Optical Resolution and Absolute Configuration of Branched 4-Nonylphenol Isomers and Their Estrogenic Activities

Abstract

To determine the effects of optical isomerism on the estrogenic activity of 4-nonylphenol (NP) isomers, four optically active NP isomers, (3R)-4-(3-ethyl-2-methylhexan-2-yl)phenol, (3S)-4-(3-ethyl-2-methylhexan-2-yl)phenol, (4R)-4-(2,4-dimethylheptan-4-yl)phenol and (4S)-4-(2,4-dimethylheptan-4-yl)phenol, were prepared and separated using chiral HPLC. Their absolute configurations were elucidated by X-ray crystallographic analysis of their bromobenzoylated derivatives. The estrogenic activities (recombinant yeast screen assay) of the optically active NPs were similar to those of the corresponding racemates.