Linear-dichroic infrared spectral (IR-LD) analysis of codeine and its derivatives

By means of IR-LD spectroscopy of oriented as suspension in nematic liquid crystal solids, a detailed IR-bands assignment and a stereo-structural prediction of codeine, codeinone and N-norcodeine have been carried out. The data are compared with known crystallographic ones of codeine and codeinone obtained by single crystal X-ray diffraction.