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Cannabis e-cigarettes containing Δ 8 -tetrahydrocannabinol (Δ 8 -THC) produced synthetically from hemp-derived cannabidiol (CBD) have recently risen in popularity as a legal means of cannabis consumption, but questions surrounding purity and unlabeled additives have created doubts of their safety. Herein, NMR, GC-MS, and ICP-MS were used to analyze major components of 27 products from 10 brands, and it was determined none of these had accurate Δ 8 -THC labeling, 11 had unlabeled cutting agents, and all contained reaction side-products including olivetol, Δ 4(8) - iso -tetrahydrocannabinol, 9-ethoxyhexahydrocannabinol, Δ 9 -tetrahydrocannabinol (Δ 9 -THC), heavy metals, and a novel previously undescribed cannabinoid, iso -tetrahydrocannabifuran.

The therapeutic effects of Δ 9 -tetrahydrocannabinol (Δ 9 -THC) can be enhanced by modifications of the pentyl moiety at C-3. The engineering of Cannabis sativa olivetolic acid cyclase and tetraketide synthase with F24I and L190G substitutions, respectively, in the biosynthesis of Δ 9 -THC serves as a platform for the generation of resorcylic acids up to 6-undecylresorcylic acid. These results provide insights into the development of THC analogs with chemically distinct acyl moieties at C-3.

Cannabidiol (CBD), a major non-psychoactive cannabinoid, has a lot of attention due to its potential relaxing properties and led the trend in commercial CBD aroma/oral hemp seed oil from the Japanese market. In this study, a routine assay for evaluating CBD oil samples was performed using LC coupled with tandem mass spectrometry (LC-MS/MS) and was used to apply the convertible tetrahydrocannabinol (THC) in acetic acid conditions. Based on the electrospray positive ion mode, the detection of cannabidiolic acid (CBDA; m/z 359 > 219), cannabigerolic acid (CBGA; m/z 361 > 343), cannabigerol (CBG; m/z 317 > 193), CBD (m/z 315 > 193), THC (m/z 315 > 193) and cannabinol (CBN; m/z 311 > 223) was performed by satisfying separation with high density of C 18 column. Oil samples (50 mg) were diluted with isopropanol (5 mL), to which stable isotope internal standards were added by dilution with methanol/water (50/50), and accuracy rates ranged from 97.8 to 102.2%. This method was used to evaluate the CBD oil products (5 kinds) from the Japanese market. Our survey found obvious counterfeit (non-detectable CBD) CBD oil from Japanese market. Following that, we investigated the conversion of THC in CBD oil samples in simple conditions such as 10% acetic acid and 70 °C for 6 h and discovered that converts THC proportions are approximately 5% ((THC content/CBD content) × 100) and <1.0%. Thus, our developed LC-MS/MS assay could be applied to monitor the CBD concentration and convertible THC from CBD oil.

More than 500 molecules have been identified as components of Cannabis sativa (C. sativa), of which the most studied is Δ 9 -tetrahydrocannabinol (Δ 9 -THC). Several studies have suggested that Δ 9 -THC exerts diverse biological effects, ranging from fragmentation of DNA to behavioral disruptions. Currently, it is accepted that most of the pharmacological properties of Δ 9 -THC engage the activation of the cannabinoid receptors, named CB 1 and CB 2 . Interestingly, multiple pieces of evidence have suggested that the cannabinoid receptors play an active role in the modulation of several diseases leading to the design of synthetic cannabinoid-like compounds. Advances in the development of synthetic CB 1 cannabinoid receptor selective agonists as therapeutical approaches are, however, limited. This review focuses on available evidence searched in PubMed regarding the synthetic CB 1 cannabinoid receptor selective agonists such as AM-1235, arachidonyl-2' chloroethylamide (ACEA), CP 50,556-1 (Levonantradol), CP-55,940, HU-210, JWH-007, JWH-018, JWH-200 (WIN 55,225), methanandamide, nabilone, O-1812, UR-144, WIN 55,212-2, nabiximols, and dronabinol. Indeed, it would be ambitious to describe all available evidence related to the synthetic CB 1 cannabinoid receptor selective agonists. However, and despite the positive evidence on the positive results of using these compounds in experimental models of health disturbances and preclinical trials, we discuss evidence in regards some concerns due to side effects., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Based on the Diels-Alder reaction of vinylchromenes with electron-poor dienophiles, we developed a strategy for the synthesis of tetrahydrocannabinol derivatives. Substituted vinyl chromenes could be converted with several dienophiles to successfully isolate several complex molecules. These molecules already contain the cannabinoid-like base structure and further processing of one such derivative led to a precursor of Δ 9 -tetrahydrocannabinol. The most challenging step towards this precursor was an epoxidation step that was ultimately achieved via dimethyl dioxirane., (© 2021 The Authors. Published by Wiley-VCH GmbH.)

The first total synthesis of potent cannabinoid, 9β-11-hydroxyhexahydrocannabinol, is achieved through a proline-catalyzed inverse-electron-demand Diels-Alder reaction. Using this asymmetric catalysis, the cyclohexane ring is constructed with two chiral centers as a single diastereomer with 97% ee. The creation of the third chiral center and benzopyran ring is demonstrated with the elegant synthetic strategies. This mild and efficient synthetic methodology provides a new route for the asymmetric synthesis of the other potent hexahydrocannabinols.

