Search

A new strategy is reported for the C−H/C−H functionalization of 7‐azaindazoles at the C6‐position through a regioselective oxidative arylation using N‐oxide activation. This methodology allowed selective and original access to C6‐arylated 7‐azaindazoles with different substituted arenes and heteroarenes. [ABSTRACT FROM AUTHOR]

A series of pentafluorosulfanyl-substituted acrylic esters and amides have been synthesized in moderate to good yields from 3-pentafluorosulfanyl-prop-2-enol employing a chromic oxidation and subsequent coupling reaction. New pentafluorosulfanyl-substituted allylsilanes were also obtained from a SF5-Cl addition on allylsilanes followed by a β-elimination reaction. [ABSTRACT FROM AUTHOR]

Abstract: We developed an optimized Liebeskind–Srogl reaction in order to synthesize potentially biologically active 2-aryl-1,4-dihydropyrimidines. The pallado-catalyzed cross-coupling reaction between dihydropyrimidines and tributyltin derivatives appears particularly efficient (67–95% yields) when using CuBr·Me2S as the copper cofactor. [Copyright &y& Elsevier]

Abstract: A series of 7-azaindolic ligands bearing a methoxy group and a N-acetyl chain as melatoninergic pharmacophores were synthesized and their binding affinities towards MT1 and MT2 receptors were evaluated. Compounds 7a–c and 12 (cyclohexyl ring connected at C-2 and C-3 position) appears as important melatonin MT2 and MT1 receptors agonists. On the other hand, the presence of basic groups (amines) at position C-3 was detrimental to the melatoninergic affinities. [Copyright &y& Elsevier]

We here report a unique and efficient copper bromide mediated pallado-catalyzed coupling of protecting group- free 2-thiouracil derivatives with organostannanes. The nature of the copper appears to be crucial for successful cross coupling. [ABSTRACT FROM AUTHOR]

Abstract: A new group of serotoninergic 5-HT1A or 5-HT7 receptor ligands was identified. These compounds were designed and synthesized on a benzimidazolone scaffold and they enrich the well-known arylpiperazine class of 5-HT ligands. Diverse pharmacomodulations induced a shift in the affinity and selectivity profile with final identification of new potent hits. [Copyright &y& Elsevier]

An efficient strategy for the synthesis of functionalised 2,3-dihydrofuro[2,3-b]pyridines and 3,4-dihydro-2H-pyrano[2,3-b]pyridines is reported. The strategy is based on an intramolecular inverse-electron-demand Diels-Alder reaction starting from 1,2,4-triazines appropriately functionalised with alkynes, followed by various cross-coupling reactions (Suzuki, Stille, and Sonogashira). [ABSTRACT FROM AUTHOR]

C3-Substituted-4-azaindoles were synthesized from pyridylacetonitriles in a two-step sequence allowing the easy introduction of a range of substituents. This strategy permits the rapid synthesis of 4-azamelatonin and a protected 4-azatryptophan. [ABSTRACT FROM AUTHOR]

Abstract: Polysubstituted 2,3-dihydrofuro[2,3-b]pyridines and 3,4-dihydro-2H-pyrano[2,3-b]pyridines have been synthesized from 1,2,4-triazines using the inverse electron Diels–Alder reaction. For this purpose, 3-methylsulfanyl-1,2,4-triazines were reacted with several nucleophiles allowing the formation of appropriately substituted alkynes to undergo the intramolecular inverse electron demand Diels–Alder reaction. Sealed-tube microwave activation of the cycloaddition reaction has proved to be very efficient and allowed shorter reaction times. This strategy enabled an efficient synthesis of 3-hydroxy-2,3-dihydrofuro[2,3-b]pyridines and 4-hydroxy-3,4-dihydro-2H-pyrano[2,3-b]pyridines with several points of diversity on the bicyclic scaffold. [Copyright &y& Elsevier]

Abstract: In order to define new PPARβ/δ ligands, SAR study on the selective PPARβ/δ activator L-165,041 led to the identification of one key functional group for selective PPARβ/δ activation. Furthermore, taking advantage of SAR studies done elsewhere on the most selective PPARβ/δ ligand GW501516, the conception of new ligands showing good affinity for PPARβ/δ is reported. Finally, synthesis and biological evaluation of pyridine analogues have shown the benefical effect of the pyridine ring on the PPARβ/δ subtype selectivity. [Copyright &y& Elsevier]

The synthesis of benzoxathiins bearing a retroamide function is described from 8-hydroxythiochroman, the key step involving the synthesis of the benzoxathiin ring through a sulfonium salt. These new melatonin analogues were evaluated on human receptors MT 1 and MT 2 and have a similar affinity to that of melatonin itself. [ABSTRACT FROM AUTHOR]

