As candidate structures for compound E, we considered glucuronidation on the OH-group and on the two imine N-atoms of 1'-OH-MDZ, see Figures , where the experimental IR spectrum is compared with the theoretical IR spectra of these candidate structures. Comparing the computational spectra in Figures and in Figures shows that the predicted IR spectra of the candidate structures having the same glucuronide-position, but differing in the presence or absence of the OH-group, are almost identical (see Figure in the SI for direct overlays). This suggests that the OH-group does not significantly affect the preferred conformation of the compounds, as can also be inferred from the computed 3D-conformations in the Figures. Similar to the discussion of the