Synthesis of bibenzyl cannabinoids, hybrids of two biogenetic series found in Cannabis sativa
Syntheses of a series of compounds which merge a m-dihydroxybibenzyl with a terpenoid structure, giving a series of hybrid cannabinoids in which products of two major biogenetic routes of Cannabis are united, are described. The compounds made are the bibenzyl/o- and p-cannabigerols (19) and (18)/o- and p-cannabidiols (21) and (20),/Δ1-THC (22),/Δ6-THC (23),/o- and p-cannabichromenes (25) and (24),/o- and p-cannabicyclols (28) and (27) and/cannabicitran (26). Chromatographic and spectral data are listed in order to facilitate search for such ‘crossed’ types since only the bibenzyl cannabigerols and a chromene have as yet been found in natural sources.
The bibenzyl/p-cannabigerol (18) has been reported in Helichrysum umbraculigerum(Compositae) and the liverwort Radula variabilis. Our synthetic work confirms the former observation, but the liverwort compound appears to be its o-isomer.