In the present work, the synthesis of new ethacrynic acid (EA) derivatives containing nitrogen heterocyclic, urea, or thiourea moieties via efficient and practical synthetic procedures was reported. The synthesised compounds were screened for their anti-proliferative activity against two different cancer cell lines, namely, HL60 (promyelocytic leukaemia) and HCT116 (human colon carcinoma). The results of the in vitro tests reveal that compounds 1–3, 10, 16(a–c), and 17 exhibit potent anti-proliferative activity against the HL60 cell line, with values of the percentage of cell viability ranging from 20 to 35% at 1 μM of the drug and IC50 values between 2.37 μM and 0.86 μM. Compounds 2 and 10 showed a very interesting anti-proliferative activity of 28 and 48% at 1 μM, respectively, against HCT116. Two PyTAP-based fluorescent EA analogues were also synthesised and tested, showing good anti-proliferative activity. A test on the drug-likeness properties in silico of all the synthetised compounds was performed in order to understand the mechanism of action of the most active compounds. A molecular docking study was conducted on two human proteins, namely, glutathione S-transferase P1-1 (pdb:2GSS) and caspase-3 (pdb:4AU8) as target enzymes. The docking results show that compounds 2 and 3 exhibit significant binding modes with these enzymes. This finding provides a potential strategy towards developing anticancer agents, and most of the synthesised and newly designed compounds show good drug-like properties. [ABSTRACT FROM AUTHOR]

A domino SNAr‐ihDA/rDA reaction was developed from rarely exploited 3‐fluoro‐1,2,4‐triazines with bifunctional alkyne tethered nucleophiles to construct various fused non‐aromatic/heteroaromatic bicycles in yields ranging from 56 to 99%, notably within the family of valuable spirooxindole derivatives. In this study, the challenging enantioselective phase‐transfer catalyzed arylation of a sulfonyl‐triazine was also demonstrated with up to 66% ee. In both racemic and asymmetric processes, the nature of the leaving group at C3 was key to successfully achieve these sequences. [ABSTRACT FROM AUTHOR]

Oxidation of pentafluorosulfanyl-substituted alcohols (I) and (V) followed by coupling with alcohols or amines provides the corresponding acrylic esters and amides. [ABSTRACT FROM AUTHOR]

Dihydropyrimidothione substrates are successfully coupled with tributyltins to produce potentially biologically active dihydropyrimidines. [ABSTRACT FROM AUTHOR]

The present study aims to report the design, synthesis, and biological activity of new ethacrynic acid (EA) analogs (6–10) obtained by the double modulation of the carboxylic acid moiety and the aromatic ring with the aim to increase the chemical reactivity of Michael acceptor of EA. All obtained compounds were characterized by 1H and 13C NMR, IR, and high-resolution mass spectrometry. The antiproliferative activity was evaluated in vitro using MMT test, in a first step, against HL60 cell line and in a second step, on a panel of human cancer cell lines such as HCT116, A549, MCF7, PC3, U87-MG, and SKOV3, and normal cell line MRC5 in comparison with positive control doxorubicin. Among all the tested compounds, the product 8 containing a propargyl and a hydroxyl groups, allowing an intramolecular hydrogen bond with the keto group of EA, exhibited a pronounced and selective activity in a nanomolar range against HL60, A549, PC3, and MCF7 with IC50 values of 15, 41.2, 68.7, and 61.5 nM, respectively. Compound 8 also showed a good selectivity index (SI) against HL60 and moderate SI against the other three human cancer cells (A549, PC3, and MCF7). The study of the structure-activity relationship showed that both modifications of the carboxylic group and the introduction of an intramolecular hydrogen bond are highly required to improve the antiproliferative activities. The molecular modeling studies of compound 8 revealed that it favorably binds to the glutathione S-transferase active site, which may explain its interesting anticancer activity. These new compounds have potential to be developed as novel therapeutic agents against various cancer types. [ABSTRACT FROM AUTHOR]

