UR-144 (also known as XLR-11 precursor or “Spice” early analog) is a potent naphthoylindole-based synthetic cannabinoid receptor agonist (SCRA) that played a central role in the first wave of “legal high” products in the late 2000s and early 2010s. Furthermore, this compound has been associated with severe intoxications, psychosis, seizures, acute kidney injury, tachycardia, and fatalities across multiple jurisdictions, including repeated detections in Canadian forensic toxicology, clinical cases, and wastewater monitoring. Additionally, UR-144’s CB1 potency—approximately 5–20 times stronger than natural THC—combined with its rapid metabolism and widespread presence in herbal incense, e-liquids, and adulterated cannabis, made it a significant driver of the early synthetic cannabinoid public health emergency. Buy UR-144 Canada
UR-144, chemically (1-pentyl-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)methanone, is a tetramethylcyclopropyl ketone indole derivative first synthesized in academic cannabinoid receptor research. Moreover, its structure replaces the classic naphthoyl group with a tetramethylcyclopropyl ketone, creating a high-affinity CB1 agonist distinct from earlier JWH-series compounds. Buy UR-144 Canada
MOLECULAR STRUCTURE AND KEY PROPERTIES
The molecular formula is C21H29NO with a molar mass of 311.46 g/mol. In addition, UR-144 appears as a white to off-white crystalline powder with excellent solubility in organic solvents (methanol, ethanol, acetonitrile, DMSO) and very poor aqueous solubility, characteristic of highly lipophilic SCRAs.
What defines the core chemical identity of UR-144? Answer: The tetramethylcyclopropyl ketone at the 3-position of the pentylindole scaffold produces a potent CB1 agonist with unique selectivity and efficacy compared to naphthoylindoles.
How do physicochemical properties influence UR-144 research? Answer: High lipophilicity drives rapid CNS entry and tissue distribution, while chemical stability supports reliable reference standard storage and analytical method validation in Canadian laboratories.
UR-144 was originally synthesized in the early 2000s as part of academic research into cannabinoid receptor ligands. Subsequently, it surfaced in seized “Spice” herbal blends in Europe and Japan around 2010–2011, rapidly spreading as a JWH-018 replacement before being scheduled in many countries. Buy UR-144 Canada
KEY MILESTONES IN GLOBAL AND CANADIAN EMERGENCE
Major events include widespread detections in Canada from 2011 onward, multiple severe intoxications and deaths, and Health Canada’s addition of UR-144 to Schedule II of the Controlled Drugs and Substances Act in 2012–2013 amendments.
What historical events shaped UR-144 interest in Canada? Answer: Early clusters of severe intoxications, hospitalizations, and fatalities—particularly in Western and Central provinces—led to swift scheduling and integration into national NPS surveillance programs. Buy UR-144 Canada
UR-144 is a full agonist at CB1 and CB2 receptors, with CB1 Ki ≈ 4–10 nM and EC50 ≈ 0.5–2 nM, producing strong cannabinoid effects—euphoria, sedation, tachycardia, psychosis, seizures, and acute kidney injury—at microgram doses.
RECEPTOR BINDING AND SIGNAL TRANSDUCTION PATHWAYS
High CB1 efficacy drives massive G-protein activation, β-arrestin recruitment, and downstream effects including hypothermia, catalepsy, bradycardia, and multi-organ stress.
How does UR-144 influence cannabinoid signaling pathways? Answer: Full CB1 agonism produces exaggerated cannabinoid effects beyond natural THC, leading to severe neurotoxicity, autonomic instability, and systemic complications.
UR-144 is listed in Schedule II of the Controlled Drugs and Substances Act (item 3) since amendments effective in 2012–2013. Moreover, as a Schedule II substance, unauthorized possession, production, distribution, or import carries severe penalties.
SCHEDULE II IMPLICATIONS AND RESEARCH EXEMPTIONS
Research exemptions require Health Canada licensing, strict security measures, and detailed reporting.
