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• Petroleum separation into pyrolic, phenolic-ketonic, and carboxylic acid fractions. • The reliability of separation results strongly depends on the mass of the fraction. • The relative expanded uncertainty of concentration decreases with increasing mass. • A power function can describe the relative expanded uncertainty and mass relation. • Using plastic labware may negatively affect the fractionation results. This research outlines a fast and efficient technique for separating the pyrrolic, phenolic-ketonic, and carboxylic acid fractions from oils in a small-scale setting. This approach enables the separation and analysis of neutral nitrogen fractions that contain indoles, carbazoles, and benzocarbazoles, as well as ketonic-phenolic fractions that contain phenols and ketones. The study showcases the potential for accurately measuring petroleum composition. The reliability of the fractions' concentration results is determined by the mass of the separated fraction, with completely reliable results achievable for masses exceeding 1.4 mg. The fraction's mass can also be used to evaluate the relative expanded uncertainty of a single separation procedure. As the mass and concentration of the fraction increase, the relative expanded uncertainty of the concentration decreases, and this can be modelled using a power function. [ABSTRACT FROM AUTHOR]

Zika virus (ZIKV) infection recently resulted in an international health emergency the Americas in and despite its high profile there is currently no approved treatment for ZIKV infection with millions of people being at risk. ZIKV is a member of Flaviviridae family which includes prominent members such as dengue virus (DENV) and West Nile virus (WNV). One of the best validated targets for developing anti -flaviviral treatment for DENV and WNV infection is the NS2B/NS3 protease. However the inhibitors reported to date have shown limited promise for further clinical development largely due to poor cellular activity. Prompted by the conserved nature of the viral NS2B/NS3 protease across flaviviruses, we envisaged that small molecule inhibitors of the ZIKVpro may be developed by applying rational design on previously reported scaffolds with demonstrated activity against other flaviviral proteases. Starting with an earlier WNVpro hit we performed a scaffold hopping exercise and discovered that certain carbazole derivatives bearing amidine groups possessed submicromolar potency and significant cellular activity against ZIKV. We successfully addressed various issues with the synthesis of novel N-substituted carbazole-based amidines thus permitting a targeted SAR campaign. The in vitro biochemical and cell-based inhibitory profiles exhibited by the lead molecule described in this work (ZIKVpro IC 50 0.52 μM, EC 50 1.25 μM), is among the best reported to date. Furthermore, these molecules possess capacity for further optimization of pharmacokinetics and may evolve to broad spectrum flaviviral protease inhibitors. Image 1 • The flavivirus NS2B/NS3 protease is a conserved and validated antiviral target. • Novel carbazole derivatives designed with at least one amidine are potent inhibitors. • The profile of the lead compound identified is among the best reported in the literature. • A targeted SAR revealed N-substitutions that are tolerated with respect to safety and potency. • The mechanism of inhibition appears to be via partial and reversible occupancy of the active site. [ABSTRACT FROM AUTHOR]

We report in this work the discovery of novel allosteric MEK inhibitors by pharmacophore modeling and virtual screening. Two out of 13 virtual hit compounds were identified as MEK kinase inhibitors using a MEK1 binding assay. Structural derivations on the hit compound M100 (IC 50 = 27.2 ± 4.5 μM in RAF-MEK cascading assay) by substituent transformation and bioisosterism replacement have led to the synthesis of a small library of carbazoles. The enzymatic studies revealed the preliminary structure-activity relationships and the derivative 22k (IC 50 = 12.8 ± 0.5 μM) showed the most potent inhibitory effect against Raf-MEK cascading. Compound 7 was discovered as toxic as M100 to tumor cells whereas safer to HEK293 cells (IC 50 > 100 μM) than M100 (IC 50 = 8.9 ± 2.0 μM). It suggests that carbazole is a good scaffold for the design of novel MEK inhibitors for therapeutic uses. More importantly, the developed pharmacophore model can serve as a reliable criterion in novel MEK inhibitor discovery. Image 1 • A collection of structure-based pharmacophore model of allosteric MEK1 inhibitor was constructed. • Two out of the 13 virtual hits were found active to inhibit Raf-MEK cascading. • One of the hit compound (M100) was synthesized and optimized to increase potency and to reduce cytotoxicity. • The acquired carbazole derivatives were novel in structure as allosteric MEK inhibitor. • The binding modes were analyzed by docking study. [ABSTRACT FROM AUTHOR]

