Facile Synthesis of 8-Benzoylthio-2, 6-methano-3-benzazocines and 3-Benzoylthiomorphinans Having Small-Ring Substituents

Synthesis of 3-cyclopropylmethyl-, 3-cyclobutylmethyl-, and 3-methyl-8-benzoylthio-2, 6-methano-3-benzazocines (1j-l) was performed by regio-selective chlorosulfonation of non-narcotic 8-deoxy derivatives (1a-c) followed by reduction and benzoylation. 3-Benzoylthiomorphinans (2h-j) were also obtained by the same method. Compounds having small-ring substituents (1k, 1l, 2i, 2j) were found to be weak but pure μ- and δ-opioid antagonists. The analgetic activity of 1k was almost equal to that of pentazocine.