Process for the preparation and purification of thiol-containing maytansinoids
CA 2373554 C · Owner: Widdison, Wayne Charles · Inventors: Chari, Ravi Vankeepuram Jagannatha; Widdison, Wayne Charles
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention provides a process for the preparation and purification of thiol-containing maytansinoids comprising the steps of: (1) reductive hydrolysis of a maytansinoid C-3 ester with a reducing agent selected from the group consisting lithium trimethoxyaluminum hydride (LiAl(OMe)3H), lithium triethoxyaluminum hydride (LiAl(OEt)3H) lithium , tripropoxyaluminum hydride (LiAl(OPr)3H) sodium trimethoxyaluminum , hydride (NaAl(OMe)3H) sodium triethoxyaluminum hydride (NaAl(OEt)3H) and sodium tripropoxyaluminum hydride (NaAl(OPr)3H) to yield a maytansinol; (2) purifying the maytansinol to remove side products when present; (3) esterifying the purified maytansinol with a …
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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 April 26, 2001 and granted February 15, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 26, 2021.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 26, 2023.
- 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
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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.