Graphical abstract Polymers comprising of different ratios of N -decyl substituted or N -triethylene glycol substituted 2,7-carbazoles and tetraphenylethenes were synthesized by palladium-catalyzed Suzuki Miyaura cross-coupling reaction. The copolymers showed aggregation induced emission characteristics when the composition of the tetraphenylethenes reached to 50%. The higher composition of the tetraphenylethenes, the deeper HOMO level and the larger bandgap of the polymers. Polymers with 1:1 M ratio of the carbazoles and the tetraphenylethenes exhibited sphere-like nanoaggregates with an average diameter of around 30 nm. The polymers containing carbazole and TPE units in 3:1 or 1:3 M ratio self-assembled to form nanoaggregates with a size of around 100 nm. Highlights • Polymers comprising of different ratios of carbazoles and tetraphenylethenes have been prepared. • The copolymers showed aggregation induced emission characteristics. • The higher composition of the tetraphenylethenes, the deeper HOMO level and the larger bandgap of the polymers. • Polymers exhibited sphere-like nanoaggregates with an average diameter of around 30 nm. Abstract In this work, polymers comprising of the different ratios of N -decyl or N -triethylene glycol substituted 2,7-carbazoles and tetraphenylethenes were designed and synthesized by palladium-catalyzed Suzuki Miyaura cross-coupling reaction of their corresponding comonomers. The copolymers containing carbazoles and tetraphenylethenes showed aggregation induced emission characteristics in both solid state and aggregate state when the composition of the tetraphenylethenes reached to 50%. N -triethylene glycol substituted carbazole polymers revealed lower bandgap and higher HOMO level compared to that of the N -decyl substituted carbazole polymers. The higher composition of the tetraphenylethenes, the deeper HOMO level and the larger bandgap of the polymers. Polymers with 1:1 molar ratio of the carbazoles and the tetraphenylethenes exhibited sphere-like nanoparticles with an average diameter of around 30 nm. The polymers containing carbazole and TPE units in 3:1 or 1:3 molar ratio self-assembled to form nanoaggregates with a size of around 100 nm. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • We have used carbazoles for the synthesis of fluorescent Au NPs. • The experimental and theoretical results indicated the origin of the fluorescence of Au NPs. • In-situ generation of Au NPs catalyzed the C C and N N coupling reactions of carbazoles. • Structure of the carbazoles control the morphology and fluorescence activity of Au NPs. Abstract Six structurally different carbazoles (1-6) were explored as the green reducing agents for the synthesis of the fluorescent Au nanoparticles with tailor-made morphology in anionic (sodium dodecyl sulphate, SDS), cationic (cetyltrimethylammonium bromide, CTAB) and neutral (polyvinylpyrrolidone, PVP) micelle medium. Structure of the carbazoles played an important role in controlling the morphology, rate of formation and fluorescent activity of the Au nanoparticles. The Au nanoparticles formed in-situ also simultaneously catalyzed the intermolecular C C and N N couplings between the carbazoles, leading to the corresponding bis-carbazole derivatives. The free and bis-carbazole derivatives functionalized the surface of the synthesized Au nanoparticles and thereby controlling their morphology and fluorescence activity. A computational study was also made to determine the origin of the absorption and emission bands of the synthesized nanoparticles. The combined experimental and theoretical studies unraveled the nanoparticle formation process and mechanistic pathway of this green and easily implementable synthetic protocol of Au nanoparticles. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Various carbazoles were synthesized via [4+2] annulation. • 1,3-Dicarbonyl compounds and indoles afforded excellent yields of carbazoles. • A Brønsted acid ionic liquid was proven to be effective catalyst for this reaction. • The ionic liquid catalyst can be recycled at least three times. Abstract Various carbazoles were synthesized via [4+2] annulation of 3-(2,2-diethoxyethyl)-1,3-dicarbonyl compounds with indoles. A Brønsted acid ionic liquid, [BPy]HSO 4 , was proven to be effective catalyst for this reaction. The ionic liquid catalyst can be recycled three times without significant loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

Synthesis of 1-substituted tetrahydrocarbazole is accomplished by TfOH catalyzed reaction of 3-substituted indoles tethered with secondary and tertiary alcohols. The reaction was generalized for a variety of substrates and was extended to the synthesis of 2,3,3a,6-tetrahydro-1 H -pyrido[3,2,1- jk ]carbazole and carbazoles. [ABSTRACT FROM AUTHOR]

The Borsche – Drechsel (BD) cyclization can be treated as a ' special case ' of a very well-known Fischer indole synthesis or so-called Fischer indolization (FI), now and then. To my surprise, some researchers knowingly or unknowingly treat it as the Fischer-cyclization rather than the BD – cyclization, though, it was first discovered in 1888 by Borsche et al., and further explored to a great level by the research group of Drechsel in 1908 – and hence the BD – cyclization instead of wrongly naming it as the Fischer indole synthesis. Remarkably, Borsche – Drechsel's methodology, like the Graebe-Ullmann protocol - services for both, the determination of the carbazoles structure and construction of the carbazole derivatives. In this cyclization, generally, arylhydrazones of cyclohexanone are being reacted under acidic condition to yield the corresponding 1,2,3,4-tetrahydrocarbazoles (Borsche – Drechsel cyclization) which upon subsequent dehydrogenation/aromatization afforded the corresponding carbazoles (Borsche – Drechsel carbazole synthesis). Herewith, I have tried to expose the historical background, and also the utility of this simple yet powerful method to assemble the biologically active 1,2,3,4-tetrahydrocarbazoles and/or aromatized carbazoles. [Display omitted] [ABSTRACT FROM AUTHOR]

