Synthesis,structural characterization and antibacterial activity of diorganotin(Ⅳ) complexes with ONO tridentate Schiff bases containing pyridine ring

Five organotin（IV） complexes,were obtained by reaction of SnR₂Cl₂（R = Ph,Me,Bu） with ONO donor Schiff bases.The synthesized complexes have been investigated by elemental analysis and IR,¹H NMR,and ¹¹⁹Sn NMR spectroscopy.These data show that the Schiff base acts as a tridentate dianionic ligand and coordinates via the imine nitrogen and two oxygen atoms.The Xray crystallography of complex 4 shows a dimeric structure for this molecule.The in vitro antibacterial activities of the Schiff bases and their complexes have been evaluated against Gram-positive（Bacillus subtilis and Staphylococcus aureus） and Gram-negative （Escherichia coli and Pseudomonas aeruginosa） bacteria and compared with the standard antibacterial drugs.     

Design,synthesis and biological evaluation of new rhodacyanine analogues as potential antitumor agents

In an attempt to develop potent antitumor agents,new rhodacyanine analogues containing the pyridinium ring（5a-5h）,the isoquinolinium ring（6a-6c） and the quinolinium ring（7a-7e） linked to the rhodanine ring via N-N covalent bond were designed, synthesized and evaluated for antitumor activity against human lung cancer cell line（H460） by MTT assay in vitro.Most of the tested compounds showed enhanced antitumor activity with IC₅₀ values ranging from 0.006 to 9.2 u,mol/L as compared to the lead compound MKT-077.Among them,the most promising compound 7d(IC₅₀ = 0.006μmol/L) was 216.7 times more active than MKT-077(IC₅₀ = 1.3μmol/L).The preliminary structure-activity relationship of the target compounds was discussed.     

Synthesis and biological evaluation of glyco-GA compounds as anticancer agents

A series of novel glyco-gambogic acid（GA） compounds were synthesized and evaluated for their in vitro anti-proliferative activity against human hepatocellular carcinoma（HCC） cells.All compounds showed much better aqueous solubility（0.92- 1.89 mg/mL） than GA（0.013 mg/mL）,and displayed potent inhibition on HCC cells(IC₅₀:0.21-12.23μmol/L) and little affects on non-tumor liver cells(IC₅₀:42.56-86.43μmol/L),suggesting that glyco-GA compounds selectively inhibit HCC proliferation,and may be promising candidates for further intensive study.     

Synthesis,spectroscopic characterization and in vitro antitumor activities of some novel mononuclear Ru(Ⅱ) complexes

The synthesis and spectroscopic characterization of ruthenium complexes（R-l to R-8） of the type[Ru（A）₂（B）],(where A = 1,10-phenanthroline/2,2′-bipyridine and B = 3.4.5-tri-OCH₃DPC,4-CH₃-DPC,4-N-（CH₃）₂-DPC,4-NO₂-DPC arc described. These ligands form bidentate octahedral ruthenium complexes.The title complexes were subjected to in vitro cytotoxic activity measurements against the human cancer T-lymphocyte cell lines MTT assay.In vitro evaluation of these ruthenium complexes revealed cytotoxic activity from 0.24 to 1.4μg/mL against CEM,0.44 to 1.9μg/mL against Molt4/C8.0.28 to 1.5μg/mL against L1210,0.24 to 0.98μg/mL against HL60,and 0.25 to 1.2μg/mL against BEL7402,depending the nature of the compound.     

Synthesis and in vitro antitumor activity of novel diaryl urea derivatives

A series of novel diaryl ureas containing 4-[（2-amino-6-trifluromethyl）pyrimidine-4-yl]piperazine-l-yl group were synthesized and evaluated for their cytotoxic activities in a panel of human cancer cell lines. Compared with the reference drug Sorafenib,some compounds showed more potent and a broader spectrum of anti-cancer activities.Among them,compound 2p demonstrated significant inhibitory activities against MDA-MB-231,HT-29 and MCF-7 cell lines with IC₅₀ values of 0.016,0.63,0.001μmol/L, respectively.     