Background and Purpose: It has been suggested that the non-euphorogenic phytocannabinoid cannabidiol (CBD) can ameliorate adverse effects of Δ 9 -tetrahydrocannabinol (THC). We determined whether CBD ameliorates cognitive deficits and withdrawal signs induced by cannabinoid CB 1 /CB 2 receptor agonists or produces these pharmacological effects on its own., Experimental Approach: The effects of THC or the CB 1 /CB 2 receptor full agonist WIN55212 alone, CBD alone or their combination were tested across a range of doses. Cognitive effects were assessed in C57BL/6 mice in a conditional discrimination task and in the Barnes maze. Cannabinoid withdrawal signs were assessed following precipitated withdrawal by acute administration of the CB 1 receptor antagonist SR141716, the 5-HT 1A receptor antagonist WAY100635, the TRPV1 receptor antagonist capsazepine or the adenosine A 2A receptor antagonist SCH58261., Key Results: THC produced significant motor and cognitive impairment in the Barnes maze task, none of which were attenuated by the addition of CBD. CBD alone did not affect cognitive performance. Precipitation of withdrawal signs by SR141716 occurred in mice chronically treated with THC or WIN55,212. These withdrawal signs were not attenuated by addition of chronic CBD. Chronic treatment with CBD alone did not induce withdrawal signs precipitated by SR141716 or WAY100635. Chronic CBD treatment also produced anxiolysis, which was not altered by attempting to precipitate withdrawal-induced anxiety with a range of antagonists., Conclusions and Implications: CBD as a monotherapy may prove to be a safer pharmacological agent, than CB 1 receptor agonists alone or in combination with CBD, for the treatment of several disorders., Linked Articles: This article is part of a themed section on 8 th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc., (© 2018 The British Pharmacological Society.)

Spice drugs are herbal mixtures sprayed with synthetic cannabinoids designed to mimic the psychoactive ingredient in marijuana [Δ-tetrahydrocannabinol (Δ-THC)] and synthesized by introducing modifications to the chemical structure of parental compounds aiming to circumvent legal regulations. Synthetic cannabinoid use/abuse can be devastating as toxicological effects and adverse reactions cannot be entirely predicted and may vary with the dose, route of administration, individual vulnerability and concomitant intake with other drugs. The absence of validated testing procedures in the clinical field makes difficult the adoption of a therapeutic approach effective in coping with the synthetic cannabinoid phenomenon, posing a significant challenge for prevention, treatment and public health in general. The aim of this review is to gain insights into the epidemiological, pharmacological and toxicological properties of synthetic cannabinoids, aiming to provide a reliable background needed for the management of synthetic cannabinoid-related adverse effects. Consumers, competent authorities and medical care professionals should be aware of the risks associated with synthetic cannabinoid use.

The cannabinoid receptor 1 (CB 1 ) is the principal target of the psychoactive constituent of marijuana, the partial agonist Δ 9 -tetrahydrocannabinol (Δ 9 -THC). Here we report two agonist-bound crystal structures of human CB 1 in complex with a tetrahydrocannabinol (AM11542) and a hexahydrocannabinol (AM841) at 2.80 Å and 2.95 Å resolution, respectively. The two CB 1 -agonist complexes reveal important conformational changes in the overall structure, relative to the antagonist-bound state, including a 53% reduction in the volume of the ligand-binding pocket and an increase in the surface area of the G-protein-binding region. In addition, a 'twin toggle switch' of Phe200 3.36 and Trp356 6.48 (superscripts denote Ballesteros-Weinstein numbering) is experimentally observed and appears to be essential for receptor activation. The structures reveal important insights into the activation mechanism of CB 1 and provide a molecular basis for predicting the binding modes of Δ 9 -THC, and endogenous and synthetic cannabinoids. The plasticity of the binding pocket of CB 1 seems to be a common feature among certain class A G-protein-coupled receptors. These findings should inspire the design of chemically diverse ligands with distinct pharmacological properties.

Synthetic cannabinoids are manufactured clandestinely with little quality control and are distributed as herbal "spice" for smoking or as bulk compound for mixing with a solvent and inhalation via electronic vaporizers. Intoxication with synthetic cannabinoids has been associated with seizure, excited delirium, coma, kidney damage, and other disorders. The chemical alterations produced by heating these structurally novel compounds for consumption are largely unknown. Here, we show that heating synthetic cannabinoids containing tetramethylcyclopropyl-ring substituents produced thermal degradants with pharmacological activity that varied considerably from their parent compounds. Moreover, these degradants were formed under conditions simulating smoking. Some products of combustion retained high affinity at the cannabinoid 1 (CB 1 ) and CB 2 receptors, were more efficacious than (-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol (CP55,940) in stimulating CB 1 receptor-mediated guanosine 5'-O-(3-thiotriphosphate) (GTPγS) binding, and were potent in producing Δ 9 -tetrahydrocannabinol-like effects in laboratory animals, whereas other compounds had low affinity and efficacy and were devoid of cannabimimetic activity. Degradants that retained affinity and efficacy also substituted in drug discrimination tests for the prototypical synthetic cannabinoid 1-pentyl-3-(1-naphthoyl)indole (JWH-018), and are likely to produce psychotropic effects in humans. Hence, it is important to take into consideration the actual chemical exposures that occur during use of synthetic cannabinoid formulations to better comprehend the relationships between dose and effect., (Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.)

