ÃÂ<sup>9</sup>-Tetrahydrocannabutol (ÃÂ<sup>9</sup>-THCB, THC-B, tetrahydrocannabinol-C4, THC-C4, (C4)-ÃÂ<sup>9</sup>-THC, or butyl-THC) is a phytocannabinoid found in cannabis that is a homologue of tetrahydrocannabinol (THC), the main active component of Cannabis. Structurally, they are only different by the pentyl side chain being replaced by a butyl side chain. THCB was studied by Roger Adams as early as 1942
ÃÂ<sup>9</sup>-THCB, showed an affinity for the human CB<sub>1</sub> (Ki = 15 nM) and CB<sub>2</sub> receptors (Ki = 51 nM) comparable to that of ÃÂ<sup>9</sup>-THC. The formalin test in vivo was performed on ÃÂ<sup>9</sup>-THCB in order to reveal possible analgesic and anti-inflammatory properties. The tetrad test in mice showed a partial agonistic activity of ÃÂ<sup>9</sup>-THCB toward the CB<sub>1</sub> receptor. THCB has rarely been isolated from cannabis samples, but appears to be less commonly present than THC or THCV. It is metabolized in a similar manner to THC.
In an analysis by the University of Rhode Island on phytocannabinoids it was found that THC-Butyl had the highest 3C-like protease inhibitor activity against COVID-19 out of all the phytocannabinoids tested within that study but not as high as the antiviral drug GC376 (81% THCB vs. 100% GC376).
Similarly to THC, it has 7 double bond isomers and 30 stereoisomers. The ÃÂ<sup>8</sup> isomer is known as a synthetic cannabinoid under the code name JWH-130, and the ring-opened analogue cannibidibutol (CBDB) is also known. THC-Butyl can be synthesized from 4-butylresorcinol. ] ]
THCB is not scheduled internationally under the Convention on Psychotropic Substances, but may be controlled under analogue law in some individual jurisdictions as a homologue of THC.