to 2, m is 1 to 4 and A is alkyl interrupted or , uninterrupted, alkylene alkanetriyl or pentaerythrityl, by transesterifying the corresponding lower, alkyl with a higher alkanol of the formula A-(OH)m in the presence of a tin catalyst;, wherein the improvement comprises reacting the tin catalyzed transesterification, reaction mass with a carboxylic acid or hydrate thereof neat in the absence , of an, aqueous medium until the tin catalyst forms an insoluble derivative and then, separating the insoluble derivative from the reaction mass by filtration …
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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 January 29, 1999. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 29, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 29, 2021.
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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.