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The first generation of CB(1) positive allosteric modulators (e.g., ZCZ011) featured a 3-nitroalkyl-2-phenyl-indole structure. Although a small number of drugs include the nitro group, it is generally not regarded as being “drug-like”, and this is particularly true for aliphatic nitro groups. There are very few case studies where an appropriate bioisostere replaced a nitro group that had a direct role in binding. This may be indicative of the difficulty of replicating its binding interactions. Herein, we report the design and synthesis of ligands targeting the allosteric binding site on the CB(1) cannabinoid receptor, in which a CF(3) group successfully replaced the aliphatic NO(2). In general, the CF(3)-bearing compounds were more potent than their NO(2) equivalents and also showed improved in vitro metabolic stability. The CF(3) analogue (1) with the best balance of properties was selected for further pharmacological evaluation. Pilot in vivo studies showed that (±)-1 has similar activity to (±)-ZCZ011, with both showing promising efficacy in a mouse model of neuropathic pain.

We describe the chemical synthesis of the fungal naphthopyrones YWA1 and fonsecin B, as well as their functionalization with an amine-spacer arm and the conjugation of the resulting molecules to three different functional tags (i.e., biotin, Oregon green, 1-[3-(succinimidyloxycarbonyl)benzyl]-4-[5-(4-methoxyphenyl)-2-oxazolyl]pyridinium bromide (PyMPO)). The naphthopyrone-biotin and -PyMPO constructs maintained the ability to bind the C-type lectin receptor MelLec, whose interaction with immunologically active fungal metabolites (i.e., 1,8-dihydroxynaphthalene-(DHN)-melanin and YWA1) is a key step in host recognition and induction of protective immune responses against

We describe the chemical synthesis of the fungal naphthopyrones YWA1 and fonsecin B, as well as their functionalization with an amine-spacer arm and the conjugation of the resulting molecules to three different functional tags (i.e., biotin, Oregon green, 1-[3-(succinimidyloxycarbonyl)benzyl]-4-[5-(4-methoxyphenyl)-2-oxazolyl]pyridinium bromide (PyMPO)). The naphthopyrone-biotin and -PyMPO constructs maintained the ability to bind the C-type lectin receptor MelLec, whose interaction with immunologically active fungal metabolites (i.e., 1,8-dihydroxynaphthalene-(DHN)-melanin and YWA1) is a key step in host recognition and induction of protective immune responses against Aspergillus fumigatus. The fluorescent Fonsecin B-PyMPO construct 21 was used to selectively visualize MelLec-expressing cells, thus validating the potential of this strategy for studying the role and functions of MelLec in immunity.

The tetrazine/trans-cyclooctene (TCO) inverse electron-demand Diels-Alder (IEDDA) reaction is the fastest bioorthogonal "click"ligation process reported to date. In this context, TCO reagents have found widespread applications; however, their availability and structural diversity is still somewhat limited due to challenges connected with their synthesis and structural modification. To address this issue, we developed a novel strategy for the conjugation of TCO derivatives to a biomolecule, which allows for the creation of greater structural diversity from a single precursor molecule, i.e., trans,trans-1,5-cyclooctadiene [(E,E)-COD] 1, whose preparation requires standard laboratory equipment and readily available reagents. This two-step strategy relies on the use of new bifunctional TCO linkers (5a-11a) for IEDDA reactions, which can be synthesized via 1,3-dipolar cycloaddition of (E,E)-COD 1 with different azido spacers (5-11) carrying an electrophilic function (NHS-ester, N-succinimidyl carbonate, p-nitrophenyl-carbonate, maleimide) in the ω-position. Following bioconjugation of these electrophilic linkers to the nucleophilic residue (cysteine or lysine) of a protein (step 1), the resulting TCO-decorated constructs can be subjected to a IEDDA reaction with tetrazines functionalized with fluorescent or near-infrared (NIR) tags (step 2). We successfully used this strategy to label bovine serum albumin with the TCO linker 8a and subsequently reacted it in a cell lysate with the fluorescein-isothiocyanate (FITC)-derived tetrazine 12. The same strategy was then used to label the bacterial wall of Gram-positive Staphylococcus aureus, showing the potential of these linkers for live-cell imaging. Finally, we determined the impact of structural differences of the linkers upon the stability of the bioorthogonal constructs. The compounds for stability studies were prepared by conjugation of TCO linkers 6a, 8a, and 10a to mAbs, such as Rituximab and Obinutuzumab, and subsequent labeling with a reactive Cy3-functionalized tetrazine.

