A process for the preparation of 2,3,5,6-tetrachloropyridine
CA 2126675 A1 · Owner: Cheminova Agro A/S · Inventors: Friis, Niels; Frolich, Per
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
28, A process for the preparation of 2,3,5,6-tetrachloropyridine. A B S T R A C T, An improved process for the preparation of 2,3,5,6-tetrachloropyrldine of the formula, conæists in that 3,3,5-trichloroglutarimide of the formule is reacted either, a. with phosphorus trichloride or phosphorus oxytrichloride or mixtures thereof in the presence from the start of catalytic amounts of hydrogen chloride followed, by a conversion of polyphosphorous compounds formed into phosphorus oxytrichloride by supplying chlorine optionally, only after supplying further phosphorus trichloride or, b. with phosphorus trichloride and chlorine option-, ally in the presence of phosphorus oxytrichloride as a …
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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 December 1, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 1, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 1, 2015.
- 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
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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.