Solid‐state and solution conformations of methadone hydrochloride and related compounds

Abstract

AbstractCarbon‐13 NMR data for salts of methadone and methadol in the solid‐state were used to elucidate the crystalline forms of the compounds and to determine if more than one conformer contributes to a single crystalline form. A comparison of 13C NMR isotropic chemical shift data for these compounds in the solid‐state and in various solvents was used to correlate solution and solid‐state conformations (determined from x‐ray data). Three‐bond 1H13C and 1H1H coupling constants, measured by various one‐ and two‐dimensional NMR techniques, were compared with those calculated from x‐ray dihedral angle data in order to confirm or dispute the conformational predictions based on chemical shift comparisons.