A-834735.

A-834735 is a synthetic cannabinoid receptor agonist of the indole ketone family: the same tetramethylcyclopropyl head as UR-144 and XLR-11, but a tetrahydropyran-4-ylmethyl chain on the indole nitrogen. Its binding favours CB2 (15-fold in the rat in the assay of Chin et al., 17-fold at human receptors in Thomas et al.), which in no way attenuates the risk, because its intrinsic efficacy is high at both receptors: at human CB1, the stimulation measured in a functional assay approaches twice that of the reference CP55,940. Where THC is a partial agonist whose response plateaus, a full agonist of such efficacy knows no such ceiling, and it is this difference that explains the particular severity of poisonings by synthetic cannabinoids. In the rat, the molecule crosses the blood-brain barrier and produces a regional brain activation abolished by a CB1 antagonist, which shows that the central signal passes through this receptor despite the binding selectivity. A second point counts just as much: when heated, the molecule ring-opens into a degradation product whose affinity for human CB1 is about eight times greater than that of the parent compound. What the literature does not establish is just as clear: no study in humans, no metabolism data, no published clinical case, no documented action at TRPV1, PPAR gamma or 5-HT1A (at human GPR55, only a weak antagonism was measured in vitro, extrapolated IC50 of 6.88 µM). Human data are entirely lacking.

Source

An entirely synthetic molecule, absent from hemp and from every living organism: it exists neither in cannabis, nor in hemp extracts, nor in any cannabidiol product. It was designed by the pharmaceutical industry as an analgesic candidate directed at the CB2 receptor, then taken up as a reference agonist in brain imaging in rodents. An appearance outside the laboratory is documented: a Japanese team found it in illegal products, a context in which neither the content, nor the purity, nor even the real identity of the substance present is known to the person buying it.

No biosynthetic pathway: the molecule derives from no plant or animal metabolism and has no natural precursor. It belongs solely to synthetic chemistry.

European Union

No control at Union level: the substance does not appear in the annex to Framework Decision 2004/757/JHA, which retains among synthetic cannabinoid agonists only a short list of compounds that have been formally risk-assessed by the European drugs monitoring centre. A-834735 has never been submitted to such an assessment. It is likewise absent from the schedules of the 1971 Convention on Psychotropic Substances, and no critical review by the WHO Expert Committee on Drug Dependence has been devoted to it: there is therefore no international control measure targeting it. Classification is a matter for each Member State, and France has chosen to name it.

France

A-834735 is entered by name on the French list of narcotics and also falls under a generic family. It appears in annex IV of the decree of 22 February 1990 (ANSM consolidated list, updated 16 February 2026), cited under its code and its full systematic name as an example ("notamment") of the generic family of "indol-3-yl methanones": a substituent on the nitrogen of the indole ring of the alkyl, haloalkyl, cycloalkylmethyl, methyl-oxane type (here tetrahydropyran-4-ylmethyl) or related, and a naphthyl, benzyl, phenyl, cyclopropyl or adamantyl group on the carbon of the methanone bridge. This family and this mention were introduced into annex IV by the decree of 31 March 2017 (JORF of 6 April 2017). This is therefore not the case of the esters and ethers of tetrahydrocannabinol, captured by a generic definition specific to THC: the substance is cited in its own right. Production, importation, possession, transfer and use fall under the criminal regime for narcotics, and no legally sold cannabidiol product may contain it.

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

Family

Synthetic CB receptor agonist › Research ligand or medicine

Class

tetramethylcyclopropylketone

Verification

Classification, sources and binding values checked on 20 October 2026; text read against its sources and Wikipedia.

Wikipedia (English)

A-834,735 (new tab)

Article paired by the molecule's structure (InChIKey), revision read on 19 October 2026. Read as a second opinion, never cited as a source.

1. 1Chin CL et al., British Journal of Pharmacology, 2008: regional effects of A-834735 on rat brain activity in pharmacological MRI, CB1 and CB2 affinities, blockade by rimonabant (new tab)PMID 17965748
2. 2Thomas BF et al., Journal of Pharmacology and Experimental Therapeutics, 2017: thermolytic degradation of A-834735, affinity and efficacy of the ring-opened product at human CB1 and CB2 (new tab)PMID 28087785
3. 3Uchiyama N et al., Forensic Toxicology, 2014, volume 32, pages 9 to 18: identification of two new types of designer drug, with the synthetic cannabinoid A-834735, in illegal products (new tab)DOI 10.1007/s11419-013-0194-5
4. 4Hess C et al., Forensic Toxicology, 2016: human Ki values of A-834735 (25.0 nM at CB1, 0.566 nM at CB2) and GPR55 antagonism in β-arrestin recruitment (extrapolated IC50 of 6.88 µM) (new tab)PMID 27429655
5. 5Frost JM et al., Journal of Medicinal Chemistry, 2008: the indol-3-yl-tetramethylcyclopropyl ketone series as CB2 receptor ligands; Ki of A-834735 at human CB1 and CB2 (new tab)PMID 18311894
6. 6Frost JM et al., Journal of Medicinal Chemistry, 2010: variations of the chain borne by the indole nitrogen in the same series; Ki of A-834735 at human CB1 and CB2 (new tab)PMID 19921781
7. 7Order of 22 February 1990 setting the list of substances classified as narcotics, Annex IV, consolidated version on Légifrance: A-834,735 named under its systematic name (new tab)
8. 8ANSM, consolidated list of substances classified as narcotics, updated 16 February 2026: A-834,735 cited as an example of the « indol-3-yl methanone » family (Annex IV) (new tab)
9. 9Order of 31 March 2017 amending the order of 22 February 1990 setting the list of substances classified as narcotics (Légifrance, JORF of 6 April 2017) (new tab)

SMILES

CC1(C(C1(C)C)C(=O)C2=CN(C3=CC=CC=C32)CC4CCOCC4)C

Machine-readable entry (JSON)

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