Patent ID: 6162949
Filing Date: 2000-12-19
Classification: C07B,C07C,C12C

Abstract:
In a process for preparation of compounds I of formula ##STR6## by converting a 3-substituted-1-phenylpropene of formula IVC.sub.6 H.sub.5 CH.dbd.CH--CH.sub.2 X IVunder achiral conditions to the racemic epoxide V of formula ##STR7## and selectively converting V to I, where R.sub.1 is hydrogen or a lower alkyl group containing from 1 up to about 5 carbon atoms, R.sub.2 is a lower alkyl group containing from 1 up to about 5 carbon atoms, where Y is 4-trifluoromethylphenyl, 2-methylphenyl, or 2-ethoxyphenyl, and where X is a halogen, hydroxyl, ester, or amino group, the improvement comprising the selective preparation of (S)-I of at least 95% enantiomeric purity by:a) resolving racemic epoxide V by simulated moving bed chromatography using a chiral adsorbent to afford a first enantiomer of V in at least 95% enantiomeric purity and a second enantiomer of V;b) selectively converting the first enantiomer of epoxide V to compounds I having the (S) configuration with at least 95% enantiomeric purity in the selective conversion stage of V to I; andc) racimizing the second enantiomer of V to the racemic epoxide V and recycling the racemic epoxide V to stage (a).