In the present study, new 2-phenyl-5,6,7,8-tetrahydroimidazo [1,2-b]pyridazines bearing sulfonamides were synthesized, characterized and evaluated for their anticancer activities. The structures of these derivatives were elucidated by 1H NMR, 13C NMR, infrared and high-resolution mass spectrometry for further validation of the target compound structures. The anticancer activities of the new molecules were evaluated against five human cancer cell lines, including A-549, Hs-683, MCF-7, SK-MEL-28 and B16-F10 cell lines using 5-fluorouracil and etoposide as the reference drugs. Among the tested compounds, 4e and 4f exhibited excellent activities in the same range of the positive controls, 5-fluorouracil and etoposide, against MCF-7 and SK-MEL-28 cancer cell lines, with IC50 values ranging from 1 to 10 μM. The molecular docking studies of 4e and 4f showed a strong binding with some kinases, which are linked to MCF-7 and SK-MEL-28 cancer cell lines. [ABSTRACT FROM AUTHOR]

The use of polypyridyl Ru complexes to inhibit metastasis is a novel approach, and recent studies have shown promising results. We have reported recently that Ru (II) complexes gathering two 4,7-diphenyl-1,10-phenanthroline (dip) ligands and the one being 2,2′-bipyridine (bpy) or its derivative with a 4-[3-(2-nitro-1H-imidazol-1-yl)propyl (bpy-NitroIm) or 5-(4-{4′-methyl-[2,2′-bipyridine]-4-yl}but-1-yn-1-yl)pyridine-2-carbaldehyde semicarbazone (bpy-SC) moieties can alter the metastatic cascade, among others, by modulating cell adhesion properties. In this work, we show further studies of this group of complexes by evaluating their effect on HMEC-1 endothelial cells. While all the tested complexes significantly inhibited the endothelial cell migration, Ru-bpy additionally interrupted the pseudovessels formation. Functional changes in endothelial cells might arise from the impact of the studied compounds on cell elasticity and expression of proteins (vinculin and paxillin) involved in focal adhesions. Furthermore, molecular studies showed that complexes modulate the expression of cell adhesion molecules, which has been suggested to be one of the factors that mediate the activation of angiogenesis. Based on the performed studies, we can conclude that the investigated polypyridyl Ru (II) complexes can deregulate the functionality of endothelial cells which may lead to the inhibition of angiogenesis. [ABSTRACT FROM AUTHOR]

G protein-coupled receptors (GPCRs) are involved in regulation of manifold physiological processes through coupling to heterotrimeric G proteins upon ligand stimulation. Classical therapeutically active drugs simultaneously initiate several downstream signaling pathways, whereas biased ligands, which stabilize subsets of receptor conformations, elicit more selective signaling. This concept of functional selectivity of a ligand has emerged as an interesting property for the development of new therapeutic molecules. Biased ligands are expected to have superior efficacy and/or reduced side effects by regulating biological functions of GPCRs in a more precise way. In the last decade, 5-HT7 receptor (5-HT7R) has become a promising target for the treatment of neuropsychiatric disorders, sleep and circadian rhythm disorders, and pathological pain. In this study, we showed that Serodolin is unique among a number of agonists and antagonists tested: it behaves as an antagonist/inverse agonist on Gs signaling while inducing ERK activation through a ß-arrestin-dependent signaling mechanism that requires c-SRC activation. Moreover, we showed that Serodolin clearly decreases hyperalgesia and pain sensation in response to inflammatory, thermal, and mechanical stimulation. This antinociceptive effect could not be observed in 5-HT7R knockout (KO) mice and was fully blocked by administration of SB269-970, a specific 5-HT7R antagonist, demonstrating the specificity of action of Serodolin. Physiological effects of 5-HT7R stimulation have been classically shown to result from Gs-dependent adenylyl cyclase activation. In this study, using a ß-arrestin-biased agonist, we provided insight into the molecular mechanism triggered by 5-HT7R and revealed its therapeutic potential in the modulation of pain response. [ABSTRACT FROM AUTHOR]

The extraction of americium(III), curium(III), and lanthanides(III) from nitric acid by 2,6-bis-(5,6-dimethyl-[1,2,4]-triazin-3-yl)-pyridine and 2,6-bis-(5,6-dimethyl-[1,2,4]-triazin-3-yl)-4-methoxypyridine was studied. The physico-chemical properties of these ligands, such as the protonation and complexation constants, were also determined to describe the influence of different substituent groups. The selectivity of substituted-BTP was confirmed both in complexation and in solvent extraction experiments. The presence of an alkoxy-group in position 4 of the pyridine decreases the BTP selectivity. Influence of a long alkyl chain on protonation and complexation constants was also studied with 2,6-bis-(5,6-dimethyl-[1,2,4]-triazin-3-yl)-4-dodecyloxypyridine. [ABSTRACT FROM AUTHOR]

