Synthesis and antinociceptive activity of 7-methoxycodeine.

(-)-7-Methoxycodeine was synthesized from (-)-1-bromosinomeninone in three steps with an overall yield of 29%. The introduction of the 7-methoxy group into the C ring of codeine did not decrease its oral activity. 7-Methoxycodeine was unstable in acidic media. Its oral activity was however, not likely to be due to conversion to the acid-stable (-)-sinomeninone, since the latter was orally inactive.