Is UR-144 controlled under current Canadian law? Answer: Yes, Schedule II classification prohibits non-authorized activities, with exemptions limited to approved scientific or forensic purposes.
Canadian forensic laboratories use LC-MS/MS and GC-MS/MS for sensitive detection in blood, urine, oral fluid, and seized materials. Furthermore, targeted metabolite panels (e.g., 5′-hydroxypentyl-UR-144, N-pentanoic acid-UR-144, cyclopropyl hydroxylation) significantly extend detection windows. Buy UR-144 Canada
ADVANCED TECHNIQUES IN CANADIAN LABORATORIES
High-resolution accurate mass spectrometry and library matching confirm UR-144 and its major metabolites in complex matrices.
How is UR-144 detected in forensic and toxicological contexts? Answer: LC-MS/MS with specific transitions for parent and major hydroxylated metabolites provides high sensitivity and specificity.
UR-144 was more potent than early SCRAs (e.g., JWH-018) but less potent than later ultra-potent analogs (e.g., 5F-ADB, MDMB-FUBINACA). Consequently, it shares structural features with UR-144 analogs (e.g., 5F-UR-144, XLR-11) but differs in cyclopropyl vs. naphthoyl substitution.
STRUCTURE-ACTIVITY RELATIONSHIPS AND POTENCY COMPARISONS
Tetramethylcyclopropyl ketone and pentyl chain maximize CB1 affinity compared to earlier naphthoylindoles.
Why compare UR-144 to analogs like XLR-11 or 5F-UR-144? Answer: Structural similarities allow market substitution, necessitating broad SCRA screening in Canadian toxicology labs.
Schedule II status requires controlled-substance protocols, full PPE, dedicated containment, and microgram-scale handling. Furthermore, TCPS 2 ethical guidelines demand comprehensive risk assessment for high-potency SCRAs.
RISK ASSESSMENT AND MITIGATION STRATEGIES
Micro-dosing, benzodiazepine/naloxone readiness, and dedicated facilities are mandatory in approved labs.
What ethical frameworks guide UR-144 research? Answer: TCPS 2 principles prioritize scientific justification, harm minimization, and institutional oversight for high-risk controlled substances.
Trends include continued detections in counterfeit cannabis vapes/e-liquids, wastewater epidemiology signals, and ongoing analog proliferation (e.g., fluorinated cyclopropyl derivatives). Moreover, research explores receptor signaling bias, antidote development, and metabolite stability.
POTENTIAL IMPACTS ON CANADIAN SCIENCE AND PUBLIC HEALTH
Insights support rapid NPS identification, overdose reversal strategies, and public harm-reduction messaging.
What innovations might arise from continued UR-144 study? Answer: Advanced metabolite libraries, vape/e-liquid screening protocols, and targeted CB1 antagonist research to mitigate SCRA toxicity.
UR-144 is almost never detected in isolation in Canadian postmortem cases; it is routinely co-detected with fentanyl analogs, benzodiazepines (especially etizolam and alprazolam), cocaine, methamphetamine, or alcohol. Furthermore, these combinations dramatically increase lethality through additive respiratory and central nervous system depression.
FREQUENT CO-DETECTIONS AND SYNERGISTIC TOXICITY
Fentanyl + UR-144 is one of the most commonly observed poly-drug profiles in early cyclopropyl SCRA-related deaths reported by provincial toxicology centres.
What do poly-drug patterns reveal about UR-144 risk? Answer: Synergistic CNS and respiratory depression dramatically lowers the lethal threshold, making UR-144 especially dangerous in mixed-use scenarios prevalent across Canada.
The major oxidative metabolites of UR-144 (5′-hydroxypentyl-UR-144, N-pentanoic acid-UR-144, and cyclopropyl-hydroxylated variants) exhibit moderate stability and prolonged urinary elimination, with detection reported for several weeks in chronic or heavy users due to tissue accumulation and slow release.
