Chitosan-supported Borohydride Reducing Agent

Borohydride exchange resin (BER) a useful reducing reagent has been used in reduction of some carbonyl compounds and acyl halides1. When BER combines with a transition metal catalyst, it can reduce C=C double bonds2, halides2, nitro compounds3, cyano, diazo3 and azide compounds4. The support of BER is the synthetic macromolecule polystyrene. Here, we used chitosan as the support of borohydride. As known, chitosan is a renewable and abundant natural polysaccharide. Scheme 1 Preparat…     

SmI2－Mediated Addition Reaction of α－Halomethylsulfones to Carbonyl Compounds. A Convenient Synthesis of β－Hydroxysulfones

Due to the chemoselective dehalogenation by SmI2, the addition of a-halomethylsulfones to carbonyl compounds afforded ,β-hydroxysulfones. Those reactions with α-bromomethylsulfones gave the products in moderate to good yields. The SmI2-mediated addition of gem-dihalomethylsulfones to ketones also afforded α-halo-β-hydroxysulfones in moderate yields.     

One pot synthesis of N-ethylaniline from nitrobenzene and ethanol

A novel method for the one pot synthesis of N-alkyl arylamines from nitro aromatic compounds and alcohols is proposed through the combination of the aqueous-phase reforming of alcohol for hydrogen production, the reduction of nitro aromatic compounds for the synthesis of aromatic amine and the N-alkylation of aromatic amine for the production of N-alkyl arylamine over an identical catalyst under the same conditions of temperature and pressure in a single reactor. In this process, hydrogen generated from the aqueous-phase reforming of alcohols was used in-situ for the hydrogenation of nitro aromatic compounds for aromatic amine synthesis, followed by N-alkylation of aromatic amine with alcohols to form the corresponding N-alkyl arylamines at a low partial pressure of hydrogen. For the system composed of nitrobenzene and ethanol, under the conditions of 413 K and PN2 = 1 MPa, the conversion degrees of nitrobenzene and aniline were 100%, the selectivity to N-ethylaniline and N, N-diethylaniline were 85.9% and 0%-4%, respectivity, after reaction for 8 h at the volumetric ratio of nitrobenzene:ethanol:water = 10:60:0. The selectivity for N, N-diethylaniline production is much lower than that through the traditional method. In this process, hydrogen and aromatic amines generated from the aqueous-phase reforming of alcohols and hydrogenation of nitro aromatic compounds, respectively, could be promptly removed from the surface of the catalyst due to the occurrence of in-situ hydrogenation and N-alkylation reactions. Thus, this may be a potential approach to increase the selectivity to N-alkyl arylamine.     

Reduction of Sulphur-containing Aromatic Nitro Compounds with Hydrazine Hydrate over Iron(III) Oxide-MgO Catalyst

Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron(III) oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.     

Reduction of Sulphur-containing Aromatic Nitro Compounds with Hydrazine Hydrate over Iron（Ⅲ） Oxide-MgO Catalyst

Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron（Ⅲ） oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.     

The reaction of perfluoroalkanesulfinates——Ⅶ.Fenton reagent-initiated addition of sodium perfluoroalkanesulfinates to alkenes

The addition of sodium perfluoroalkanesulfinates (R_FSO_2Na) to various olefins (CH_2=CHR)initiated by Fenton reagent (Fe~(2+)-H_2O_2) in the presence of sodium azide gave the adduets R_FCH_2-CHN_3R in good yield.A radical mechanism was proposed based on the EPR and other evidences.The adducts were readily reduced through catalytic hydrogenation to give the corresponding aminesR_FCH_2CH(NH_2)R in high yield.The reaction represents a convenient and effective route to theseuseful organofluorine compounds.     

