Process for preparing naproxen
CA 1238341 A · Owner: Blaschim S.P.A. · Inventors: Valoti, Ermanno; Piccolo, Oreste; Visentin, Giuseppina
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention discloses a novel and efficient process for preparing 6-methoxy- ? -methyl-2naphthaleneacetic acid (hereinafter Naproxen) via a, sequence of sterospectic reactions. The process comprises condensing 1-chloro-2-methoxy-naphthalene with a (s)-2-halopropionyl halide according to the Friedel-Crafts reaction ketalization of the thus produced (s)-2-halo-1-(5'-chloro- 6'-methoxy-2'-naphthyl)- propan-1-one, rearrangement of the ketal to form an ester, hydrolysis of the ester and removal of the the chlorine atom in the 5-position by hydrogenolysis.
Read the whole patent
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
- Granted June 21, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 21, 2005.
- 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.