Synthesis of Cannabinoid Model Compounds. Part 2): (3R,4R)-δ1(6)-Tetrahydrocannabinol-5"-oic Acid and 4"(R,S)-Methyl-(3R,4R)-δ1(6)-Tetrahydrocannabinol-5"-oic Acid

Article abstract of DOI:10.1002/hlca.19800630845

Two novel cannabinoid model compounds, (3R,4R)-Δ¹⁽⁶⁾-tetrahydrocannabinol-5"-oic acid (22) and 4"(R,S)-methyl-(3R,4R)-Δ¹⁽⁶⁾-tetrahydrocannabinol-5"-oic acid (23) were synthesized by acid-catalyzed condensation of (+)-trans-p-mentha-2,8-dien-1-ol (1) with the substituted resorcinols 18 and 19 obtained by a Wittig reaction between 3,5-bis(benzyloxy)benzaldehyde (7) and methyl 4-bromobutanoate (10) or methyl 4-bromo-2(R,S)-methylbutanoate (11) resp. with subsequent hydrogenation.The resulting methyl esters 20 and 21 were hydrolyzed to give acids 22 and 23.