Method for producing diphenyl sulfone compounds
CA 2049045 A1 · Owner: Yoshitomi Pharmaceutical Industries Ltd. · Inventors: Kinishi, Ryoichi; Ozaki, Yoshihiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of producing diphenyl sulfone compounds of the formula (I), (I), wherein R is an alkyl having l to 8 carbon atoms a cycloalkyl, having 3 to 8 carbon atoms an alkenyl having 2 to 8 carbon, atoms or an arylalkyl which may have substituent(s) on the aromatic ring, comprising reacting 4,4'-dihydroxydiphenyl sulfone with a compound of the formula R - X, wherein R is as defined above and X is halogen characterized by, conducting the reaction in 0.3-1.5 weight parts of an aqueous solvent per weight part of 4,4'-dihydroxydiphenyl sulfone in the presence of 1.5-3 moles of an alkali per mole of 4,4'dihydroxydiphenyl sulfone. Since the method of the invention permit production of 4substituted …
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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 28, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 28, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 28, 2013.
- 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.