Cu(OTf)2-catalyzed C3 aza-Friedel-Crafts alkylation of indoles with N,O-acetals.

An efficient approach to access functionalized indole derivatives has been developed through Cu(OTf)2-catalyzed C3 aza-Friedel-Crafts alkylation of substituted indoles 5a-5m, N-methyl-pyrrole with linear N,O-acetals 4a-4l. As a result, a series of C3 amide aza-alkylated indole derivatives 6a-6ag and 7 were synthesized in moderate to excellent yields.

Separation, quantification and characterisation of the pigment produced by Paecilomyces lilacinus TD16.

Fungal pigments are important natural products with a wide range of applications. In this study, the purple-red pigment produced by the fungus Paecilomyces lilacinus TD16 (TD16 pigment) was separated with acidulated ethyl acetate and purified by silica gel column chromatography. Results of UV-visible spectrum and HPLC analyses showed that TD16 pigment is a new polyketide pigment with three absorption peaks at 228, 272 and 527 nm and a retention time of 11.4665 min distinct from those of other Paecilomyces-sourced pigments. Results of kinetic analysis and antimicrobial activity assay showed that TD16 pigment is a non-growth-associated secondary products with broad-spectrum antimicrobial activity on both bacteria and fungi and thus of potential application in industry.[Formula: see text].

Copper(i)-catalyzed intermolecular cyanoarylation of alkenes: convenient access to α-alkylated arylacetonitriles.

A novel Cu(i)-catalyzed intermolecular cyanoarylation of alkenes with diaryliodonium salts as a radical arylating reagent and tetra-butylammonium cyanide as an electrophilic cyanating reagent was established. A broad range of α-alkylated arylacetonitriles were efficiently constructed in good to excellent yields under base- and oxidant-free and mild conditions.

Copper-catalyzed synthesis of α-ketoamides using water and dioxygen as the oxygen source.

The reaction employing H2O and O2 as the co-oxygen source in the catalytic synthesis of α-ketoamides is described. This copper-catalyzed reaction is carried out in a tandem manner constituted by the hydroamination of alkyne, hydration of vinyl-Cu complex and subsequent oxidation. Isotope labeling and radical capture experiments reveal that the oxygen atom of α-ketone at α-ketoamides derives from O2 and the oxygen atom of amide group originates from H2O.

A Bifunctional Luminescent Metal-Organic Framework for the Sensing of Paraquat and Fe3+ Ions in Water.

The hydrothermal reaction of Zn2+ ions with a mixture of two ligands, Hcptpy and H3 btc (Hcptpy=4-(4-carboxyphenyl)-2,2':4',4''-terpyridine; H3 btc=1,3,5-benzenetricarboxylic acid), led to the formation of a 3D metal-organic framework (MOF) with 1D channels, [Zn2 (cptpy)(btc)(H2 O)]n (1), which was structurally characterized by using single-crystal X-ray diffraction (SXRD). In MOF 1, two independent Zn2+ ions were interconnected by btc3- ligands to form a 1D chain, whilst adjacent Zn2+ ions were alternately bridged by cptpy- ligands to generate a 2D sheet, which was further linked by 1D chains to form a 3D framework with a new (3,3,4,4)-connected topology. Furthermore, compound 1 also exhibited excellent stability towards air and water and, more importantly, luminescence experiments indicated that it could serve as a probe for the sensitive detection of paraquat (PAQ) and Fe3+ ions in aqueous solution.

TBAI-catalyzed selective synthesis of sulfonamides and ß-aryl sulfonyl enamines: coupling of arenesulfonyl chlorides and sodium sulfinates with tert-amines.

A simple, practical and metal-free method has been developed for the synthesis of sulfonamides and ß-arylsulfonyl enamines via the selective cleavage of C-N and C-H bonds through the iodine-catalyzed oxidation of arenesulfonyl chlorides and sodium sulfinates with tert-amines. The method uses commercially available inexpensive catalysts and oxidants, and has a wide substrate scope and operational simplicity.

Metal-free difunctionalization of alkynes leading to alkenyl dithiocyanates and alkenyl diselenocyanates at room temperature.

