Metal 2-Hydroxy-1-Naphthaldehyde Thiosemicarbazone (Me-HNT) Complexes-A New Kind of Biomimic Enzyme Catalyst

Metal (Me=Fe(III), Mo(VI), Mn(II), Co(II), Ni(II), Zn(II) and Cu(II)) 2-hydroxy-1-naphthaldehyde thiosemicarbazone complexes (MeHNT) were synthesized and used as mimic-enzyme catalysts to mimic the active group of horseradish peroxidase (HRP). The results showed that Fe-HNT, Mo-HNT are effective catalysts, which have similar catalytic activity as HRP. The sequence of catalytic activities of tested biomimic peroxidas is Mo-HNT > Fe-HNT > Zn-HNT > Ni-HNT > Mn-HNT. Among them, Fe-HNT is used as a mimic-enzyme catalyst in determination of ascorbic acid and glucose by coupling the catalytic reaction of glucose oxidase.

Synthesis and Crystal Structure of 4-Bromo-5-ethoxy-3-methyl-5- (naphthalen-1-yl)-1-tosyl-1H-pyrrol-2(5H)-one

The title compound 4-bromo-5-ethoxy-3-methyl-5-（naphthalen-l-yl）-l-tosyl-lH- pyrrol-2（5H）-one 1 （C24H22BrNO4S, Mr = 500.40） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 8.8562（15）, b = 18.118（3）, c = 14.055（2）A, β = 99.855（3）^o, V= 2221.9（6）A3, Z = 4, Dc = 1.496 g/cm^3,μ= 1.975 mm^-1, 2 = 0.71073A, F（000） = 1024, R = 0.0607 and wR = 0.1371.

Kinetics and Mechanism of Oxidation of 1-Methoxy-2-propanol and 1-Ethoxy-2-propanol by Ditelluratocuprate（lll） in Alkaline Medium

The kinetics of oxidation of 1-methoxy-2-propanol and l-ethoxy-2-propanol by ditelluratocuprate（III） （DTC） in alkaline liquids has been studied spectrophotometrically in the temperature range of 293.2-313.2 K. The reaction rate showed first order dependence in DTC and fractional order with respect to l-methoxy-2-propanol or 1-ethoxy-2-propanol. It was found that the pseudo-first order rate constant kobs increased with an increase in concentration of OH- and a decrease in concentration of TeO4^2- . There is a negative salt effect. A plausible mechanism involving a pre-equilibrium of a adduct formation between the complex and 1-methoxy-2-propanol or 1-ethoxy-2-propanol was proposed. The rate equations derived from mechanism can explain all experimental observations. The activation parameters along with the rate constants of the rate-determining step were calculated.

A novel and efficient strategy involving a CuI catalyzed cascade reaction to synthesize acenaphtho[1,2-b]quinoline derivatives

A novel and efficient approach for the straightforward synthesis of biologically significant acenaphtho[1,2-b]quinoline derivatives in good yields utilizing CuI as a catalyst with a broad array of substrates has been developed. The strategy features as a CuI-catalyzed cascade reaction involving the formation of two new C–C bonds and one new C–N bond with high atom economy. A proposed mechanism for the reaction is described.

Isolation and structural elucidation of cytotoxic compounds from the root bark of Diospyros quercina (Baill.) endemic to Madagascar

Objective:To isolate and characterize the cytotoxic compounds from Diospyros quercina(Baill.)G.E.Schatz&Lowry(Ebenaceae).Methods:An ethno-botanical survey was conducted in the south of Madagascar from July to August 2010.Bio-guided fractionation assay was carried out on the root bark of Diospyros quercina,using cytotoxicity bioassay on murine P388 leukemia cell lines as model.The structures of the cytotoxic compounds were elucidated by 1D and 2D NMR spectroscopy and mass spectrometry.Results:Biological experiments resulted in the isolation of three bioactive pure compounds(named TR-21,TR-22,and TR-23)which exhibited very good in vitro cytotoxic activities with the IC_(50)values of(0.017 5±0.0060)μg/mL,(0.089±0.005)μg/mL and(1.027±0.070)μg/mL respectively.Thus,they support the claims of traditional healers and suggest the possible correlation between the chemical composition of this plant and its wide use in Malagasy folk medicine to treat cancer.Conclusions:The ability of isolated compounds in this study to inhibit cell growth may represent a rational explanation for the use of Diospyros quercina root bark in treating cancer by Malagasy traditional healers.Further studies are,therefore,necessary to evaluate the in vivo antineoplastic activity of these cytotoxic compounds as effective anticancer drugs.

Crystal Structure and Aggregation-induced Emission of an Azine Derivative

An AIE-active azine derivative(1)was facilely synthesized by aldehyde-amine condensation of 2-hydroxy-1-naphthaldehyde and 3-methyl-2-benzothiazolinone hydrazone.It crystallizes in the monoclinic space group P21/n with a=8.2176(5),b=13.1733(7),c=14.5731(8)Å,β=90.521(5)º,and Z=4.Compound 1 exhibits aggregation-induced emission characteristics.In dilute solution,it is non-emissive,while strong emission was observed in the aqueous medium as a result of the molecular aggregation in poor solvent.The powder and crystals of 1 also exhibit strong fluorescence.In its crystal lattice,the molecules stack in a face-to-face style,but there is noπ-πstacking interaction due to the long distance between adjacent molecules.It is the loose stacking mode that blocks the nonradiative decay channel resulting in its AIE effect.