Background & Objective: Cannabis is the most widely used illicit drug. The two most important natural cannabinoids are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). The THC content of cannabis has been increasing during the last years and recently appeared in the market as a series of synthetic cannabinoids with potent agonist activity. Recreational users frequently combine cannabis with other drugs of abuse as alcohol, amphetamines and derivatives, nicotine and cocaine. In addition, these subjects can be taking medicines for acute and chronic medical conditions. The increasing use of medicinal cannabis for chronic pain and neurological and psychiatric disorders can produce potential interactions with medications used for the symptomatic treatment of these or other diseases., Conclusion: THC and CBD are metabolized mainly in the liver by cytochrome P-450 isoenzymes (mainly CYP2Cs and CYP3A4). In vitro studies indicate that THC and CBD both inhibit CYP1A1, 1A2 and 1B1 enzymes, and recent studies have indicated that CBD is also a potent inhibitor of CYP2C19 and CYP3A4. Both cannabinoids may interact with other medications metabolized by the same pathway or by inducers/inhibitors of the isoenzymes. Cannabis produces sedation, impairs psychomotor performance, and increases blood pressure and heart rate. Pharmacodynamic interactions with other sedatives can potentiate the central effects but can be decreased by psychostimulants. This review focuses on the interactions between cannabinoids and alcohol, other drugs of abuse, and prescription medicines., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Synthetic cannabinoids (SCs) are gaining increasing importance in clinical and forensic toxicology. They are consumed without any preclinical safety studies. Thus, controlled human pharmacokinetic (PK) studies are not allowed, although being relevant for interpretation of analytical results in cases of misuse or poisoning. As alternative, in a controlled animal experiment, six pigs per drug received a single intravenous dose of 200μg/kg BW each of Δ(9)-tetrahydrocannabinol (THC), 4-ethylnaphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-210), or 2-(4-methoxyphenyl)-1-(1-pentyl-indol-3-yl)methanone (RCS-4). In addition, six pigs received a combination of the three drugs with the identical dose each. The drugs were determined in serum using LC-MS/MS. A population (pop) PK analysis revealed that a three-compartment model described best the PK data of all three cannabinoids. Central volumes of distribution were estimated at 0.29L/kg, 0.20L/kg, and 0.67L/kg for THC, JWH-210, and RCS-4, respectively. Clearances were 0.042L/min/kg, 0.048L/min/kg, and 0.093L/min/kg for THC, JWH-210, and RCS-4, respectively. The popPK THC pig model was upscaled to humans using allometric techniques. Comparison with published human data revealed that the concentration-time profiles could successfully be predicted. These findings indicate that pigs in conjunction with PK modeling technique may serve as a tool for prediction of human PK of SCs., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

The addition of MeLi to boron enolates produced by the 1,4-addition of Ar2Cu(CN)Li2 to BF3·OEt2-activated enones was followed by the reaction with ClP(O)(OEt)2 to afford the corresponding enol phosphates in moderate to good yields. The scope of this method was examined with sterically hindered or electronically biased enones and/or reagents. This activation of boron enolates was successfully applied to the synthesis of the methyl ether of Δ(9)-tetrahydrocannabinol.

Short and highly efficient stereoselective syntheses provide machaeriols and cannabinoids in a divergent approach starting from a common precursor, commercially available (S)-perillic acid. Key features of the novel strategy are a stereospecific palladium-catalyzed decarboxylative arylation and a one-pot sequence comprising a stereoselective hydroboration followed by oxidation or reduction of the corresponding intermediary boranes. The divergent approach is convincingly demonstrated by the five-step syntheses of (+)-machaeriol B, (+)-machaeriol D, and related analogues, and the four-step synthesis of (+)-Δ(8)-THC and an analogue., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

There is an emerging mechanism of burn injury as a result of the ignition of butane, during the manufacture of a tetrahydrocannabinol concentrate known as butane honey oil. The authors report of a series of patients who presented with this mechanism of injury and a description of the process that causes these burns. Patient data were gathered from the medical records of eight patients treated at the University of California Davis Medical Center and Shriners Hospital of Northern California. Information on the manufacturing process of butane honey oil was gathered from Internet searches and published literature on the topic. The burns witnessed at the abovementioned institutions ranged from 16 to 95% TBSA, with an average of 49.9%. The average length of stay for the patients was 118.3 hospital days and 114.4 intensive care unit days, with an average of 43.8 days spent on mechanical ventilation. The average age of patients was 22 years, with only one patient above the age of 30 years. Accidents during honey oil production have resulted in a surge of burn injuries in our community during the past year. The manufacture of this product, which involves the use of volatile butane gas, is gaining in popularity. Although considered to be safer than previous methods, multiple casualties with extensive burn injuries have resulted from this process. Associated injuries from blast trauma or chemical burns are not likely to occur in these types of explosions and have not been observed in the series reported in this article. In light of the increasing popularity of honey oil, it is important for burn care providers to gain awareness and understanding of this problem and its growing presence in the community.

All four stereoisomers of Δ(9)-tetrahydrocannabinol (Δ(9)-THC) were synthesized in concise fashion using stereodivergent dual catalysis. Thus, following identical synthetic sequences and applying identical reaction conditions to the same set of starting materials, selective access to the four stereoisomers of THC was achieved in five steps., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Δ(9)-tetrahydrocannabinol (Δ(9)-THC) is the major psychoactive cannabinoid in hemp (Cannabis sativa L.) and responsible for many of the pharmacological effects mediated via cannabinoid receptors. Despite being the major cannabinoid scaffold in nature, Δ(9)-THC double bond isomers remain poorly studied. The chemical scaffold of tetrahydrocannabinol can be assembled from the condensation of distinctly substituted phenols and monoterpenes. Here we explored a microwave-assisted one pot heterogeneous synthesis of Δ(3)-THC from orcinol (1a) and pulegone (2). Four Δ(3)-THC analogues and corresponding Δ(4a)-tetrahydroxanthenes (Δ(4a)-THXs) were synthesized regioselectively and showed differential binding affinities for CB1 and CB2 cannabinoid receptors. Here we report for the first time the CB1 receptor binding of Δ(3)-THC, revealing a more potent receptor binding affinity for the (S)-(-) isomer (hCB1Ki = 5 nM) compared to the (R)-(+) isomer (hCB1Ki = 29 nM). Like Δ(9)-THC, also Δ(3)-THC analogues are partial agonists at CB receptors as indicated by [(35)S]GTPγS binding assays. Interestingly, the THC structural isomers Δ(4a)-THXs showed selective binding and partial agonism at CB2 receptors, revealing a simple non-natural natural product-derived scaffold for novel CB2 ligands., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

