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Antimicrobial susceptibility testing plays a pivotal role in the discovery of new antibiotics. However, the development of simple, sensitive, and rapid assessment approaches remains challenging. Herein, we report an activated alkyne- based cascade signal ampli- fication strategy for ultrafast and high- throughput antibiotic screening. First of all, a novel water- soluble aggregation- induced emission (AIE) luminogen is synthesized, which contains an activated alkyne group to enable fluorescence turn- on and metal- free click bioconjugation under physiological conditions. Taking advantage of the in- house established method for bacterial lysis, a number of clickable biological substances (i.e., bacterial solutes and debris) are released from the bacterial bodies, which remarkably increases the quantity of analytes. By means of the activated alkyne- mediated turn- on click bioconjugation, the system fluorescence signal is significantly amplified due to the increased labeling sites as well as the AIE effect. Such a cascade signal amplification strategy efficiently improves the detection sensitivity and thus enables ultrafast antimicrobial susceptibility assessment. By integration with a microplate reader, this approach is further applied to high- throughput antibiotic screening. [ABSTRACT FROM AUTHOR]

The development of a facile and efficient polymerization to prepare cyclopentadiene-containing polymers is of vital importance and highly desired. In this work, a metal-free multicomponent polymerization of activated diyne, electrophilic styrene and isocyanide for the preparation of highly substituted poly(cyclopentadiene) was established. Soluble and thermally stable polymers with high molecular weights are obtained in high yields under mild conditions. By introducing the tetraphenylethene or triphenylamine moiety into polymer backbones, the resultant polymers show unique aggregation-induced emission (AIE) characteristics. Interestingly, AIE polymers can also be generated in situ from non-AIE monomers. Moreover, the prepared polymers can generate photopatterns to function as photoresists and can also serve as visualizing agents to selectively stain the lipid droplets in live cells. This efficient polymerization will open up enormous opportunities for preparing functional cyclopentadiene-containing polymers applicable in diverse areas. [ABSTRACT FROM AUTHOR]

In this work, 2-alkyl-10-chloro-1,2,3,4-tetrahydrobenzo[b][1,6]naphthyridines were obtained and their reactivity was studied. Novel derivatives of the tricyclic scaffold, including 1-phenylethynyl (5), 1-indol-3-yl (8), and azocino[4,5-b]quinoline (10) derivatives, were synthesized and characterized herein for the first time. Among the newly synthesized derivatives, 5c–h proved to be MAO B inhibitors with potency in the low micromolar range. In particular, the 1-(2-(4-fluorophenyl)ethynyl) analog 5g achieved an IC50 of 1.35 μM, a value close to that of the well-known MAO B inhibitor pargyline. [ABSTRACT FROM AUTHOR]

In this work, 2-alkyl-10-chloro-1,2,3,4-tetrahydrobenzo[b][1,6]naphthyridines were obtained and their reactivity was studied. Novel derivatives of the tricyclic scaffold, including 1-phenylethynyl (5), 1-indol-3-yl (8), and azocino[4,5-b]quinoline (10) derivatives, were synthesized and characterized herein for the first time. Among the newly synthesized derivatives, 5c–h proved to be MAO B inhibitors with potency in the low micromolar range. In particular, the 1-(2-(4-fluorophenyl)ethynyl) analog 5g achieved an IC50 of 1.35 μM, a value close to that of the well-known MAO B inhibitor pargyline.

Pyridinium 1,4‐zwitterionic thiolates as a class of sulfur‐containing synthons were applied to a [3+2] cascade cyclization reaction with activated alkynes, affording a library of polysubstituted thiophenes with excellent regioselectivities, especially those bearing various fluorine‐containing groups. The freshly disclosed pyridinium 1,4‐zwitterionic thiolates decorated with acyl or trifluoromethyl groups exhibited powerful potential in the synthesis of polysubstituted thiophenes. Of particular note is that pyridinium A4 could introduce sulfur and CF3 groups to target products simultaneously. [ABSTRACT FROM AUTHOR]

