Antiparasitic agents
CA 2183453 C · Owner: Pfizer Inc. · Inventors: Walshe, Nigel Derek Arthur
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Antiparasitic avermectin and milbemycin derivatives of formula (I) wherein the broken lines represent independently optional bonds R1 and R2 being absent , when the C22-C23 double bond is present R1, R2, R6 are independently H, OH, halo oximino or an organic radical, R4 and R5 organic radicals R3 is H or an , organic radical, and A and B may be a wide variety of substituents are , prepared by reacting a compound of formula (I) in which A is an optionally substituted hydrazone group with an electrophilic species to effect substitution at the 3-position, followed by further synthetic steps if necessary.
Read the whole patent
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 February 1, 1995 and granted December 26, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 1, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 1, 2017.
- 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.