Cyclopropane derivatives
CA 2062299 C · Owner: Sekiyama, Takaaki · Inventors: Hatsuya, Satoshi; Sekiyama, Takaaki; Okunishi, Masahiko
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A cyclopropane derivative of formula (I) (see fig. I), wherein B1 is a purine or pyrimidine residue R1 and R2, are, independently, hydrogen or a protecting group for hydroxyl and each of k, m and n represents independently, an integer of 1 or 2 is useful for its antiviral effect.
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 March 4, 1992 and granted May 25, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 4, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 4, 2014.
- 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.