AB-FUBINACA 2-fluorobenzyl isomer.

The 2-fluorobenzyl isomer of AB-FUBINACA is a presumed cannabinoid receptor agonist, built on the indazole-3-carboxamide skeleton common to the whole FUBINACA series. What makes this family dangerous is full agonism at the CB1 receptor: where THC activates that receptor only partially, the synthetic carboxamides can activate it maximally, without the ceiling effect that limits cannabis. For this particular isomer, however, the pharmacology remains undocumented: no binding study, no functional assay, no metabolism or pharmacokinetic data have been published, and human data are lacking. What is established concerns it as an analytical problem: the laboratory of the Drug Enforcement Administration has published a reference monograph (revision of March 2016) and two mass spectrometry studies (Murakami et al., 2016 and 2018) have developed the methods that allow it to be distinguished from AB-FUBINACA and from its other positional isomers. That distinction is no detail: the ANSM consolidated list names "AB-FUBINACA" while attaching to it a 2-fluorophenyl systematic name, and confusing two isomers has direct consequences, judicial as well as health-related.

Source

Entirely synthetic origin. This molecule occurs neither in hemp nor in any plant: it is produced by chemical synthesis. It is known chiefly as analytical reference material (DEA SWGDRUG monograph, 2016) and as a positional isomer to be distinguished from AB-FUBINACA.

No known biological pathway: this molecule comes from no living organism. It arises entirely from chemical synthesis. It has never been demonstrated in hemp nor in any other plant.

European Union

At international level, AB-FUBINACA, the para isomer, was placed in Schedule II of the 1971 Convention on psychotropic substances by decision of the United Nations Commission on Narcotic Drugs at its 63rd session, in March 2020, on the recommendation of the World Health Organization expert committee that met in 2019; the decision entered into force on 3 November 2020. That listing covers the named substance and its stereoisomers, not its positional isomers: the 2-fluorobenzyl isomer is therefore not caught by that text. No measure applicable across the European Union names it, and its status depends on the law of each Member State; France applies a generic definition that encompasses it. The United Nations Office on Drugs and Crime records it among the synthetic cannabinoid receptor agonists in its early warning system.

France

In France, this isomer is not listed by name on the narcotics list, but it is captured by a generic clause. Annex IV of the decree of 22 February 1990 classifies any molecule belonging to the family of 3-carboxamide indazole derivatives bearing, on the nitrogen at position 1 of the indazole core, a substituent of the halobenzyl type, and bearing, on the nitrogen of the carboxamide bridge, a group of the 1-amino-1-oxo-butan-2-yl type, whether or not that group is substituted at position 3 by one or two alkyl groups. The 2-fluorobenzyl group and the valinamide residue of this molecule fulfil both conditions: classification as a narcotic therefore arises through a generic clause, and not through listing by name. As a point of reference, the named entry "AB-FUBINACA" appears in annex III of the consolidated list, which reproduces the schedules of the 1971 Convention; but the systematic name the list attaches to it, N-[(1S)-1-(aminocarbonyl)-2-methylpropyl]-1-[(2-fluorophenyl)methyl]-1H-indazole-3-carboxamide, is that of the 2-fluorobenzyl isomer described here, whereas the AB-FUBINACA of the literature bears a 4-fluorobenzyl group: the code and the systematic name of that entry therefore do not designate the same molecule, and the exact reach of the named entry with respect to this isomer cannot be settled here. Possessing, supplying or consuming a substance classified as a narcotic is a criminal offence in France; this paragraph describes the state of the law and does not constitute legal advice.

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

Family

Synthetic CB receptor agonist › New psychoactive substance

Class

indazole-3-carboxamide

Verification

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

Wikipedia (English)

No dedicated article.

1. 1Murakami T, Iwamuro Y, Ishimaru R, Chinaka S, Takayama N, Hasegawa H. Differentiation of AB-FUBINACA and its five positional isomers using liquid chromatography-electrospray ionization-linear ion trap mass spectrometry and triple quadrupole mass spectrometry. Forensic Toxicology. 2018;36(2):351-358. (new tab)PMID 29963205
2. 2Murakami T, Iwamuro Y, Ishimaru R, Chinaka S, Sugimura N, Takayama N. Differentiation of AB-FUBINACA positional isomers by the abundance of product ions using electron ionization-triple quadrupole mass spectrometry. Journal of Mass Spectrometry. 2016;51(11):1016-1022. (new tab)PMID 27441731
3. 3SWGDRUG monograph: AB-FUBINACA 2-fluorobenzyl isomer, drawn up by the Special Testing and Research Laboratory of the Drug Enforcement Administration on structurally confirmed material (proton NMR, electron-impact GC-MS, infrared spectrum), 2016 revision. (new tab)
4. 4UNODC, Early Warning Advisory on New Psychoactive Substances, substance record AB-FUBINACA 2-fluorobenzyl isomer (group: synthetic cannabinoids; effect: synthetic cannabinoid receptor agonist). (new tab)
5. 5ANSM, consolidated list of substances classified as narcotics (updated 16 February 2026): Annex IV, generic clause « Indazole-3-carboxamide derivatives »; Annex III, AB-FUBINACA named. (new tab)
6. 6Légifrance, order of 22 February 1990 setting the list of substances classified as narcotics, Annex IV (version in force). (new tab)
7. 7Légifrance, order of 3 October 2017 amending the order of 22 February 1990, introducing the generic definitions of the synthetic cannabinoid families. (new tab)
8. 8WHO, Expert Committee on Drug Dependence (42nd meeting, 2019), critical review of AB-FUBINACA: pharmacological and clinical data relating to the para isomer, not to the 2-fluorobenzyl isomer. (new tab)
9. 9UNODC, announcement of the entry into force on 3 November 2020 of the decision of the 63rd session of the Commission on Narcotic Drugs placing AB-FUBINACA in Schedule II of the 1971 Convention. (new tab)

SMILES

CC(C)[C@@H](C(=O)N)NC(=O)C1=NN(C2=CC=CC=C21)CC3=CC=CC=C3F

Machine-readable entry (JSON)

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