Cannabinoids with a Propyl Side Chain in Cannabis: Occnmnce and Chromatographic Behayior

Neutral cannabinoids with a pentyl side chain— for example, cannabidiol, tetrahydrocannabinol, and cannabinol— are générally accompanied by homologs with a propyl side chain, of which at least one has psychotropic activity. Samples of hashish and marihuana from Asia especially sometimes have abundant amounts of propyl cannabinoids, the quantities being of the same order as that of the accompanying pentyl cannabinoids. Detection and identification of the propyl and pentyl cannabinoids in gas chromatography and thin-layer chromatog­ raphy is discussed. The chemical composition of hashish and marihuana has been well studied (/). Cannabidiol (1), AMetrahydrocannabinol (2) (monoterpenoid numbering), and cannabinol (3) were identified as the major neutral cannabinoids (/) of which AMetrahydrocannabinol was found to be psychotropically active (2). The neu­ tral cannabinoids can be accompanied by their respective acids, having a carboxyl group in one of the free positions at the aromatic ring. The cannabinoid acids are psychotropically inactive (7) and not very stable. Under the influence of light and heat, for example on smoking, decarboxylation to neutral cannabinoids rapidly occurs. These cannabinoids can be regarded as monoterpenoids coupled with olivetol (5-w-pentylresorcinol), with the structural differences occurring in the terpenoid part of the molecule.