The 1H and 13C NMR spectra of 4, 8, 9, 10-tetraaryl-1, 3-diazatricyclo[3.3.1.13, 7]decan-6-ones were measured at 400 and 500 and at 100 and 125 MHz, respectively. The chemical shifts were assigned unambiguously using one-and two-dimensional (H, H-COSY, C, H-COSY, NOESY, ROESY and HMBC) NMR spectroscopic data. 1D-INADEQUATE data also provide an independent assignment of the signals of the carbons of the heterocyclic rings. These results clearly indicate the axial orientation of two aryl groups in one piperidone ring and the equatorial orientation, of the other two aryl groups in another ring. © 2001 John Wiley & Sons, Ltd.