N-Demethylation of N-methyl alkaloids with ferrocene
作者:Gaik B. Kok、Peter J. Scammells
DOI:10.1016/j.bmcl.2010.06.031
日期:2010.8
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
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
An Improved Process for the N-Demethylation of Opiate Alkaloids using an Iron(II) Catalyst in Acetate Buffer
作者:Gaik Kok、Trent D. Ashton、Peter J. Scammells
DOI:10.1002/adsc.200800632
日期:2009.1
An improvedprocess to N-demethylate opiatealkaloids utilising a solution of the ferrous porphyrin, tetrasodium 5,10,15,20-tetra(4-sulfophenyl)porphyrinatoiron(II) [=Fe(II)-TPPS (8)], in acetatebuffer is described. This method provided the corresponding N-demethylated opiates in good yield with high reproducibility.
Approaches to Short-Acting Neuromuscular Blocking Agents: Nonsymmetrical Bis-tetrahydroisoquinolinium Mono- and Diesters
作者:Nirmal C. Dhar、Robert B. Maehr、Luke A. Masterson、John M. Midgley、John B. Stenlake、William B. Wastila
DOI:10.1021/jm950477z
日期:1996.1.1
moiety have been studied as a means of promoting short action with high-potency neuromuscularblock. Atracurium-related nonsymmetrical diesters showed high potency, freedom from vagal blockade at neuromuscularblocking doses, and short action. Nonsymmetrical monoesters were short acting but showed varying degrees of vagal block.
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.