Reactions of morphine derivatives with phenyliodo(III)diacetate (PIDA): Synthesis of new morphine analogues

The reactions of morphine and its derivatives with phenyliodo(III)diacetate (PIDA) have been studied. This methodology has not been introduced to morp hine alkaloids, despite the fact that such a strategy would ensure dearomat ization of the electrophilic aromatic ring of morphine derivatives leading to nucleophilic ortho-quinoidal structures with potential pharmacological i nterest. The products, formed in regio- and diastereoselective or diastereo specific reactions, carry mixed-acetal or 1,3-dioxolane moieties. At low co ncentrations 6a has mu -opioid agonist character but in higher concentratio ns showed a non receptorial antagonist effect on isolated mouse vas deferen s.