Metal precursors of the type [(p -cymene)RuCl 2 ] 2 and [Cp*MCl 2 ] 2 (M = Rh/Ir) on reacting with benzothiazole hydrazones ligands (L1 = benzylidenehydrazinyl benzothiazole, L2 = 4-flourobenzylidenehydrazinyl benzothiazole and L3 = 4-methylbenzylidenehydrazinyl benzothiazole) in the ratio of 1:2 (M:L), leads to the formation of range of complexes. In the case of ruthenium precursor with ligand L1, a cationic complex [(p -cymene)Ru{κ2 (NN') L1}Cl]Cl (1) is formed whereas with L2 and L3 neutral complexes [(p -cymene)Ru{κ2 (NN') L2/L3}Cl 2 ] (4 and 7) are obtained. Rhodium precursor with L1 and L2 forms mono dentate neutral complexes [Cp*Rh{κ1 (N) L1/L2}Cl 2 ] (2 and 5) while with L3 bidentate NN′ bonding complex [Cp*Rh{κ1 (NN') L3}Cl] (8) is obtained. However, iridium precursor with these ligands yielded neutral bidentate complexes (3 , 6 and 9) having the general formula [Cp*Ir{κ2 (NN') L}Cl] where L = L1, L2 and L3 respectively. Some of these complexes have been treated with sodium azide to yield azido compounds. Conformational switching of the benzothiazole hydrazone derivatives of complexes 2 and 5 from trans (E) to cis (Z) are observed on treatment with sodium azide. These azido complexes obtained, have been treated with activated acetylenes of dimethyl and diethyl acetylene carboxylates, which undergo [3 + 2] cycloadditions to form arene ruthenium triazolato complexes. All these complexes have been characterized by analytical, spectroscopic and single crystal x-ray diffraction studies. These complexes have also been carried out for antibacterial studies, but unfortunately none of these compounds or ligands exhibits antibacterial activity towards gram-positive and gram-negative bacteria. Image 1 • Benzothiazole derivatives undergoes conformational switching from E to Z conformers. • Versatility of benzothiazole derivatives is due to the presence of acidic NH proton. • Substitution at para position of phenyl ring (H, F, CH 3) changes the bonding modes. • None of these complexes exhibited antibacterial activity. [ABSTRACT FROM AUTHOR]

A comparative theoretical study on the reactivity of the complexes [ReY(CO)3(bipy)] (Y = NH2, NHMe, NHpTol, OH, OMe, OPh, PH2, PHMe, PMe2, PHPh, PPh2, PMePh, SH, SMe, SPh; bipy = 2,2′-bipyridine) towards methyl propiolate was carried out to analyze the influence of both the heteroatom (N, O, P, S) and the alkyl and/or aryl substituents of the Y ligand on the nature of the product obtained. The methyl substituent tends to accelerate the reactions. However, an aromatic ring bonded to N and O makes the reaction more difficult, whereas its linkage to P and S favour it. On the whole, ligands with O and S heteroatoms seem to disfavour these processes more than ligands with N and P heteroatoms, respectively. Phosphido and thiolato ligands tend to yield a coupling product with the bipy ligand, which is not the general case for hydroxo, alcoxo or amido ligands. When the Y ligand has an O/N and an H atom the most likely product is the one containing a coupling with the carbonyl ligand, which is not always obtained when Y contains P/S. Only for OMe and OPh, the product resulting from formal insertion into the Re-Y bond is the preferred.

1-(p-Methoxyphenyl)tetrazolyl-substituted 6,7-dimethoxy(6,7-methylenedioxy)-1,2,3,4-tetrahydroisoquinolines formed tetrazolyl-substituted azocines in high yields by using activated alkynes. Unsubstituted at 6,7,8-aromatic fragment 1-tetrazolylisoquinoline interacted in several pathways forming tetrazolyl-substituted azocines, 1-tetrazolyl-1-R-vinylisoquinolines and 3-azaspiro[5.5]undeca-1,7,9-triene.