9H-carbazole is generated from incomplete combustion of diverse fossil fuels and biomass, in tobacco smoke and from industrial processes, while halogenated carbazoles have natural and anthropogenic sources. We analyzed 9H-carbazole and 14 halogenated carbazoles in dust samples from 14 schools, 13 daycare centers, and 13 residences, as well as 5 indoor air samples from residences in Munich, Germany. Overall, we present first data of various carbazoles in different indoor environments without visible combustion sources. The median (95th percentile) values of the halogenated analytes mainly detected in the entire study group were 10.3 ng/g (308 ng/g) for 9H-carbazole, 13.3 ng/g (735 ng/g) for 3,6-dichloro-9H-carbazole, 6.2 ng/g (159 ng/g) for 1,3,6-tribromo-9H-carbazole, and 1.2 ng/g (21.1 ng/g) for 2,7-dibromo-9H-carbazole. For most of the target analytes, the highest concentrations were observed in dust samples from schools, and the lowest were found in residences. In the air samples, all analytes were found only at low levels, with median values of 7.7 pg/m 3 for 9H-carbazole and 6.1 pg/m 3 for 2,3,6,7-tetrachloro-9H-carbazole. For 9H-carbazole, “typical” and “high” non-dietary intake of children through dust ingestion using median and 95th percentile values were calculated to be 0.03 ng/kg b.w. and 1.1 ng/kg b.w. daily, respectively. Due to limited toxicological information and exposure data for other relevant pathways (e.g., dietary intake), the risk assessment is inconclusive. Nevertheless, there are indications that 9H-carbazole has carcinogenic properties and that halogenated carbazoles have dioxin-like toxicities. Therefore, further research is essential. [ABSTRACT FROM AUTHOR]

Polyhalogenated carbazoles (PHCs) are a class of emerging organic contaminants that have received increasing concern due to their widespread distribution and dioxin-like toxicity. Although previous studies have suggested possible natural sources of PHCs in the environment, the formation pathways are poorly understood. Here we explored the production of PHCs from halogenation of carbazole in the presence of Br − and/or Cl − under the catalysis of chloroperoxidase (CPO) isolated from the marine fungus Caldariomyces fumago . Overall, a total of 25 congeners including mono-to tetra-substituted chlorinated, brominated, and mixed halogenated carbazoles (with substitution patterns of –BrCl, –BrCl 2 , –BrCl 3 , –Br 2 Cl, –Br 2 Cl 2 , and –Br 3 Cl) were produced from the reactions under various conditions. The PHC product profiles were apparently dependent on the halide concentrations. In the CPO-mediated chlorination of carbazole, 3-mono- and 3,6-dichlorocarbazoles predominated in the formation products. In addition to the less abundant mixed halogenated carbazoles (-Br 2 Cl), 1,3,6-tri- and 1,3,6,8-tetrabromocarbazoles were the dominant products in reactions containing both Br − and Cl − . The CPO-catalyzed halogenation of carbazole could take place in pH 3–7, but the formation products were pH dependent. Results of this study suggest that CPO-catalyzed halogenation of carbazole may play an important role in the natural formation of PHCs. [ABSTRACT FROM AUTHOR]

A series of 49 oxygenated tricyclic carbazole derivatives has been tested for inhibition of the growth of Mycobacterium tuberculosis and a mammalian cell line (vero cells). From this series, twelve carbazoles showed a significant anti-TB activity. The four most active compounds were the naturally occurring carbazole alkaloids clauszoline-M ( 45 ), murrayaline-C ( 41 ), carbalexin-C ( 27 ), and the synthetic carbazole derivative 22 with MIC 90 values ranging from 1.5 to 3.7 μM. The active compounds were virtually nontoxic for the mammalian cell line in the concentration range up to 50 μM. [ABSTRACT FROM AUTHOR]

New 3-(1 H -imidazol-2-yl)-9 H -carbazoles and 6,6′-di(1 H -imidazol-2-yl)-9 H ,9′ H -3,3′-bicarbazoles have been prepared, starting from 9-ethyl-9 H -carbazole-3-carbaldehyde or 9,9′-diethyl-9 H ,9′ H -[3,3′-bicarbazole]-6,6′-dicarbaldehyde through their reactions with 4-methoxyaniline or 4-fluoroaniline, benzil or 2,2′-thenil [1,2-di(thien-2,2′-yl) glyoxal] and ammonium acetate on reflux in glacial acetic acid. The obtained compounds have been shown to demonstrate an effective fluorescence in the blue spectral region, exhibiting quantum yields in the range of 0.08–0.51, depending on their molecular structure and solvent polarity. The nature of the observed absorption spectra has been elucidated by the TDDFT calculations. [ABSTRACT FROM AUTHOR]

The study of Pd-catalyzed preferential C H activation of sterically hindered α, β-olefinic indoles onto alkenes beyond [4 + 2] cycloaddition has been described. The carbazole derivatives were readily synthesized via activation of vinylic C H bonds with excellent regioselectivity. Further, the one-pot strategy has been employed for the synthesis of tricyclic carbazoles. The double and triple C H activation followed by concomitant Michael addition provides an economical approach for the synthesis of N-protected carbazole. A wide range of alkenes at the α- and β-position are compatible with this reaction. The mechanistic and X-ray crystallographic studies supported the designed chemistry of C H activation. [ABSTRACT FROM AUTHOR]

A series of D–π–A–π–D type dyes based on pyrimidines, bearing thiophene linkers, have been studied as sensing fluorophores. Fluorescence studies have demonstrated that the emission of all derivatives is sensitive to the presence of 2,4,6-trinitrotoluene (TNT) and other nitroaromatic compounds (NACs), in their acetonitrile solutions. The detection limits of fluorophores to NACs proved to be in the range from 10 −4 to 10 −6 mol/L. The time-resolved fluorescence measurements and theoretical investigation into the quenching mechanism in the presence of fluorophore has been performed. The two types of sensor prototypes for handheld sniffer «Nitroscan» (Plant «Promautomatika», Ekaterinburg, Russia) on the basis of non-woven dry wipe and spunlace non-woven fabric with various quantities of the most sensitive fluorophore have been fabricated. The reusable, reversible and sensitive response of the designed prototypes to NACs enables one to qualify these compounds as promising fluorescent sensory materials for detection of NACs. [ABSTRACT FROM AUTHOR]

