55(P1-3) 4,5-エポキシジヒドロモルフィノンの異常反応とオピオイドリセプターアンタゴニスト合成への応用(ポスター発表の部)  [in Japanese] 55(P1-3) ABNORMAL REACTION OF 4,5-EPOXYDIHYDRO-MORPHINONES AND ITS APPLICATION TO THE SYNTHESES OF OPIOID RECEPTOR ANTAGONISTS  [in Japanese]

A number of studies on opiates that contain a C-6 carbonyl function have suggessted that they can more readily be converted to enols or enolic derivatives than conventional ketones. For example, it has been reported that dihydromorphinone and related ketones are relatively resistant to addition by Grignard reagents and can form tertiary alcohols only with organolithium compounds. Further, crystallographic studies have shown ring C to be in a flattened chair conformation. In this symposium we report chemical studies that provide evidence for the greater stability of opiate products that contain a 6,7-double bond. Treatment of naltrexone, dihydromorphinone, or related opiates that contain a 6-keto group with acetic anhydride or t-butyldimethylsilyl chloride under mild conditions afforded enol derivetives having a 6,7-double bond. Naltrexone also was found to undergo the Robinson annelation reaction with methylvinyl ketone with facility and in high yield to give the β-hydroxyketone. We applied the abnormal reaction of naltrexone to the syntheses of opioid receptor antagonists, nor-BNI 13(pyrrole derivative) and NTI(indole derivative). We also report the intramolecular rearrangement of the acetyl group in 14-acetylnaltrexone.