Improved 7-chloroquinaldine synthesis
CA 2080406 C · Owner: Song, Zhiguo · Inventors: Hughes, David L.; Song, Zhiguo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An improved process is described which utilizes tetrachloro-1,4(or 1,2)-quinone as an oxidant in the Doebner-Miller synthesis of 7-chloroquinaldine, a starting material in the preparation of leukotriene antagonists. The process improves yield and eliminates the need of forming a ZnC1 2 complex to isolate the end product.
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 October 13, 1992 and granted June 10, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 13, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 13, 2014.
- 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.