Synthesis and spectroscopic characterization of cannabinolic acid.

Cannabinoids, the main constituents of the cannabis plant, are being increasingly studied for their medicinal properties. Cannabinolic acid (CBNA; 1) was synthesized from tetrahydrocannabinolic acid (THCA; 2), a major constituent of the cannabis plant, by aromatization using selenium dioxide mixed with trimethylsilyl polyphosphate as catalyst in chloroform. Purification was achieved by centrifugal partition chromatography, and the final product had a purity of over 96% by GC analysis. Spectroscopic data on CBNA such as 1H-NMR and IR, and molar extinction coefficients, as well as chromatographic data are presented as useful references for further research on CBNA. The developed method allows production of CBNA on a preparative scale, making it available for further studies on its biological activities as well as use as a reference standard for analytical procedures.