(-)-∆9-Tetrahydrocannabinol is the principal psychoactive component of the cannabis plant and also the active ingredient in some prescribed drugs. To detect and control misuse and monitor administration in clinical settings, reference samples of the native drugs and their metabolites are needed. The accuracy of liquid chromatography/mass spectrometric quantification of drugs in biological samples depends among others on ion suppressing/alteration effects. Especially, 13C-labeled drug analogues are useful for minimzing such interferences. Thus, to provide internal standards for more accurate quantification and for identification purpose, synthesis of [13C4]-∆9-tetrahydro-cannabinol and [13C4]-11-nor-9-carboxy-∆9-tetrahydrocannabinol was developed via [13C4]-olivetol. Starting from [13C4]-olivetol the synthesis of [13C4]-11-nor-9-carboxy-∆9-tetrahydrocannabinol was shortened from three to two steps by employing nitromethane as a co-solvent in condensation with (+)-apoverbenone.

An LC-MS/MS method for the quantification of the synthetic cannabinoids JWH-200, JWH-250, JWH-073, JWH-018, HU-211, CP 47,497 and CP 47,497-C8, and THC in oral fluid was developed and validated. Samples (0.5 mL) were extracted using Strata X cartridges (Phenomenex). Chromatographic separation was achieved with a Sunfire™ IS column (20×2.1 mm, 3.5 μm) (Waters Corp.), with formic acid 0.1% and acetonitrile as mobile phase. A different chromatographic gradient was applied for the separation of the analytes depending on the ionization mode employed, with a total chromatographic run of 14 min. Detection was performed in a Quattro Micro™ API ESCI (Waters Corp.), using electrospray in the positive mode (ESI+) for JWH-200, JWH-250, JWH-073, JWH-018 and THC, and ESI- for HU-211, CP 47,497, and CP 47,497-C8. Validation of the method included the assessment of selectivity, linearity (0.1-2.5 to 200 ng/mL), limits of detection (0.025-1 ng/mL) and quantification (0.1-2.5 ng/mL), imprecision (%CV≤14.4%), accuracy (91.8-109.7% of target concentration), extraction recovery (65.4-105.6%) and Quantisal recovery (56.1-66.7%), and matrix effect (neat oral fluid: -56.0% to 38.5%; oral fluid in Quantisal buffer: -15.1% to -71.7%). The application of this method to oral fluid samples from roadside testing will provide unique information on the use of these new synthetic drugs by Spanish drivers., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The highly efficient asymmetric total syntheses of (-)-Δ(8)-tetrahydrocannabinol ((-)-Δ(8)-THC) (13 steps, 35%) and (-)-Δ(9)-tetrahydrocannabinol ((-)-Δ(9)-THC) (14 steps, 30%) have been developed by using ruthenium-catalyzed asymmetric hydrogenation of racemic α-aryl cyclic ketones via dynamic kinetic resolution and intramolecular S(N)Ar cyclization.

Diels-Alder reactions of a range of 1-(alkoxy/alkyl-substituted phenyl)buta-1,3-dienes with methyl vinyl ketone and methyl acrylate carried out in ethanol as the reaction medium under 9 kbar pressure were investigated. The use of high pressure as the activating method of the Diels-Alder reactions allows the efficient and endodiastereoselective generation of a series of cis-cyclohexenyl-benzene cycloadducts, which are selectively converted into their trans-epimers. The cis-cyclohexenyl-benzenes and trans-cyclohexenyl-benzenes produced are useful precursors for accessing substituted privileged cis-6a,7,8,10a-tetrahydro-6H-benzo[c]chromene and trans-6a,7,8,10a-tetrahydro-6H-benzo[c]chromene skeletons. The total syntheses of Δ(9)-cis-tetrahydrocannabinol (THC) and Δ(9)-trans-THC, through the use of selected Diels-Alder adducts, are described. Finally, a route for obtaining Δ(9)-trans-THC in both enantiomeric pure forms based on the (S)-(-)-1-amino-2-(methoxymethyl)pyrrolidine (SAMP)-hydrazone method is also reported.

Δ(8)-Tetrahydrocannabinol (26), 3-(1',1'-dimethylbutyl)- (12), 3-(1',1'-dimethylpentyl)- (13), 3-(1',1'-dimethylhexyl)- (14) and 3-(1',1'-dimethylheptyl)-Δ(8)-tetrahydrocannabinol (15) have been converted into the corresponding 1-bromo-1-deoxy-Δ(8)-tetrahydrocannabinols (25, 8-11). This was accomplished using a protocol developed in our laboratory in which the trifluoromethanesulfonate of a phenol undergoes palladium mediated coupling with pinacolborane. Reaction of this dioxaborolane with aqueous-methanolic copper(II) bromide provides the aryl bromide. The affinities of these bromo cannabinoids for the cannabinoid CB(1) and CB(2) receptors were determined. All of these compounds showed selectivity for the CB(2) receptor and one of them, 1-bromo-1-deoxy-3-(1',1'-dimethylhexyl)-Δ(8)-tetrahydrocannabinol (10), exhibits 52-fold selectivity for this receptor with good (28nM) affinity., (Copyright © 2010. Published by Elsevier Ltd.)

