Process for the resolution of enantiomers of benzopyran derivatives
CA 2029107 A1 · Owner: Devant, Ralf · Inventors: Gericke, Rolf; Devant, Ralf
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a process for the resolution of enantiomers of 3,4-epoxy-3,4-dihydro-2,2dimethyl-3-R-2H-1-benzopyran-6-carbonitriles (I) in, which R is H or CH3, characterized in that racemic I is dissolved in an inert solvent or solvent mixture together with a small amount of (-)-I or (+)-I, the solution is seeded with (-)-I or (+)-I, the precipitated (-)-I or (+)-I is isolated, further racemic I is dissolved in the filtrate, seeded with (+)-I or (-)-I, the precipitated (+)-I or (-)-I is isolated and, if desired this, crystallization cycle is repeated one or more times.
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 November 1, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 1, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 1, 2012.
- 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.