Separation and Characterization of the Stereoisomers of N,N′-Ethylenebis-[2-(o-hydroxyphenyl)]-glycine

Abstract

THE exceptional efficiency of the commercially available iron chelate of N,N′-ethylenebis-[2-(o-hydroxyphenyl)]-glycine (EHPG) in correcting iron chlorosis induced by lime in plants has long been recognized¹. Extensive studies of solution equilibria², analytical³ and medical⁴ applications of this substance have also been conducted. The fact that stereo-isomeric forms of it are possible has not been indicated previously. On inspection of the molecular structure of EHPG: it is apparent that two like asymmetric carbon atoms are present as indicated by the asterisks. Accordingly, two forms of the compound with different physical and chemical properties should exist, a meso form and a dl-racemic mixture. It was of interest, therefore, to separate and characterize these isomers and to determine their possible significant difference in translocating iron to plants.