Preparation process of n-substituted maleimides
CA 2004654 A1 · Owner: Tsumura, Ryuichiro · Inventors: Fukumura, Kunimitsu; Tsumura, Ryuichiro; Muraishi, Teruo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
of the Invention, A process for the preparation of N-substituted maleimides by conducting heat-dehydration and dehydrating imidization of N-substituted maleamic acids under azeotropic distillation of generated water in a solvent mixture containing a solvent capable of forming water azeotrope and an organic aprotic polar solvent in the, presence as catalyst of a zinc salt of a maleamic acid metallic zinc, or a zinc compound which forms a zinc salt of the N-substituted maleamic acid in the reaction system. - 4 8 -
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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 December 5, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 5, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 5, 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.