Electrospray Lonization Fourier Transform Ion Cyclotron Resonance Mass Spectrometric Study on Sodium Azide Cluster Ions

Sodium azide has rarely been studied in gas phase or in the form of cluster ions and as a model of solid energetic substances and inorganic azide salt was ionized by electrospray ionization (ESI) and studied by high resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS) systematically. This paper highlights the effects of experimental conditions on the formation of salt cluster and the collision activation dissociation pathways of cluster ions to develop a microscopic understanding of inorganic azide salt clusters.     

Bismuth Mediated Organic Reaction: A Convenient Method for the Synthesis of Allylic (Benzylic) Selenides and α-Organylselenocarbonyl Compounds in Aqueous Media

Organic reactions promoted by active metals have aroused much interest in recent years. Active bismuth has been used in Barbier-type reaction of allylic halides with aldehydes1 and aldimines2 as well as Reformatzky type reaction3. Other publications referred to the cross coupling between aldehydes and α-diketones4, the substitution to benzotriazole drivatives5 and the reductive coupling reaction of nitro compounds6. These reactions generally promoted by elemental bismuth generated in situ fr…     

Synthesis of A Novel Fulleroaziridine Carrying 4-Deoxy-4''''-demethylepipodophyllotoxin

Functionalization by cycloaddition reactions1 represents a useful strategy to modify fullerenes1,2. Stable cycloadducts are interesting in regarding to the development of new materials with unique physical properties or biological activities3. One of the typical reactions is the cycloadditions of C60 with azide compounds. Wudl and Miyata et al. reported that C60 reacted with alkyl azides4 or benzyl azides5 to give the same kind of adduct azafulleroids with an opened 6,5-ring junction by th…     

Nanocomposites of graphene-CdS as photoactive and reusable catalysts for visible-light-induced selective reduction process

Graphene （GR）-CdS nanocomposites with different weight addition ratios of GR have been assembled by a facile solvothermal treatment. The GR-CdS nanocomposite photocatalyst with an appropriate ratio of GR exhibits enhanced photoactivity for selective reduction of aromatic nitro compounds to the corresponding aromatic amines in water under visible light irradiation as compared with blank-CdS. The characterization of GR-CdS nanocomposite photocatalysts by a collection of techniques discloses that： i） GR can tune the microscopic morphology of CdS nanoparticles and improve light absorption intensity in the visible light region; ii） GR scaffolds act as an electron reservoir to trap and shuttle the electrons photogenerated from CdS semiconductor under the visible light illumination; iii） the introduction of GR enhances the adsorption capacity of GR-CdS nanocomposites toward the substrates, aromatic nitro compounds. The synergistic effect of these factors should account for the photoactivity advancement of GR-CdS nanocomposites toward the probe reactions. Furthermore, because the photogenerated holes in the system are trapped by the quenching agent ammonium oxalate, the as-obtained GR-CdS photocataiyst is stable during the photocatalytic reduction reactions. A reasonable model has also been proposed to illustrate the reaction mechanism.     

Comparison of （η^6－Fluoroarene）tricarbonylchromium Complexes with Their Chloro－analogs in Radical Aromatic Substitutions

Reactions of fluoroarene-Cr(CO)3 complexes with SmI2 and earbonyl compounds in THF/HMPA at -40～- 60℃ afforded the correspoDdin~ radical aromatic substitution products in high yield. Compared to the corresponding chloroarene-Cr(CO)3 complexes, fluoroarene-Cr(CO)3 complexes showed a higher efficiency and slightly lower regioselectivity.     

Synthesis and thermal properties of novel calix[4]arene derivatives containing 1,2,3-triazole moiety via K2CO3-catalyzed 1,3-dipolar cycloaddition reaction

Two calix[4]arene derivatives containing 1,2,3-triazole moiety were synthesized via K2CO3-catalyzed1,3-dipolar cycloaddition reaction between calix[4]arene-based azide and active methylene compounds in good yields.The structures of the two compounds synthesized herein were fully confirmed by 1HNMR,,（13）C NMR,and MS（ESI）.The thermal analysis showed that the mass losses of the synthesized compounds 4 and 5 containing 1,2,3-triazole groups are similar to each other.     

