The role of fluorine substitution in the structure–activity relationships (SAR) of classical cannabinoids

A facile synthesis of 1-fluoro-1-deoxy-Δ8-THC analogs with side chains seven carbons in length, in the alkane/ene/yne- series (6, 5, and 4), was achieved from 1-fluoro-3,5-dimethoxybenzene (1). In vitro studies show that substitution by a fluorine has a significant detrimental effect on CB1 binding which is supported by in vivo testing. The implications of these results on the SAR of classical cannabinoids are discussed.