| Popis: |
The Delft total synthesis of morphinans starts from 1-benzylisoquinolines (Scheme 2, 7) and gives both the morphinans with the natural (-)-morphine configuration and the corresponding enantiomers. This route has been used as a basis for an improved synthesis of (-)-naloxone and also provides the possibility of preparing (+ )-naloxone, which is of interest in pharmacological research (Scheme 1, 6). We report here in particular on the conversion of 1-(3,5-dibenzyloxy-4-methoxybenzyl)-1,2,3,4-tetrahydro-6-methoxyisoquinoline (7) into dihydrocodeinone (2) via dihydrothebainone (1), the yield of which was raised from 6 to 17%. An improved procedure has been evolved for the conversion of noroxycodone (5) into naloxone (6). |
