Cannabinoid skeleton

Lactone 5 can be obtained in both enantiomeric forms or as a racemate according to the described procedure. The reaction sequence includes the in situ formation of an alkylidene-1,3-dicarbonyl system 7 which can act as a heterodiene in an intramolecular hetero-Diels-Alder addition. A small amount of the ene product 4 with de > 98% is formed at room temperature as well. The remarkable selectivity in formation of diastereomer 3 is explained by an energetically more favorable exo transition state 8 with a pseudo-chair arrangement having the methyl group quasi-equatorial. Polycyclic cis-fused compounds can also be synthesized by the procedure above,9 and a related sequence to the cannabinoid skeleton has been described using appropriate 1,3-dicarbonyl reactants.10... 

The challenge to the synthetic chemist that was posed by these structures was the control of C6 stereochemistry. An early solution to this problem involved the intramolecular oxymercuration-demercuration approach, as illustrated in Scheme 9 (46,58). Thus, the stereoselective cyclization of 38 to the tricycUc cannabinoid skeleton by means of the intramolecular oxymercuration-demercuration reaction (58,61) gave the 6P-isomer predominantly (6P 6a = 85 15). The enantiomers were separated by chiral high-performance liquid chromatography (HPLC) using Chiralpak OD columns. The probable... 

Until the mid 1960 s the only plant cannabinoid whose structure was fully elucidated was cannabinol (CBN) — a constituent which actually may represent an oxidation artifact. However, on the basis of CBN, the main cannabinoid structure skeleton became known. Thus, cannabidiol (CBD), which had been independently isolated in pure form by Adams and by Todd, was correctly assumed to be, like CBN, a terpenoid derivative attached to olivetol. But its exact structure was not elucidated. The psychoactive components of cannabis were assumed to be related tricyclic derivatives. On the basis of the tentatively elucidated constituents, Todd suggested that the cannabinoids may be formed initially in the plant by condensation of a menthatriene with olivetol. 

Some azocane-substituted pyrazoline compounds have been reported as cannabinoid receptor modulators <2007W00009723, 2007WO131538>. An azocane derivative with a 3,3-diphenylpentane skeleton was reported to be an inhibitor of human 5a-reductase 1 <2007BMCL5414>. A dipyridamole analog having a bis-azocane structure was identified as a highly potent Nucleoside Transporter 1 inhibitor <2007JMC3906>. 

Bab I, Zimmer A, Melamed E (2009) Cannabinoids and the skeleton from marijuana to reversal of bone loss. Ann Med 41 560-567... 

Cannabinoids.—New compounds (259 OH at C-8 or at C-10)847 and (259 OH at both C-9 and C-10)848 have been isolated from Cannabis sativa. p-Menth-2-ene-1,8-diol is an excellent synthon for the A9-tetrahydrocannabinol (THC) skeleton, coupling (ZnCl2-catalysed) with olivetol (3-n-pentylresorcinol) to form the (—)-parent compound, and forming the biologically potent 3-OH metabolite by appropriate modification of the reaction.849 The structurally equivalent substrate p-menth-1,8-dien-1 -ol reacted with other substituted resorcinols and led to A8- and A9-THC analogues differing in the side-chain attached at C-3.850-851 Use of the synthon (260) in a similar manner gave 2, 1 l-dihydroxy-A9-THC this was claimed... 

Taglialatela-Scafati O, Pagani A, Scala F, De Petrocellis L, Di Marzo V, Grassi G, Appendino G (2010) Cannabimovone, a Cannabinoid with a rearranged terpenoid skeleton from hemp. Fur J Org Chem 11 2067... 

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