Delta(9)-Tetrahydrocannabinol hemisuccinate (THC-HS), an ester prodrug of Delta(9)-tetrahydrocannabinol (THC) has been investigated for its potential to form inclusion complexes with modified synthetic beta-cyclodextrins (CDs). Phase solubility studies were performed to determine the stoichiometric ratio of complexation of THC-HS with random methylated beta-cyclodextrin (RAMEB) and 2-hydroxypropyl beta-cyclodextrin (HPBCD). THC-HS/RAMEB and THC-HS/HPBCD solid systems were prepared by lyophilization and the lyophilized complexes were characterized by Fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic spectroscopy, and molecular modeling techniques. The formation of inclusion complexes of THC-HS/RAMEB and THC-HS/HPBCD was demonstrated by an A(L) type curve with the slopes less than unity by the phase solubility method. The association constants for THC-HS/RAMEB and THC-HS/HPBCD were found to be 562.48 and 238.83 M(-1), respectively. The stoichiometry of both of the complexes was found to be 1:1 as determined from the Job's plot. This was confirmed by (1)H NMR and FT-IR techniques. The results obtained from the molecular modeling studies were in accordance with the data obtained from nuclear magnetic resonance and FT-IR. The docking studies revealed the most probable mode of binding of THC-HS with RAMEB in which the alkyl chain was submerged in the hydrophobic pocket of the CD molecule and hydrogen bonding interactions were observed between the hemisuccinate ester side chain of THC-HS and the rim hydroxy groups of RAMEB. The solubility of THC-HS was significantly higher in RAMEB compared to HPBCD. Solid dispersions of THC-HS with CDs will be further utilized to develop oral formulations of THC-HS with enhanced bioavailability.

A novel series of Delta9-tetrahydrocannabinol (Delta9-THC) analogues were synthesized to determine their potential as cannabinoid receptor modulators. Chemistry focused on conversion of the phenol of Delta9-THC to other functionality through palladium catalyzed reactions with an intermediate triflate 2. Two analogues with sub 100 nM affinity for the CB1 and CB2 receptors were identified., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Structure-activity relationship studies of classical cannabinoid analogues have established that the C3 aliphatic side chain plays a pivotal role in determining cannabinergic potency. In earlier work, we provided evidence for the presence of subsites within the CB1 and CB2 cannabinoid receptor binding domains that can accommodate bulky conformationally defined substituents at the C3 alkyl side chain pharmacophore of classical cannabinoids. We have now extended this work with the synthesis of a series of Delta (8)-THC analogues in which bornyl substituents are introduced at the C3 position. Our results indicate that, for optimal interactions with both CB1 and CB2 receptors, the bornyl substituents need to be within close proximity of the tricyclic core of Delta (8)-THC and that the conformational space occupied by the C3 substituents influences CB1/CB2 receptor subtype selectivity.

The synthesis and characterization of novel C1'-phenyl-substituted Delta(8)-THC analogs were previously reported by our laboratory. Within this small series of compounds, the C1'-dimethyl phenyl group was found to impart 13.5-fold selectivity for the CB2 receptor with a K(i) 0.91 nM. The current study expands on the previous report by evaluating the effects of aromatic ring substitution on CB1 and CB2 receptor subtype binding and selectivity. The ring substituents synthesized in this study include aliphatic, halogen, nitrile, and acetamido functional groups. In addition, the isosteric replacement of the phenyl group by thiophene was evaluated. The anti-glioma activities of selected compounds were evaluated in vitro and compared to the lead compound 2.

The first stereoselective total synthesis of the bibenzyl tetrahydrocannabinol, (-)-perrottetinene, has been achieved from readily available starting materials. The absolute stereochemistry is derived from a chiral gamma-hydroxy vinylstannane. The key reaction is the synthesis of the cis-disubstituted cyclohexene ring of perrottetinene by diastereoselective Ireland-Claisen rearrangement and a ring-closing metathesis reaction. The absolute configuration of (-)-perrottetinene is proposed.

In earlier work we have provided evidence for the presence of a subsite within the CB1 and CB2 cannabinoid receptor binding domains of classical cannabinoids. This putative subsite corresponds to substituents on the C1'-position of the C3-alkyl side chain, a key pharmacophoric feature in this class of compounds. We have now refined this work through the synthesis of additional C1'-cycloalkyl compounds using newly developed approaches. Our findings indicate that the C1'-cyclopropyl and C1'-cyclopentyl groups are optimal pharmacophores for both receptors while the C1'-cyclobutyl group interacts optimally with CB1 but not with CB2. The C1'-cyclohexyl analogs have reduced affinities for both CB1 and CB2. However, these affinities are significantly improved with the introduction of a C2'-C3' cis double bond that modifies the available conformational space within the side chain and allows for a better accommodation of a six-membered ring within the side chain subsite. Our SAR results are highlighted by molecular modeling of key analogs.

[reaction: see text] Delta9-THC is synthesized in enantiomericaly pure form, where all of the stereochemistry is derived from the molybdenum-catalyzed asymmetric alkylation reaction of the extremely sterically congested bis-ortho-substituted cinnamyl carbonate in high regio- and enantioselectivity.

The objective of the present research was to investigate the stability of an amorphous drug, Delta(9)-tetrahydrocannabinol (THC) in polymer-based transmucosal systems. THC was incorporated in polyethylene oxide and hydroxypropylcellulose matrices by a hot-melt fabrication procedure, utilizing various processing aids. The chemical stability of the drug in the polymeric matrices was investigated with respect to processing temperature, processing time, formulation additives, and storage conditions. HPLC analysis of the THC-loaded systems indicated that the extent of drug degradation was influenced by all of the above mentioned variables. THC was particularly unstable in the vitamin E succinate-processed films, indicating a potential incompatibility. Thermal stability of the drug, polymers, and other ingredients at the elevated processing temperatures during the fabrication procedure, was evaluated using the isothermal mode of thermo-gravimetric analysis. When held at 160 and 200 degrees C, the weight percentage of THC decreased linearly as a function of time. Weight loss was controlled by blending the drug with polymers, PEO and HPC, of which PEO was determined to be more effective. Although higher temperatures lowered the polymer melt viscosity, THC and other materials were chemically and thermally unstable at such high temperatures. Due to this, matrix fabrication was found to be favorable at relatively lower temperatures, such as 120 degrees C., (Copyright 2006 Wiley-Liss, Inc.)

