A series of novel cannabinoid-type derivatives were synthesized by the coupling of (1S,4R)-(+) and (1R,4S)-(-)-fenchones with various resorcinols/phenols. The fenchone-resorcinol derivatives were fluorinated using Selectfluor and demethylated using sodium ethanethiolate in dimethylformamide (DMF). The absolute configurations of four compounds were determined by X-ray single crystal diffraction. The fenchone-resorcinol analogs possessed high affinity and selectivity for the CB2 cannabinoid receptor. One of the analogues synthesized, 2-(2',6'-dimethoxy-4'-(2″-methyloctan-2″-yl)phenyl)-1,3,3-trimethylbicyclo[2.2.1]heptan-2-ol (1d), had a high affinity (K(i) = 3.51 nM) and selectivity for the human CB2 receptor (hCB2). In the [(35)S]GTP$\gamma$S binding assay, our lead compound was found to be a highly potent and efficacious hCB2 receptor agonist (EC(50) = 2.59 nM, E((max)) = 89.6%). Two of the fenchone derivatives were found to possess anti-inflammatory and analgesic properties. Molecular-modeling studies elucidated the binding interactions of 1d within the CB2 binding site.

Multiple sclerosis (MS) is an autoimmune disease leading to the destruction of myelin with consequent axonal degeneration and severe physical debilitation. The disease can be treated with immunosuppressive drugs that alleviate the symptoms and retard disease aggravation. One such drug in clinical use is glatiramer acetate (Copaxone). The non-psychotropic immunosuppressive cannabinoid compound cannabidiol (CBD) has recently been shown to have beneficial effects on experimental autoimmune encephalomyelitis (EAE). The aim of our study was to compare the efficacy of CBD and standardized extracts from a CBD-rich, ∆ 9 -THC low Cannabis indica subspecies (Avidekel) with that of Copaxone. Our data show that CBD and purified Avidekel extracts are as efficient as Copaxone to alleviate the symptoms of proteolipid protein (PLP)-induced EAE in SJL/J mice. No synergistic effect was observed by combining CBD or Avidekel extracts with Copaxone. Our data support the use of Avidekel extracts in the treatment of MS symptoms. © 2018, Springer Nature Switzerland AG.