The tetrazine/

A small library of guanidino-lactams were synthesized in four steps and good overall yields by following the routes: preparation of guanylating agents, synthesis of protected guanidino-acids, cyclization to fully protected guanidino-lactams, and deprotection to the target compounds. The guanidino-lactams were assayed as antimicrobials on E. coli showing no significant antibiotic activity.

A high-performance liquid chromatography tandem mass spectrometry method was developed for the detection and quantification of 6-methyl-3-(2-nitro-1-(thiophen-2-yl)propyl)-2-phenyl-1H-indole (ZCZ-011) using 2-phenylindole as the internal standard (ISTD). ZCZ-011 was synthesized as a possible positive allosteric modulator with the CB1 cannabinoid receptor. The analytical method employs a rapid extraction technique using Clean Screen FASt™ columns with a Positive Pressure Manifold. FASt™ columns were originally developed for urine drug analysis but we have successfully adapted them to the extraction of brain tissue. Chromatographic separation was performed on a Restek Allure Biphenyl 5 µ, 100 × 3.2 mm column (Bellefonte, PA). The mobile phase consisted of 1:9 deionized water with 10 mmol ammonium acetate and 0.1% formic acid–methanol. The following transition ions (m/z) were monitored for ZCZ-011: 363 > 207 and 363 > 110 and for the ISTD: 194 > 165 and 194 > 89. The FASt™ columns lowered and stabilized the ion suppression over the linear range of the assay (40–4,000 ng/g). The method was evaluated for recovery, ion suppression, accuracy/bias, intraday and interday precision, bench-top stability, freeze–thaw and post-preparative stability. The method was successfully applied to brain tissue from C57BL/6J mice that received intraperitoneal (i.p.) injections with 40 mg/kg of ZCZ-011 or vehicle.

© 2018 Macmillan Publishers Limited, part of Springer Nature. All rights reserved., Resistance to infection is critically dependent on the ability of pattern recognition receptors to recognize microbial invasion and induce protective immune responses. One such family of receptors are the C-type lectins, which are central to antifungal immunity. These receptors activate key effector mechanisms upon recognition of conserved fungal cell-wall carbohydrates. However, several other immunologically active fungal ligands have been described; these include melanin, for which the mechanism of recognition is hitherto undefined. Here we identify a C-type lectin receptor, melanin-sensing C-type lectin receptor (MelLec), that has an essential role in antifungal immunity through recognition of the naphthalene-diol unit of 1,8-dihydroxynaphthalene (DHN)-melanin. MelLec recognizes melanin in conidial spores of Aspergillus fumigatus as well as in other DHN-melanized fungi. MelLec is ubiquitously expressed by CD31+ endothelial cells in mice, and is also expressed by a sub-population of these cells that co-express epithelial cell adhesion molecule and are detected only in the lung and the liver. In mouse models, MelLec was required for protection against disseminated infection with A. fumigatus. In humans, MelLec is also expressed by myeloid cells, and we identified a single nucleotide polymorphism of this receptor that negatively affected myeloid inflammatory responses and significantly increased the susceptibility of stem-cell transplant recipients to disseminated Aspergillus infections. MelLec therefore recognizes an immunologically active component commonly found on fungi and has an essential role in protective antifungal immunity in both mice and humans., Funding was provided by the Wellcome Trust (102705, 097377, 093378, 099197, 108430, 101873), the Medical Research Council Centre for Medical Mycology and the University of Aberdeen (MR/N006364/1). K.J.K.-C is supported by the intramural program of the National Institute of Allergy and Infectious Diseases, National Institutes of Health; V.A. by an ANR-DST COMASPIN grant (ANR-13-ISV3-0004); B.H. by German Science Foundation (www.dfg.de) grant no. HE 7565/1-1; J.-P.L., I.V. and V.A. by the ANR and FRM DEQ2015-331722; A.C. by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000013), and by the Fundação para a Ciência e Tecnologia (FCT) (IF/00735/2014 and SFRH/BPD/96176/2013)