The synthesis of new N-homopiperazinyl-based ligands is reported. Various structural modifications along with the corresponding biological activities on 5-HT1A/5-HT7 receptors give further insights into this class of serotoninergic ligands. Among the tested central heterocyles, the 7-azaindole gave the best results on the above-mentioned receptors. [ABSTRACT FROM AUTHOR]

Abstract: Structure–activity relationships of a series of bis-arylic compounds, investigated as 5-HT7R ligands, are reported. The main structural modifications involved a central aryl moiety (phenyl, pyridine, diazine, triazine) and the nature and position of an amine-containing aliphatic chain. The affinity of the synthesized compounds (26nM–10μM) was systematically correlated with other previously reported series of bis-arylic ligands and rationalized by a ligand-based pharmacophore approach. [Copyright &y& Elsevier]

Abstract: The synthesis of unprecedented fused azaheterocyclic ring systems is described. Tricycles with either a central pyrazole or a triazole ring were obtained via a nitrene-mediated reaction of nitro bis(hetaryl) derivatives in the presence of triethylphosphite. The cyclization proceeded with complete chemoselectivity for the desired N–N bond formation and was completed within minutes under microwave activation. The key nitro bicycles were synthesized using either Stille couplings or aromatic nucleophilic substitution. [Copyright &y& Elsevier]

Palladium-catalyzed copper(I)-mediated cross-coupling reaction of 3-methylthio-6-(morpholin-4-yl)-1,2,4,5-tetrazine with a wide range of boronic acids and organotin derivatives led to new unsymmetrical aryl- and hetaryl-substituted tetrazines in moderate to good yields. These results represent the first cross-coupling reactions of readily available 3-methylthiotetrazine under Suzuki-like and Stille-like conditions and could extend the scope of tetrazine chemistry. [ABSTRACT FROM AUTHOR]

Direct and site‐selective C5 and C7 palladium‐catalyzed C−H arylations of 4‐azaindazole N‐oxide have been achieved. A bidentate ligand and Pd(OAc)2 catalyst in toluene promoted the activation of C5 position, while a phosphine ligand and PdCl2 catalyst in DMA directed the arylation at C7 position. Using this new method, the synthesis of C5, C7‐diarylated 4‐azaindazole N‐oxides as well as the C3, C5, C7‐triarylated 4‐azaindazoles was achieved towards future medicinal compounds development. [ABSTRACT FROM AUTHOR]

The 5-hydroxytryptamine 7 receptor (5-HT 7) is necessary for 5-HT to cause a concentration-dependent vascular relaxation and hypotension. 5-HT 7 is recognized as having biased signaling, transduced through either Gs or β -arrestin. It is unknown whether 5-HT 7 signals in a biased manner to cause vasorelaxation/hypotension. We used the recently described β-arrestin selective 5-HT 7 receptor agonist serodolin to test the hypothesis that 5-HT 7 activation does not cause vascular relaxation or hypotension via the β -arrestin pathway. Isolated abdominal aorta (no functional 5-HT 7) and vena cava (functional 5-HT 7) from male Sprague Dawley rats were used in isometric contractility studies. Serodolin (1 nM – 10 μM) did not change baseline tone of isolated tissues and did not relax the endothelin-1 (ET-1)-contracted vena cava or aorta. In the aorta, serodolin acted as a 5-HT 2A receptor antagonist, evidenced by a rightward shift in 5-HT-induced concentration response curve [pEC 50 5-HT [M]: Veh = 5.2 +/- 0.15; Ser (100 nM) = 4.49 +/- 0.08; p < 0.05]. In the vena cava, serodolin acted as a 5-HT 7 receptor antagonist, shifting the concentration response curve to 5-HT left and upward (%10 μM NE contraction; Veh = 3.2 +/- 1.7; Ser (10 nM) = 58 +/- 11; p < 0.05) and blocking relaxation of pre-contracted tissue to the 5-HT 1A/7 agonist 5-carboxamidotryptamine. In anesthetized rats, 5-HT or serodolin was infused at 5, 25 and 75 μg/kg/min, iv. Though 5-HT caused concentration-dependent depressor responses, serodolin caused an insignificant small depressor responses at all three infusion rates. With the final dose of serodolin on board, 5-HT was unable to reduce blood pressure. Collectively the data indicate that serodolin functions as a 5-HT 7 antagonist with additional 5-HT 2A blocking properties. 5-HT 7 activation does not cause vascular relaxation or hypotension via the β -arrestin pathway. [Display omitted] • 5-HT 7 receptor stimulation mediates the 5-HT stimulated hypotension, but it is unknown whether the receptor functions through Gs or β-arrestin to cause these effects • The β -arrestin biased agonist serodolin was unable to relax isolated vessels nor cause dose-dependent hypotension. • These findings point to the actions that proceed from 5-HT stimulation of the 5-HT 7 receptor to be dependent on Gs signaling. [ABSTRACT FROM AUTHOR]

