Synthesis of Functionalized Cannabilactones

Axially Chiral Cannabinoids: Design, Synthesis, and Cannabinoid Receptor Affinity

The resorcinol-terpene phytocannabinoid template is a privileged scaffold for the development of diverse therapeutics targeting the endocannabinoid system. Axially chiral cannabinols (axCBNs) are unnatural cannabinols (CBNs) that bear an additional C10 substituent, which twists the cannabinol biaryl framework out of planarity creating an axis of chirality. This unique structural modification is hypothesized to enhance both the physical and biological properties of cannabinoid ligands, thus ushering in the next generation of endocannabinoid system chemical probes and cannabinoid-inspired leads for drug development. In this full report, we describe the philosophy guiding the design of axCBNs as well as several synthetic strategies for their construction. We also introduce a second class of axially chiral cannabinoids inspired by cannabidiol (CBD), termed axially chiral cannabidiols (axCBDs). Finally, we provide an analysis of axially chiral cannabinoid (axCannabinoid) atropisomerism, which spans two classes (class 1 and 3 atropisomers), and provide first evidence that axCannabinoids retain─and in some cases, strengthen─affinity and functional activity at cannabinoid receptors. Together, these findings present a promising new direction for the design of novel cannabinoid ligands for drug discovery and exploration of the complex endocannabinoid system.

Oxa-adamantyl cannabinoids

As a continuation of earlier work on classical cannabinoids bearing bulky side chains we report here the design, synthesis, and biological evaluation of 3'-functionalized oxa-adamantyl cannabinoids as a novel class of cannabinergic ligands. Key synthetic steps involve nucleophilic addition/transannular cyclization of aryllithium to epoxyketone in the presence of cerium chloride and stereoselective construction of the tricyclic cannabinoid nucleus. The synthesis of the oxa-adamantyl cannabinoids is convenient, and amenable to scale up allowing the preparation of these analogs in sufficient quantities for detailed in vitro evaluation. The novel oxa-adamantyl cannabinoids reported here were found to be high affinity ligands for the CB1 and CB2 cannabinoid receptors. In the cyclase assay these compounds were found to behave as potent and efficacious CB1 receptor agonists. Isothiocyanate analog AM10504 is capable of irreversibly labeling both the CB1 and CB2 receptors.

Structural and Functional Insights into Cannabinoid Receptors

Cannabinoid receptors type 1 (CB1) and 2 (CB2) are widely expressed in the human body, and are attractive drug targets in the prevention and management of central nervous system (CNS) and immune system dysfunction, respectively. Recent breakthroughs in the structural elucidation of cannabinoid receptors and their signaling complexes with G proteins, provide the important molecular basis of ligand-receptor interactions, activation and signaling mechanism, which will facilitate the next-generation drug design and the precise modulation of the endocannabinoid system. Here, we provide an overview on the structural features of cannabinoid receptors in different functional states and the diverse ligand binding modes. The major challenges and new strategies for future therapeutic applications targeting the endocannabinoid system (ECS) are also discussed.