Triazolinone ring formation in tert-butanol
CA 2131183 C · Owner: Halfon, Marc · Inventors: Halfon, Marc; Sortore, Eric W.; Bailey, Allan R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for the production of aryl triazolinones of formula (II) wherein R is lower alkyl; X is independently halogen lower alkyl, nitro, hydroxy, NHSO2R', -N(SO2R')2 -N(R')SO2R' where R' is lower alkyl, and n is an integer from 0 to 3; which comprises treating, in a tert-butanol medium an aryl hydrazine of formula (a) sequentially with (i) a C1-C3 aldehyde (ii) a cyanate and weak organic acid, and (iii) a hypochlorite a salt thereof, or a halogen.
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 April 29, 1993 and granted April 7, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 29, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 29, 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.