1H NMR Spectral Simplification with Achiral and Chiral Lanthanide Shift Reagents. Lofexidine |
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| Authors: | Joel Ross Robert Rothchild |
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| Affiliation: | 1. The City University of New York John Jay College of Criminal Justice Toxicology Research and Training Center, Department of Science , 445 West 59th St., New York , N. Y. , 10019-1199;2. St. Michael's College , Winooski , VT;3. The City University of New York John Jay College of Criminal Justice Toxicology Research and Training Center, Department of Science , 445 West 59th St., New York , N. Y. , 10019-1199 |
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| Abstract: | The 1H NMR spectra of the potent anti-hypertensive drug, lofexidine, 1, have been studied in CDCl3 at 60 and 300 MHz. Both the achiral shift reagentr tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionatol-europium(III), 2 and the chiral reagents1 tris[3-(heptafluoropropylhydroxymethylenel-d-camphoratoleuropium(III), 3 and tris[3-(trifluoromethylhydroxymethylenel-d-camphoratoleuropium(III), 4, were employed. Substantial lanthanide induced shifts were observed with 2, 3 or 4, with the largest shifts seen for the methine at the chiral centerr followed by the signal of the NH. Enantiomeric shift differences for the CH3 signal of 1 were seen with 3 OK 4, with 4 inducing larger values of potential analytical utility. Using a non-racemic sample of 1, the (-) enantiomer was shown to have a downfield sense of magnetic nonequivalence for the methyl resonance in the presence of added 4. |
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| Keywords: | Lofexidine Lanthanide NMR Shift Reagents Optical Purity Enantiomers Chiral |
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