Dimethylarginine dimethylaminohydrolase (DDAH) is a key enzyme involved in the metabolism of asymmetric dimethylarginine (ADMA) and N-monomethyl arginine (NMMA), which are endogenous inhibitors of the nitric oxide synthase (NOS) family of enzymes. Two isoforms of DDAH have been identified in humans, DDAH-1 and DDAH-2. DDAH-1 inhibition represents a promising strategy to limit the overproduction of NO in pathological states without affecting the homeostatic role of this important messenger molecule. Here we describe the design and synthesis of 12 novel DDAH-1 inhibitors and report their derived kinetic parameters, IC50 and K-i. Arginine analogue 10a, characterized by an acylsulfonamide isosteric replacement of the carboxylate, showed a 13-fold greater inhibitory potential relative to the known DDAH-1 inhibitor, L-257. Compound 10a was utilized to study the putative binding interactions of human DDAH-1 inhibition using molecular dynamics simulations. The latter suggests that several stabilizing interactions occur in the DDAH-1 active-site, providing structural insights for the enhanced inhibitory potential demonstrated by in vitro inhibition studies.

The cannabinoid signaling system is found throughout the CNS and its involvement in several pathological processes makes it an attractive therapeutic target. Because orthosteric CB1 cannabinoid receptor ligands have undesirable adverse effects there has been great interest in the development of allosteric modulators - both negative (NAMs) and positive (PAMs) - of these receptors. NAMs of CB1 appeared first on the scene, followed more recently by PAMs. Because allosteric modulation can vary depending on the orthosteric ligand it is important to study their function in a system that employs endogenous cannabinoids. We have recently surveyed first generation NAMs using cultured autaptic hippocampal neurons. These neurons express depolarization induced suppression of excitation (DSE), a form of synaptic plasticity that is mediated by CB1 and 2-arachidonoyl glycerol (2-AG); they are therefore an excellent neuronal model of endogenous cannabinoid signaling in which to test CB1 modulators. In this study we find that while two related compounds, GAT211 and ZCZ011, each show PAM-like responses in autaptic hippocampal neurons, they also exhibit complex pharmacology. Notably we were able to separate the PAM- and agonist-like responses of GAT211 by examining the enantiomers of this racemic compound: GAT228 and GAT229. We find that GAT229 exhibits PAM-like behavior while GAT228 appears to directly activate the CB1 receptor. Both GAT229 and ZCZ011 represent the first PAMs that we have found to be effective in using this 2-AG utilizing neuronal model system. Because these compounds may exhibit both probe selectivity and biased signaling it will be important to test them with anandamide as well as other signaling pathways.

We report the synthesis of terminally fluorinated HU-210 and HU-211 analogues (HU-210F and HU-211F, respectively) and their biological evaluation as ligands of cannabinoid receptors (CB1 and CB2) and N-methyl d-aspartate receptor (NMDAR). [(18)F]-labelled HU-210F was radiosynthesised from the bromo-substituted precursor. In vitro assays showed that both HU-210F and HU-211F retain the potent pharmacological profile of HU-210 and HU-211, suggesting that [(18)F]-radiolabelled HU-210F and HU-211F could have potential as PET tracers for in vivo imaging.