A regioselective synthesis of carbazole analogs belonging to both the categories of natural origin, viz., microorganisms and higher plant source is reported. The synthesis of carbazole derivatives possessing a methylester group at C-1 position has been achieved by Cadogan cyclization of nitro bi-phenyl derivatives, whereas, the carbazole analog possessing a methylester group at C-3 position was synthesized by Buchwald–Hartwig Pd-catalyzed cyclization of amino bi-phenyl derivatives. Suitably substituted bi-phenyl precursors were accessed from norbornyl α-diketones via Grob fragmentation, O-methylation and DBU aromatization reaction sequence. The reported carbazole derivatives possess structural features that are common with many carbazole natural products: mukonine, clausine-L, murrayafoline-A, and their sibling natural products. [ABSTRACT FROM AUTHOR]

Prion diseases are characterized by the self-assembly of pathogenic misfolded scrapie isoforms (PrPSc) of the cellular prion protein (PrPC). In an effort to achieve a theranostic profile, symmetrical bifunctional carbazole derivatives were designed as fluorescent rigid analogues of GN8, a pharmacological chaperone that stabilizes the native PrPC conformation and prevents its pathogenic conversion. A focused library was synthesized via a four-step route, and a representative member was confirmed to have native fluorescence, including a band in the near-infrared region. After a cytotoxicity study, compounds were tested on the RML-infected ScGT1 neuronal cell line, by monitoring the levels of protease-resistant PrPSc. Small dialkylamino groups at the ends of the molecule were found to be optimal in terms of therapeutic index, and the bis-(dimethylaminoacetamido)carbazole derivative 2b was selected for further characterization. It showed activity in two cell lines infected with the mouse-adapted RML strain (ScGT1 and ScN2a). Unlike GN8, 2b did not affect PrPC levels, which represents a potential advantage in terms of toxicity. Amyloid Seeding Assay (ASA) experiments showed the capacity of 2b to delay the aggregation of recombinant mouse PrP. Its ability to interfere with the amplification of the scrapie RML strain by Protein Misfolding Cyclic Amplification (PMCA) was shown to be higher than that of GN8, although 2b did not inhibit the amplification of human vCJD prion. Fluorescent staining of PrPSc aggregates by 2b was confirmed in living cells. 2b emerges as an initial hit compound for further medicinal chemistry optimization towards strain-independent anti-prion compounds. [Display omitted] • Synthesis of a new generation of carbazole derivatives for concomitant treatment and diagnosis of prion diseases. • The carbazole derivatives were designed as fluorescent rigid analogues of GN8, an antiprion compound. • Many of the compounds showed antiprion activity in two infected cell lines. • The best-performing compound was able to reduce and stain at the same time prion aggregates in cell models. [ABSTRACT FROM AUTHOR]

As a continuation of our research on the synthetic exploitation of the nitrobutadienic building-blocks obtained from the ring-opening of nitrothiophenes, we herein report about their reaction with the π-nucleophilic indole. Thanks to their double Michael-acceptor nature, 2,3-dinitro and 2-nitro-3-phenylsulfonyl substituted 1,3-butadienes produce poly-functionalized carbazoles through a double (inter-+intra-molecular) conjugate addition, followed by aromatization of the newly built ring. Significance is attached to the results obtained in fluorinated solvents such as trifluoroethanol, whereby a mild process, with no need for catalysis, overcomes some practical difficulties otherwise limiting the scope of the reaction. Besides the mechanistic aspects, the reaction encompasses motifs for a synthetic interest, mainly in the field of further-tunable arylcarbazoles endowed with predictable applicative properties, e.g., as fluorescent devices. [ABSTRACT FROM AUTHOR]

Six new carbazole alkaloids, murrastanine-A ( 1 ), murrastinine-A, -B, -C ( 2 – 4 ), murrayatanine-A ( 5 ) and bismahanimboline ( 6 ), were isolated from the bark and leaves of Murraya koenigii (Linn.) Spreng along with 24 known carbazole alkaloids. The structure of these compounds were elucidated by extensive spectroscopic analysis. Murrastinine-C ( 4 ) and murrayatanine-A ( 5 ) exhibited cytotoxic activity against HL-60 and HeLa (CD 50 <20 μg/mL) via MTT assay. [ABSTRACT FROM AUTHOR]

A one-pot Rh(I)-catalyzed synthesis of 9- H carbazoles via C–N bond cleavage by activation of aldehyde C–H bonds is reported. This protocol offers good yields and tolerates a broad range of functional groups. Based on the extensive control experiments, we propose a plausible decarbonylation mechanism. [ABSTRACT FROM AUTHOR]