The compounds reported in this study are Delta(8)-THC analogues in which the C3 five-carbon linear side chain of Delta(8)-THC was replaced with aryl and 1',1'-cycloalkyl substituents. Of the compounds described here analogues 2d (CB(1), K(i)=11.7 nM. CB(2), K(i)=9.39 nM) and 2f (CB(1), K(i)=8.26 nM. CB(2), K(i)=3.86 nM) exhibited enhanced binding affinities for CB(1) and CB(2), exceeding that of Delta(8)-THC. Efficient procedures for the synthesis of these novel cannabinoid analogues are described.

Two new series of cannabinoids were prepared and their affinities for the CB1 and CB2 receptors were determined. These series are the (2'R)- and (2'S)-1-methoxy- and 1-deoxy-3-(2'-methylalkyl)-delta8-tetrahydrocannabinols, with alkyl side chains of three to seven carbon atoms. These compounds were prepared by a route that employed the enantioselective synthesis of the resorcinol precursors to the cannabinoid ring system. All of these compounds have greater affinity for the CB2 receptor than the CB1 receptor and four of them, (2'R)-1-methoxy-3-(2'-methylbutyl)-delta8-THC (JWH-359), (2'S)-1-deoxy-3-(2'-methylbutyl)-delta8-THC (JWH-352), (2'S)-1-deoxy-3-(2'-methylpentyl)-delta8-THC (JWH-255), and (2'R)-1-deoxy-3-(2'-methylpentyl)-delta8-THC (JWH-255), have good affinity (K(i) = 13-47 nM) for the CB2 receptor and little affinity (K(i) = 1493 to >10,000 nM) for the CB1 receptor. In the 1-deoxy-3-(2'-methylalkyl)-delta8-THC series, the 2'S-methyl compounds in general have greater affinity for the CB2 receptor than the corresponding 2'R isomers.

Indevus Pharmaceuticals Inc is developing ajulemic acid, a non-steroidal anti-inflammatory drug derived from tetrahydrocannabinol, for the potential treatment of pain, inflammation and cystitis.

Immunopharmacotherapy as an approach to combat drugs of abuse has become an active area of investigation. Marijuana is the most commonly used illicit drug in the U.S. The main active chemical in marijuana is delta9-tetrahydrocannabinol (delta9-THC); hence, monoclonal antibodies with high affinity and specificity for delta9-tetrahydrocannabinol could be valuable immunopharmacotherapeutic intervention and diagnostic tools. We have synthesized immunoconjugates that induce an effective immune response to delta9-THC and describe a convenient synthesis of radiolabeled delta9-THC. We demonstrate the value and use of this probe to select anti-delta9-THC antibodies that bind delta9-THC with good affinity. The synthetic route to radiolabeled delta9-THC has enabled the correct assessment of the affinity of these antibodies to their ligand and may facilitate future binding studies between delta9-THC and its analogues and the cannabinoid receptors.

Structure-activity relationship studies have established that the aliphatic side chain plays a pivotal role in determining the cannabinergic potency of tricyclic classical cannabinoids. We have now synthesized a series of analogues in which a variety of adamantyl substituents were introduced at the C3 position of Delta(8)-THC. Our lead compound, (-)-3-(1-adamantyl)-Delta(8)-tetrahydrocannabinol (1a, AM411), was found to have robust affinity and selectivity for the CB1 receptor as well as high in vivo potency. The X-ray crystal structure of 1a was determined. Exploration of the side chain conformational space using molecular modeling approaches has allowed us to develop cannabinoid side chain pharmacophore models for the CB1 and CB2 receptors. Our results suggest that although a bulky group at the C3 position of classical cannabinoids could be tolerated by both CB1 and CB2 binding sites, the relative orientation of that group with respect to the tricyclic component can lead to receptor subtype selectivity.

Ajulemic acid (CT-3, IP-751, 1',1'-dimethylheptyl-Delta8-tetrahydrocannabinol-11-oic acid) (AJA) has a cannabinoid-derived structure; however, there is no evidence that it produces psychotropic actions when given at therapeutic doses. In a variety of animal assays, AJA shows efficacy in models for pain and inflammation. Furthermore, in the rat adjuvant arthritis model, it displayed a remarkable action in preventing the destruction of inflamed joints. A phase-2 human trial with chronic, neuropathic pain patients suggested that AJA could become a useful drug for treating this condition. Its low toxicity, particularly its lack of ulcerogenicity, further suggests that it will have a highly favorable therapeutic index and may replace some of the current anti-inflammatory/analgesic medications. Studies to date indicate a unique mechanism of action for AJA that may explain its lack of adverse side effects.

The aim of this study was to develop a dry powder formulation that stabilises the chemically labile lipophilic Delta(9)-tetrahydrocannabinol (THC), that rapidly dissolves in water in order to increase the bioavailability and that opens new routes of administration. It was investigated whether these aims can be achieved with solid dispersions consisting of a matrix of inulin, an oligo-fructose, in which THC is incorporated. These solid dispersions were prepared by lyophilisation of a solution of THC and inulin in a mixture of water and tertiary butyl alcohol (TBA). Both 4 and 8 wt.% of THC could be incorporated in a glassy matrix of inulin. In the solid dispersions only 0.4-0.5 wt.% of residual TBA was present after storage at 20 degrees C/45% relative humidity (RH) for 7 days. Unprotected THC was completely degraded after 40 days of exposure to 20 degrees C and 45% RH. However, solid dispersions exposed to the same conditions still contained about 80% non-degraded THC after 300 days. Dissolution experiments with tablets compressed from inulin glass dispersion material showed that THC and inulin dissolved at the same rate. Tablets weighing 125 mg and containing 2mg THC were prepared from a mixture of THC containing solid dispersion, polyvinylpolypyrrolidone (PVPP) and mannitol. Dissolution tests revealed that from these tablets 80% of the THC was dissolved within 3 min, which makes them promising for sublingual administration. It was concluded that THC can be strongly stabilized by incorporating it in a matrix of inulin. The aqueous dissolution rate was high which may improve bioavailability.

