The Optical Resolution and Asymmetric Transformation of DL-p-Hydroxyphenylglycine with (+)-1-Phenylethanesulfonic Acid

Article abstract of DOI:10.1246/bcsj.60.649

Optically active 1-phenylethanesulfonic acid was found to be an efficient resolving agent for the optical resolution and asymmetric transformation of DL-p-hydroxyphenylglycine.When DL-p-hydroxyphenylglycine was resolved by the fractional crystallization of its diastereomeric salt with (+)-1-phenylethanesulfonic acid, less soluble D-p-hydroxyphenylglycine (+)-1-phenylethanesulfonate was obtained in a good yield.Soluble L-HPG*(+)-PES was easily epimerized into DL-HPG*(+)-PES by heating it at 100 deg C in glacial acetic acid in the presence of a small amount of salicylaldehyde.Under such epimerizing conditions, the asymmetric transformation of DL-HPG*(+)-PES was attempted by simultaneously combining the fractional crystallization of the less soluble D-HPG*(+)-PES and the epimerization of the soluble L-HPG*(+)-PES.This asymmetric tranformation was achieved succesfully; that is, 80percent of the DL-HPG used as the starting material was converted into D-HPG.