Insights into the Decomposition and Polymerization of Cage Energetic Crystal Octanitrocubane under High Pressure: a DFT-D Study

Dispersion-corrected DFT calculations have been performed to study the crystal structure, initial decomposition mechanism, polymerization mechanism, electronic structure and absorption properties of the most powerful CHNO energetic compound octanitrocubane(ONC) under hydrostatic pressure of 0~200 GPa. Our results show that the lattice parameter c is sensitive to van der Waals interactions and the structure is the stiffest in the a direction. ONC decomposes by the breaking of N–O bond in nitro group at 195 GPa. At 200 GPa, ONC decomposes through the breaking of N–O bond in nitro group and polymerizes through the forming of a new C–O covalent bond between a carbon atom in the cage skeleton and one oxygen atom of nitro group in another ONC molecule. ONC becomes more and more sensitive under high pressure and transforms into a metallic phase in the pressure range of 175~200 GPa. ONC also has higher optical activity and wider absorption range under compression.     

Deviations from bulk morphologies in thin films of block copolymer/additive binary blends

Deviations from bulk morphologies in thin films of binary blends of alkyne-functionalized diblock copolymer poly(ethylene oxide)-block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) and Rhodamine B azide are reported, where thermal click reaction between the two components leads to microphase separated morphologies. Both in the bulk and in thin films, increasing the azide loading ratio resulted in the transition from a lamellar microdomain morphology to a hexagonally packed cylindrical mircodomain morphology. However, in thin films the lamellae-cylinder transition was observed at a different azide loading ratio, which was determined by film thickness. As a result, significant deviations from the bulk morphology were observed. These results indicate that surface interactions and confined geometry can play an important role in dictating the morphology in thin films of BCP/additive binary blends.     

Synthesis and antioxidant activities of flavonoids derivatives, troxerutin and 3’, 4’, 7-triacetoxyethoxyquercetin

Syntheses of two very important derivatives of quercetin,troxerutin and 3’,4’,7-triacetoxyethoxyquercetin were described.The latter was synthesized by highly selective esterification reaction in first time.The compounds were characterized by NMR,IR and Mass spectroscopy.Additionally,the antioxidant activities of the compounds were tested by means of improved pyrogallol autoxidation method.This was the first in using this method to test the antioxidant activities of these two compounds in vitro.The optimum system of pyorgallol autoxidation spectrophotometry was investigated and established according to the reaction rules.The assay indicated that these compounds showed noticeable antioxidant activities,and compound 2 was much more effective as a free radical scavenger than the compound 1 vitamin C was used as a reference material.     

Synthesis and Evaluation of Nicotinoylamino Acid Compounds as Radiosensitizer

Nicotinoylamino acid compounds 4, 5, 9a, 9b, 9c, 10a and 10b were synthesized with nicotinoyl chloride or nicotinoyl azide as acetylating agents of amino acid esters or amino acids. The compounds were tested for their radiosensitizing activity in Leukemia cell line（L1210） and compared with nicotinamide; among them, compounds 9a and 9c showed significant radiosensitizing effects, the sensitizer enhancement ratio（SER） was 1.64 and 1.58, respectively, while nicotinamide did not show good radiosensitizing effect under the same conditions. Compound 9c was alone tested for radiosensitization in LA 795 cell-bearing T-739 mice, or hyperthermia and breathing carbogen（5%CO2＋95%O2） were together tested for radiosensitization. The results showed that radiation-induced growth delay was enhanced by 9c alone or by the combination of hypertheimia and carbogen. The tumor-bearing mice were irradiated locally by total 10 Gy, and the tumors grew to three times that of the original volume in an average of 5.8 d. The mice were given i.p. compound 9c at 1000 mg/kg 60 min before irradiation and treated at 43 ℃ for 30 min after irradiation or treated with breathing carbogen for 5 min before radiation or with hyperthmia（43 ℃） for 30 min after irradiation; the time required for the tumor to grow to three times the orginal volume was in an average of 12.9 and 13 d, respectively.     