Synthesis and antitumor evaluation of fluoroquinolone C3 fused heterocycles(Ⅱ):From triazolothiadiazines to pyrazolotriazoles

To further expand an effective modified route for the shift from an antibacterial fluoroquinolone（FQ） to an antitumor FQ,two series of title compounds based on an isostere of the FQ C3 carboxylic group with two fused heterocyclic rings,[1,2,4]triazolo[3,4- b][1,3,4]thiadiazine and pyrazolo[5,1-c][1,2,4]triazole,respectively,were designed and synthesized starting from the current antibacterial FQs,and their in vitro antitumor activity against L1210,CHO cell lines were evaluated via their respective IC₅₀ values.     

Synthesis and in vitro cytotoxic evaluation of 2-hydrazinylpyrido[2,3-b]pyrazin-3(4H)-one derivatives

A series of novel 2-hydrazinylpyrido[2,3-b]pyrazin-3（4H）-one derivatives were synthesized and evaluated for their cytotoxic activities against A549,MDA-MB-231 and HT-29 cell lines in vitro.Pharmacological data indicated that compounds 5b,5c,10a and 10g possessed marked cytotoxicity,especially 10a(with IC₅₀ values of 0.81,2.56 and 1.63μmol/L against A549,MDA-MB- 23 1 and HT29 cell lines,respectively),which had emerged as a lead compound.     

Synthesis and biological evaluation of hydrazino-containing polyamine skeletons as drug delivery system

A new series of polyamine-toxic cargo conjugates was synthesized with aryl aldehydes conjugating to hydrazino-containing triamine skeletons.The in vitro cytotoxicity of target compounds was evaluated in several cancer cell lines（e.g.,L1210,HeLa and B16） and the cellular entry of these polyamine conjugates via polyamine transporter was investigated on SPD- or DFMO-treated B16 cell line.Of these compounds,6c show significant cytotoxicity on L1210,HeLa and B16 cell lines(IC₅₀ value,3.74μmol/L, 5.66μmol/L and 4.04μmol/L,respectively).The polyamine transporter assay demonstrated the suitability of hydrazino-containing polyamine backbones for application as vectors in drug delivery systems.     

Design, synthesis and in vitro evaluation of mono (2, 2, 2-trifluoroethyl) esters, mono l-amino acid ester prodrugs of acyclic nucleoside phosphonates as anti-HBV agents

A series of novel mono（2,2,2-trifluoroethyl） esters,mono L-amino acid ester prodrugs of acyclic nucleoside phosphonates was synthesized and their in vitro anti-HBVactivity was evaluated in HepG 2 2.2.15 cells.Compound 1d exhibited more potent anti-HBV activity and lower cytotoxicity than those of adefovir dipivoxil and alamifovir（MCC-478） with EC₅₀ and CC₅₀ values of 0.01μmol/L and >8000μmol/L respectively.     

A new isocoumarin from metabolites of the endophytic fungus Alternaria tenuissima (Nees & T. Nees : Fr.) Wiltshire

A new isocoumarin,tenuissimasatin（1）,was isolated from metabolites of the endophytic fungus Alternaria tenuissima（Nees & T.Nees:Fr.） Wiltshire,which was isolated from the bark of Erythrophleum fordii Oliver,together with 11 known compounds（2- 12）.The structure and absolute configuration of 1 was determined by means of NMR and CD analysis.Compound 3 shows selective cytotoxic activity on human colon cancer cell HCT-8(IC₅₀ = 1.78μmol/L) by MTT test in vitro.Other compounds show no such activities(IC₅₀>10μmol/L).     

Design, synthesis, and screen of cathepsin K inhibitors

We synthesized a series of epoxysuccinic acid derivatives and evaluated their in vitro cathepsin K inhibitory activity The screening results show that the potency of compounds 9e,9d,9p,9j and 9k (IC₅₀≤0.005μmol/L) were equal to or greater than that of the lead compound 9a.Less hydrophobic compounds showed weaker potency,which can be explained by the hydrophobic nature of the cathepsin K binding pockets.     

