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 Crystal Structure of a Novel Fe(Ⅲ) Schiff Base Complex

A novel Fe(Ⅲ) Schiff base complex,FeⅢ(HL) {H4L = 1,1,1,1-tetrakis[(salicylaldimino)methyl]methane},has been prepared and characterized by elemental analyses,IR spectrum,and single-crystal X-ray diffraction analysis.The crystal belongs to the monoclinic system,space group P21/n with a = 12.569(3),b = 12.955(3),c = 17.647(4) ,β = 91.896(9)°,V = 2871.9(1) 3,Z = 4,Dc = 1.391 g/cm3,F(000) = 1252.0,Mr = 601.45,R = 0.0383 and wR = 0.1025.The structural analysis reveals that the Fe(Ⅲ) ions are six-coordinated by imine nitrogen atoms and phenolic oxygen atoms form three pendant arms of Schiff base ligands,and one of the salicylaldimine chelating units remains uncoordinated.Discrete complex molecules were further assembled into 1D supramolecular aggregations by C-H…O hydrogen bonding and C-H…π interactions.     

Synthesis,spectral studies,thermal behavior,and antibacterial activity of Ni(Ⅱ),Cu(Ⅱ),and Zn(Ⅱ) complexes with an ONO tridentate Schiff base

Three new transition metal complexes have been synthesized with a Schiff base,3-(2-hydroxy-5-chlorophenylimino)-l,3- diphenylpropen-1-one.In all complexes Schiff base is completely deprotonated and coordinated to metal as tridentate ligand via phenolic and enolic oxygens and imine nitrogen.Thermal decomposition of the complexes has been studied by thermogravimetry. The in vitro antibacterial activity of Schiff bases and their complexes has been evaluated and compared with the standard drugs.     

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.     

A New Method of Synthesis of Azo Schiff Base Ligands with Azo and Azomethine Donors: Synthesis of N-4-Methoxy- benzylidene-2-(3-hydroxyphenylazo)-5-hydroxy- aniline and Its Nickel(II) Complex

A new method for the synthesis of azo Schiff an base ligand in which the azo and azomethine groups are coordination sites was developed through a Schiff base precursor. The precursor, N-4-methoxybenzylidene-3-hydroxy- phenylamine (SB) derived from 3-aminophenol was regioselectively coupled with a diazonium ion para to the hydroxyl group of the amine component of the Schiff base. The para selectivity was controlled by the directing effect of the hydroxyl group. The ligand and its nickel(II) complex were characterized by elemental analyses, IR and UV-Vis spectroscopy. The analytical and spectral data supported the mononuclear formulation of the complex with metal to ligand ratio (M∶L＝1∶2) and suggested a square planar geometry for the complex.     

Synthesis and catalytic activity of novel heteronuclear Ln(Ⅲ)-Cu(Ⅱ) complexes with noncyclic polyether-amino acid Schiff base

A series of novel heteronuclear Ln(Ⅲ)-Cu(Ⅱ) complexes with noncyclic polyether-amino acid Schiff base were synthesized. The general formula is [LnCu_2(H_2TALY)(NO_3)_5](NO_3)_2' nH_2O(Ln=La, Nd, Sm, Gd, n= 4; Ln=Yb, Y, n=3), where H_2TALY = tetraglycol aldehyde bis-lysine Schiff base. It is the first time to report the synthetic method for this new Cu(Ⅱ) complexes and Ln(Ⅲ)-Cu(Ⅱ) heteronuclear complexes. The complexes were characterized by elemental analysis, IR spectra, TG-DTA, magnetic susceptibility, and especially by a 500 MHz NMR spectrometer for 2D-COSY NMR. Coordination mechanism and structures of complexes have been suggested as well. Of particular interest is the potential that the novel complexes obtained may be used as a catalyst, which prompted us to investigate them. It shows 100% conversion with the viscosity-average molecular weight 120 000 for the polymerization of methyl methacrylate (MMA) without addition of any cocatalyst. Furthermore, the complexes with such aliphatic Schiff bas     

Synthesis of bis(indolyl) methanes catalyzed by Schiff base-Cu(Ⅱ) complex

Schiff base-Cu(Ⅱ) complex is found to be an effective catalyst for the condensation reaction of indole with aldehydes using ethanol as the solvent.The characterization of the catalysts was carried out using XRD and FT-IR.     

Synthesis and antitumor activity of derivatives of 23-hydroxybetulinic acid

A series of natural product 23-hydroxybetulinic acid derivatives were prepared.In the preparation of mono-O-benzoyl ester derivative,it was observed that benzoyl group migrated from 3-O-to 23-O-position during the detritylation.     

