HU-336

HU-336 is the para-quinone of Δ8-tetrahydrocannabinol, an oxidation product of Δ8-THC described since the 1960s, whose para-quinone structure was confirmed in 2004 by Kogan, Mechoulam and colleagues. It showed antiproliferative activity on several human cancer cell lines in vitro, markedly lower than that of HU-331, the quinone of cannabidiol. A 2021 review judges that the closed pyran ring (ring B), which prevents free rotation of the rings, is probably unfavourable to this activity. No CB1 or CB2 affinity constant was found for the molecule itself. In 2026, a study identified it as a major constituent of commercial Δ8-THC distillates and disposable vapes, where its mean content rises from 7.72 to 22.45 nmol/mg after vaping, a mean increase of 3.67-fold, reaching 30.24 mM in one cartridge. At 8.5 µM on human bronchial cells, it alters the expression of 3139 genes at 24 h, whereas Δ8-THC produces no distinct signature. No pharmacokinetic or clinical data are published in the sources consulted.

Source

Oxidation product of Δ8-tetrahydrocannabinol: the phenolic ring of Δ8-THC is converted into a para-quinone. No presence in the cannabis plant is reported in the sources consulted. In 2026, a study identified it as a major constituent of commercial Δ8-THC distillates and disposable vapes, where its content rises after vaping.

No biosynthetic pathway described: HU-336 arises from the oxidation of Δ8-THC, which converts its phenolic ring into a para-quinone, obtained by chemical synthesis for research. In vaping, its measured content rises after heated aerosolisation. The 2026 authors compare this process with the oxidation of CBD to CBDQ and consider free-radical oxidation of Δ8-THC likely, without having demonstrated it. No enzymatic pathway in the plant is described in the sources consulted.

European Union

No harmonised control measure at European Union level targets this molecule; its control falls to national legislation. It does not appear in the schedules of the 1971 Convention: the 2026 INCB Green List names, under tetrahydrocannabinol, only specifically named dibenzopyran-1-ol isomers, including Δ8-THC. HU-336, with molecular formula C21H28O3, is not one of these isomers.

France

HU-336 is named in no annex of the order of 22 February 1990, nor in the ANSM consolidated list updated on 16 February 2026. It is not named in the annex III entry on tetrahydrocannabinols, their esters, ethers and salts. The generic clause for the benzo[c]chromene nucleus, from the ANSM decision of 22 May 2024 (annex IV), covers any derivative of that nucleus, fully or partially hydrogenated on ring A, substituted or not at position 1, 2, 3, 4, 6 or 9 by the groups it lists. HU-336 has a partially hydrogenated ring A, a pentyl chain at position 3, two methyls at position 6 and a methyl at position 9, which match that list. However, its positions 1 and 4 carry quinone ketone functions, which the clause does not provide for (at position 1: a hydroxyl function, esterified or not, or an alkoxy; at position 4: a carboxyl function), and its quinone ring is no longer aromatic. The text does not settle whether these substitutions exclude the molecule, so its status remains uncertain at this stage. This absence of scheduling is not an authorisation: no authorised medical, food or cosmetic use is documented in the sources consulted.

Sources: EUR-Lex, UNODC, CND, ANSM, IUPHAR/BPS, ChEBI, EUDA. Our method.

1. 1Kogan, Mechoulam et coll., synthèse et activité antitumorale de dérivés quinonoïdes des cannabinoïdes, Journal of Medicinal Chemistry 2004 (new tab)PMID 15239658
2. 2Kogan, Peters et Mechoulam, les quinones cannabinoïdes : revue et observations nouvelles, Molecules 2021 (new tab)PMID 33801057
3. 3Galal Osman et coll., produits bioactifs de la photo-oxygénation des cannabinoïdes par l'oxygène singulet, European Journal of Medicinal Chemistry 2018 (new tab)PMID 29232588
4. 4Love et coll., réponses transcriptomiques et fonctionnelles de cellules bronchiques humaines au Δ8-THC vapoté et à son produit d'oxydation, le Δ8-THCQ, Scientific Reports 2026 (new tab)PMID 42141046
5. 5ANSM, décision du 22 mai 2024 portant modification de la liste des substances classées comme stupéfiants (clause générique benzo[c]chromène) (new tab)
6. 6ANSM, liste consolidée des substances classées comme stupéfiants, mise à jour du 16 février 2026 (new tab)
7. 7OICS, liste verte 2026 des substances psychotropes placées sous contrôle international (convention de 1971) (new tab)
8. 8ChEMBL, CHEMBL2111830 : mesures enregistrées pour HU-336 (new tab)
9. 9PubChem CID 11370880 : HU-336 (identifiants) (new tab)

SMILES

CCCCCC1=CC(=O)C2=C(C1=O)OC([C@H]3[C@H]2CC(=CC3)C)(C)C

InChIKey

GOZGLSHDDOJPJS-HZPDHXFCSA-N

Machine-readable entry (JSON)

LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.