Asymmetric transfer hydrogenation of ketones catalyzed by nickel complex with new PNO-type ligands

The new polydentate mixed-N,P,O chiral ligands have been synthesized by the condensation of bis（o-formylphenyl）- phenylphosphane and R-phenylglycinol in CHCl₃,and fully characterized by IR,NMR and EIMS spectra.These ligands were employed with a simple Ni complex Ni（PPh_s）₂Cl₂ in situ as catalytic systems for asymmetric transfer hydrogenation of ketones,and the corresponding optical alcohols were obtained with up to 84%ee under mild conditions.     

Syntheses and Characterizations of Luminescent Complexes [(BINAP)Pt(C≡CC_6H_4R-p)_2] (R = H, 1; CH_3, 2) (BINAP = 2,2’-Bis(diphenylphosphino)-1,1’-binaphthyl)

1 INTRODUCTION σ-Alkynyl complexes of platinum have attracted considerable attention over the last few years not only for their structural aspect and reactivity[1~5], but also for their role as building blocks for molecular materials with interesting properties[6~10]. These complexes are usually stabilized by neutral ligands, such as tertiary phosphines PR3, diphosphines, and so on. However, as far as we know, similar platinum acetylide compounds containing the chiral diphos- phine liga…     

A new ginsengenin containing an oxacyclopentane-ring isolated from the acid hydrolysate of total ginsenosides

Bioassay-guided fractionation of the acid hydrolysate of total ginsenosides of Panax ginseng C.A.Meyer （Araliaceae） led to the isolation of a novel ginsengenin（1）.The structure of 1 was determined as （20S,22S）-dammar-22,25-epoxy-3β,12β,20-triol by extensive spectroscopy and single-crystal X-ray diffraction analyses.The cytotoxicity of 1 was further tested against SWl 116,HCTl 16,and A549 cells by the MTT method,with IC₅₀ values in the range of 2.96-30.9μmol/L.     

Preparation of a PTE simulacrum based on surface molecular imprinting

Firstly,we synthesized N-methacryloyl-histidine monomer and N-methacryloyl-histidine-Cu²⁺ complex(MAH-Cu²⁺).Then the molecular imprinting polymers（MIP） has been prepared by surface grafting on uniform polystyrene（PS） core using reversible addition-fragmentation transfer polymerization（RAFT） with MAH-Cu²⁺ as the functional monomer,methyl paraoxon as the template to simulate phosphodiesterase（PTE）.Finally,we have investigated the catalytic hydrolytic activities of MIP and non-imprinting polymers（NIP） to the template methyl paraoxon and the template analogue ethyl paraoxon respectively by UV spectrophotometry.The results showed that the catalytic hydrolytic activity of MIP to the template methyl paraoxon was highest and the value of k is 8.67×10^-5 mmol L^-1 min^-1,3.89-fold higher than MIP to the template analogue ethyl paraoxon,2.79-fold higher than NIP to the template methyl paraoxon.The K_M,r_m of MSP are also determined,and K_M = 3.95×10^-4mol/L,r_m = 2.12μmol/ min.The MIP can be reused with only lose 7%of catalytic activity for four cycles.     

Crystal structure and DNA binding studies of a cobalt(Ⅱ) complex containing mixed-ligands of 1,10-phenathroline and glycollic acid

A cobalt（11） complex containing mixed-ligands of 1,10-phenathroline（phen） and glycollic acid（GA）.|Co（GA）₂（phen）| was synthesized and its structure was characterized by X-ray diffraction.The interaction of the complex with DNA was investigated by electronic absorption spectra and electrochemical methods.Electronic absorption spectrum experiments showed that after interaction with DNA.the characteristic absorption peaks of |Co（GA）₂（phen）| underwent hypochromic effect as well as redshift. Also,the binding strength of 3.8×10⁴L/mol was estimated by titration method.Electrochemical assays revealed that the redox peak currents of the complex decreased obviously accompanied by a positive shift of the formal potential after association with DNA.All these results revealed that the synthesized cobalt complex bound with DNA via an intercalation mode.     