Synthesis and Crystal Structure of a New 2D O-bridged Copper(Ⅱ) Coordination Polymer Constructed from Sulfonate-derived Schiff Base

A new chain-like coordination polymer, namely, [CuL ]n(1, Na2 L = 2-[(2-hydroxybenzylidene)-amino]-benzenesulfonic acid sodium salt), has been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy and elemental analysis. Complex 1 crystallizes in monoclinic system, space group P21/c with a = 9.2296(16), b = 10.4754(18), c = 12.200(2) A, β =102.392(2)°, V = 1152.0(3) A3, C13H9 CuN O4S, Mr = 338.83, Dc = 1.953 g/cm3, Z = 4, F(000) = 684,μ = 2.089 mm-1, the final R = 0.0376 and w R = 0.0956. X-ray diffraction analyses indicate that 1displays a square-pyramidal metal center with NO4 donor sets. The sulfonate-derived Schiff base serves as a common N,O,O′-tridentate and a unique O-bridged ligand connecting the metals.Dinuclear copper complexes serve as secondary building blocks(SBUs) to construct an unusual2 D coordination network. In the crystal, the components form a stable 3D supramolecular architecture by C–H···O interactions and π-stacking.     

Synthesis, Crystal Structure and Electrochemistry Properties of a (N,N'-Ethylene-bis(salicylaldiminato)) Nickel(Ⅱ) Complex, [Ni2(salen)2]·NCS-NH4

A new Ni(Ⅱ) complex [Ni2(salen)2]·(NCS)·NH4 (salen = N,N'-bis(salicylidenea-mino)ethanato) has been prepared and structurally characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a = 16.8725(13), b = 19.0046(15), c = 20.0583(16) (A), Z = 8, V = 6431.8(9) (A)3, C33H32N6Ni2O4S1, Mr= 726.13, Dc = 1.500 g/cm3, F(000) = 3008, μ = 1.284 mm-1, the final R = 0.0394 and wR = 0.0767 for 4449 observed reflections with Ⅰ＞2σ(Ⅰ). The complex involves a N,N'-ethylene-bis(salicylaldiminato) Schiff base, an isothiocyanato anion and an ammonium cation. The nickle(Ⅱ) ion adopts a distorted square coordination geometry with N2O2 set of Schiff base ligand. The complexes are linked into a dimmer via intermolecular hydrogen bonds and the [Ni(salen)] moieties are connected together to form a 2-D layer structure by intermolecular N-H…O hydrogen bonds and π-π stacking. Cyclic-voltammetry method was used to characterize electrochemically the complex.     

Synthesis and antitumor activity of heterocyclic acid ester derivatives of 20S-camptothecins

A series of heterocyclic acid esters of camptothecins as new compounds had been synthesized by acylation method,their in vitro and in vivo antitumor activities were evaluated.The cytotoxic results showed that 6 possessed the best efficacy on six human cancer cell lines in the six classes of CPTs' derivatives.In vivo testing results indicated that 9 had better antitumor activity against mouse liver carcinoma H_(22) than topotecan.     

New Synthesis of (±)-Cherylline and Mono- and Dimethyl Ethers

The synthesis of 4-aryl-1,2,3,4-tetrahydroisoquinolines is achieved via the ether rearrangement methodology. Subsequent reactions yielded cherylline and ether derivatives of amaryllidaceac alkaloids.     

Synthesis of La(Ⅲ), Y(Ⅲ) complexes with polyglycol aldehyde-amino acid Schiff base and their high resolution solid state ~(13)C NMR spectra

La(Ⅲ), Y(Ⅲ) complexes with diglycol aldehyde bis-arginine (H_2DAAR) and tetraglycol aldehyde bislysine (H_2TALY) Schiff bases were synthesized. They were characterized and formulated as La(H_2DAAR) (NO_3)_3·6H_2O and Y (H_2TALY)(NO_3)_3·5H_2O separately by elemental analyses. The obtained complexes were investigated in detail by high resolution solid state (HRSS) ~(13)C NMR using cross polarization, magic angle spinning (CPMAS), and total suppression of sidebands (TOSS)techniques. The results are supported by the liquid state 2D-~1H-~(13)C COSY NMR spectra. Some new information about the splitting peaks of ~(13)C for—CH=N—group and alkene carbon bands, etc. in HRSS ~(13)C NMR spectra are given.     

Synthesis and evaluation of new β-carboline-3-(4-benzylidene)-4H-oxazol-5-one derivatives as antitumor agents

In the present work, we report the synthesis and in vitro anticancer and antimicrobial activity evaluation of a new series of 1-substituted-β-carboline derivatives bearing a 4-benzylidene-4H-oxazol-5-one unity at C-3. The compound 2-[1-(4-methoxyphenyl)-9H-β-carbolin-3-yl]-4-(benzylidene)-4H-oxazol-5-one (11) was the most active derivative, exhibiting a potent cytotoxic activity against glioma (U251), prostate (PC-3) and ovarian (OVCAR-03) cancer cell lines with IC50 values of 0.48, 1.50 and 1.07 μM, respectively. An in silico study of the ADME properties of the novel synthesized β-carboline derivatives was also performed.     

