Abstract
The axially chiral sedative/hypnotic drug of abuse, mecloqualone, 1, has been studied in CDC13 by 1H NMR at 60 and 300 MHz with the added achiral lanthanide shift reagent (LSR), tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5- octanedionato)europium(III), 2, and the chiral LSR, tris[3-(heptafluoropropylhydroxymethylene)-(+)-camphorato] europium-(III), 3. Rigorous distinctions between the two (CH)4 spin systems of 1 with added 2 or 3 were achieved by two-dimensional homonuclear chemical shift correlation spectroscopy, COSY. Substantial up field (“anomalous”) shifts were observed for several nuclei of 1 with each LSR. Use of the chiral 3 elicited enantiomeric shift differences with baseline separations for several nuclei that should permit direct determinations of enantiomeric excess. COSY spectra allow determination of the relative sense of magnetic nonequivalence of selected nuclei of 1 with 3.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have