Process for the production of n,n'-bis-(3-aminophenyl)-ureas
CA 2003107 C · Owner: Kopp, Richard · Inventors: Grogler, Gerhard; Kopp, Richard; Ruckes, Andreas
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention is directed to a process for the preparation of N,N'-bis-(3-aminophenyl)-ureas corresponding to formula (I), (see fig. I), wherein, R represents a linear or branched C1-C6 alkyl group which is in the 2-, 4- and/or 6-position characterized in that the corresponding phenylene diamines are reacted with urea in a molar ratio of greater than 2:1 in chlorobenzene as solvent.
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 November 16, 1989 and granted April 20, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 16, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 16, 2011.
- 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.