Earlier work from our laboratories has provided evidence for the existence of a subsite within the CB1 and CB2 cannabinoid receptor binding domain corresponding to substituents at the benzylic side chain position of classical cannabinoids. The existence and stereochemical features of this subsite have now been probed through the synthesis of a novel series of (-)-Delta(8)-tetrahydrocannabinol analogues bearing C1'-ring substituents. Of the compounds described here, those with C1'-dithiolane (1c), C1'-dioxolane (2d), and cyclopentyl (2a) substituents exhibited the highest affinities for CB1 and CB2. We used molecular modeling approaches to better define the stereochemical limits of the putative subsite. In vitro pharmacological testing found 1c to be a potent CB1 agonist.

A series of 1',1'-dimethylalkyl-Delta(8)-tetrahydrocannabinol analogues with C-3 side chains of 2-12 carbon atoms has been synthesized and their in vitro and in vivo pharmacology has been evaluated. The lowest member of the series, 1',1'-dimethylethyl-Delta(8)-THC (8, n=0) has good affinity for the CB(1) receptor, but is inactive in vivo. The dimethylpropyl (8, n=1) through dimethyldecyl (8, n=8) all have high affinity for the CB(1) receptor and are full agonists in vivo. 1',1'-Dimethylundecyl-Delta(8)-THC (8, n=9) has significant affinity for the receptor (K(i)=25.8+/-5.8 nM), but has reduced potency in vivo. The dodecyl analogue (8, n=10) has little affinity for the CB(1) receptor and is inactive in vivo. A quantitative structure-activity relationship study of the side chain region of these compounds is consistent with the concept that for optimum affinity and potency the side chain must be of a length which will permit its terminus to loop back in proximity to the phenolic ring of the cannabinoid.

1',1'-Cyclopropyl side chain substituents enhance the affinities of Delta(8)-tetrahydrocannabinol and respective cannabidiol analogues for the CB1 and CB2 cannabinoid receptors. The results support the hypothesis for a subsite within CB1 and CB2 binding domain at the level of the benzylic side chain carbon in the tetrahydrocannabinol and cannabidiol series. Efficient procedures for the synthesis of 1',1'-cyclopropyl analogues are described.

Three series of new cannabinoids were prepared and their affinities for the CB(1) and CB(2) cannabinoid recptors were determined. These are the 1-methoxy-3-(1',1'-dimethylalkyl)-, 1-deoxy-11-hydroxy-3-(1',1'-dimethylalkyl)- and 11-hydroxy-1-methoxy-3-(1',1'-dimethylalkyl)-Delta(8)-tetrahydrocannabinols, which contain alkyl chains from dimethylethyl to dimethylheptyl appended to C-3 of the cannabinoid. All of these compounds have greater affinity for the CB(2) receptor than for the CB(1) receptor, however only 1-methoxy-3-(1',1'-dimethylhexyl)-Delta(8)-THC (JWH-229, 6e) has effectively no affinity for the CB(1) receptor (K(i)=3134+/-110nM) and high affinity for CB(2) (K(i)=18+/-2nM).

The synthesis and pharmacology of 15 1-deoxy-delta8-THC analogues, several of which have high affinity for the CB2 receptor, are described. The deoxy cannabinoids include 1-deoxy-11-hydroxy-delta8-THC (5), 1-deoxy-delta8-THC (6), 1-deoxy-3-butyl-delta8-THC (7), 1-deoxy-3-hexyl-delta8-THC (8) and a series of 3-(1',1'-dimethylalkyl)-1-deoxy-delta8-THC analogues (2, n = 0-4, 6, 7, where n = the number of carbon atoms in the side chain-2). Three derivatives (17-19) of deoxynabilone (16) were also prepared. The affinities of each compound for the CB1 and CB2 receptors were determined employing previously described procedures. Five of the 3-(1',1'-dimethylalkyl)-1-deoxy-delta8-THC analogues (2, n = 1-5) have high affinity (Ki = < 20 nM) for the CB2 receptor. Four of them (2, n = 1-4) also have little affinity for the CB1 receptor (Ki = > 295 nM). 3-(1',1'-Dimethylbutyl)-1-deoxy-delta8-THC (2, n = 2) has very high affinity for the CB2 receptor (Ki = 3.4 +/- 1.0 nM) and little affinity for the CB1 receptor (Ki = 677 +/- 132 nM).

Structure-activity relation studies have established that the alkyl side chain in tetrahydrocannabinol (THC) plays a crucial role in the activation of the cannabinoid receptor. Unfortunately, the flexible nature of this side chain has hampered efforts to elucidate the precise nature of the interaction of THC with its receptors. Therefore, a series of analogs with structurally restrained side chains of varying length was synthesized and evaluated for pharmacological potency in mice and for receptor affinity. The introduction of cis double bonds inserted rigid angles, whereas triple bonds developed regions of planarity. Receptor affinity for the acetylenic and saturated side chains were the same, whereas double bond substitution increased affinity 10-fold. Moreover, the relationship between receptor affinity and potency was 10-fold less than that of Delta(8)-THC in the case of some acetylenic derivatives, whereas changing the triple bond to a double bond restored the potency/affinity ratio. Additionally, an acetylene at C2-C3 in the octyl and nonyl side chains favored antinociception by as much as 70-fold. Surprisingly, several high-affinity acetylenic derivatives, especially those with cyano substitutions at the terminus of the side chain, were partial agonists or were inactive. Some of these low-efficacy, high-affinity ligands elicited antagonistic activity. The finding that manipulations of the side chain produces high- affinity ligands with either antagonist, partial agonist, or full agonist effects reveals a critical structural feature for receptor activation.

