Efficient Iron-Catalyzed N-Demethylation of Tertiary Amine-N-oxides under Oxidative Conditions
作者:Gaik B. Kok、Peter J. Scammells
DOI:10.1071/ch11320
日期:——
investigation into the influence of oxidative conditions on the efficiency of opiateN-demethylationusingiron 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
Further investigation of the N-demethylation of tertiary amine alkaloids using the non-classical Polonovski reaction
作者:Shanti Thavaneswaran、Peter J. Scammells
DOI:10.1016/j.bmcl.2006.03.017
日期:2006.6
iron salt-mediated Polonovski reaction efficiently N-demethylates certain opiate alkaloids. In this process, the use of the hydrochloride salt of the tertiary N-methyl amine oxide was reported to give better yields of the desired N-demethylated product. Herein, we report further investigation into the use of N-oxide salts in the iron salt-mediated Polonovski reaction. An efficient approach for the
Efficient N-Demethylation of Opiate Alkaloids Using a Modified Nonclassical Polonovski Reaction
作者:Kristy McCamley、Justin A. Ripper、Robert D. Singer、Peter J. Scammells
DOI:10.1021/jo035243z
日期:2003.12.1
A modified Polonovskireaction has been employed to N-demethylate several opiate alkaloids in moderate to high yield. This method provides an alternative to traditional N-demethylation procedures which utilize toxic reagents such as cyanogen bromide or expensive reagents such as vinyl chloroformate. The current synthesis involves N-oxide formation, isolation of the corresponding N-oxide hydrochloride
Two-Step Iron(0)-Mediated N-Demethylation of <i>N</i>-Methyl Alkaloids
作者:Gaik B. Kok、Cory C. Pye、Robert D. Singer、Peter J. Scammells
DOI:10.1021/jo1008492
日期:2010.7.16
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.