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.

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.

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.

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.

A study on the interaction between 3-spiro-piperidones and bovine serum albumin using spectroscopic approaches.

The interaction between 3-spiro-2'-pyrrolidine-3'-spiro-3″-piperidine-2,3″-dione (PPD) and bovine serum albumin (BSA) in aqueous solution was studied using fluorescence and UV-vis spectroscopy. Fluorescence emission data revealed that BSA (1.00 × 10(-5) mol/L) fluorescence was statically quenched by PPD at various concentrations, which implies that a PPD-BSA complex was formed. The binding constant (KA ), the number of binding sites (n) and the specific binding site of the PPD with BSA were determined. Energy-transfer efficiency parameters were determined and the mechanism of the interaction discussed. The thermodynamic parameters, ΔG, ΔH and ΔS, were obtained according to van't Hoff's equation, showing the involvement of hydrophobic forces in these interactions. The effect of PPD acting on the BSA conformation was detected by synchronous fluorescence.

1,3-Dipolar cycloaddition of 2,6-dichlorobenzonitrile oxide to 2-methyl-N-confused porphyrin. Regio- and stereoselective synthesis and structural characterization of 2-aza-21-carbabacteriochlorin and resolution of 2-aza-21-carbachlorin enantiomers.

The 1,3-dipolar cycloaddition reaction of 2-methyl-N-confused porphyrin with 2,6-dichlorobenzonitrile oxide yielded four isomeric monoadducts of carbachlorin type and one diadduct of carbabacteriochlorin type. Two major carbachlorin products, constituting 82% of the monoadducts, were shown to be structural precursors of the unique 2-aza-21-carbabacteriochlorin. Enantiomers of the most abundant isomer of 2-aza-21-carbachlorin (55% of all carbachlorin products) have been resolved. The crystal structures of 2-aza-21-carbabacteriochlorin and the most abundant isomer of 2-aza-21-carbachlorin were characterized by X-ray diffraction.

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].

Synthesis of N-confused porphyrin derivatives with a substituted 3-C position.

Active methylene compounds such as 5,5-dimethylcyclohexane-1,3-dione, cyclohexane-1,3-dione, 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one, 1,3-dimethyl-1H-pyrazol-5(4H)-one, and 3-methylisoxazol-5(4H)-one react with the 3-C position of N-confused porphyrin in THF for 5 min to afford a novel type of N-confused porphyrin derivatives in good yield without the need of any catalyst.

Spectroscopic and DFT study on the interaction system of vanadium with L-proline in aqueous solution.

To gain more insight into the interactions between vanadium and l-proline, the dynamic transformation of the reaction system of vanadium with l-proline and the coordination structures of the vanadium-containing products in 0.15 mol/L NaCl ionic medium mimicking physiological conditions were explored by multinuclear ((1)H, (13)C, (51)V) NMR, ESR, ESI-MS as well as density functional theory (DFT) calculations. Spectroscopic evidence and computational results showed that a monoperoxovanadium species [VO(O(2))(l-proline)(2)](-) was a major product, where l-proline coordinated to vanadium via nitrogen and oxygen atoms in a bidentate manner to form a distorted pentagonal bipyramidal structure. The species [VO(O(2))(l-proline)(2)](-) underwent chemical changes in solution at room temperature, finally leading to the reduction of vanadium(V) to vanadium(IV) and the formation of [VO(l-proline)(2)]. In the tetrahedral structure of the reduction product [VO(l-proline)(2)], l-proline also coordinated to vanadium in a bidentate manner. Such an investigation may be helpful for a better understanding of vanadium complexes as insulin-enhancing agents for the treatment of diabetes.

Structure, properties, and nature of the pyridine-XY (X, Y = F, Cl, Br) complexes: an ab initio study.

Structure and properties (energies, electronic, and thermodynamic properties) of complexes pyridine-XY (X, Y = F, Cl, Br) have been investigated at the MP2/aug-cc-pVDZ level. Two types of geometries (pi-halogen bonded and sigma-halogen bonded) are observed. In contrast with the previous results on similar furan and thiophene complexes, the sigma-halogen bonded structures are more stable and the reasons are discussed. Charge transfer is found to be important in the formation of title system and the possible existing complexes under experimental conditions have been forecasted too. A symmetry-adapted perturbation theory energy decomposition analysis reveals that the pyridine-XY complexes are dominantly inductive in nature.

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.

Investigation on the complex of diperoxovanadate with picolinamide.

