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.