微乳液合成胶体CuO/γ-Al_2O_3及其催化芳香硝基化合物还原(英文)

Monodispersed colloidal copper oxide nanoparticles were synthesized by water-in-oil microemulsion using CuCl 2·H2O and NaOH.The effect on CuO particle size was studied by varying the water-to-surfactant molar ratio,precursor concentration and molar ratio of NaOH to CuCl2.The morphology,size and size distribution of the particles were studied by transmission electron microscopy and dynamic light scattering.Dispersion destabilization of the colloidal copper oxide nanoparticles was detected by a Turbiscan apparatus.CuO/γ-Al2O3 catalysts were prepared by dispersing highly stable CuO nanoparticles on γ-alumina by mechanical stirring.The catalysts were analyzed by scanning electron microscopy,transmission electron microscopy,X-ray photoelectron,and X-ray diffraction,which confirmed the uniform dispersion of CuO on the support.The reduction of the nitro aromatic compounds,4-nitrophenol,3-nitrophenol,and 2-nitrophenol,were studied.The CuO/γ-Al2O3 catalysts were active for the reduction of these nitro aromatic compounds.     

微乳液合成胶体CuO/γ-Al2O3及其催化芳香硝基化合物还原（英文）

Monodispersed colloidal copper oxide nanoparticles were synthesized by water-in-oil microemulsion using CuCl 2·H2O and NaOH.The effect on CuO particle size was studied by varying the water-to-surfactant molar ratio,precursor concentration and molar ratio of NaOH to CuCl2.The morphology,size and size distribution of the particles were studied by transmission electron microscopy and dynamic light scattering.Dispersion destabilization of the colloidal copper oxide nanoparticles was detected by a Turbiscan apparatus.CuO/γ-Al2O3 catalysts were prepared by dispersing highly stable CuO nanoparticles on γ-alumina by mechanical stirring.The catalysts were analyzed by scanning electron microscopy,transmission electron microscopy,X-ray photoelectron,and X-ray diffraction,which confirmed the uniform dispersion of CuO on the support.The reduction of the nitro aromatic compounds,4-nitrophenol,3-nitrophenol,and 2-nitrophenol,were studied.The CuO/γ-Al2O3 catalysts were active for the reduction of these nitro aromatic compounds.     

High-performance anion-exchange chromatography of carbohydrates using a new resin and pulsed amperometric detection

Summary This paper reports the results of a study on the use of a new polymer-based, strong anion-exchange, stationary phase for rapid and selective separation of carbohydrates and related compounds by high-pH, anion-exchange chromatography with pulsed amperometric detection. The new adsorbent has been obtained by direct nitration of 2.8 μm, spherical non-porous highly cross-linked, styrene-divinylbenzene copolymer beads, followed by reduction of superficially introduced nitro groups with nascent hydrogen and quaternization of the resultant amino groups with iodomethane. It is reported that by optimizing the ionic strength of the mobile phase, columns packed with the new anion-exchanger can be successfully employed to separate, either in isocratic or gradient elution mode, oligosaccharides, positional isomers of gluco-disaccharides, as well as uronic acids and sugar monophosphates.     

Efficient Debromination of Vicinal a, b-Dibromo Carboxylic Acid Derivatives with the Sm/HOAc System

The chemistry of samarium (II) iodide (SmI2) is of current interest in organic synthesis. SmI2 has been developed as a powerful, versatile and ether-soluble single-electron reductant and many examples have been reported of its use in the reduction of various functional groups1. Though SmI2 is a useful reagent, storage is difficult because it is very sensitive to air oxidation. On the other hand, metallic samarium is stable in air and has strong reducing power (Sm3+/Sm=-2.41 V). These pr…