Process for preparing alkanephosphonic anhydrides
CA 2134633 A1 · Owner: Hoechst Aktiengesellschaft · Inventors: Roscher, Gunter
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Process for preparing alkanephosphonic anhydrides Process for preparing phosphonic anhydrides of the formula (I), (I), in which R is (C1-C10)-alkyl which is unsubstituted or substituted by alkyl groups, alkoxy groups fluorine, chlorine or bromine atoms, nitro groups cyano groups, trifluoromethyl groups, phenyl groups it being possible, for the phenyl radical in turn to carry alkyl groups alkoxy groups, fluorine, chlorine, bromine atoms nitro, groups, cyano groups or alkoxycarbonyl groups and n ? 3, by reacting a phosphonic acid of the formula (II) (II), in which R has the meaning given with diketene, if, appropriate at elevated temperature.
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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 28, 1994. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 28, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 28, 2016.
- 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.