title: Synthesis of o,p-EDDHA and its detection as the main impurity in o,o-EDDHA commercial iron chelates.
abstract: Ethylenediamine-N,N'bis(o-hydroxyphenyl)acetic acid (o,o-EDDHA) is one of the most efficient iron chelates employed to relieve iron chlorosis in plants. However, the presence of positional isomers of EDDHA in commercial iron chelates has been recently demonstrated, and among them, it has been claimed that ethylenediamine-N(o-hydroxyphenylacetic)-N'(p-hydroxyphenylacetic) acid (o,p-EDDHA) is the main impurity present in EDDHA fertilizers. Here we report the preparation of o,p-EDDHA, a compound whose synthesis had not been previously reported. The synthetic o,p-EDDHA is able to form ferric complexes, and it has been used as a standard in the analysis of the impurities of commercial iron fertilizers. The presence of o,p-EDDHA/Fe(3+) in commercial samples has been unambiguously demonstrated by HPLC.
authors.affiliation: Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Gómez-Gallego
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Sierra
authors.forename: Roberto
authors.initials: R
authors.lastname: Alcázar
authors.forename: Pedro
authors.initials: P
authors.lastname: Ramírez
authors.forename: Carmen
authors.initials: C
authors.lastname: Piñar
authors.forename: María José
authors.initials: MJ
authors.lastname: Mancheño
authors.forename: Sonia
authors.initials: S
authors.lastname: García-Marco
authors.forename: Felipe
authors.initials: F
authors.lastname: Yunta
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Lucena
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005029:Ethylenediamines / Q000032:analysis / Q000737:chemistry*; D005308:Fertilizers / Q000032:analysis*; D007502:Iron Chelating Agents / Q000032:analysis / Q000737:chemistry*; D007536:Isomerism
chemical_list: D005029:Ethylenediamines; D005308:Fertilizers; D007502:Iron Chelating Agents; C011813:ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid)