Polyether bis-phosphonic acid compounds
CA 2001340 A1 · Owner: Betzdearborn Inc. · Inventors: Kumar, Ranjit; Carter, Charles G.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Polyether bis-phosphonic acid compounds are disclosed which have the formula (HO)20P-R-(OR')n-OR-PO(OH)2 where R is selected from the group consisting of methylene and ethylene, R' is selected from the group consisting of ethylene and ethylene substituted with one or more methyl groups, and n is an integer from 1 to 4 water soluble, salts thereof, and esters thereof with alkyl groups having from 1 to 6 carbon atoms. Also disclosed is a novel preparation of certain of these compounds by reacting certain hydroxyalkylphosphonic acid dialkyl ester compounds with certain 2-benzyloxyalkyl organic sulfonates; reacting the intermediate formed therefrom with hydrogen or a hydrogen source; reacting …
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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 October 24, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 24, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 24, 2011.
- 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.