Heating a benzene solution of the unsaturated cluster Os 3 (CO) 8 (μ-dppm)(μ-H) 2 ( 1 ) [dppm = bis(diphenylphosphino)methane] with MeO 2 CC CCO 2 Me (DMAD) or EtO 2 CC CCO 2 Et (DEAD) at 80 °C furnished the dinuclear compounds Os 2 (CO) 4 (μ-dppm)(μ-η 2 ;η 1 ;к 1 -RO 2 CCCHCO 2 R)(μ-H) ( 3a , R = Me, 3b , R = Et) and the saturated trinuclear complexes Os 3 (CO) 7 (μ-dppm)(μ 3 -η 2 ;η 1 ;η 1 -RO 2 CCCCO 2 R)(μ-H) 2 ( 4a , R = Me, 4b , R = Et). In contrast, similar reactions using unsaturated Os 3 (CO) 8 (μ-dppf)(μ-H) 2 ( 2 ) [dppf = bis(diphenylphosphino)ferrocene] afforded only the trinuclear complexes Os 3 (CO) 8 (μ-dppf)(μ-η 2 ;η 1 -RO 2 CCHCCO 2 R)(μ-H) ( 5a , R = Me; 5b , R = Et) and Os 3 (CO) 7 (μ-dppf)(μ 3 -η 2 ;η 1 ;η 1 -RO 2 CCCCO 2 R)(μ-H) 2 ( 6a , R = Me; 6b , R = Et). Control experiments confirm that 5a and 5b decarbonylate at 80 °C to give 6a and 6b , respectively. Both 5a and 5b exist as a pair of isomers in solution, as demonstrated by 1 H NMR and 31 P{ 1 H} NMR spectroscopy. DFT calculations on cluster 5a (as the dppf-Me 4 derivative) indicate that the isomeric mixture derives from a torsional motion that promotes the conformational flipping of the cyclopentadienyl groups of the dppf-Me 4 ligand relative to the metallic plane. VT NMR measurements on clusters 6a and 6b indicate that while the hydride ligand associated with the dppf-bridged Os-Os bond is nonfluxional at room temperature, the second hydride rapidly oscillates between the two non-dppf-bridged Os-Os edges. DFT examination of this hydride fluxionality confirms a “windshield wiper” motion for the labile hydride that gives rise to a time-average coupling of this hydride to both phosphorus centers of the dppf ligand. Thermolysis of 6a and 6b in refluxing toluene yielded Os 3 (CO) 7 (μ-dppf)(μ-η 2 ;η 1 ;к 1 -CCHCO 2 R) ( 7a , R=Me; 7b , R=Et). The vinylidene moieties in 7a and 7b derive from the carbon-carbon bond cleavage of coordinated alkyne ligands, and these two products exhibit high thermal stability in refluxing toluene. [ABSTRACT FROM AUTHOR]

Antimicrobial susceptibility testing plays a pivotal role in the discovery of new antibiotics. However, the development of simple, sensitive, and rapid assessment approaches remains challenging. Herein, we report an activated alkyne-based cascade signal amplification strategy for ultrafast and high-throughput antibiotic screening. First of all, a novel water-soluble aggregation-induced emission (AIE) luminogen is synthesized, which contains an activated alkyne group to enable fluorescence turn-on and metal-free click bioconjugation under physiological conditions. Taking advantage of the in-house established method for bacterial lysis, a number of clickable biological substances (i.e., bacterial solutes and debris) are released from the bacterial bodies, which remarkably increases the quantity of analytes. By means of the activated alkyne-mediated turn-on click bioconjugation, the system fluorescence signal is significantly amplified due to the increased labeling sites as well as the AIE effect. Such a cascade signal amplification strategy efficiently improves the detection sensitivity and thus enables ultrafast antimicrobial susceptibility assessment. By integration with a microplate reader, this approach is further applied to high-throughput antibiotic screening.

The Cu(I)-catalyzed azide-alkyne click polymerization is well developed and broadly applied to the preparation of functional polymers. The removal of copper residues from the resultant polymers is, however, difficult. One way to completely circumvent this difficulty is to develop click polymerization without the use of metallic catalysts, i.e., metal-free click polymerization (MFCP). Herein, recent efforts towards developing MFCP of activated alkynes and azides, and of activated azides and alkynes, to produce regioregular polytriazoles are summarized, and the properties and applications of the resultant polymers are also briefly discussed. [ABSTRACT FROM AUTHOR]

1-Aryl-substituted tetrahydrothieno[3,2-с]pyridines easily undergo domino reactions with activated alkynes, giving good yields of the corresponding tetrahydrothieno[2,3-d]azocines. The reactions of 1-methyl-substituted tetrahydrothieno[3,2-с]pyridine were more complicated. [ABSTRACT FROM AUTHOR]

