From CBD to CBN: A Small-Scale, Project-Like Undergraduate Organic Lab Experiment Integrating Chemical Synthesis, TLC Co-spotting, Dry Column Vacuum Chromatography, and Antibacterial Testing

Cannabis-related chemistry is gradually becoming incorporated into the undergraduate curriculum, and laboratory experiments focusing on chemical analysis of cannabis products have appeared in this Journal; however, experiments focusing on the reactions and chemical synthesis of cannabinoids have yet to appear. We report a project-like, undergraduate organic chemistry teaching lab experiment in which students convert cannabidiol (CBD) to cannabinol (CBN) on a small scale using an experimentally straightforward, one-pot reaction. Students then establish the extent of conversion by TLC co-spotting their crude reaction mixture versus authentic samples of CBD and CBN. CBN is then isolated from the crude product mixture via a small-scale modification of dry column vacuum chromatography (DCVC), a convenient and rapid reduced-pressure alternative to flash column chromatography that employs common lab glassware. Finally, students qualitatively assess the antibacterial activities of CBD and CBN by evaluating inhibition of bacterial growth on nutrient agar plates, using cannabinoid samples they recrystallized from commercially available crude distillates.