• Updated GC–MS/MS method for the analysis of carbazole molecules. • Prior sample treatment is not always necessary for GC–MS/MS analysis. • Carbazole analysis is combined with SIM-MRM biomarker and molecular marker method. • With clean-up, MRM analysis can detect carbazoles in samples where SIM cannot. Analysis of carbazoles, nitrogen-bearing molecules found in most petroleum fluids, is often limited to GC–MS or GC × GC methods, both of which require prior sample treatment to concentrate components and minimize matrix interference. Recently, workers have introduced a novel method for analysis of carbazoles, using GC–MS/MS, without these required cleanup procedures. In this study, six thermal condensate and crude oil samples are analyzed for carbazoles and other components in their whole-petroleum and fractionated forms by both Selective Ion Monitoring (SIM) and Multiple Reaction Monitoring (MRM) methods to compare the differences. Five additional samples are then analyzed by a new hybrid MRM-SIM mode in a single run measuring over 200 components. We provide a geochemical interpretation of each sample set, based primarily on the MRM-derived carbazole abundance. In addition, we present an updated method for the analysis of carbazoles using GC–MS/MS. This study explores (1) the benefits of a hybrid MRM-SIM method for the analysis of carbazoles and other molecular markers in a single run, (2) surrogate standards to accurately quantify up to 21 species of carbazole molecules, and (3) evidence for the advantage of GC–MS/MS over previous methods for evaluations of thermal condensates and heavy crude oil. Our recommended process for the analysis of carbazole species is whole petroleum analysis using the hybrid MRM-SIM method. Even if unsuccessful with whole petroleum, the analysis of concentrated fractions analyzed on the hybrid MRM-SIM method has advantages over previous methods. [ABSTRACT FROM AUTHOR]

We report a simple, one-pot, and metal free benzannulation protocol to carbazoles starting with indoles, carbonyl compounds and an appropriate dienophiles. Mechanistically, this strategy generates an in situ diene by condensation between indole and carbonyl compound succeed and subsequent dehydration. Later, Diels–Alder reaction of this diene with a suitable dienophile followed by oxidation delivers the carbazole derivative. This methodology provide an easy access to carbazoles containing 1,4-naphthoquinone moiety. [ABSTRACT FROM AUTHOR]

A series of star-shaped carbazole derivatives were prepared via Suzuki-Miyaura and Stille coupling procedures. Received monomers were characterized by UV-Vis spectroscopy, fluorescence spectroscopy and cyclic voltammetry in order to estimate their basic spectral, electrochemical and electronic properties important for wide scale of applications in organic electronics and photovoltaics. Experimental results were supported by DFT calculations. Synthesised compounds were also used as monomers in the electrodeposition of conjugated polymers. Spectroelectrochemical EPR and UV-Vis-NIR measurements were carried out in order to study the influence of structure on charge carrier formation. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa strains resistant towards all currently available antibiotics are increasingly encountered, raising the need for new anti-pseudomonal drugs. We therefore conducted a medium-throughput screen of a small-molecule collection resulting in the identification of the N -alkylated 3,6-dihalogenocarbazol 1-( sec -butylamino)-3-(3,6-dichloro-9 H -carbazol-9-yl)propan-2-ol (MIC = 18.5 μg mL −1 ). This compound, compound 1 , is bacteriostatic towards a broad spectrum of Gram-positive and Gram-negative pathogens, including P. aeruginosa . Importantly, 1 also eradicates mature biofilms of P. aeruginosa . 1 displays no cytotoxicity against various human cell types, pointing to its potential for further development as a novel antibacterial drug. [ABSTRACT FROM AUTHOR]

Abstract: We present the design, synthesis, photophysical properties and application for sensing mercury ion, of a series of excellent near infrared fluorescent aza-boron-dipyrromethene (aza-BODIPY) dyes. The introduction of different aromatic substituents to the aza-BODIPY core induced red-shifted absorption and emission wavelengths due to the extension of the π-system. In addition, “turn-off” fluorescence responses and solution color changes selectively toward mercury ion have also been realized. The Hg2+-induced fluorescence quenching may be assigned to the energy or electron transfer from emissive aza-BODIPY core to Hg2+. [Copyright &y& Elsevier]

Abstract: Here we report the preparation of 3,6- bis(bithenyl)-N-decylcarbazole with low oxidation potential due to extended conjugation that underwent facile electrochemical polymerization to form stable electroactive polymer. We extended the conjugation of the monomers in comparison to the carbazole and large decrease were observed in the oxidation potential at which polymerization occurs. To lower the oxidation potential of the monomer and control the optical and electronic properties of the polycarbazole, we attached the thiophene, bithiophene and 3,4-ethylenedioxythiophene (EDOT) at both the 3 and 6 positions of N-substituted carbazole. The monomers and their polymers were compared through electron paramagnetic resonance (EPR) and UV-Vis-NIR spectroelectrochemistry resulting in interesting properties. As optically active materials the CIE L*a*b chromaticity and other optical properties were observed. [Copyright &y& Elsevier]

Abstract: Several new alkylguanidines derived from carbazole have been synthesized in a simple one-pot reaction starting from 3-aminocarbazole derivatives. The aminocarbazoles were reacted with ethoxycarbonylisothiocyanate, to give thiourea intermediates, followed by the addition of an alkylamine and HgCl2 to give ethoxycarbonylguanidine intermediates. The reaction mixture was then heated at 160°C to give the N-(1,4-dimethyl-9H-carbazol-3-yl)-N′-alkylguanidines. The cytotoxic activity of all the synthesized guanidines was evaluated against different cell lines. [Copyright &y& Elsevier]

Abstract: A compact synthesis of Murrayaquinone A is reported, based on sequential Buchwald–Hartwig amination/annulative C–H activation followed by oxidation of the intermediate carbazole. The methodology can be readily extended to other analogues with electron-rich quinone rings. [Copyright &y& Elsevier]

