Process for preparing polyalkyl-2-alkoxy-7-hydroxychroman derivatives
CA 2020232 C · Owner: Fukuoka, Daisuke · Inventors: Ishitoku, Takeshi; Tan, Hiroaki; Tashiro, Takashi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Process for preparing polyalkyl-2-alkoxy-7hydroxychroman derivative of the general formula(V): (V), wherein R1 denotes lower primary alkyl R2 denotes, hydrogen or lower primary alkyl and R3 denotes loweralkyl by reacting resorcin with either an aliphatic ketone of the general formula(I):, (I), wherein R1 and R2 are as defined above and an alcohol of, the formula(II):, R3OH (II) wherein R3 is as defined above, in the presence of an acid catalyst, or an aliphatic ketone acetal of the general formula(III):, (III), wherein R1, R2 and R3 are as defined above in the, presence of an acid catalyst.
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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 June 28, 1990 and granted November 19, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 28, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 28, 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.