POLYMER-SUPPORTED β-CYCLODEXTRIN CATALYST FOR SELECTIVE SYNTHESISOF 4-H YDROXYBENZOIC ACID

4-hydroxybenzoic acid was synthesized by one pot method using polymer-bonded β-aminopropionic acid-2-β-cyclodextrin as a catalyst.by which the selectivity for 4-hydroxybenzoic acid is 87%. A possible carboxylation mechanism in the presence of the title catalyst is discussed. Also.the recovery and reusage of the catalyst is studied.

Selective Synthesis of Different-Sized Gold Nanoclusters through HCI-Etching and-Growth Effect

Controllable syntheses of different-sized gold nanoclusters are of great significance for their fundamental science and practical applications. In this work, we achieve the controllable and selective syntheses of Au7 and Au13 clusters through adding HCl to the traditional Aull synthetic route at different reaction time. Time-dependent mass spectra and UV- Vis spectra were ernployed to monitor these two HCl-directed processes, and revealed the distinct roles of HCl as an etchant or a growth prornotor, respectively. Furthermore, parallel experiments on independent synthetic routes involving only non-chlorine H＋ （acetic acid） or Cl （tetraethy larnrnoniurn chloride） instead of HCl were perforrned, which illustrated the main role of H^＋-etching and Cl^ -assisted growth in HCl-directed cluster synthetic routes. We propose the HCl-etching is mainly achieved via the H＋ action to break the Au（I）-PPh3 part of clusters, while the HCl-prornoted growth is realized via the attachment of Au-Cl species to the pre-forrned clusters.

Multicomponent cascade reaction of 3-formylchromones:Highly regioselective synthesis of functionalized pyridin-2(1H)-ones

A novel protocol was developed for the construction of highly functionalized pyridin-2(1H)-ones from 3-formylchromones,ethyl 2-(pyridin-2-yl)acetate derivatives and amines via a complex multicomponent cascade reaction involving targeted duplicated ring-opening and duplicated cyclization reactions which form skeleton-reorganized target compounds.A series of pyridin-2(1H)-ones were produced by this reaction accompanied by the formation of three bonds(one C–N and two C–C bonds)and the cleavage of one bond in one step.This protocol can be used in combinatorial and parallel syntheses of various pyridin-2(1H)-ones with potent biological activity.The advantages of this approach include simple and practical operation(multicomponent one-pot),high yields(up to 91%),and products with potential biological activity.

Stereoselective Synthesis of (E)-α-Aryltellurenylvinyl- stannanes and Their Application in the Synthesis of Stereodefined Trisubstituted Alkenes

E)-α-Aryltellurenylvinylstannanes have been synthesized stereoselectively via the hydrozirconation of alkynyl- stannanes, followed by the reactions with aryltellurenyl iodides. (E)-α-Aryltellurenylvinylstannanes can undergo sequential cross coupling reactions with both electrophiles and nucleophiles in the presence of transition metal complexes to form two carbon-carbon bonds in the same olefinic carbon leading to trisubstituted alkenes stereose- lectively.

An environmentally benign multi-component reaction:Highly regioselective synthesis of functionalized 2-(diarylphosphoryl)-1,2-dihydro-pyridine derivatives

A novel protocol was developed for the construction of highly functionalized 2-(diarylphosphoryl)-1,2-dihydropyridine derivatives(DAPDHPs)from 3-formylchromones(1),heterocyclic ketene aminals(HKAs,2),and phosphine oxides(R_(2)P(O)H,3)via a novel,one-pot cascade reaction.Optimization of the reaction conditions determined that refluxing the mixture of the 3-formylchromones,HKAs,and various R_(2)P(O)H in propylene carbonate(PC)in the presence of triethylamine as a base facilitated the highest yields of the DAPDHP products.This cascade reaction,which involved the cleavage of one C-O bond in the 3-formylchromone substrates and the formation of three new bonds(one C-C,one C-N,and one C-P bond),enabled the synthesis of a small library of DAPDHP products.The dearomatized DAPDHP products were formed by the regioselective nucleophilic addition of the R_(2)P(O)H reagents to the intermediate pyridinium salts 8.This approach has several advantages such as the use of an environmentally-friendly solvent,simple and practical operation(with filtration and washing without column chromatography separation),good yields,and a product with potential biological activity.

THE SELECTIVE OXIDATION OF ALCOHOLS-STUDIES ON THE SYNTHESIS AND PROPERTIES OF HEXAHYDROPYRIDINE CHROMIUM TRIOXIDE HYDROCHLORIDE

A new Cr(Vl)complex,hexahydropyridine chromium trioxide hydrochloride is developed.Its behavior and seiectivity on alcohols are investugated

Synthesis of Novel Cyclodextrin Dimers Linked by Multidentate Coordination Units

A new type of cyclodextrin dimers (2a-c) bridged with multidentate coordination units has been synthesized by treatment of 6-deoxy-6-hydroxyethylamino-beta-cyclodextrin 1 with corresponding dibromides in the presence of base.