Abstract: The signalling pathway of Janus tyrosine Kinases-Signal Transducers and Activators of Transcription (JAK-STAT) is activated by a number of cytokines, hormones (GH, erythropoietin and prolactin), and growth factors. JAK-STAT signalling is involved in regulation of cell proliferation, differentiation and apoptosis. These activities are due to different members of JAK-STAT family consisting of: JAK1, JAK2, JAK3, Tyk2 and STAT1, STAT2, STAT3, STAT4, STAT5a, STAT5b, STAT6. Recent studies suggest a key role for STAT family proteins, in particular for STAT3, in selectively inducing and maintaining a pro-carcinogenic inflammatory microenvironment, that promote tumour cells transformation. Moreover, a striking correlation between cancer development/progression and STAT3 persistent activation exists, probably due to STAT3 promoting of the pro-oncogenic inflammatory pathways, like NF-kB, IL-6 and JAK family kinases. Recent study demonstrated that carbazoles can inhibit STAT3 mediated transcription. From these evidences, STAT3 represents a therapeutic target, so we have synthesized a new set of N-alkylcarbazole derivatives substituted in positions 2, 4 and 6, to evaluate their activity on STAT3. Some of these compounds showed an interesting activity as STAT3 selective inhibitors; in particular, compounds 9a 9b and 9c revealed to inhibit the STAT3 activation for the 50%, 90% and 95%, respectively. [Copyright &y& Elsevier]

Abstract: Phosphorescent bis-cyclometallated iridium (III) complexes based on 2-phenyl-1,2,3-benzotriazole with additional donoric diphenylamine or carbazole moieties were synthesized, studied and tested as phosphorescent materials in the single-layer phosphorescent organic light emitting diodes. These single-layer devices were fabricated employing a simple technological approach, based upon the simultaneous vacuum deposition from one crucible of host material and the corresponding phosphorescent 1,2,3-triazole-based iridium complexes. Red and orange electrophosphorescent single-layer devices with current efficiencies of 5.3 cd/A and 6.8 cd/A respectively are reported. Results of the impedance spectroscopy suggest that the proposed method of formation of the working layer provides homogeneous distribution of molecular guest in the matrix of host. [Copyright &y& Elsevier]

Abstract: The multifaceted behavior of nitrobutadienes deriving from the initial ring-opening of nitrothiophenes finds a further clear-cut example in their Michael-type acceptor reactivity towards indole. Thus, depending on the starting diene, either newly-functionalized indoles or carbazoles are produced, the latter as the result of an appealing double (intermolecular+intramolecular) Michael-type addition to a nitrovinylic moiety. The outcome encompasses motifs for both mechanistic and synthetic interest in the field of heterocycles endowed with possible pharmacological activity. [Copyright &y& Elsevier]

Abstract: Pd(II)-catalyzed intramolecular C–H activation/C–C cross coupling within N,N-diphenyl-acetamides allows the efficient formation of differently substituted carbazoles. In this cross-dehydrogenative coupling, many different functional groups are tolerated and the starting material N,N-diphenyl-acetamides can be easily prepared in one step from commercially available acetanilides and iodobenzenes. [Copyright &y& Elsevier]

Abstract: Carbazole linked porphyrin dimers were synthesized in good yields via stepwise Suzuki coupling reactions using bromoporphyrins and borylated carbazoles as the precursors, the latter of which were synthesized via known procedures from biphenyl derivatives. For comparative purposes porphyrin–carbazole monomers were synthesized. Single layer organic light emitting diodes (OLEDs) were created to demonstrate the optical properties of these materials. Light emission from these carbazole substituted porphyrins showed better results compared to previously examined bromo substituted porphyrins with better electroluminescence and lower turn-on voltages. Dimers exhibited turn-on voltages of 3 V compared to 6 V for monomeric porphyrin–carbazoles. [Copyright &y& Elsevier]

Abstract: Novel tricyclic carbazoles 4a–k were synthesized in one-pot employing sydnone derivatives 3a–k as masked hydrazines by the ring transformation in presence of conc. HCl and cyclohexanone. The title compounds were screened for anti-tubercular, anti cancer, DNA cleavage, antioxidant activity. MIC, GI50, LC50, TGI were evaluated. The title compounds have exhibited significant antitubercular, DNA cleavage and antioxidant activities and partial anticancer activity. [Copyright &y& Elsevier]

Abstract: A green and efficient preparation of functionalized δ-carbolines/carbazoles via reductive ring closure by 1,2-bis(dipenylphosphino)ethane under solvent-free conditions is described. The starting materials 3-nitro-2-phenylpyridines/2-nitrobiphenyl derivatives are readily prepared through Suzuki–Miyaura cross-coupling reaction from commercially available compounds. And the polar by-product ethane-1,2-diylbis(diphenylphosphine oxide) is easily removed from the relatively polar reaction mixture. Various substituted δ-carbolines/carbazoles are obtained in acceptable yields. It is particularly worth mentioning that substrates with electron-withdrawing groups (EWG) also give the desired products in good yield. [Copyright &y& Elsevier]