(Z)-Vinyl iodides 6a–d were synthesized in high yield with good diastereo- and enantioselectivity using a Marshall–Tamaru, Pd-catalyzed allenylzinc reaction as the key step. The addition of 6a–d to the dictyostatin C1–C9 β-silyloxy aldehyde 5 was carried out through the vinyllithium and lithium vinylzincate routes. The lithium vinylzincate additions always proceeded in higher yields and gave fewer side products than the corresponding vinyllithium additions. The configuration of the newly created C9 stereocenter was assigned through Rychnovsky's acetonide 13C NMR method. The diastereoselectivity in this particular type of (Z)-vinylmetal addition reaction appears to be controlled by a subtle balance between the intrinsic stereochemical preference of the β-silyloxy aldehyde (1,3-anti-selective) and that of the chiral lithium (Z)-vinylzincates. The latter becomes more influential with increasing stereochemical complexity, that is, passing from a stereodyad (6a,6b) to a stereotriad (6c,6d).

The total synthesis of (+)-9-epi-dictyostatin (1b), a diastereomer of the antimitotic marine-sponge-derived macro-lide (-)-dictyostatin (1a), was achieved by creating 11 stereogenic centers and 4 stereogenic double bonds with a high level of stereocontrol. The yield for the 29-step longest linear sequence from Roche ester was 1.53 %. The final key steps to this unnatural product were the vinylzincate C10-C26 addition to aldehyde C1-C9 (leading surprisingly to a complete stereoselectivity for the 9R-epimer), followed by Yamaguchi macrolactonization and global deprotection.

A stereoselective synthesis of the C1-C9 fragment of (-)-dictyostatin has been achieved by use of a titanium(IV) chloride mediated chelation-controlled Mukaiyama aldol reaction and two modified Homer-Wadsworth-Emmons olefinations (Roush-Masamune and Still-Gennari).

A small library of guanidino-lactams were synthesized in four steps and good overall yields by following the routes: preparation of guanylating agents, synthesis of protected guanidino-acids, cyclization to fully protected guanidino-lactams, and deprotection to the target compounds. The guanidino-lactams were assayed as antimicrobials on E. coli showing no significant antibiotic activity.

The CB1 receptor represents a promising target for the treatment of several disorders including pain-related disease states. However, therapeutic applications of Δ(9)-tetrahydrocannabinol and other CB1 orthosteric receptor agonists remain limited because of psychoactive side effects. Positive allosteric modulators (PAMs) offer an alternative approach to enhance CB1 receptor function for therapeutic gain with the promise of reduced side effects. Here we describe the development of the novel synthetic CB1 PAM, 6-methyl-3-(2-nitro-1-(thiophen-2-yl)ethyl)-2-phenyl-1H-indole (ZCZ011), which augments the in vitro and in vivo pharmacological actions of the CB1 orthosteric agonists CP55,940 and N-arachidonoylethanolamine (AEA). ZCZ011 potentiated binding of [(3)H]CP55,940 to the CB1 receptor as well as enhancing AEA-stimulated [(35)S]GTPγS binding in mouse brain membranes and β-arrestin recruitment and ERK phosphorylation in hCB1 cells. In the whole animal, ZCZ011 is brain penetrant, increased the potency of these orthosteric agonists in mouse behavioral assays indicative of cannabimimetic activity, including antinociception, hypothermia, catalepsy, locomotor activity, and in the drug discrimination paradigm. Administration of ZCZ011 alone was devoid of activity in these assays and did not produce a conditioned place preference or aversion, but elicited CB1 receptor-mediated antinociceptive effects in the chronic constriction nerve injury model of neuropathic pain and carrageenan model of inflammatory pain. These data suggest that ZCZ011 acts as a CB1 PAM and provide the first proof of principle that CB1 PAMs offer a promising strategy to treat neuropathic and inflammatory pain with minimal or no cannabimimetic side effects.

Starting from 3-bromo benzaldehyde, an eleven step synthesis of the substrate (I) is described which is further transformed to the title compounds.

