16553-22-3Relevant academic research and scientific papers
Polonovski-type N-demethylation of N-methyl alkaloids using substituted ferrocene redox catalysts
Kok, Gaik B.,Scammells, Peter J.
experimental part, p. 2587 - 2594 (2012/09/22)
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 FcCH2CO2H, 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. Georg Thieme Verlag Stuttgart · New York.
Two-step iron(0)-mediated N-demethylation of N -methyl alkaloids
Kok, Gaik B.,Pye, Cory C.,Singer, Robert D.,Scammells, Peter J.
experimental part, p. 4806 - 4811 (2010/10/19)
(Figure Presented) A mild and simple two-step Fe(0)-mediated N-demethylation of a number of tertiary N-methyl alkaloids is described. The tertiary N-methylamine is first oxidized to the corresponding N-oxide, which is isolated as the hydrochloride salt. Subsequent treatment of the N-oxide hydrochloride with iron powder readily provides the N-demethylated amine. Representative substrates include a number of opiate and tropane alkaloids. Key intermediates in the synthesis of semisynthetic 14-hydroxy pharmaceutical opiates such as oxycodone and oxymorphone are also readily N-demethylated using this method.
N-Demethylation of N-methyl alkaloids with ferrocene
Kok, Gaik B.,Scammells, Peter J.
supporting information; experimental part, p. 4499 - 4502 (2010/09/15)
Under Polonovski-type conditions, ferrocene has been found to be a convenient and efficient catalyst for the N-demethylation of a number of N-methyl alkaloids such as opiates and tropanes. By judicious choice of solvent, good yields have been obtained for dextromethorphan, codeine methyl ether, and thebaine. The current methodology is also successful for the N-demethylation of morphine, oripavine, and tropane alkaloids, producing the corresponding N-nor compounds in reasonable yields. Key pharmaceutical intermediates such oxycodone and oxymorphone are also readily N-demethylated using this approach.
