Synthesis and testing of novel classical cannabinoids: exploring the side chain ligand binding pocket of the CB1 and CB2 receptors.

A series of C3 cyclic side-chain analogues of classical cannabinoids were synthesized to probe the ligand binding pocket of the CB1 and CB2 receptors. The analogues were evaluated for CB1 and CB2 receptor binding affinities relative to delta(8)-THC. The C3 side-chain geometries of the analogues were studied using high field NMR spectroscopy and quantum mechanical calculations. The results of these studies provide insights into the geometry of the ligand binding pocket of the CB1 and CB2 receptors.