Abstract: Di-, tri- and tetra-alkenylindoles were prepared by palladium(0)-catalyzed Heck cross-coupling reactions of di-, tri- and tetrabromo-N-methylindoles. The reactions were carried out at 90 °C using a novel biaryl monophosphine ligand developed by Buchwald and co-workers. 1,2-Dihydrocarbazoles were formed by a domino ‘twofold Heck/6π-electrocyclization’ when the reaction was carried out at higher temperature. The regioselectivity of the Heck reaction of 2,3,6-tribromo-N-methylindoles was in favour of carbon atoms C-2 and C-3. The 1,2-dihydrocarbazoles were transformed, by Pd/C-catalyzed dehydrogenation, into the corresponding carbazoles in high yield. [Copyright &y& Elsevier]

Abstract: New 1,5-Dihydro-4-(substituted phenyl)-3H-furo[3,4-b]carbazol-3-ones were synthesised via a key step Diels–Alder reaction under microwave irradiation. 3-Formylindole was successfully used in a 6-step synthesis to obtain those complex heterocycles. The Diels–Alder reaction generating the carbazole ring was optimised under thermal conditions or microwave irradiation. After cleavage of functional groups, DNA binding, topoisomerase inhibition and cytotoxic properties of the new-formed furocarbazoles were investigated. These carbazoles do not present a strong interaction with the DNA, and do not modify the relaxation of the DNA in the presence of topoisomerase I or II except for one promising compound. This compound is a potent topoisomerase II inhibitor, and its cellular activity is not moderated compared to etoposide. The synthesis of these molecules allowed the generalisation of the method using indole and 5-OBn indole and several benzaldehydes. The synthesis of these molecules produced chemical structures endowed with promising cytotoxic and topoisomerase II inhibition activities. [ABSTRACT FROM AUTHOR]

Abstract: A series of tetrafluorophenyl-modified oligo(3,6-carbazole ethynylene)s (CfCzCf, CfCz2Cf, CfCz3Cf, (CfCz)2Cf, and Cf2CzCf2) were synthesized by a Pd/Cu-catalyzed Sonogashira coupling reaction and fully characterized. Their photophysical and electronic properties as well as their thermal stabilities were investigated. It is noteworthy that these tetrafluorophenyl modified compounds showed relative thermal stabilities and low-lying HOMO levels ranging from −5.54 to −5.60eV, which might be the promising candidates for hole-transporting materials in OLEDs. [ABSTRACT FROM AUTHOR]

• Cyanomethylation of 2,3,4,9-tetrahydro-1H-carbazol-1-one. • FT-IR, NMR, UV–vis studies were performed and compared with the calculated results. • Antioxidant potency was investigated by CUPRAC method. • Global reactivity analyses were performed. • NBO analyses were conducted. C-2 and C-6 monoalkyl nitrile substituted reactant (1) , which constitute the tricyclic framework of carbazole derivatives along with the substructure of the Strychnos alkaloids family, have been synthesized by using different bases to produce substitution reactions. In addition, the antioxidant capacity of the synthesized compound by the CUPRAC (cupric reducing antioxidant capacity) method was evaluated and the obtained TEAC (Trolox equivalent antioxidant capacity) coefficient implied that product (2) has antioxidant feature. The B3LYP/6-311G(d,p) level calculations were performed in the gas phase, and the optimized geometries obtained from these calculations were used for the solvation media calculations. The SMD variation of the IEFPCM (polarized continuum model) was used to conduct the quantum chemical calculations in the solvent environment such as CHCl 3 , CH 3 OH, and H 2 O (water, ε=78.4). Also, the NMR chemical shifts of the products were calculated using GIAO (Gauge-Independent Atomic Orbital) approach and compared with the corresponding experimental data. The TD-DFT calculations disclosed that the observed peaks for both products were attributed to the n→ π* and π→ π* excitations. Moreover, NBO analysis revealed that the n→ π* and π→ π* interactions have a great importance for lowering the stabilization energy for all compounds. Also, the FMO (Frontier Moleular Orbital) analyses implied that the product P2 would prefer the intermolecular interactions would rather than the intramolecular interactions. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: A ZnBr2-mediated arylation of N-protected 2/3-bromomethylindoles containing an electron-deficient malonylidene unit with arenes at 80°C led to the formation of arylated products, which on unprecedented 1,5-sigmatropic rearrangement followed by electrocyclization and subsequent aromatization with loss of diethylmalonate furnished the corresponding annulated carbazoles in reasonable yields. [Copyright &y& Elsevier]

Abstract: The composition of crude oils and rock extracts has been investigated by Iatroscan and combined gas chromatography–mass spectrometry. The Iatroscan technique reveals that core extracts from petroleum reservoirs are enriched in bulk NSO composition compared to the producible mobile phases recovered during drill stem tests. The NSO component appears to interact with the reservoir phase and if understood may indicate the degree of fluid–rock interaction in the reservoir during production. A comparative study of the polar non-hydrocarbon composition of core extract petroleum from a tar sand reservoir over a period of 6 months reveals that alteration processes occurring during sample storage modifies the composition of petroleum in stored cores. We find that the concentrations of fluorenones often increase in stored samples, while carbazole concentrations decrease with time. In our view, geochemical samples require immediate analysis after recovery from the subsurface, otherwise the procedures of core sampling, storage and handling need to be revised. Storage of samples for geochemical analysis appears not to be so critical for hydrocarbon determinations. However, some aromatic hydrocarbons, such as fluorene, are very easily affected by oxidation processes. [Copyright &y& Elsevier]

