Septische Chirurgie in O&amp;U: Wo stehen wir?

Weigl, Sabrina; Nerlich, Michael; Siebert, H.

doi:10.1055/s-0033-1363954

Cited by 1 publication

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“…Naltrexone, prepared from oxymorphone in several steps, is converted into (R)-methylnaltrexone 10 by alkylation with iodomethane, bromomethane, or dimethyl sulfate, followed by multiple crystallizations to pure (R)-methylnaltrexone (MNTX). Although direct methylations of naltrexone have been reported 10,11 it is more customary to protect the C-3 phenol with benzyl, 12 acyl, 13 ethyloxycarbonyl, 14 or silyl 15 protecting groups (Scheme 2). After deprotection the NMTX salt is carefully deprotonated to obtain zwitterion 10, which, because of its limited solubility, is easily filtered off and later dissolved in aqueous HBr.…”

Section: Letter Syn Lettmentioning

confidence: 99%

Synthesis of Naltrexone and (R)-Methylnaltrexone from Oripavine via Direct Oxidation of Its Quaternary Salts

Machara¹,

Werner

Leisch³

et al. 2015

Synlett

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O O N HO OH O O N HO OH Br Me O MeO N HO Br O MeO N HO Br O O Me O MeO N HO Me O MeO N HO Me oripavine cyclopropylmethyl nororipavine naltrexone (R)-methylnaltrexoneAbstract (R)-Methylnaltrexone and naltrexone were each prepared in four steps from oripavine in practical yields. The procedure involved quaternization of oripavine with cyclopropylmethyl halides, singlet oxygen oxidation of the quaternary salts, and the reduction of endo peroxides to 14-hydroxyketone functionalities. (R)-Methylnaltrexone was prepared from the corresponding R-diastereomer of the oripavine salt. All diastereomeric mixtures of the quaternary salts were subjected to N-demethylation with sodium thiolate to yield cyclopropyl methylnororipavine, which was converted into naltrexone by peracid oxidation and hydrogenation according to established procedures.

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Section: Letter Syn Lettmentioning

confidence: 99%