Process for the preparation of methylenebisphosphonic acids
CA 2066430 C · Owner: Lampi, Klaus · Inventors: Lampi, Klaus; Nieminen, Kauko; Ruohonen, Jarkko
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The object of the invention is a process for the preparation of optionally mono- or dihalogen substituted methylenebisphosphonic acids, whereby the corresponding lower alkyl tetraester is hydrolyzed in an aqueous solution of the tetraester and hydrochloric acid, which solution contains 1 to 5 % by weight of HCl calculated on the mixture.
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
- Filed August 15, 1990 and granted February 2, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 15, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 15, 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.