Patent ID: 7265106
Filing Date: 2007-09-04
Classification: A61K,A61P,C07D

Abstract:
1. A method of isolating (R)-tofisopam, substantially free of the (S)-enantiomer of tofisopam, said method comprising: (a) adsorbing a mixture of enantiomers of tofisopam onto a chiral separation medium; (b) passing a solvent system through the chiral separation medium in an amount sufficient to elute the tofisopam enantiomers from the separation medium; (c) isolating the (R)-enantiomer of tofisopam, substantially free of the (S)-enantiomer of tofisopam; wherein said chiral separation medium comprises: (2S)-2-{(1S)[(3,5-dinitrophenyl)carbonylamino]phenylmethyl}-3,3-dimethylbutanoate covalently bound to silica, or an amylose derivative of formula I: wherein each R wherein R n is an integer from about 10 to about 100; said amylose derivative coated on a porous inorganic carrier or a porous organic carrier.