Norcodeine prepn - by reduction of 1-halo-norcodeinones, novel intermedi-ates for narcotic antagonists

摘要

Prepn. of norcodeins by reaction of 1-halo-norcodeinones of formula: where X is Cl or Br; and Y is CHO, -CO2Me or -CO2Et with a suitable reagent to give a cpd. of formula: which in turn is reduced to norcodeins (III): Cpds. are new. Removal of the protecting gp. Y requires mild conditions to avoid possible rearrangement of the mol. When Y = -CHO this is performed with H2O2, or aq. or alcoholic HCl or HBr. When Y is CO2Me or CO2Et alkaline hydrolysis in an inert atmos. is prefd. Norcodeine is an inter. in the prepn. of narcotic antagonists such as nalorphine or normorphine.