A simple and practical method for the synthesis of alkenyl dithiocyanates and alkenyl diselenocyanates has been developed via stereoselective difunctionalization of alkynes with NaSCN or KSeCN at room temperature. Through this methodology, a series of alkenyl dithiocyanates and alkenyl diselenocyanates could be efficiently and conveniently obtained in moderate to good yields under mild and metal-free conditions by the simple use of oxone and PhI(OAc)2 as the oxidants.

Palladium-catalyzed selective synthesis of 3,4-dihydroquinazolines from electron-rich arylamines, electron-poor arylamines and glyoxalates.

A simple palladium-catalyzed selective synthesis of structurally diverse 3,4-dihydroquinazolines from electron-rich arylamines, electron-poor arylamines and glyoxalates has been developed under mild conditions. This reaction is carried out in a tandem manner constituted by the condensation of arylamines and glyoxalates, the selective Diels-Alder cycloaddition and oxidation processes, in which 4-nitrothiophenol was used as the key ligand.

Facile Access to Y2C2n (2n = 92-130) and Crystallographic Characterization of Y2C2@C1(1660)-C108: A Giant Nanocapsule with a Linear Carbide Cluster.

A series of giant metallofullerenes Y2C2n (2n = 92-130) have been successfully obtained through the treatment of the fraction enriched by 1,2-dichlorobenzene with SnCl4. Subsequent chromatographic separation gives a pure sample with a composition of Y2C110. Crystallographic results reveal that this endohedral takes the carbide form, namely Y2C2@C1(1660)-C108, representing as the largest metallofullerene that has been characterized by crystallography to date. Despite the disorder of the metal cluster, the major Y2C2 adopts a previously predicted linear configuration, indicating that the compression of the internal cluster by the cage is almost negligible in this giant cage. Electrochemical studies suggest that Y2C2@C1(1660)-C108 is a good electron donor instead of an electron acceptor.

Interaction between fasudil hydrochloride and bovine serum albumin: spectroscopic study.

The interaction between fasudil hydrochloride (FSD) and bovine serum albumin (BSA) was investigated using fluorescence and ultraviolet spectroscopy under imitated physiological conditions. The Stern-Volmer quenching model has been successfully applied and the results revealed that FSD could quench the intrinsic fluorescence of BSA effectively via static quenching. The binding constants and binding sites for the BSA-FSD system were evaluated. The corresponding thermodynamic parameters obtained at different temperatures indicated that hydrophobic force played a major role in the interaction of FSD and BSA. The distance between the donor (BSA) and the acceptor (FSD) was obtained according to fluorescence resonance energy transfer (FRET). Synchronous fluorescence spectroscopy and FT-IR spectra showed that the conformation of BSA was changed in the presence of FSD. Copyright © 2015 John Wiley & Sons, Ltd.

Study on the interaction between Besifloxacin and bovine serum albumin by spectroscopic techniques.

The interaction between Besifloxacin (BFLX) and bovine serum albumin (BSA) was investigated by spectroscopic (fluorescence, UV-Vis absorption and circular dichroism) techniques under imitated physiological conditions. The experiments were conducted at different temperatures (298, 304 and 310 K) and the results showed that the BFLX caused the fluorescence quenching of BSA through a static quenching procedure. The binding constant (Ka), binding sites (n) were obtained. The corresponding thermodynamic parameters (ΔH, ΔS and ΔG) of the interaction system were calculated at different temperatures. The results revealed that the binding process was spontaneous and the acting force between BFLX and BSA were mainly electrostatic forces. According to Förster non-radiation energy transfer theory, the binding distance between BFLX and BSA was calculated to be 4.96 nm. What is more, both synchronous fluorescence and circular dichroism spectra confirmed conformational changes of BSA.

Study on the interaction between 21-(Ph-NN)-NCTPP and bovine serum albumin by spectroscopic techniques.

The interaction between 21-(Ph-NN)-NCTPP and bovine serum albumin (BSA) was investigated by fluorescence and ultraviolet-visible (UV-Vis) spectroscopy under imitated physiological conditions. The results showed that the intrinsic fluorescence of BSA was quenched strongly by 21-(Ph-NN)-NCTPP. The binding constants (Ka) and the binding sites (n) were obtained at three different temperatures (298, 304, and 310K). The thermodynamic parameters (ΔH, ΔS and ΔG) of the interaction system were calculated, the results indicated that the binding process was spontaneous and the hydrophobic interaction played a major role in [21-(Ph-NN)-NCTPP]-BSA binding process. Based on the Förster non-radiation energy transfer theory, the binding distance from 21-(Ph-NN)-NCTPP to BSA was estimated to be about 3.51nm. What's more, the synchronous fluorescence spectra indicated that the conformation of BSA has not been changed.