The facile synthesis of 1-oxo-pyrrolo[2,1- a ]isoquinolines from the reaction of 1-aroyl-3,4-dihydroisoquinolines and symmetrical alkynes in toluene is described. The novel compounds contain functional groups that are suitable for further modification. [ABSTRACT FROM AUTHOR]

We optimized the reaction of tetrahydropyridine ring expansion in 1-aryl-substituted tetrahydro-β-carbolines by the action of activated alkynes and achieved higher than 70% yields of the target indoloazocines. The substituents in the 1-aryl ring and at the indole nitrogen atom were shown to affect the rate and selectivity of this transformation. [ABSTRACT FROM AUTHOR]

It has been established that the reaction of pyrrolo[1,2- a][1,4]benzodiazepines with activated alkynes gives pyrrolo[1,2- a][1,6]benzodiazonines as the products of diazepine ring expansion. In the case of pyrrolo[1,2- a][1,4]benzodiazepine, substituted with formyl group at the pyrrole ring, both expansion and cleavage of the diazepine fragment can occur. [ABSTRACT FROM AUTHOR]

A study was carried out on the domino transformations of tetrahydrobenzofuro[2,3- c]pyridines and tetrahydrobenzofuro[3,2- c]pyridines by the action of activated alkynes in methanol and acetonitrile. This reaction is a new method for the synthesis of spiro[benzofuropyridines] showing acetylcholinesterase inhibition activity. [ABSTRACT FROM AUTHOR]

Abstract: A facile strategy for the synthesis of functionalized spirolactones from isatin, primary amines, and activated alkynes through Huisgen dipolar additions are discussed. A novel route for the formation of dispirodihydrofuranyl oxindoles from activated cyclic electrophiles, amines, and DMAD has also been developed. This method offers several advantages like high yield, readily available starting materials, and involves less hazardous chemical techniques. [Copyright &y& Elsevier]

Abstract: An efficient preparation of a series of spiro dihydropyridines via one pot four-component reactions of mono/di/tri-ketones, malononitrile, primary amines, and acetylenic esters is reported. The reaction is atom-efficient, high yielding, and follows a simple experimental procedure. [Copyright &y& Elsevier]

Stereoselective reaction of various substituted phenols with alkyl propiolates in the presence of a catalytic amount of sodium azide in tert-butyl alcohol at reflux temperature leads to alkyl ( Z)-3-phenoxy-2-propenoates in good yields. Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

It has been shown that, on interacting 2-ethyl-3,3,5,5-tetramethyl- and 2-ethyl-1,3,3,5,5-pentamethyl-1,2,4,5-tetrahydro-3H-benz-2-azepines with ethyl propiolate in methanol, fission of the azepine ring occurs at the C(1)–N(2) bond involving a molecule of solvent. The indicated azepines do not react with acetylenedicarboxylic acid ester under these conditions. [ABSTRACT FROM AUTHOR]

The transformations of 1-substituted tetrahydro-β-carbolines by the action of activated alkynes were studied. The action of dimethyl acetylenedicarboxylate in methanol gives products of the opening of the tetrahydropyridine fragment, namely, 2-methoxyalkylindoles. The action of ethyl propiolate in ethanol and of tosylacetylene in methanol gives mixtures of azocino[5,4-b]indoles and 2-alkoxyindoles. The action of ethyl propiolate in acetonitrile gives azocinoindoles. [ABSTRACT FROM AUTHOR]

As a nanoparticle support material, carbon nanotubes (CNTs) provide a certain potential activation of catalysis in heterogeneous catalytic organic reactions. Herein, an efficient Ag/CNT-catalyzed synthesis of enamines via hydroamination of activated alkynes with aromatic amines has been described. This catalyst still retains catalytic activity after being recycled and reused three times. In addition, it represents a green and environmentally friendly process for preparation of enamines. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article offers information about new method of synthesis of bisindolylarylmethane. It states that transformations of 1-substituted 2-ethyltetrahydro-&-;#x03B2;-carbolines by the action of dimethyl acetylenedicarboxylate (DMAD) depends on the type of solvent used and the electronic effects of the substituents at C-1. It states that reaction of fluorophenylcarbolines in discloromethane gave multicomponent mixtures which could not be separated.

