Synthesis and mu-opioid receptor affinity of a new series of nitro substituted 3,8-diazabicyclo[3.2.1]octane derivatives.

A new series of analogues (1c-j; 2c-i) of the previously reported analgesic 3,8-diazabicyclo[3.2.1]octanes (1a,b; 2a,b) was synthesized and tested for their affinity towards mu-opioid receptors. Modifications were introduced either at the cinnamyl or the acyl side chains. The majority of the new compounds, with the exception of 1c,j and 2c, showed Ki values better or comparable with those of the models.