Role of the solvent in optical resolution of trans-chrysanthemic acid via diastereomeric salt formation with (1R,2R)-1-(4-nitrophenyl)-2-dimethylaminopropane-1,3-diol

Abstract

Optical resolution of trans-chrysanthemic acid via diastereomeric salt formation with (1R,2R)-1-(4-nitrophenyl)-2-dimethylaminopropane-1,3-diol (DMAD) has been studied in different solvents. Ether type solvents containing MeOH were found to be preferred. The role of MeOH was interpreted on the basis of powder and single crystal X-ray diffraction and DSC/TG measurements. We found that MeOH was incorporated into the crystals of the less soluble diastereomer salt of the 1R acid with DMAD in a non-stochiometric amount and postulated to promote nucleation and crystal growth.