Diene systems in N-formylmorphinans; formation of a dibenz[d,f]azonine: A new example of molecular acrobatics in morphinans1 (chemistry of opium alkaloids, part XXVII)

Economical synthesis of 13C-labeled opiates, cocaine derivatives and selected urinary metabolites by derivatization of the natural products

The illegal use of opiates and cocaine is a challenge world-wide, but some derivatives are also valuable pharmaceuticals. Reference samples of the active ingredients and their metabolites are needed both for controlling administration in the clinic and to detect drugs of abuse. Especially, ¹³C-labeled compounds are useful for identification and quantification purposes by mass spectroscopic techniques, potentially increasing accuracy by minimizing ion alteration/suppression effects. Thus, the synthesis of [acetyl-¹³C₄]heroin, [acetyl-¹³C₄-methyl-¹³C]heroin, [acetyl-¹³C₂-methyl-¹³C]6-acetylmorphine, [N-methyl-¹³C-O-metyl-¹³C]codeine and phenyl-¹³C₆-labeled derivatives of cocaine, benzoylecgonine, norcocaine and cocaethylene was undertaken to provide such reference materials. The synthetic work has focused on identifying ¹³C atom-efficient routes towards these derivatives. Therefore, the ¹³C-labeled opiates and cocaine derivatives were made from the corresponding natural products.

Efficient Iron-Catalyzed N-Demethylation of Tertiary Amine-N-oxides under Oxidative Conditions

An investigation into the influence of oxidative conditions on the efficiency of opiate N-demethylation using iron powder has been carried out under non-classical Polonovski conditions. This approach involves a two-step process of N-oxidation and subsequent treatment of the intermediate N-oxide hydrochloride with the redox catalyst. Significant improvements in rate and yield have been realized for these reactions in the presence of molecular oxygen. In this context, further rate enhancement was achieved by the judicious addition of small amounts of ferric ions, leading to a concomitant reduction in the amount of the zero-valent iron primary catalyst that is required. This has led to a generalized improved methodology for the N-demethylation of oripavine, codeine, morphine, and thebaine. This protocol can also be carried out in one-pot without the need to isolate the intermediate N-oxide.