Abstract: The prediction of fluid flow behaviour in petroleum reservoirs is influenced by the physical and chemical processes active in interacting crude oil/brine/rock systems. It is usually not possible to assess these complex systems directly so proxies for molecular scale behaviour are needed. By their very nature, polar non-hydrocarbons are sensitive to fluid–rock interactions, and if properly exploited they may be utilised as proxies for describing reservoir engineering properties (e.g. wettability) that are also sensitive to fluid–rock interactions. We have identified a group of aromatic oxygen (alkylphenols and alkylfluorenones) and aromatic nitrogen (alkylcarbazoles) compounds present in petroleum that appear to respond to variations in fluid–rock properties. Here we describe the chemical and physical changes in a series of core samples obtained from North Sea reservoirs. A number of petrophysical parameters displayed strong correlations with polar non-hydrocarbon occurrence. For example, deflections in gamma ray logs in response to clay content in a coarsening upwards sandstone unit also showed similar deflections from a number of geochemical logs. A core-flood experiment was designed to monitor the chemical and physical changes during oil migration in a siltstone core. Following completion of the core-flood experiment, Environmental Scanning Electron Microscopy (ESEM) analysis of core samples indicated hydrophilic and hydrophobic surface tendencies grading throughout the core. The distributions of polar non-hydrocarbons (e.g. C0–C3–phenols) appear to correspond closely to the observed wettability alteration. The results confirm the potential for developing proxies for fluid–rock interactions through monitoring the surface active compounds present in the polar non-hydrocarbon fraction of petroleum. [Copyright &y& Elsevier]

Abstract: Two sequential palladium-catalyzed reactions, an intermolecular Stille cross-coupling followed by a recently developed palladium-catalyzed reductive N-heteroannulation, have been employed as the key synthetic steps toward six tetrahydrocarbazolones. The products are advanced intermediates toward a number of naturally occurring carbazole alkaloids. [Copyright &y& Elsevier]

Abstract: Epoxidation of the trisilyl-protected carbazomadurins A and B with dimethyldioxirane followed by desilylation provides a simple route to racemic epocarbazolin A and a non-diastereoselective access to epocarbazolin B. The Shi epoxidation has been applied to an asymmetric synthesis of the non-natural (−)-epocarbazolin A. [Copyright &y& Elsevier]

Abstract: A blue fluorescence of N-ethylcarbazole (EtCz) and of its dimer N,N′-diethyl-3,3′-bicarbazyl ((EtCz)2) as dopants of poly(methyl methacrylate) (PMMA) matrices, under laser pulsed UV irradiation, was observed. The fluorescence lifetimes were found to be 16.1 and 11.6ns for EtCz and (EtCz)2, respectively. Concomitantly, a green phosphorescence occurred at room temperature and peaking at 444nm for EtCz and 486nm for (EtCz)2. From both luminescence spectra, singlet–triplet energy transition was estimated to be 0.56eV for EtCz and 0.45eV for (EtCz)2. Moreover, under UV irradiation, photoluminescence spectra exhibited a strong degradation with exposure time, accompanied by the appearance of new bands in the 400–500nm range. Species associated to these new signals exhibited shorter lifetimes than those of the main peaks. Photodegradation of the doped PMMA matrices were not observed under nitrogen atmosphere, whereas in the presence of oxygen gas, they readily appeared. In the same way, thin film of pure (EtCz)2 did not show any modification under vacuum, whereas in air the photochemical evolution clearly appears. Possible causes of the oxygen-sensitive photodegradation of both the EtCz and (EtCz)2-doped PMMA matrices, were discussed. [Copyright &y& Elsevier]

Abstract: N,N′-aryl- and N,N′-alkyl-buta-1,3-diyne-1,4-ditosylamides have been synthesized for the first time, in good to excellent yields, by copper-catalyzed dimerization of the corresponding N-aryl or N-alkyl tosylynamides. Negishi coupling of N-ethynylzinc tosylamides derivatives with (hetero)aryl iodides in the presence of Pd2dba3 and triphenylphosphine affords N-aryl and N-alkyl arylynamides in yields of up to 90%. Intramolecular [4+2] cycloaddition reactions of N-ethynylphenyl ynamides and arylynamides allow the synthesis of carbazoles and benzannulated and heteroannulated carbazoles in moderate-to-good yields. [Copyright &y& Elsevier]

Abstract: Starting from simple indole precursors the synthesis of naphtho[a]carbazoles and benzo[c]carbazoles is described. Key steps include the use of the Suzuki–Miyaura reaction to afford 2- or 3-aryl substituted indoles, as well as a potassium t-butoxide and light assisted aromatic ring-forming reaction. [Copyright &y& Elsevier]

Abstract: Novel monodisperse linear 3,9-linked oligocarbazoles (OCAs) were prepared stepwise using Ullmann coupling reaction in seal-tubes. The resulting OCAs were soluble in common organic solvents. The UV–vis spectra of OCAs exhibited small red shift and their intensities increased linearly with the increase of the carbazole moieties, suggesting that no intramolecular π-interactions appeared at ⩽8-mer. All the OCAs gave strong fluorescence and it was found that the conjugated degree of linear OCAs would be saturated when the number of carbazole units reaches four. [Copyright &y& Elsevier]

Abstract: Facile synthetic method of 2H-indazole derivatives was developed involving DDQ oxidation of pyrazoles, which were prepared starting from the Baylis–Hillman adducts of 2-cyclohexen-1-one. [Copyright &y& Elsevier]