Direct preparation of pyrrolo¬3,4-c pyrroles
CA 2273392 A1 · Owner: Hendi, Shivakumar Basalingappa · Inventors: Hendi, Shivakumar Basalingappa
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 direct preparation of pigmentary 1,4-diketopyrrolo-(3,4-cpyrroles of the formula (I) (see formula I), wherein each of R1 and R2 independently of the other is an isocyclic or heterocyclic aromatic, radical, which process comprises heating an appropriate molar ratio of a disuccinate with a, nitrite of the formula (II) R1-CN (II), or of the formula (III), R2-CN (III) or with mixtures of said nitrites, in an organic solvent and in the presence of a strong base, and an effective amount of a selected particle growth inhibitor of formula (IV)-(X), and then, obtaining the compound of formula (I) from the reaction product by protolysis. The process, yields …
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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 May 31, 1999. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 31, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 31, 2021.
- 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
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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.