Nitrosation process
CA 2131019 C · Owner: Smithkline Beecham P.L.C. · Inventors: Kitteringham, John; Hughes, Mark J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for preparing compounds of formula (I) by nitrosating, compounds (II), compounds of formula (I) having pharmaceutical activity. (see formula I) wherein R1 represents, (see formula III) in which r represents an integer of 2 to 4 s represents 1 or 2 and t, represents 0 or 1; R2 is a group OR4 where R4 is C1-4, alkyl, C2-4 alkenyl or C2-4 alkynyl or a group OCOR5 where R5 is hydrogen or R4; and R3 is CN ;, (see formula II) wherein R1' is R1 or a group convertible thereto and R3', is an electron withdrawing group.
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 February 11, 1993 and granted December 24, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 11, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 11, 2015.
- 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.