Synthesis, biological evaluation and docking studies of a novel class of sulfur-bridged diazabicyclo[3.3.1]nonanes

A small library of 3-thia-7,9-diazabicyclo[3.3.1]nonanes was synthesized and their opioid receptors affinity and selectivity evaluated. Among these novel sulfur-bridged compounds, the (E) 9-[3′-(3-chlorophenyl)-but-2′-en-1′- yl]-7-propionyl-3-thia-7,9-diazabicyclo[3.3.1]nonane 2i emerged as the derivative with the highest μ receptor affinity (Ki = 85 nM) and selectivity (Ki μ/δ = 58.8, Ki μ/κ > 117.6). The antinociceptive activity of 2i was also evaluated in acute thermal pain. Docking studies disclosed the specific pattern of interactions of these derivatives.