Synthesis and Structural Features of 3,5-Dihydroxy N′-(3-nitrobenzylidene) Benzohydrazide and Its Effect on the Intestinal Smooth Muscle

A new compound,3,5-dihydroxy-N-(3-nitrobenzylidene)benzohydrazide (DNBB) methanol solvate,was synthesized and characterized by single-crystal X-ray diffraction.DNBB crystallizes in a monoclinic system,space group P2 1/c with a=8.387(4),b=23.237(10),c=9.133(3),β=122.10(3)o,Z=4,V=1507.8(12) 3,D c=1.464 g/cm 3,F(000)=696.0,μ=0.116 mm-1,the final R=0.0480 and wR=0.1294.DNBB exhibited low toxicity on Caco-2 cell culture and produced significant inhibitory effect on the contraction of rat jejunal longitudinal smooth muscle (JLSM).The mechanism of DNBB on JLSM was correlated to the stimulation of α and β adrenergic receptors since α receptor antagonist phentolamine and β receptor antagonist propranolol abolished the inhibitory effects of DNBB on the contraction of JLSM,respectively.     

Synthesis, Crystal structure and Antioxidant of 3,5-Dihydroxy-N＇-（5-bro-2-hydroxybenzylidene） benzohydrazide Hydrate

A new compound, 3,5-dihydroxy-N′-(5-bro-2-hydroxybenzylidene)benzohydrazide hydrate, has been synthesized and characterized by single-crystal X-ray diffraction. The title compound crystallizes in a monoclinic system, space group P21/c with a = 14.267(6), b = 8.079(4), c = 13.157(6) , β = 108.114(4), Z = 4, V = 1441.4(11) 3, Dc = 1.701 g/cm3, F(000) = 744.0, μ = 2.878 and S = 1.021. The final R = 0.0457 and wR = 0.1149 for 3500 observed reflections with I > 2 (I). The ability with which the compound scavenges free radicals of ABTS and DPPH, IC50, is 34.13 and 101.6 μM, respectively.     

Crystal Structure of Binuclear Manganese(Ⅲ) Complex with Schiff-base Ligand,〔Mn_2(C_(22)H_(22)N_2O_2)_2(EtOH)_2 (bipy)〕(ClO_4)_2

1INTRODUCTIONThecoordinationchemistryofmanganeseinthe 2, 3and 4oxidationstatesisreceivingconsiderableattentionduetothebio1ogicalimportanceoftheseions(1i.Anattractivesystemformode1ingthestructureandreactivityofsomemanganoenzymesisbinuclearMn(M)complexescontainingpolydentateSchiffbaseligands.Bothphotochemicalwateroxidationtogeneratedioxygen"'andacid-pro-motedhydrogenperoxideproductiont3ihavebeenreportedforsuchdimer.Wereportherethestructureofthetitlecomplex.2EXPERIMENTAL2.lSynthesisof…     

Synthesis and herbicidal activity evaluation of novel β-carboline derivatives

Based on the original structure of harmine, several novel 1,2,3,4-tetrahydro-β-carboline, β-carboline and 1-substituted-β-carboline derivatives bearing a substituted carbohydrazide group at C-3 were designed and synthesized to investigate the structure-activity relationship of their analogues. All of the compounds were characterized by infrared (IR), proton and carbon nuclear magnetic resonance (1H-NMR, 13C-NMR), and mass spectroscopy (MS). The bioassay tests showed that N'-benzylidene-1-phenyl-β-carboline-3-carbohydrazide (C(25)H(18)N(4)O, m.w. 390.4) (c2) and N'-(4-trifluoromethyl-benzylidene)-1-phenyl-β-carboline-3-carbohydrazide (C(26)H(17)N(4)OF(3), m.w. 458) (d2) exhibited good inhibitory activity against dicotyledonous and monocotyledonous weeds, with EC(50) values of 4.83 μM and 14.25 μM, respectively.     

Synthesis of 6,8-dichloroquinolones utilizing new method and evaluation of their antibacterial activities

Several 6,8-dichloroquinolone analogues were synthesized from the key intermediate compound of 2,3,4,5-tetrachlorobenzene carbonyl chloride,which was obtained from the starting material of tetrachlorophthalic anhydride.Their in vitro antibacterial activities were evaluated.As a result of this study,compounds 21c and 21d were twofold more potent than ciprofloxacin (CPFX) and norfloxacin (NFLX) against Staphylococcus aureus-9,and with the same potent as CPFX and NFLX while against Escherichia coli-2,but were less potent than references in against Pseudomonas aeruginosa-17.     

Synthesis and antitumor evaluation of C3/C3 fluoroquinolone dimers(Ⅰ):Tethered with a fused heterocyclic s-triazolo[2,1-b][1,3,4]thiadiazole

<正>Five C3/C3 fluoroquinolone dimers tethered with a fused heterocyclic ring of s-triazolo[2,1-b][1,3,4]thiadiazole derived from antibacterial quinoiones were synthesized and characterized,and their in vitro antitumor activity against L1210,CHO cell lines was evaluated via the respective IC_(50) values.