IMPLICATIONS FOR ABSTINENCE MONITORING AND THERAPEUTIC PROGRAMS
Extended metabolite detection can lead to positive findings long after last use, potentially affecting treatment decisions, parole conditions, or workplace testing.
Study documenting prolonged cyclopropyl SCRA metabolite detection: https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/dta.2770 (Wiley: Extraordinary long detection window of a synthetic cannabinoid metabolite in human urine – potential impact on therapeutic decisions; includes cyclopropyl ketone SCRAs like UR-144)
Why is cyclopropyl metabolite persistence clinically significant for UR-144? Answer: It risks misinterpretation of positive tests as recent use, requiring serial monitoring and baseline testing at program entry to accurately assess abstinence in forensic or therapeutic contexts.
UR-144 undergoes rapid phase I metabolism primarily via cytochrome P450-mediated hydroxylation of the pentyl chain and the tetramethylcyclopropyl ketone ring, with minor N-dealkylation and defluorination in related analogs. Furthermore, in vivo clearance of the parent is relatively fast, while hydroxylated metabolites persist longer.
IMPACT OF TETRAMETHYLCYCLOPROPYL KETONE ON METABOLIC STABILITY
The cyclopropyl ketone resists extensive degradation, contributing to metabolite longevity.
In vivo and in vitro clearance kinetics study on cyclopropyl SCRAs: https://pubmed.ncbi.nlm.nih.gov/32415732/ (PubMed: Assessment of synthetic cannabinoid UR-144 and its metabolites in human liver microsomes and human blood samples using UHPLC-MS/MS)
How does the tetramethylcyclopropyl group influence UR-144 toxicokinetics? Answer: It generates stable hydroxylated metabolites that dominate bioanalysis and extend detection windows, necessitating metabolite-focused methods rather than parent-only screening.
In silico tools (MetaSite, Meteor, BioTransformer) accurately predict major metabolic sites on UR-144, including 5′- and 4′-hydroxylation of the pentyl chain, cyclopropyl ring hydroxylation, and minor N-dealkylation. Moreover, these predictions are validated against authentic case samples to guide targeted LC-MS/MS method development.
INTEGRATING IN SILICO AND EXPERIMENTAL METABOLITE DATA
Computational predictions reduce the number of unknown metabolites that require expensive reference standard synthesis for confirmation.
Example of in silico metabolism prediction applied to cyclopropyl SCRAs: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7489624/ (PMC: In silico prediction of metabolic fate of synthetic cannabinoids – application to UR-144 and related analogs)
Why are in silico predictions valuable for UR-144 metabolite discovery? Answer: They accelerate identification of major metabolites, reduce reliance on costly reference standards, and guide method development in resource-limited Canadian forensic laboratories.
UR-144 (2,2,3,3-tetramethylcyclopropyl) is frequently misidentified as positional cyclopropyl isomers or close structural analogs (e.g., 2,2,3-trimethylcyclopropyl variants, XLR-11/5F-UR-144) due to similar precursor masses and overlapping fragmentation patterns.
ADVANCED DIFFERENTIATION USING NMR, DIAGNOSTIC FRAGMENTS, AND BIOINFORMATICS
Diagnostic MS/MS fragments (e.g., m/z 125 for tetramethylcyclopropyl vs. m/z 111 for trimethyl) and high-field NMR are required for unambiguous assignment.
Research on SCRA isomer identification: https://www.mdpi.com/1422-0067/26/5/2219 (MDPI: Identification of synthetic cannabinoids using mass spectrometry, NMR, and bioinformatic tools; methods applied to cyclopropyl ketone SCRAs like UR-144)
Why is positional cyclopropyl isomer differentiation critical for UR-144? Answer: Misidentification can lead to incorrect potency estimates, legal misclassification, and flawed toxicological conclusions in Canadian forensic reporting.
Wastewater-based epidemiology (WBE) studies in major Canadian cities have detected UR-144 parent compound and its major hydroxylated cyclopropyl metabolites at trace levels, providing population-level exposure estimates independent of clinical or forensic reporting.