A simple and highly stereoselective method has been developed for the synthesis of E-configured α,β-unsaturated ketones using gallium(III) chloride as a novel catalyst. This new procedure offers significant advantages such as high conversions, short reaction times and enhanced E-selectivity together with mild reaction conditions. [ABSTRACT FROM AUTHOR]

A comparative theoretical study on the reactivity of the complexes [ReY(CO)3(bipy)] (Y = NH2, NHMe, NHpTol, OH, OMe, OPh, PH2, PHMe, PMe2, PHPh, PPh2, PMePh, SH, SMe, SPh; bipy = 2,2′-bipyridine) towards methyl propiolate was carried out to analyze the influence of both the heteroatom (N, O, P, S) and the alkyl and/or aryl substituents of the Y ligand on the nature of the product obtained. The methyl substituent tends to accelerate the reactions. However, an aromatic ring bonded to N and O makes the reaction more difficult, whereas its linkage to P and S favour it. On the whole, ligands with O and S heteroatoms seem to disfavour these processes more than ligands with N and P heteroatoms, respectively. Phosphido and thiolato ligands tend to yield a coupling product with the bipy ligand, which is not the general case for hydroxo, alcoxo or amido ligands. When the Y ligand has an O/N and an H atom the most likely product is the one containing a coupling with the carbonyl ligand, which is not always obtained when Y contains P/S. Only for OMe and OPh, the product resulting from formal insertion into the Re-Y bond is the preferred. [ABSTRACT FROM AUTHOR]

Cycloaddition reaction of 4-chloro-2-oxo-2 H -chromene-3-carbaldehydes (3a-g) and 4-chloro-2 H -chromene-3-carbaldehydes (7a-h) with activated alkynes (4a-b) provided the 2-oxo-2 H -chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (5a-n) and 2 H -chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (8a-p). All the prepared compounds were screened for anti-inflammatory activity. In vitro anti-inflammatory activity data demonstrated that the compounds 5g , 5i , 5k-l and 8f are effective among the tested compounds against TNF-α (1.108 ± 0.002, 0.423 ± 0.022, 0.047 ± 0.001, 0.070 ± 0.002 and 0.142 ± 0.001 µM) in comparison with standard compound Prednisolone (0.033 ± 0.002 µM). Based on in vitro results, three compounds (5i , 5k and 8f) have been selected for in vivo experiments and these compounds are identified as better compounds with respect to anti-inflammatory activity in LPS induced mice model. Compound 5i was identified as potent and showed significant reduction in TNF-α and IL-6. [ABSTRACT FROM AUTHOR]

Abstract: The reactions of oxidative coupling of dimethylacetylene dicarboxylate (DMA) with palladium (0) olefin complexes bearing a pyridylthioether as ancillary ligand give rise to the corresponding palladacyclopentadienyl complexes as the main product and in some cases to the highly symmetric hexamethyl mellitate molecule, especially when a low alkyne(DMA)/complex ratio is employed. A plausible mechanism based on several pieces of experimental evidence is proposed, and the most effective complexes promoting the hexamethyl mellitate synthesis were identified. [Copyright &y& Elsevier]

1-(p-Methoxyphenyl)tetrazolyl-substituted 6,7-dimethoxy(6,7-methylenedioxy)-1,2,3,4-tetrahydroisoquinolines formed tetrazolyl-substituted azocines in high yields by using activated alkynes. Unsubstituted at 6,7,8-aromatic fragment 1-tetrazolylisoquinoline interacted in several pathways forming tetrazolyl-substituted azocines, 1-tetrazolyl-1-R-vinylisoquinolines and 3-azaspiro[5.5]undeca-1,7,9-triene. [ABSTRACT FROM AUTHOR]

The article presents information on the study related to the transformations of nitro-substituted dihydroisoindoles after reacting with activated alkynes. Dihydroisobenzofurans is formed after recycling dihydropyrrole fragment, and this makes the reaction of 4-hydroxymethyl-substituted dihydroisoindoles with activated alkynes possible at the room temperature.