A new fluorescent sensor for imaging cancer cells was designed by bioconjugation of holo-transferrin (hTf) with a nitro-pyrazinotriazapentalene moiety (PyTAP-NO 2) as a bioreductive fluorescent unit. hTf was chosen to increase its selective delivery to cancer cells through transferrin receptor (TfR) mediated endocytosis. PyTAP-NO 2 was applied to enhance the fluorescent signal in oxygen-deprived cells due to the increased expression of nitroreductases under such conditions. A protein-dye bioconjugate had an average of 8 fluorophore molecules per protein that effectively amplifying the fluorescence signal. The designed hTf- PyTAP-NO 2 was non-toxic and its efficient accumulation through TfR, as well as its high stability and sustained intracellular retention, was proven. hTf-PyTAP-NO 2 bioconjugate allows selective accumulation in cancer cells containing increased levels of TfRs with simultaneous slight enhancement of signal in hypoxic cells due to increased expression of nitroreductases. [Display omitted] • Bioconjugation of holo-transferrin with a nitro-pyrazinotriazapentalene for cell imaging. • Fast and efficient cellular uptake exclusively via transferrin receptor endocytosis. • A high fluorescent signal in cells additionally amplified under hypoxic conditions. • Resistant to degradation and sustained intracellular retention. [ABSTRACT FROM AUTHOR]

A simple method for the direct Pd(OAc)2‐catalyzed oxidative arylation of inactivated 1H‐indazole derivatives with simple arenes is reported. This method exhibits good reaction efficiency and good functional‐group tolerance. Using the developed method, 28 arylated products were prepared in yields up to 80 %. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis of unprecedented fused nitroazaheterocyclic ring systems. Nitro tricycles with a central 1,2,3-triazole ring were obtained via a nitrene-mediated reaction of azidonitrobis(hetaryl) derivatives under thermolysis. The cyclization proceeded with complete chemoselectivity for the desired N-N bond formation. The key azidonitro bicycles were synthesized through an aromatic nucleophilic substitution from nitroazoles and 3-azido-2-chloropyrazine. [ABSTRACT FROM AUTHOR]

Formation of N−N bonds may offer an original approach to various nitrogen‐containing heterocycles with numerous applications. For this purpose, we found that readily available heteroaromatic amines are appropriate substrates for providing an efficient and innovative approach for the formation of N−N bonds in the presence of iodine (III) reagent in very mild conditions. This method makes it possible to synthesize nitrogen rich triazapentalene derivatives exhibiting fluorescent properties, inaccessible with existing approaches. [ABSTRACT FROM AUTHOR]

In this paper we describe the design and synthesis of bis(Het)Aryl-1,2,3-triazole quinuclidine α7R ligands using an efficient three-step sequence including a Suzuki-Miyaura cross coupling reaction with commercially available and home-made boron derivatives. The exploration of SAR required the preparation of uncommon boron derivatives. Forty final drugs were tested for their ability to bind the target and nine of them exhibited Ki values below nanomolar concentrations. The best scores were always obtained when the 5-phenyl-2-thiophenyl core was attached to the triazole. The selectivity of these compounds towards the nicotinic α4β2 and serotoninergic 5HT3 receptors was assessed and their brain penetration was quantified by the preparation and in vivo evaluation of two [18F] radiolabelled derivatives. It can be expected from our results that some of these compounds will be suitable for further developments and will have effects on cognitive disorders. Image 1 • 47 new potent triazole/quinuclidinic alpha 7 nAChR ligand have been synthesized. • Identified leads exhibited a affinity in the subnanomolar range (10 cpds with 0.2 < Ki < 1 nM). • Leads exhibit strict selectivity toward the α4β2 nicotinic and 5-HT3 receptors. • Brain penetration and distribution was evaluated by preparing [18F] radiolabelled derivatives. [ABSTRACT FROM AUTHOR]

Based on both the chemical and the biological importance of the pyrazole and the thiazole backbones, we report herein a convenient design of new pyrazolo[3,4‐d]thiazoles for the development of molecules with a high therapeutic potential. The effective and appropriate strategy chosen consists of an intramolecular copper‐catalysed N‐arylation followed by the Liebeskind‐Srogl cross‐coupling reaction. The efficiency of copper and palladium catalysts for the first step of the synthesis was evaluated. These efforts allowed the synthesis of a variety of modulated heterobicycles. [ABSTRACT FROM AUTHOR]

