Patent ID: 6455736
Filing Date: 2002-09-24
Classification: C07B,C07C,C12C,G01N

Abstract:
In a process for preparation of compounds formula II by selectively converting a compound of formula IV to II where R1 is selected from the group consisting of hydrogen, fluoro, chloro, bromo, trifluoromethyl, and alkoxy having from 1 to 3 carbon atoms, where X and Y are independently selected from the group consisting of hydrogen, fluoro, chloro, bromo, trifluoromethyl, cyano, and alkoxy having from 1 to 3 carbon atoms with at least one of X or Y being other than hydrogen, and where Z1 and Z2 are selected from the group consisting of hydrogen and alkyl having from 1 to 3 carbon atoms, the improvement comprising the selective preparation of II of at least 95% enantiomeric purity by:a) resolving cis and trans racemic IV in a first resolution zone by simulated moving bed chromatography using a non-chiral or chiral adsorbent to afford a first isomer of racemic IV in at least 95% enantiomeric purity and a second isomer of racemic IV; b) resolving the first isomer of racemic IV in a second resolution zone by simulated moving bed chromatography using a chiral adsorbent to afford a first enantiomer pair of II in at least 95% enantiomeric purity and a second enantiomer pair of II; c) resolving the first enantiomer pair of II in a third resolution zone by simulated moving bed chromatography using a chiral adsorbent to afford a first enantiomer of II in at least 95% enantiomeric purity and a second enantiomer of II; and d) racemizing the second enantiomer pair of II, and recycling to the first or second resolution zone.