Production of avermectin compounds
CA 2294928 C · Owner: Nagakura, Isao · Inventors: Morita, Hiromasa; Kadoi, Hiroshi; Nagakura, Isao
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention provides a process for preparing a compound of formula (I): wherein R1 is H or a hydroxyimino-protecting group; R2 is H C1-4 alkyl or C1-, 4 alkoxy; R3 is C1-8 alkyl C2-8 alkenyl or C3-8 cycloalkyl; and R4 is H halo, C1-4 alkyl or C1-4 alkoxy, which process comprises the steps of: (a) reacting an avermectin B2 derivative with an oxidizing agent to form a 5-oxo compound; (b) allowing the 5-oxo compound to react with a compound of formula R1-O-NH2 wherein R1 is H or a hydroxyimino-protecting group to form a 5-imino , compound; (c) reacting the 5-imino compound with a thionocarbonizing agent to form a 4'', 23-bisthionocarbonyl ester; (d) reacting the 4'' 23-, …
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 June 25, 1998 and granted January 14, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 25, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 25, 2020.
- 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.