Process for the preparation of morphine analogs via the reaction of organometallic reagents with an oxazolidine derived from morphinans

摘要

The oxazolidine derived from the reaction of oxymorphone with the Burgess reagent, temporarily protected at O-3 and C-6, reacts with Grignard or other suitable metallic or organometallic reagents to directly provide, for example, A/-allyl, A/-methylcyclopropyl and /V-methylcyclobutyl derivatives that are further converted into naltrexone, naloxone, nalbuphone and nalbuphine in excellent yields. These morphine analogs can be prepared from the oxazolidine in a one-pot synthesis.