AN IMPROVED PROCESS FOR THE MINIMIZATION OF RACEMIZATION IN THE PREPARATION OF OPTICALLY ACTIVE [(ARYLOXY)PHENOXY]PROPIONATE HERBICIDES

摘要

One of the routes to prepare optically active 2-(4-aryloxyphenoxy)propionic acid ester herbicide is to couple optically active 2-(4-hydrophenoxy)propionic acid esters with halogenated aromatic or heteroaromatic compounds. Conversion of the optically active 2-(4-hydroxyphenoxy)propionic acid ester into the acid salt prior to the coupling step effectively prevents the racemization that unexpectedly occurs otherwise.