Ma. Cremonini et al., NMR analysis of the iron ligand ethylenediaminedi(o-hydroxyphenyl)acetic acid (EDDHA) employed in fertilizers, J AGR FOOD, 49(8), 2001, pp. 3527-3532
The exceptional efficiency of the iron chelate of ethylenediaminedi(o-hydro
xyphenyl)acetic acid (o,o-EDDHA) in correcting iron chlorosis in plants and
the medical applications of various metallic chelates of this compound hav
e long been recognized. As commercial preparations of o,o-EDDHA usually con
tain impurities, a method for their detection is proposed. By using one- an
d two-dimensional nuclear magnetic resonance two impurities were identified
. The structure of one of these compounds was assigned to an isomer of EDDH
A containing at least one p-hydroxyphenyl moiety. The structure of the othe
r impurity was tentatively assigned to a byproduct of the EDDHA synthesis:
2,6-di[CH(COOH)NHCH2CH2NHCH(COOH)Ar] phenol (Ar = hydroxyphenyl). Both comp
ounds were also detected in the EDDHA extracted from a commercial iron fert
ilizer.