XLR-11

Product Name: XLR-11 (5F-UR-144) Synonyms: 5-fluoro-UR-144; 5F-UR-144; (1-(5-fluoropentyl)-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)methanone

General Description: XLR-11 is formally described as (1-(5-fluoropentyl)-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)methanone. It is a synthetic, highly psychoactive molecule belonging to the tetramethylcyclopropylindole class of synthetic cannabinoids (SCs). Structurally, it is the terminal 5-fluoro analogue of the designer drug UR-144. The addition of a terminal fluorine atom to the pentyl chain was a common modification in designer cannabinoids intended to increase receptor binding affinity and metabolic stability, while circumventing early generic bans on unhalogenated synthetic cannabinoids. XLR-11 emerged heavily on the illicit market in 2012 as a novel psychoactive substance (NPS) and a prominent active ingredient in “herbal incense” smoking blends (such as “Spice” or “K2”).

In analytical, clinical, and forensic toxicology, XLR-11 is utilized as a fundamental reference standard. It is essential for the calibration of analytical instrumentation (such as LC-MS/MS, GC-MS, and NMR) and the development of screening methodologies to identify and quantify the substance and its metabolites in seized materials, adulterated products, or biological matrices (e.g., whole blood, plasma, urine).

Technical Information:

• CAS Number: 1364933-54-9
• Molecular Formula: C₂₁H₂₈FNO
• Formula Weight: 329.45 g/mol
• SMILES: FCCCCCN1C=C(C2=C1C=CC=C2)C(=O)C3C(C)(C)C3(C)C
• InChI Key: HZLZTZZMBBIVBU-UHFFFAOYSA-N
• Formulation: Typically supplied as a neat white-to-off-white crystalline solid or as a certified reference material solution (e.g., 1 mg/mL or 100 µg/mL in methanol or acetonitrile).

Biological Action: Like its parent compound UR-144, XLR-11 acts as a highly potent, non-selective full agonist at both the central cannabinoid type 1 (CB₁) and peripheral cannabinoid type 2 (CB₂) receptors. By functioning as a full agonist (lacking the partial-agonist “ceiling effect” characteristic of natural Δ⁹-THC), it profoundly overstimulates the endocannabinoid system. Acute intoxication is notoriously associated with severe synthetic cannabinoid toxidromes, including pronounced tachycardia, hypertension, intense paranoia, acute synthetic cannabinoid-induced psychosis, severe agitation, and seizures. Most notably, toxicological and epidemiological data have strongly linked the abuse of XLR-11 to clusters of acute kidney injury (AKI), acute tubular necrosis, and acute renal failure.

Regulatory and Safety Information:

• Intended Use: This product is intended strictly for use as an analytical reference standard for forensic, toxicological, and academic research purposes.
• Warning: This product is an exceptionally potent synthetic cannabinoid and carries a severe risk of psychiatric crises, neurological emergencies (including seizures), severe renal toxicity (AKI), and potentially fatal overdose. It is not for human or veterinary use.