A Novel Method for the Introduction of a 5β‐Methyl Group into 4,5α‐Epoxymorphinan‐6‐ones via the Enol Ether |
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| Authors: | Roland Krassnig Helmut Schmidhammer Klaus Wurst |
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| Abstract: | The introduction of a 5β‐methyl group into 14‐alkoxy substituted naltrexone derivatives was accomplished via the enol ethers 2a and 2b by means of the `LICKOR' (t‐BuLi/t‐BuOK) base system. According to this new method, the highly selective δ‐opioid antagonist HS 378 ( 7b ) and its 14‐methoxy analog 7a , both originally prepared in nine steps from thebaine, are now available in only four steps. |
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