Process for the preparation of substituted isoflavone derivatives
CA 2058619 C · Owner: Imrei, Lajos · Inventors: Somfai, Eva; Montay, Tibor; Kallay, Tamas
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a process for the preparation of pure isoflavone derivatives of general formula (1), wherein R stands for hydrogen or isopropyl, R2 and R3 stand for hydrogen or C1-2 alkoxy by reacting a rezorcinol-derivative of general formula (III) wherein R2 and R3 are as given above with ethyl-orthoformiate of the formula (IV): (C2H5O)3CH in the presence of a bass and optionally by alkylating the product. The process is carried out by subjecting the compounds of general formula (III) and (IV), wherein R2 and R3 are as given above, to ring-closure at 70-100 °C in the presence of an organic solvent, preferably dimethyl-formamide and/or isopropanol in a 0.3-2-fold volume calculated …
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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 April 6, 1990 and granted May 4, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 6, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 6, 2012.
- 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.