Appended corrole manganese complexes:Catalysis and axial-ligand effect

A series of N-base appended corroles and their manganese complexes were synthesized and their binding constants with three different nitrogenous ligands, triethylamine, N-methylimidazole and pyridine, were evaluated by spectroscopy. Kinetic studies indicated that the presence of appended N- donor ligands may cause a significant enhancement of the rate of oxygen atom transfers （OAT） from （oxo）manganese（V） corrole to alkene, and the stronger axial ligand binding has impact on the rate of the oxidation reaction. Turnover frequency （TOF） for the catalytic oxidation of alkenes by appended manganese corroles varies with the following ligand order： acetamido 〈 pyridyl 〈 imidazolyl. The influence of the external axial ligands on the catalytic epoxidation was investigated by using appended acetamido manganese corrole as catalyst, with the results revealing that N-methylimidazole gave the best enhancement on the yields of total oxidation products among the investigated nitrogenous ligands.     

Simultaneous analysis of Cu and Pb as ABEDTA complexes in Rhizoma coptidis by capillary electrophoresis coupled with solid phase extraction

A novel capillary electrophoresis method for simultaneous determination of Cu and Pb has been developed in this paper.Cu（Ⅱ） and Pb（Ⅱ） ions were reacted with ABEDTA to form complex to achieve an ideal sensitivity of heavy metal complexes.The digestion solution of Rhizoma coptidis drug sample was purified by neutral Al₂O₃ column chromatography and the chromatographic behavior of metal-L complexes was investigated.The calibration curve was linear in the range of 5-60μg/mL for Cu²⁺ and 5-25μg/mL for Pb²⁺ with the correlation coefficients 0.9970 and 0.9972 for each（n = 5）.The average recoveries were 86.2%for Pb and 90.1%for Cu,while the relative standard deviations were 5.1%and 3.6%respectively.The method was successfully applied to determine Cu and Pb in R.coptidis drug samples.     

Syntheses and structures of tetranuclear Zn（Ⅱ） complexes with in situ generated macrocyclic Schiff base ligands:Applications in Zn2+ sensing

Three novel Zn（II） complexes,[Zn₄L¹Cl₄]-3H₂O（1）,[Zn₄L²Cl₄]-2DMF（2） and[Zn₄L³Cl₄]H₂O（3）,have been synthesized and structurally characterized.In these complexes,interesting 32-membered dodecadentate macrocyclic ligands were generated in situ by ’2 + 2’ type condensation reactions between a tetraamine and various dialdehydes.All the complexes are isostructurally tetranuclear Zn（Ⅱ） complexes,containing endogenous alkoxo and phenoxo bridges.Applications of the macrocyclic ligands as Zn²⁺ sensors have been investigated.Take H₄L¹ for example,it exhibits a 4-fold fluorescence enhancement upon the addition of 2 equiv.of Zn²⁺ in MeOH.     

SYNTHETIC AND CATALYTIC PROPERTY STUDIES ON SILICA SUPPORTED BIS-(ACETYLACETONATO) COBALT(Ⅱ) COMPLEXES**

This paper reports mainly the preparation of silica supported acetylacetone ligands and their cobalt complexes, the characterization of their chemical structure, and the evaluation of their catalytic activity in the reaction for the preparation of ethers directly from alkanols and benzyl chloride. The results indicate that those silica supported β-diketone cobalt complexes (SACO) not only can simplify the reaction procedure of the ether preparation but also show a much higher catalytic activity in comparison with other homogeneous catalysts. In addition, SACO can be recovered and reused although their catalytic activity descend gradually as a result of the decrease in their cobalt content.