Structural modification of the potent conformationally constrained tricyclic pyrazole CB1 ligand NESS0327 was achieved by replacing: (1) the chlorine substituent on the tricycle with a 3-fluoropropyl chain, and (2) the pyrazole 3-{[(piperidino)amino]carbonyl} substituent with a 4-substituted 1,2,3-triazole group obtained by click chemistry from an alkynyl precursor. Among the resulting compounds, two are particularly promising candidates for [18F]radiolabelling and PET imaging studies of the CB1 receptor, as they displayed K i CB1 = 62.5 nM and 42.5 nM, respectively, in the same range as that displayed by rimonabant.

(-)-Kainic acid potently increases stretch-induced afferent firing in muscle spindles, probably acting through a hitherto uncloned phospholipase D (PLD)-coupled mGlu receptor. Structural modification of (-)-kainic acid was undertaken to explore the C-4 substituent effect on the pharmacology related to muscle spindle firing. Three analogues 1a-c were synthesised by highly stereoselective additions of a CF3, a hydride and an alkynyl group to the Re face of the key pyrrolidin-4-one intermediate 5a followed by further structural modifications. Only the 4-(1,2,3-triazolyl)-kainate derivative 1c retained the kainate-like agonism, increasing firing in a dose-dependent manner. Further modification of 1c by introduction of a PEG-biotin chain on the 1,2,3-triazole fragment afforded compound 14 which retained robust agonism at 1 mu M and appears to be suitable for future use in pull-down assays and far western blotting for PLD-mGluR isolation.

Replacement of the 3-carbonylaminopiperidine substitutent with a “click” 4-[ N -(4-fluorobutyl)-(1,2,3-triazolyl)] group in Rimonabant-type pyrazoles produced a novel class of nanomolar CB 1 receptor ligands. Molecule 1d is the most promising lead with a K i = 23 nM for CB 1 , which is very close to that displayed by Rimonabant (SR141716), and fairly good CB 1 /CB 2 selectivity ( K i CB 2 / K i CB 1 = 35.5), thus representing a promising candidate for [ 18 F]radiolabeling and PET Imaging studies of the CB 1 receptor.

19 páginas, 9 esquemas, 2 tablas -- PAGS nros. 2643-2661, The total syntheses of (+)-9-epi-dictyostatin (1a) and (–)-12,13-bis-epi-dictyostatin (1b), diastereomers of the antimitotic marine sponge-derived macrolide (–)-dictyostatin (1), were achieved by creating 11 stereogenic centers and 4stereogenic double bonds with a high level of stereocontrol. The yield for the 29-step longest linear sequence from Roche ester was 1.53 and 1.52 %, respectively. The final key steps to these unnatural products were the addition of vinylzincates C10-C26 to aldehyde C1–C9 (leading surprisingly to complete stereoselectivity for the 9R-configuration in 28a and for the 9S-configuration in 12,13-bis-epimeric 28b), followed by Yamaguchi macrolactonization and global deprotection. (–)-12,13-Bis-epi-dictyostatin (1b) displayed a dramatic decrease of cytotoxicity and of the affinity toward the paclitaxel binding site of microtubules, We thank the Ministero dell'Università e della Ricerca (MIUR) for financial support (PRIN prot. 2008J4YNJY) and for a PhD fellowship (Borsa di dottorato, Progetto giovani, to C. Z.). L. P. thanks Milan University for a postdoctoral fellowship (Assegno di ricerca). Z. H. (Lanzhou University, PRC) thanks the China Scholarship Council for a PhD mobility grant. J. F. D. thanks the Spanish Ministerio de Ciencia e Innovación (MICINN) for support (grant number BIO2010-16351

Tritium-labelled fluoroazomycin arabinoside, [H-3]-FAZA, is a useful probe for the investigation of hypoxia, furthermore it is safer and easier to handle than the PET tracer [F-18]-FAZA when used in cell based assays. The only known synthesis of deuterium- and tritium-labelled FAZA was re-investigated and optimized. Then, a new and improved synthesis of [H-2]-FAZA was developed as a model process for tritium radiolabelling. This novel synthesis is expected to greatly facilitate access to [H-3]-FAZA. (C) 2013 Elsevier B.V. All rights reserved.