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Expired Canadian patentCanada

Method for the preparation of difluoromethoxyaromatic compounds

CA 1203547 A · Owner: American Cyanamid Company · Inventors: Siddens, Jack K.; Raghu, Sivaraman

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A method for the preparation of certain difluoromethoxyaromatic compounds useful as intermediates in the preparation of pyrethroid pesticides. The method comprises alkylating a p-substituted phenol with excess chlorodifluoromethane at atmospheric or superatmospheric pressures in the presence of a base, water, and an inert water miscible organic solvent or solvent mixtures.

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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

  • Granted April 22, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 22, 2003.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 22, 1983
GrantedApril 22, 1986
Term endedApril 22, 2003
Patent numberCA 1203547 A
Classification (IPC)C07C43/22 +2 more

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedAug 22, 1983Patent grantedApril 22, 1986Term endedApril 22, 2003

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.