Polonovski-Type N-Demethylation of N-Methyl Alkaloids Using Substituted Ferrocene Redox Catalysts
摘要:
Various substituted ferrocenes have been trialed as catalysts in the nonclassical Polonovski reaction for N-demethylation of N-methyl alkaloids. Earlier studies suggest that conditions facilitating a higher ferrocenium ion concentration lead to superior outcomes. In this regard, the bifunctional ferrocene FcCH(2)CO(2)H, with electron donor and acceptor moieties in the same molecule, has been shown to be advantageous for use as a catalyst in the N-demethylation of a number of tertiary N-methylamines such as codeine, thebaine, and oripavine. These substrates are readily N-demethylated under mild conditions, employing sub-stoichiometric amounts of the substituted ferrocene at ambient temperature. These reactions are equally efficient in air and may also be carried out in one pot.
Further investigations into the N-demethylation of oripavine using iron and stainless steel
作者:Gaik B. Kok、Peter J. Scammells
DOI:10.1039/c0ob01021a
日期:——
Furtherinvestigations into the direct synthesis of N-nororipavine from oripavine using iron powder under non-classical Polonovski conditions have been conducted. The stoichiometry, solvents and iron oxidation rates were found to have a dramatic effect on the rate of N-demethylation as well as product yield. Herein, we also present high-yield access to the N-demethylated product simply by employing