In this text the & and ,A6 forms of THC are identical to the g or .18 forms of THC cited in other literature. The differing notation results from the adoption of different numbering systems by various authors. Although either system is technically correct, the monoterpeniod numbering system has been adopted because it is more representative of the terpenes involved in cannabinoid biosynthesis and it is the system used by Robert Mechoulam who elucidated the structure of THC.

 

The biosynthesis of cannabinoids is still an active area of research. Since 61 different cannabinoids are knoWn to exist, the scheme shown here is a simplified picture—the reality is complicated by the probability that different strains of Cannabis have different pathways. The pathway below was proposed by Mechoulam in 1970, and is shown for the pentyl (five-carbon) compounds. Similar pathways would exist for the propyl (three-carbon) and methyl (one-carbon) compounds.