An unusual class, compact in size, of fluorescent probes based on pyridazino-1,3a,6a-triazapentalene scaffolds exhibits promising fluorescent properties (quantum yield values up to 73%, large Stokes shifts, emission wavelengths located in the green-yellow range, excellent solubility) with good photostability suitable for optical imaging applications. [ABSTRACT FROM AUTHOR]

Magnesium in methanol was found to be an effective and inexpensive reagent for the dehalogenation of (hetero)aryl chlorides, bromides and iodides under mild conditions. The halogen/hydrogen exchange proceeded at room temperature and tolerated functional groups such as esters, nitriles, alcohols, and alkenes. [ABSTRACT FROM AUTHOR]

The kinetic inertness of Mn2+ complexes is an important parameter for the in vivo safety of potential MRI contrast agents. Rigidifying the ligand structure typically leads to reinforced kinetic inertness. In this context, we studied the Mn2+ complexes of three linear poly(amino carboxylate) ligands containing a pyridine moiety in their skeleton and bearing four (L1, L2) or three carboxylates (L3). The thermodynamic stability constants of the complexes formed with Mn2+, Ca2+, Mg2+, Zn2+ and Cu2+ have been determined using pH-potentiometry, 1H relaxometry and UV/Vis spectrophotometry and are close to those of the EDTA analogues. In contrast, and despite the presence of the pyridine in the ligand backbone, the dissociation rates of the complexes are several orders of magnitude higher than that of [Mn(EDTA)]2−, resulting from a very efficient dissociation pathway catalyzed by the direct attack of Cu2+ or Cu(OH)+. Due to the fewer carboxylate functions, ligand L3 is less favorable for metal-assisted dissociation and provides higher kinetic inertness for its Mn2+ chelate than the L1 and L2 analogues. The water exchange of the monohydrated MnL3 complex has been studied in a variable temperature 17O NMR study. The exchange rate is very high, k298ex = 2.8 × 109 s−1, which is among the highest values reported for a Mn2+ complex. The NMRD profiles are typical of small molecular weight Mn2+ chelates (r1p = 2.44 mM−1 s−1 at 25 °C and 20 MHz). [ABSTRACT FROM AUTHOR]

Oxidative stress and apoptosis are both associated with various acute and chronic disorders. Thus, the aim of the present study is to synthesize imidazo[2,1- c ][1,2,4]triazines derivatives and to evaluate their effects in H 2 O 2 -induced oxidative stress in human neuroblastoma cell line (SH-SY5Y cells). The effects of the compounds on cell viability were measured by MTT assay and the changes in stress and apoptosis-related proteins were investigated by PathScan ® Stress and Apoptosis Signaling Antibody Array kit and Western Blot technique. In particular, four compounds were found to protect SH-SY5Y cells from H 2 O 2 -induced toxicity by increasing Bcl-2/Bax ratio, regulating PI3-K/Akt cascade and inhibiting the ERK pathway. [ABSTRACT FROM AUTHOR]

This work highlights the use of 3-vinyl-1,2,4-triazines as original thia-Michael acceptors and inverse electron demanding Diels-Alder platforms en route to new 7,8-dihydro-5 H-thiopyrano[4,3- b]pyridines. The required but rather unstable propargylthiol nucleophiles were successfully generated in-situ upon an innovative DBU-catalyzed methanolysis event of the corresponding propargyl thioacetate derivatives. [ABSTRACT FROM AUTHOR]

An "on water" palladium-catalyzed direct (hetero)arylation of 2H-pyrazolo[3,4-b]pyridines has been developed. The reactions proceeds smoothly with at low catalytic loading at low temperature providing the C3 (hetero)arylated products in good to excellent isolated yields. Free NH 3-arylated 7-azaindazoles were also prepared by simple cleavage of the N-protected groups. [ABSTRACT FROM AUTHOR]

A straightforward domino aza-Michael-inverse-electron-demand-hetero-Diels-Alder/retro-Diels-Alder reaction between primary and secondary propargylamine derivatives and 3-vinyl-1,2,4-triazines is developed highlighting not only the uniqueness of this dual-heterocyclic platform but also a novel and unprecedented path to polysubstituted tetrahydro-1,6-naphthyridine scaffolds. [ABSTRACT FROM AUTHOR]

Ortho-chelation assistance was proved to be crucial for the success of the desulfitative Sonogashira cross-coupling reaction of thioamide-type pyridine derivatives and alkynes. Corresponding alkynylated products were obtained with moderate to excellent yields. Thanks to this reaction, furo[3,2- b ]pyridine and 1 H -pyrrolo[3,2- b ]pyridine derivatives were synthesized through a one-pot cross-coupling reaction/heteroannulation sequence. [ABSTRACT FROM AUTHOR]

