Process for the purification of 7-chloroquinoline-8-carboxylic acids
CA 2068429 C · Owner: Richarz, Winfried · Inventors: Reissenweber, Gernot; Richarz, Winfried; Koob, Knut
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Purification of 7-chloroquinoline-8-carboxylic acids I, (See formula I), (X = H, halogen lower alkyl group), by recrystallization from lower alcohols which are miscible with water, by carrying the recrystallization in the presence of small amounts of a base. The quinolinecarboxylic acids I are valuable crop protection agents.
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 January 25, 1991 and granted April 16, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 25, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 25, 2013.
- 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.