Precursors of the mammalian synthesis of morphine: (+)-salutaridine and (-)-thebaine from (+)-6-demethylsalutaridine, and (-)-N-13CH3-thebaine from (-)-northebaine.

Standard samples of pure (+)-salutaridine and (-)-thebaine required to study the mammalian origin of morphine, were prepared from (+)-6-demethylsalutaridine by published procedures and were characterized by CD spectra and physical data. Reductive N-methylation of (-)-northebaine afforded (-)-thebaine, and when 13C-labeled formalin was used, (-)-thebaine with a 13C label on the N-methyl carbon atom resulted. The latter represents a model procedure to prepare ultimately N-14CH3-labeled (-)-thebaine and 14C-labeled congeners.