Xanthine derivatives
CA 2098846 A1 · Owner: Beecham Group P.L.C. · Inventors: Smith, David G.; Fenwick, Ashley E.; Buckle, Derek R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A compound of formula (I) or if appropriate, a pharmaceutically , acceptable salt thereof wherein R1 and R2 each independently, represent an alkyl group or a moiety of formula (a): -(CH2)m-A, wherein m represents zero or an integer 1 2 or 3 and A, represents a substituted or unsubstituted cyclic hydrocarbon radical; R3 represents hydrogen, NO2 or a halogen atom an alkoxy, group or a group of formula NRsRt wherein Rs and Rt each independently represent hydrogen or alkyl or Rs and Rt together with the nitrogen to which they are attached form a phthalimido group, the phthalimido group being substituted or unsubstituted in the phenylene moiety or R3 represents a moiety of formula (b) wherein …
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 December 19, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 19, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 19, 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
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.