Background and Purpose: The paradigm that GPCRs are able to prolong or initiate cellular signalling through intracellular receptors recently emerged. Melatonin binds to G protein-coupled MT1 and MT2 receptors. In contrast to most other hormones targeting GPCRs, melatonin and its synthetic analogues are amphiphilic molecules easily penetrating into cells, but the existence of intracellular receptors is still unclear mainly due to a lack of appropriate tools.Experimental Approach: We therefore designed and synthesized a series of hydrophilic melatonin receptor ligands coupled to the Cy3 cyanin fluorophore to reliably monitor its inability to penetrate cells. Two compounds, one lipophilic and one hydrophilic, were then functionally characterized in terms of their affinity for human and murine melatonin receptors expressed in HEK293 cells and their signalling efficacy.Key Results: Among the different ligands, ICOA-13 showed the desired properties as it was cell-impermeant and bound to human and mouse MT1 and MT2 receptors. ICOA-13 showed differential activities on melatonin receptors ranging from partial to full agonistic properties for the Gi /cAMP and ERK pathway and β-arrestin 2 recruitment. Notably, ICOA-13 enabled us to discriminate between Gi /cAMP signalling of the MT1 receptor initiated at the cell surface and neuronal mitochondria.Conclusions and Implications: We report here the first cell-impermeant melatonin receptor agonist, ICOA-13, which allows us to discriminate between signalling events initiated at the cell surface and intracellular compartments. Detection of mitochondrial MT1 receptors may have an important impact on the development of novel melatonin receptor ligands relevant for neurodegenerative diseases, such as Huntington disease. [ABSTRACT FROM AUTHOR]

The mechanism of cell death induced by the ruthenium polypyridyl complexes comprising two 4,7-diphenyl-1,10-phenanthroline ligands as well as one unmodified 2,2′-bipyridyl or modified with 2-nitroimidazole moiety attached by shorter ( C 3 H 6 ) or longer ( C 6 H 12 ) linker was investigated. Cytotoxicity and proliferation assays revealed that the studied Ru polypyridyl complexes are more toxic against human pancreas carcinoma PANC-1 cell line than normal human keratinocytes HaCaT with IC 50 of 3–5 μM. The Ru complexes despite accumulation in mitochondria do not lead to mitochondrial disfunction, though decreasing of mitochondrial Ca 2 + causes mitochondria membrane hyperpolarization. The Ru polypyridyl conjugates induce some phenotypical characteristic of apoptosis, such as condensation of chromatin or phosphatidylserine translocation, however no caspase or calpain activation in the studied cell lines was observed, indicating that detected cell death does not occur via mitochondria- or ER-activated pathways. Caspase-independent cell death is caused by enormous ROS formation, mainly hydrogen peroxide and peroxyl radicals as well as by intracellular Ca 2 + homeostasis disruption. Accumulation of the Ru compounds inhibits the completion of DNA synthesis, arresting cells in S-phase of cell cycle. [ABSTRACT FROM AUTHOR]

Neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, and Huntington's disease affect millions of people in the world. Thus several new approaches to treat brain disorders are under development. The aim of the present study is to synthesize potential neuroprotective heterocyclic compounds based on pyrazolopyridine derivatives and then to evaluate their effects in MPP + -induced neurodegeneration in human neuroblastoma cell line (SH-SY5Y cells). The effects of the compounds on cell viability were measured by MTT assay and the changes in apoptosis-related proteins including bax, Bcl-2, Bcl-xl and caspase-3 were investigated by western blot technique. Based on the cell viability results obtained by MTT assay, the percentage of neuroprotection-induced by compounds against MPP + -induced neurotoxicity in SH-SY5Y cells was between 20% and 30% at 5 μM concentrations of all synthesized compounds. Moreover, the downregulation in pro-apoptotic proteins including bax and caspase-3 were found following the novel synthesized compounds treatments and these effects were observed in a dose-dependent manner. Our results provide an evidence that these heterocyclic compounds based on pyrazolopyridine derivatives may have a role on dopaminergic neuroprotection via antiapoptotic pathways. [ABSTRACT FROM AUTHOR]

The "Journées Franco-Belges de Pharmacochimie" is a recognized annual meeting in organic and medicinal chemistry known for the quality of scientific exchange and conviviality. Young researchers were encouraged to present their work and share ideas with senior scientists. Abstracts of plenary lectures, oral communications, and posters presented during the meeting are collected in this report. [ABSTRACT FROM AUTHOR]