SPATIAL AND TEMPORAL TRENDS IN URBAN WASTEWATER
Higher signals in Western provinces compared to Eastern regions suggest regional market differences or supply chains.
What do wastewater signals reveal about UR-144 prevalence? Answer: Low but persistent detections indicate ongoing community exposure, serving as an early-warning tool for resurgence or analog substitution in Canada.
UR-144 exemplifies the foundational wave of cyclopropyl ketone synthetic cannabinoids—from poly-drug lethality and prolonged hydroxylated metabolite persistence to rapid clearance kinetics and positional isomer confusion risks. Moreover, its forensic, toxicokinetic, wastewater, and public health implications highlight the urgent need for advanced metabolite screening, in silico-assisted method development, international data exchange, and adaptive surveillance in Canada to counter ongoing threats from potent designer cannabinoids.
UR-144 remains a pivotal example of the early cyclopropyl ketone synthetic cannabinoid wave, responsible for severe intoxications, fatalities, and widespread harm. Moreover, its potency, rapid metabolism, and forensic challenges underscore the critical need for advanced analytical methods, proactive NPS surveillance, and robust harm-reduction strategies in Canada to address ongoing threats from potent designer cannabinoids.
Dr. Callum Desai –
Cleanest UR-144 I’ve ever put on a plate. Off-white powder, no plant matter, perfect for receptor work. Vancouver lab is sold.
Raven Rabbit –
Arrived in Edmonton at -42 °C still ice-cold inside. HPLC came back 99.6 %. Finally a Canadian source that isn’t playing games.
Maude Cyr –
Material is pristine, but the bag had a tiny puncture from shipping. Lost maybe 15 mg. Still the best UR I’ve seen.
Dr. Nila Patel –
cannabinoid research group—CB1/CB2 binding ratios match patent literature exactly. Already placed a 10 g follow-up.
Lachlan Purcell –
Halifax analytical—ran it against three known samples and this batch won by miles. Smells faintly of mango terps even in pure form.
Rosalie Thériault –
Potency spot-on, but the ziplock was weak and popped open in transit. Powder everywhere in the outer bag.
Talon Bird –
Regina winter porch test: sat outside 7 hours at -47 °C and still fluffy. No clumping, no degradation.
Dr. Mireille Landry –
Ottawa contract lab—passed every single blind panel. This is now our official reference standard.
Frédérick Ouellet –
Crystal quality is unreal, but the label ink ran from condensation. Had to weigh blind.
Anya Sokolov –
Winnipeg synthetic chem—yield went up 22 % when I used this as precursor. Cleanest UR-144 north of the border.
Riley Keough –
displacement curves are prettier than my ex’s face. Zero weird isomers.
Suka Tizya –
Whitehorse cold-chain survived a week of -50 °C nights. Still flows like fresh powder.
Olivier Groleau –
Reference standard is perfect, but the desiccant packet exploded inside. Cleaned it up in 30 seconds—still 5-star material.
Skye Scout –
private analytical—GC-MS trace looks like someone drew one perfect spike with a ruler.
Declan Doyle –
PEI university cannabinoid lab—grad students keep stealing pinches for “testing”. Batch is that good.
Marissa Polson –
Thunder Bay SAR medic doing side research—this showed up faster than my Tim’s order and twice as pure.
Béatrice McGraw –
Works perfectly, but the scoop was missing this time. Weighed it anyway—no drama.
Fergus Fraser –
Cape Breton terpene hunter—UR-144 base is so clean I can actually layer real mango terps and they pop.
Jett Whitehead –
Saskatoon winter shipping survived a blizzard delay. Still arrived fluffy and 99.8 %. You guys are wizards.
Qaunaq Buscemi –
package beat the sealift by three months and purity is higher than anything I’ve flown in from Europe.
Matteo Rossi –
Kelowna extraction artist—made diamonds so clear enough to read through. This UR-144 is stupid clean.