Can Two Molecules Have the Same NMR Spectrum? Hexacyclinol Revisited

An in-depth DFT computational investigation (B97-2/cc-pVTZ level) of the 1H and 13C NMR spectra of the recently disputed natural substance hexacyclinol, including J(1H,1H) couplings, is presented. Structures 1 and 2 have been compared with regard to the suggested possibility that two molecules have very similar NMR spectra as to be indistinguishable. Despite a remarkable similarity of functional groups present, the two calculated spectra differ in many features related both to chemical shifts and connectivities.