Structural and conformational studies of 3,8-diazabyciclo[3.2.1]octane derivatives, selective agonists of µ-opioid receptors

Quantum mechanic calculations have been done on a set of 3,8-diazabicyclo[3.2.1]octane derivatives in order to elucidate their electronic structure in relation to the affinity towards the μ-opioid receptors. The conformations are compared with morphine, chosen for its μ-affinity and structural rigidity. The X-Ray crystal and molecular structures of 3-p-nitrocinnamyl-8-propionyl-3,8-diazabicyclo[3.2.1]octane (1b) and of two higher homologs 8-n-butyroyl- (1c) and pivaloyl- (1d) have been compared with the theoretical results.