Preparation process of quinone derivative and intermediate for the preparation thereof
CA 2116611 A1 · Owner: Eisai Co. Ltd. · Inventors: Hamamura, Kimio; Iwama, Tetsuo; Konishi, Masayuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed herein are a quinone derivative represented by the following formula:, wherein R1 and R2 are identical with or different from each other and mean individually a lower alkyl or lower alkoxy group, or may form an aromatic ring together R3 denotes a, lower alkyl group, n stands for O or an integer of 1-9 and, a linkage --- is a single or double bond such as a vitamin, K derivative or coenzyme Q derivative; and a process for the preparation of the quinone derivative at a high yield without forming any geometric isomers; as well as a 1,4,4a,8a-tetrahydro-4a.alpha.-alkenyl-1.alpha.4.alpha.-methanonaphthalene- 5,8-dione derivative which is useful as an intermediate for the preparation of …
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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 February 28, 1994. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 28, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 28, 2016.
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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.