Process for production of 5-amino-3-methylpyrazole
CA 2107944 A1 · Owner: Sekiguchi, Masahito · Inventors: Saito, Kenji; Sekiguchi, Masahito; Minamisaka, Kazuya
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The process for producing 5-amino-3-methylpyrazole includes the steps of reacting 2,3-dichloropropene with a cyanogenating agent in the presence of a cuprous salt and water at a pH of 3-8 to obtain at least one intermediate selected from the group consisting of 3-chloro-3-butenonitrile and 2,3-butadienenitrile; reacting the at least one intermediate with a base in the presence of water at a pH of 12.5 or above to obtain 2-butynenitrile; and reacting the 2-butynenitrile with hydrazine. This process is advantageous in that it enables the production of 5-amino-3-methylpyrazole in high yield without using any reagent which may produce fire. 5-Amino-3-methylpyrazole is a useful intermediate for …
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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 October 7, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 7, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 7, 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.