Spectroscopic analyses on interaction of bovine serum albumin with novel spiro[cyclopropane-pyrrolizin].

The interaction between novel spiro[cyclopropane-pyrrolizin] (NSCP) and bovine serum albumin (BSA) was analyzed by fluorescence and ultraviolet-visible (UV-Vis) spectroscopy at 298 K, 304 K and 310 K under simulative physiological conditions. The results showed that NSCP can effectively quench the intrinsic fluorescence of BSA via static quenching. The binding constants, binding sites of NSCP with BSA were calculated. Hydrogen binds and van der Waals force played a major role in stabilizing the complex and the binding reaction were spontaneous. According to the Förster non-radiation energy transfer theory, the average binding distances between NSCP and BSA were obtained. What is more, the synchronous fluorescence spectra indicated that the conformation of BSA has been changed.

Study on the interaction between carbonyl-fused N-confused porphyrin and bovine serum albumin by spectroscopic techniques.

The interaction between carbonyl-fused N-confused porphyrin (CF-NCP) and bovine serum albumin (BSA) was investigated by fluorescence and ultraviolet-visible (UV-Vis) spectroscopy. The results indicated that CF-NCP has strong ability to quench the intrinsic fluorescence of BSA by forming complexes. The binding constants (Ka), binding sites (n) were obtained. The corresponding thermodynamic parameters (ΔH, ΔS and ΔG) of the interaction system were calculated at three different temperatures. The results revealed that the binding process is spontaneous, and the acting force between CF-NCP and BSA were mainly electrostatic forces. According to Förster non-radiation energy transfer theory, the binding distance between CF-NCP and BSA was calculated to be 4.37nm. What is more, the conformation of BSA was observed from synchronous fluorescence spectroscopy.

Interaction between pirenoxine and bovine serum albumin in aqueous solution.

This work concerns the interaction of prenoxine sodium (PRX) and bovine serum albumin (BSA), which was conducted by spectroscopic means: fluorescence spectra, ultraviolet-visible spectra (UV-vis) and circular dichroism spectra (CD spectra) in physiological conditions. The results revealed the PRX can quench the fluorescence of BSA remarkably in aqueous solution. The quench mechanism has been obtained after corrected the fluorescence intensities for inner filter effects. The binding constants (Ka) were calculated according to the relevant fluorescence data at different temperatures. Moreover, from a series of analyses, we have obtained the binding sites, the binding distance and binding force. The effect of PRX on the conformation of BSA has been analyzed using synchronous fluorescence under experimental conditions. In addition, the CD spectra proved that the secondary structure of BSA changed in the presence of PRX in aqueous solution.

Spectroscopic studies on the interaction of Phacolysin and bovine serum albumin.

The interaction between Phacolysin (PCL) and bovine serum albumin (BSA) under imitated physiological conditions was investigated by spectroscopic (fluorescence, UV-Vis absorption and Circular dichroism) techniques. The experiments were conducted at different temperatures (294K, 302K, 306K and 310K) and the results showed that the PCL caused the fluorescence quenching of BSA through a static quenching procedure. The binding constant (Ka), binding sites (n) were obtained. The corresponding thermodynamic parameters (ΔH, ΔS and ΔG) of the interaction system were calculated at different temperatures. The results revealed that the binding process was spontaneous and the acting force between PCL and BSA were mainly hydrogen bonding and van der Waals forces. According to Förster non-radiation energy transfer theory, the binding distance between PCL and BSA was calculated to be 2.41nm. What is more, both synchronous fluorescence and Circular dichroism spectra confirmed the interaction, which indicated the conformational changes of BSA.

The investigation of the interaction between Tropicamide and bovine serum albumin by spectroscopic methods.

