NMR Studies of Agricultural Compounds. Applications of Achiral and Chiral Lanthanide Shift Reagents to the Herbicide,Fenoxaprop-Ethyl |
| |
Authors: | Marcie V Brown Kunisi S Venkatasubban Helen Lee Robert Rothchild |
| |
Institution: | 1. University of North Florida, Department of Natural Sciences , Jacksonville, FL, 32216;2. The City University of New York John Jay College of Criminal Justice, Department of Science Toxicology Research and Training Center , 445 West 59th Street, New York, NY, 10019-1199;3. The Doctoral Faculty , The Graduate School and University Center , City University of, New York |
| |
Abstract: | The 200 MHz H NMR spectra of the herbicide, fenoxaprop-ethyl, 1, have been studied in CDCl3 solution at ambient temperatures as the racemic ester free base with the added chiral lanthanide shift reagent (LSR), tris 3 - (heptafluoropropylhydroxymethylene) - (+) - camphorato]europium(III), Eu(HFC)3, 2, with some additional runs using the achiral LSR, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) europium(III), Eu(FOD)3, 3, for supplemental spectral simplification. With 2, definite enantiomeric shift differences (ΔΔδ) were observed only for the CH3CH2O resonance. Although increased spectral complexity for the CH2O signal was seen with added 2, this could have resulted from anisochrony of the diastereotopic protons, Ha and Hb, of this methylene group rather than true ΔΔδ, since the achiral 3 led to near-baseline separation between the CHaHbO signals. Lanthanide-induced shift (LIS) magnitudes were interpreted as consistent with predominant LSR binding at the ester carbonyl. |
| |
Keywords: | 2-[4-[(6-Chloro-2-benzoxazolyl)oxy]phenoxy]propanoic acid ethyl ester HOE 33171 Europium LSR Eu(FOD)3 Eu(HFC)3 Analysis Enantiomeric excess Stereoisomer |
|
|