Cannabis’ notorious resin is a complex mixture of cannabinoids, terpenes, and waxes, etc. There are about 100 known cannabinoids that occur only in hemp, with the exception of Cannabichromene, which is found in a few other plants. The entire hemp plant contains several hundred known chemicals.(1-3)
The cannabinoids are thought to be formed by condensation of monoterpene derivatives such as geraniol phosphate with a depside-type olivetolic acid. This leads initially to the formation of Cannabigerol (CBG) and Cannabichromene (CBC) and their carboxylic acids, then to Cannabidiolic Acid (CBDA), which undergoes ring closure to form TetraHydroCannabinol (THC) and its acid (THCA). The latter decarboxylates to form THC. Other biogenetic pathways featuring CBC have been proposed by De Faubert Maunder and by Turner and Hadley. (4, 5) (Fig. 6.1)
Figure 6.1 ~ Cannabinoids
The acids comprise up to 40% of the cannabinoid content of young plants. THC dehydrogenates to form Cannabidiol (CBD). THC is a primary psychoactive cannabinoid. The minor constituent Cannabiverol (CBV) possesses only about 20% of THC’s activity. CBD and CBN are not psychoactive, but they have valuable medical properties. (6-10)
Many synthetic analogs of THC are more or less potent than the parent molecule. The dimethylheptyl derivative is over 50 times more active, with effects lasting several days. Some nitrogen and sulfur analogs also are psychoactive.
The total synthesis of THC has been accomplished in many ways, most of which are difficult. However, the extraction of cannabinoids, their purification, isomerization and acetylation are easy experiments for dilettante souffleurs who would possess this elixir.