Highly substituted pyrido[4,3- b]indole derivatives were synthesized through a straightforward one-pot silver-catalyzed process involving 2-alkynylindole-3-carbaldehyde oximes. The tandem cyclization/nucleophilic addition sequence was optimized and applied to a wide range of nucleophiles, which reacted regioselectively at the pyrido[4,3- b]indole C4 position. The scope and limitations of the methodology were evaluated and the final compounds were obtained in fair to very good yields. This versatile method proved to be compatible with various chemical functionalities or (hetero)cycles. [ABSTRACT FROM AUTHOR]

Age-related neurodegenerative diseases have in common the occurrence of cognitive impairment, a highly incapacitating process that involves the cholinergic neurotransmission system. The vesicular acetylcholine transporter (VAChT) positron emission tomography (PET) tracer [18F]fluoroethoxybenzovesamicol ((−)-[18F]FEOBV) has recently demonstrated its high value to detect alterations of the cholinergic system in Alzheimer's disease, Parkinson's disease and dementia with Lewy body. We present here the development of the new vesamicol derivative tracer (−)-(R,R)-5-[18F]fluorobenzovesamicol ((−)[18F]FBVM) that we compared to (−)[18F]FEOBV in the same experimental conditions. We show that: i) in vitro affinity for the VAChT was 50-fold higher for (−)FBVM (Ki = 0.9 ± 0.3 nM) than for (−)FEOBV (Ki = 61 ± 2.8 nM); ii) in vivo in rats, a higher signal-to-noise specific brain uptake and a lower binding to plasma proteins and peripheral defluorination were obtained for (−)[18F]FBVM compared to (−)[18F]FEOBV. Our findings demonstrate that (−)[18F]FBVM is a highly promising PET imaging tracer which could be sufficiently sensitive to detect in humans the cholinergic denervation that occurs in brain areas having a low density of VAChT such as the cortex and hippocampus. [Display omitted] • The absolute configuration of (−)-(R,R)-5-FBVM chemical structure is identified. • (−)-FBVM has 50-fold higher affinity for vesicular acetylcholine transporter than (−)-FEOBV. • In vivo striatum/cerebellum ratio uptake is 1.6-fold higher for (−)-FBVM vs. (−)-FEOBV. • Signal/noise ratio in rat brain is better for (−)-FBVM vs. (−)-FEOBV. • (−)-[18F]FBVM is a new promising PET tracer for the vesicular acetylcholine transporter. [ABSTRACT FROM AUTHOR]

A modified approach to synthesize and isolate arylnitromethanes is described. The method takes advantage of the significant difference in acidity between the arylnitromethane and the major impurity of the reaction, the nitrite ester. The arylnitromethanes resulting from this process are obtained in high yields and are analytically pure, i.e., they do not require distillation or further purification, which is a comfortable improvement of the ancestral Victor Meyer reaction. [ABSTRACT FROM AUTHOR]

We report herein an efficient synthesis of 2-substituted furo[3,2- b ]pyridines and their biological evaluation as melatonin receptors ligands. The proposed eight-step sequence ending with a Suzuki coupling allowed a rapid access to various analogues. The steric hindrance and the conformation of the aryl group in C 2-position were evaluated regarding the selectivity of the molecule for one of the two high affinity melatonin receptors as well as the activity profile of the compound. Introduction of 1-naphthyl substituent gave the best result in terms of selectivity with a MT 1 /MT 2 ratio of about 150 (MT 1 K i = 198 nM, MT 2 K i = 1.3 nM). [ABSTRACT FROM AUTHOR]

We report here the synthesis of a large library of 1,2,3-triazole derivatives which were in vitro tested as α7 nAchR ligands. The SAR study revealed that several crucial factors are involved in the affinity of these compounds for α7 nAchR such as a ( R ) quinuclidine configuration and a mono C -3 quinuclidine substitution. The triazole ring was substituted by a phenyl ring bearing small OMe/CH 2 F groups or fluorine atom and by several heterocycles such as thiophenes, furanes, benzothiophenes or benzofuranes. Among the 30 derivatives tested, the two derivatives 10 and 39 with Ki in the nanomolar range were identified (2.3 and 3 nM respectively). They exhibited a strict selectivity toward the α4β2 nicotinic receptor (up to 1 μM) but interacted with the 5HT 3 receptors with Ki around 3 nM. Synthesis, SAR studies and a full description of the derivatives are reported. [ABSTRACT FROM AUTHOR]