The fluorescence and ultraviolet-visible (UV-Vis) spectroscopy were explored to study the interaction between Tropicamide (TA) and bovine serum albumin (BSA) at three different temperatures (292, 301 and 310K) under imitated physiological conditions. The experimental results showed that the fluorescence quenching mechanism between TA and BSA was static quenching procedure. The binding constant (Ka), binding sites (n) were obtained. The corresponding thermodynamic parameters (ΔH, ΔS and ΔG) of the interaction system were calculated at different temperatures. The results revealed that the binding process is spontaneous, hydrogen binds and vander Waals were the main force to stabilize the complex. According to Förster non-radiation energy transfer theory, the binding distance between TA and BSA was calculated to be 4.90 nm. Synchronous fluorescence spectroscopy indicated the conformation of BSA changed in the presence of TA. Furthermore, the effect of some common metal ions (Mg(2+), Ca(2+), Cu(2+), and Ni(2+)) on the binding constants between TA and BSA were examined.

A spectroscopic study on the coordination and solution structures of the interaction systems between biperoxidovanadate complexes and the pyrazolylpyridine-like ligands.

In order to understand the substitution effects of pyrazolylpyridine (pzpy) on the coordination reaction equilibria, the interactions between a series of pzpy-like ligands and biperoxidovanadate ([OV(O2)2(D2O)](-)/[OV(O2)2(HOD)](-), abbrv. bpV) have been explored using a combination of multinuclear ((1)H, (13)C, and (51)V) magnetic resonance, heteronuclear single quantum coherence (HSQC), and variable temperature NMR in a 0.15 mol L(-1) NaCl D2O solution that mimics the physiological conditions. Both the direct NMR data and the equilibrium constants are reported for the first time. A series of new hepta-coordinated peroxidovanadate species [OV(O2)2L](-) (L = pzpy-like chelating ligands) are formed due to several competitive coordination interactions. According to the equilibrium constants for products between bpV and the pzpy-like ligands, the relative affinity of the ligands is found to be pzpy > 2-Ester-pzpy ≈ 2-Me-pzpy ≈ 2-Amide-pzpy > 2-Et-pzpy. In the interaction system between bpV and pzpy, a pair of isomers (Isomers A and B) are observed in aqueous solution, which are attributed to different types of coordination modes between the metal center and the ligands, while the crystal structure of NH4[OV(O2)2(pzpy)]·6H2O (CCDC 898554) has the same coordination structure as Isomer A (the main product for pzpy). For the N-substituted ligands, however, Isomer A or B type complexes can also be observed in solution but the molar ratios of the isomer are reversed (i.e., Isomer B type is the main product). These results demonstrate that when the N atom in the pyrazole ring has a substitution group, hydrogen bonding (from the H atom in the pyrazole ring), the steric effect (from alkyl) and the solvation effect (from the ester or amide group) can jointly affect the coordination reaction equilibrium.

A highly porous 4,4-paddlewheel-connected NbO-type metal-organic framework with a large gas-uptake capacity.

A highly porous 4,4-paddlewheel-connected NbO-type metal-organic framework (HNUST-2, HNUST represents Hunan University of Science and Technology) has been designed and synthesized by self-assembling [Cu2(COO)4] SBUs with a nanosized tetracarboxylate ligand prolonged by alkyne groups, 5,5'-(naphthalene-1,4-diylbis(ethyne-2,1-diyl))diisophthalic acid (H4NDED). HNUST-2 exhibits high structural stability, a porous non-interpenetration framework with open metal sites and excellent gas-uptake capacity. This MOF material possesses a high BET surface area of 2366 m² g⁻¹, a large unsaturated excess and total H2 uptake of 4.57 wt% and 5. 20 wt% at 20 bar and 77 K, respectively. Meanwhile, HNUST-2 also exhibits an excellent adsorption capacity for CO2 (18.07 mmol g⁻¹ at 20 bar and 298 K) and CH4 (85.6 cm³ cm⁻³ at 20 bar and 298 K) with a high selectivity for CO2 over N2 (22.9) and CH4 (4.9) at 298 K.

Spectroscopic studies on the interaction of carteolol hydrochloride and urea-induced bovine serum albumin.

The interaction of carteolol hydrochloride, to 0.2 mol L(-1) urea-induced bovine serum albumin in aqueous solution has been first investigated by fluorescence spectra and ultraviolet-visible (UV-vis) spectra at pH 7.40. The quenching mechanism, binding parameter and sites (n), the binding mode (ΔG, ΔH, and ΔS) as well as the binding distance (r) have been obtained according to the experimental results. We also use the synchronous fluorescence method to study the effect of CTL on the conformation change of urea-induced BSA.