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Note | Special issue | Vol 47, No. 2, 1998, pp.1029-1032
Published online, 1st January, 1970
DOI: 10.3987/COM-97-S(N)92
A New and Efficient Synthesis of the μ Opioid Receptor Antagonists 14-O-Methyl-and 14-O-Ethylnaloxone and -naltrexone

Roland Krassnig, Martin Koch, Herwig K. Jennewein, Elisabeth Greiner, and Helmut Schmidhammer*

*Institute of Pharmaceutical Chemistry, University of Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria


The μ opioid receptor antagonists 14-O-methyl- and 14-O-ethylnaloxone (3 and 4, respectively) and 14-O-methyl- and 14-O-ethylnaltrexone (5 and 6, respectively) have been prepared in a three-step sequence starting from either naloxone (1) or naltrexone (2). The 3-hydroxy group of 1 and 2 was protected with a benzyl group prior to 14-O-alkylation with either dimethyl or diethyl sulfate to give the enol ethers (9 - 12). Acid hydrolysis afforded compounds (3 - 6).