Novel analogs of (-)-delta8-tetrahydrocannabinol (delta8-THC) in which the conformation of the side chain was restricted by incorporating the first one or two carbons into a six membered ring fused with the aromatic phenolic A ring were synthesized. The affinities of the novel ligands for CB1 and CB2 indicated that the "southbound" chain conformer retained the highest affinity for both receptors.

Binocular depth inversion represents an illusion of visual perception that is sensitive to various behavioural and psychiatric conditions. It is affected by cannabinoids, reflecting associated changes in perception. The present study investigated the differences in binocular depth inversion of different classes of natural and artificial objects and the effect of synthetic delta9-tetrahydrocannabinol (Dronabinol) on these illusionary perceptions. Using this model, the effects of orally administered Dronabinol on binocular depth inversion were investigated in 17 healthy male volunteers. Pictures from natural and artificial objects were presented stereoscopically and the depth perception of the volunteers was scored in an operationalized way. The timecourse of the effects of Dronabinol on binocular depth inversion was analyzed with regard to the stimulus classes (natural and synthetic objects). Significant differences in binocular depth inversion of the different groups of stimuli were revealed. Objects with a higher degree of everyday familiarity were generally seen as more illusionary than those with a lower degree of everyday familiarity. A strong impairment of binocular depth inversion due to Dronabinol was found in most classes of objects. Analysis of different stimulus classes provides further information on the underlying perceptual processing of binocular depth inversion. An impairment of top-down processing of visual sensory data by Dronabinol is suggested. The anandamidergic system seems to be involved in areas of visual information processing.

The synthesis of the 3-heptyl, and the eleven isomeric 3-methylheptyl-delta8-tetrahydrocannabinols (3-7, R and S methyl epimers, and 8) has been carried out. The synthetic approach entailed the synthesis of substituted resorcinols, which were subjected to acid catalyzed condensation with trans-para-menthadienol to provide the delta8-THC analogue. The 1'-, 2'- and 3'-methylheptyl analogues (3-5) are considerably more potent than delta8-THC. The 4'-, 5'- and 6'-methylheptyl isomers (6-8) are approximately equal in potency to delta8-THC.

A tetracyclic, conformationally constrained analogue of delta8-THC (2) has been synthesized in which a two carbon bridge exists between C2 and C2'. Two conceptually related syntheses of 2 are described, both of which employ 5,7-dimethoxy-4-oxo-1,2,3,4-tetrahydronaphthoic acid (11) as starting material. This substrate was converted to 5,7dimethoxy-2-propyl-1,2,3,4-tetrahydronaphthalene (7) and its 4-keto derivative (18). Demethylation of 11 and 18 provided the corresponding resorcinols, which were condensed with trans-p-menthadienol to afford cannabinoid 2, and a keto derivative (20). LiA1H4/A1C1(3) reduction of 20 provided 2. Cannabinoid 2 has relatively low affinity for the cannabinoid brain receptor (Ki = 703+/-98 nM).

The synthesis and pharmacological profile of several cyano (1a-e) and carboxamido (2a-h) side-chain-substituted analogues of 1', 1'-dimethyl-Delta8-THC are described. Commercially available cyano compound 3 was transformed to the resorcinol 6 in a three-step sequence. Condensation of 6 with p-menth-2-ene-1,8-diol formed the THC 7a which, with sodium cyanide/DMSO, gave 1b. Protection of the phenol in 7a as the MOM derivative provided the common intermediate 8 for the synthesis of 1a,c,e. Compound 1d was also synthesized from 7a via the aldehyde 9a. Base hydrolysis of 1b gave the acid 10 which, via its acid chloride and subsequent treatment with the appropriate amine, formed the target compounds 2a-h. The pharmacological profile indicated that the cyano analogues 1a-e had very high CB1 binding affinity (0.36-13 nM) and high in vivo potency as agonists. Two analogues (1a,b) had extremely high potency in the mouse tetrad tests. The dimethylcarboxamido analogue 2a showed a similar profile to 1a,b. The high potency was also retained in analogue 2c. In contrast the sulfonamide analogue 2d was unique as it had greater affinity than Delta9-THC, yet it was practically devoid of agonist effects. This study suggests that the incorporation of a cyano or an amide substituent in the side chain of Delta8-THC-DMH can enhance potency and can also lead to compounds with a unique profile which have high binding affinity and are practically devoid of agonist effects.

Accumulated evidence indicates that within the cannabinoid structure the aliphatic side chain plays a pivotal role in determining cannabimimetic activity. We describe the synthesis and affinities for the CB1 and CB2 receptors of a series of novel delta 8-THC analogues in which the side-chain pharmacophores are conformationally more defined than in the parent molecule. No analogue has the side-chain pharmacophore in a fully restricted conformation. However, our design serves to narrow down the scope of options for conformational requirements at the receptor active sites. All the analogues tested showed nanomolar or subnanomolar affinities for the receptors; 2-(6a,7,10,10a-tetrahydro-6,6,9-trimethyl-1-hydroxy-6H- dibenzo[b,d]pyranyl)-2-hexyl-1,3-dithiolane was found to possess very high affinity for both cannabinoid receptors (CB1, Ki = 0.32 nM; CB2, Ki = 0.52 nM).