Novel analgesics and molecular rearrangements in the morphine–thebaine group. Part XXV. Substitution of the piperidine ring in derivatives of 6,14-endo-ethenotetrahydrothebaine

Abstract

Various 6,14-endo-ethenotetrahydrothebaines substituted at positions 15 and 16 have been prepared by electrophilic attack on the corresponding 15,16-didehydro-compounds or nucleophilic attack on the iminium salts derived from these bases. The less hindered approach to C-15 or C-16 is from the α-side (i.e. aromatic ring A side) of the molecule.