- Unexpected N-demethylation of oxymorphone and oxycodone N-oxides mediated by the burgess reagent: Direct synthesis of naltrexone, naloxone, and other antagonists from oxymorphone
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N-Oxides derived from oxycodone and O-acyloxymorphone were treated with the Burgess reagent to provide the corresponding oxazolidines in excellent yields. Oxazolidines derived from Oacyloxymorphone were further hydrolyzed to noroxymorphone, whose alkylation furnished naltrexone, naloxone, and nalbuphone, which can be converted to nalbuphine, the mixed agonist-antagonist analgesic. The entire sequence from oxymorphone to the various antagonists was reduced to three one-pot operations, proceeding in excellent overall yields. In addition, quaternary salts of the oxazolidines with allyl or cyclopropylmethyl groups in fixed equatorial configurations were synthesized. Complete spectral and experimental data are provided for all compounds.
- Werner, Lukas,Wernerova, Martina,MacHara, Ales,Endoma-Arias, Mary Ann,Duchek, Jan,Adams, David R.,Cox, D. Phillip,Hudlicky, Tomas
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supporting information
p. 2706 - 2712
(2013/01/15)
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- Processes and Intermediates in the Preparation of Morphine Analogs via N-Demethylation of N-Oxides Using Cyclodehydration Reagents
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A high-yielding method for the N-demethylation of oxycodone- and oxymorphone-N-oxides by the reaction of these compounds with cyclodehydration reagents has been performed. This method has been utilized to improve the synthesis of various morphine analogs, such as naltrexone, nalbuphone and naloxone.
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Page/Page column 14
(2012/11/13)
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- Efficient N-Demethylation of Opiate Alkaloids Using a Modified Nonclassical Polonovski Reaction
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A modified Polonovski reaction 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, and an FeS04·7H20 mediated Polonovski reaction to afford the desired secondary amine.
- McCamley, Kristy,Ripper, Justin A.,Singer, Robert D.,Scammells, Peter J.
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p. 9847 - 9850
(2007/10/03)
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