Process for the preparation of substituted pentaalkylchromenes
CA 2082003 A1 · Owner: Sankyo Company, Limited · Inventors: Laffan, David
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A novel process is disclosed for the preparation of pentaalkylchromenes of the general formula: (I), wherein each R denotes a lower alkyl group having from 1 to 4 C atoms and R1 denotes a phenyl group which is unsubstituted or substituted by a lower alkyl group having from 1 to 4 C atoms, by halogen or by a nitro group or an, alkanoyl group having from 1 to 4 C atoms. In the process a trialkylhydroquinone is reacted with a halogenated butenol to give a substituted tetraalkylhydroquinone which, is oxidised and then the halogen atom is substituted with a suitable nucleophile. The resulting compound is finally cyclised to give the final product of formula I. The pentaalkylchromenes I are …
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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 November 3, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 3, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 3, 2014.
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Timeline
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.