Synthesis of carboxyalkylthiosuccinic acids
CA 2243667 A1 · Owner: Elf Aquitaine Exploration Production France · Inventors: Labat, Yves; Muller, Jean-Pierre
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
To prepare carboxyalkylthiosuccinic acids of the formula (I): wherein n = 1 to 3 and R = H or CH3, a mercapto-ester of the formula: HS-(CH2)n-COOR' wherein R' is an alkyl radical with C1 to C4 is reacted with maleic acid, citraconic acid or their anhydride in an aqueous medium without a catalyst. This process produces directly and without a catalyst, compounds of the formula (I) and is aimed more specifically at the preparation of carboxyethylthiosuccinic acid (CETSA).
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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 August 18, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended August 18, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 18, 2020.
- 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.