A novel diperoxovanadate complex NH(4)[OV(O(2))(2)(picolinamide)].H(2)O was synthesized from aqueous solution under physiological conditions. The solution structure of the complex was characterized by multinuclear ((1)H, (13)C, (14)N, and (51)V), variable temperature as well as two-dimensional (DOSY) NMR techniques in the interaction system of NH(4)VO(3)/H(2)O(2)/picolinamide at room temperature. The crystal structure of the complex was determined at 223K by single-crystal X-ray diffraction method. It belongs to the monoclinic space group P21/c with a=7.323(3)A, b=14.255(7)A, c=10.022(5)A, beta=99.524(9) degrees , V=1031.7(8)A(3), and Z=4. The crystal is composed of ammonium ions, picolinamide oxodiperoxovanadate(V) ions, and water molecules, which are held together by ionic and hydrogen bond forces. The species [OV(O(2))(2)(picolinamide)](-) is seven-coordinated with a distorted pentagonal bipyramidal geometry both in solution and in crystal.

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.

Preparation and optical properties of worm-like gold nanorods.

A type of worm-like nanorods was successfully synthesized through conventional gold nanorods reacting with Na2S2O3 or Na2S. The generated worm-like gold nanorods comprise shrunk nanorod cores and enwrapped shells. Therefore, a gold-gold sulfide core-shell structure is formed in the process, distinguishing from their original counterparts. The formation of the gold chalcogenide layers was confirmed by transmission electron microscopy and X-ray photoelectron spectroscopy. Experimental results showed that the thickness of the gold chalcogenide layers is controllable. Since the increase of shell thickness and decrease of gold nanorod core take place simultaneously, it allows one to tune the plasmon resonance of nanorods. Proper adjustment of reaction time, temperature, additives and other experimental conditions will produce worm-like gold nanorods demonstrating desired longitudinal plasmon wavelength (LPW) with narrow size distributions, only limited by properties of starting original gold nanorods. The approach presented herein is capable of selectively changing LPW of the gold nanorods. Additionally, the formed worm-like nanorods possess higher sensitive property in localized surface plasmon resonance than the original nanorods. Their special properties were characterized by spectroscopic methods such as Vis-NIR, fluorescence and resonance light scattering. These features imply that the gold nanorods have potential applications in biomolecular recognition study and biosensor fabrications.

Spectroscopic and theoretical study on the interaction between diperoxovanadate and oxazole.

Detailed investigations were carried out to explore the interaction systems of NH(4)VO(3)/H(2)O(2)/oxazole in aqueous solution under physiological conditions by a combined use of multinuclear NMR ((1)H, (13)C, (14)N and (51)V), diffusion ordered spectroscopy (DOSY), variable temperature NMR, electrospray ionization mass spectrometry (ESI-MS), spin-lattice relaxation and density functional calculations. The results indicated the formation of a new peroxovanadate species [OV(O(2))(2)(oxazole)](-) with oxazole coordinating to vanadium through nitrogen atom. The solution structure of the new species was predicted from theoretical calculations.

NMR and theoretical study on interactions between diperoxovanadate complex and 4-substituted pyridines.

To understand the substituting group effects of organic ligands on the reaction equilibrium, the interactions between diperoxovanadate complex [OV(O2)2(D2O)]-/[OV(O2)2(HOD)](-) and a series of 4-substituted pyridines in solution were explored using multinuclear (1H, 13C, and 51V) magnetic resonance, DOSY, and variable temperature NMR in 0.15 mol/L NaCl ionic medium for mimicking the physiological condition. Some direct NMR data are given for the first time. The reactivity among the 4-substituted pyridines is pyridine > isonicotinate > N-methyl isonicotinamide > methyl isonicotinate. The competitive coordination results in the formation of a series of new six-coordinated peroxovanadate species [OV(O2)2L](n-) (L = 4-substituted pyridines, n = 1 or 2). The results of density functional calculations provide a reasonable explanation on the relative reactivity of the 4-substituted pyridines. Solvation effects play an important role in these reactions.

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.

Multinuclear NMR spectroscopic and theoretical study on the interactions between diperoxovanadate complex and picoline-like ligands.

To understand the substituting effects of organic ligands on the reaction equilibrium, the interactions between diperoxovanadate complex [OV(O(2))(2)(H(2)O)](-) and a series of picoline-like ligands in solution were explored using 1D multinuclear ((1)H, (13)C, and (51)V) magnetic resonance, 2D diffusion ordered spectroscopy (DOSY), and variable temperature NMR in 0.15 mol/l NaCl ionic medium for mimicking the physiological conditions. The order of reactive capability of the picoline-like ligands with [OV(O(2))(2)(H(2)O)](-) is found to be picolinamide>N-methylpicolinamide>methyl picolinate>ethyl picolinate approximately propyl picoliniate>isopropyl picolinate. The substituting group influences the reactivity by either steric effect or electron-donating effect. Competitive coordination interactions result in a series of new seven-coordinated peroxovanadate species [OV(O(2))(2)L](-) (L=picoline-like ligands). Their coordination ways were confirmed by density functional calculations.