Process for the production of bismaleinimide derivatives
CA 2084027 A1 · Owner: Lonza Ltd. · Inventors: Hardt, Peter; Volker, Theodor
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process is disclosed for the production of bismaleinimide derivatives of the formula: (I), wherein R1 and R2 are alkyl groups and R3 is a halogen or hydrogen atom. In a first step, maleic acid anhydride of the formula:, (II), is converted with a methyl-bis-aniline of the formula: (III), in an unhalogenated aromatic hydrocarbon as solvent into, the corresponding amide acid. In a second step the amide, acid is converted, without isolation in the presence of an, acid catalyst, into the end product of formula I.
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 27, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 27, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 27, 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.