Preparation of beta-ketoesters useful in preparing quinolone antibiotics
CA 2039306 C · Owner: Pfizer Limited · Inventors: Lehner, Richard S.; Busch, Frank R.; O'Neill, Brian T.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for preparing a compound of the formula (see fig I), wherein Q is C-H or N; R1 is C1-C4 alkyl benzyl or, p-nitrobenzyl and X and Y are independently selected from fluoro and chloro comprising reacting a compound of the formula, (see fig. II), wherein Q is C-H or N; X and Y are independently selected from fluoro and chloro; and Z is fluoro chloro, 1-imidazolyl or substituted 1-imidazolyl wherein the, 1-imidazolyl group is substituted with one or two substituents independently selected from C1 to C4 alkyl with a compound of the formula, (see fig. III) wherein M is an alkaline earth metal, Cu or Mn n is 2, VP-, wherein p is 1 or 2, is an anion of the formula (see fig. IV), or a …
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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 March 25, 1991 and granted January 26, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 25, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 25, 2013.
- 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.