Process for the preparation of 2,2,6,6-tetraalkylpiperidin-1-oxyl via 1,2,3,6-tetrahydro-2,2,6,6-tetraalkylpyridine
CA 2352507 A1 · Owner: Steiner, Heinz · Inventors: Siebenhaar, Bernd; Steiner, Heinz; Casagrande, Bruno
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to a process for the preparation of a compound of formula (I), wherein R1, R2, R3 and R4 are each independently of one another C1-C4alkyl; R5 is H or CH3; and R6 is H or C1-C18alkyl; from a compound of formula II, which comprises dehydrating the compound of formula (II) either a1) in the form of an aqueous solution or suspension or a2) in the form of an , atomised melt together with water vapour at a temperature of above 150~ C on a metal oxide or semimetal oxide catalyst. This invention also relates to a process, in which the compounds of formula I are hydrated and then oxidised to the corresponding N-oxyls.
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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 31, 2000. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 31, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 31, 2022.
- 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.