Synthesis,Crystal Structure and PTPs Inhibition of a Zinc(Ⅱ) Complex with N-(4-hydroxybenzyl)-L-serine

The reaction of the reduced Schiff base HL（N-（4-hydroxybenzyl）-L-serine） with Zn（CH3COO）2·2H2O in aqueous solution afforded [Zn（L）2]·3H2O（I）. The complex has been characterized by elemental analysis, FT-IR, powder X-ray diffraction, electrospray ionization mass spectrometry and single-crystal X-ray diffraction. Complex I crystallizes in the orthorhombic system, space group P212121, with a=9.197（2）, b=10.445（2）, c=24.149（5） , V=2319.8（8） 3, Z=4, C（20）H（30）N2O11 Zn, Mr=539.83, Dc=1.546 g·cm3, μ=1.122 mm（-1）, F（000）=1128, GOOF=0.971, the final R=0.0206 and w R=0.0506 for 4346 observed reflections（I ＆gt; 2σ（I））. In complex I, each Zn（II） ion coordinates with three carboxyl oxygen atoms and two amine nitrogen atoms from three L-anions, forming a distorted five-coordinated trigonal bipyramidal geometry. Complex I exhibits a 1D wavy chain structure that is extended by hydrogen-bonding interactions to form a supramolecular network. The bioactivity of the complex as a potential PTPs inhibitor in vitro was investigated, displaying potent inhibition against PTP1B（IC（50）, 0.24 μM） and TCPTP（IC（50）, 0.53 μM） with a moderate selectivity.

Pd catalysts supported on rGO-TiO_2 composites for direct synthesis of H_2O_2: Modification of Pd^(2+)/Pd^0 ratio and hydrophilic property

The use of nanostructured composites as catalyst supports is a promising route to prepare catalysts with high selectivity and productivity. In this work, reduced graphene oxide-TiO_2(rGP-x) composites with a variation of reduced graphene oxide(rGO) content were synthesized by hydrothermal method. Pd/rGP-x catalysts were prepared in incipient-wetness impregnation method for the direct synthesis of H_2O_2 from H2 and O_2. The morphology and electronic properties of catalysts were investigated by XPS, TEM, and Raman spectroscopy.The ratio of Pd^(2+)/Pd^0 and the hydrophobicity of the catalysts were increased with the rising content of rGO. As the amount of rGO in the catalysts varied in the range of 0.025 wt%–2 wt%, the selectivity of H_2O_2 exhibited a tendency of increasing firstly and then decreasing from 0.1 wt% to 2 wt%. It indicates that good catalytic performance for H_2O_2 synthesis can be achieved only when appropriate amount of rGO is introduced. The H_2O_2 selectivity and productivity of Pd/r GP-0.025 both improved remarkably compared with Pd/P25. This enhancement originated from the combined effects of the proper ratio of Pd^(2+)/Pd^0 and hydrophobicity of the catalyst.

Cleaner and convenient preparation of 3-（4,6-dimethoxy-pyrimidin-2-yloxy）-2-methyl-phenol

Environmental concerns have highlighted the need of cleaner technologies. A cleaner, convenient and selective technology has been developed for the preparation of 3-(4,6-dimethoxy-pyrimidin-2-yloxy)-2-methyl-phenol (DPMP) from 2-methyl-benzene-1,3-diol in water as solvent. The isolated yield of DPMP is up to 86% in good selectivity. The product structure was characterized by conventional methods, H-NMR and MS. This technology belongs to the modern concept of 1 environmentally friendly low wastes or non-wastes technology (LWNWT).

A Solvothermal Route to Cu_2O Nanocubes and Cu Nanoparticles

Cu2O nanocubes and Cu nanoparticles were prepared by reducing Cu（ Ⅱ ） salt with ethanol as the reducing agent and solvent in the presence of multidentate ligand poly（vinylpyrrolidone） （PVP） under different conditions. The morphologies and the crystalline structures of the products were characterized by using scanning electron microscopy （SEM）, transmission electron microscopy（TEM）, selected-area electron diffraction（ SAED）, and powder X-ray diffraction（XRD）. In particular, the influences of the solvothennal reaction temperature and alkalinity on the products were investigated. A lower temperature and a lower alkali concentration favor the formation of the Cu2O phase, whereas a higher temperature and a higher alkali concentration generally lead to the formation of the Cu phase.

Microwave-assisted controllable synthesis of 2-acylbenzothiazoles and bibenzo[b][1,4]thiazines from aryl methyl ketones and disulfanediyldianilines

A condition-controlled strategy for selectively synthesis of 2-acylbenzothiazoles and bibenzo[b][1,4]thiazines from aryl methyl ketones and disulfanediyldianilines was realized using I_(2)/DMSO or I_(2)/MeCN systems,respectively.The desired products were synthesized in only 15 min with moderate to excellent yields(50%-90%)under microwave-assisted,metal-free conditions.The strategy provides a great advantage for selective synthetic applications in the efficient synthesis of benzothiazoles and bibenzothiazines heterocycle compounds.

Bi(OTf)3-catalyzed tandem reaction of naphthols with β,γ-unsaturated a-ketoesters.Efficient synthesis of functionalized 4H-chromenes

An efficient synthesis of functionalized 4H-chromenes by the tandem reaction of β,γ-unsaturated α- ketoesters with 2-naphthols, 1 -naphthols, and 1,3-dihydroxynaphthalenes has been accomplished with high selectivity and excellent yields in the presence of a catalytic amount of bismuth triflate [Bi（OTf）3, 5 mol%] under mild conditions. The functionalized 4H-chromene synthesis and our previous 2H- chromene hemiacetal synthesis could complement each other to enrich reaction diversity.

A green synthesis of a simple chemosensor that could instantly detect cyanide with high selectivity in aqueous solution

A novel and simple cyanide chemosensor 2-（naphthalen-1-ylmethylene）malononitrile（L） was designed and synthesized via a green chemistry method in water without using any catalyst.The chemosensor showed an excellent sensitivity and selectivity for CN in aqueous solution.The detection limit could be as low as 1.6×10~7 moI/L（0.16μmol/L）,which is far lower than the WHO guideline of 1.9μmol/L cyanide for drink water.