To gain understanding of hindered rotations and magnetic anisotropy in drugs, compounds of much intrinsic importance, we have investigated as amodel compoundthe Diels-Alder adduct of phenycyclone with N-2, 2, 2-trifluoroethylmaleimide for study by1H,19F and13C NMR. The N-2, 2, 2-trifluoroethylmaleamic acid and maleimide precursors were examined by1H and19F NMR. The phencyclone adduct is shown by1H and13C NMR (at 300 and 75 MHz, respectively) to exhibit slow exchange limit spectra at ambient temperatures, arising from hindered rotation of the bridgehead unsubstituted phenyl groups.