Process for the preparation of cypermethrine isomers
CA 2020356 C · Owner: Nagy, Lajos · Inventors: Hegedus, Agnes; Szekely, Istvan; Somfai, Eva
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a process for the preparation of such isomer mixtures of cypermethrine of formula (I), wherein carbon atoms indicated by 1,3 and .alpha. stand for a chiral carbon atom and the wavy line indicates cis or trans configuration related to the cyclopropane ring - which contains out of the theoretically possible 8isomers of cypermethrine at least 95 % of 1 RtransS and 1StransR (Ib) isomer pair or only a mixture of 1RcisS and 1ScisR (Ia) and the isomer pair (Ib) of the ratio (Ia):(Ib) = 55:45 - 25:75 by asymmetric transformation of second order performed in the presence of an amine base and solvent from a starting cypermethrine isomer mixture which contains next to the …
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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 17, 1990 and granted September 3, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 17, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 17, 2012.
- 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.