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Canadian application, no grantCanada

Preparation of flotation of optically active aliphatic carboxylic acids

CA 2128518 A1 · Owner: Choudhury, Azfar A. · Inventors: Kadkhodayan, Abbas; Choudhury, Azfar A.; Patil, Deepak R.

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Abstract From the Canadian patent

An improved process for the separation of enantiomers of a mixture of certain aliphatic carboxylic acids or esters thereof is disclosed. The process involves adding in inert liquid to the reaction solution formed by: (i) forming a salt solution comprising said racemic mixture of a C1 to C6 linear or branched aliphatic carboxylic acid and an organic or inorganic base; (ii) treating said salt solution with less than equimolar equivalents of a chiral organic nitrogenous base; (iii) precipitating from the reaction solution formed in step (ii) the less soluble diastereomeric salt; (iv) addition of a countersolvent to the slurry formed in step (iii); (v) extracting the more soluble …

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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 December 15, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 15, 2012.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 15, 2014.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 15, 1992
GrantedNo grant recorded
Term endedDecember 15, 2012
Patent numberCA 2128518 A1
Classification (IPC)C07C53/13 +2 more

Timeline

Timeline From CIPO dates

1993199519971999200120032005200720092011Application filedDec 15, 1992Term endedDec 15, 2012

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.