The introduction of antibacterial drug pipemidic acid into the POM field: Syntheses, characterization and antitumor activity

Two new compounds based on polyoxometalates (POMs) and the quinolone antibacterial drug pipemidic acid (HPPA), {[Ni(PPA)₂]H₄[SiW₁₂O₄₀]}·HPPA·3H₂O (1), and {[Zn(PPA)₂]₂H₄[SiW₁₂O₄₀]}·3H₂O (2), have been synthesized under hydrothermal conditions and structurally characterized by routine technique. Single-crystal X-Ray diffraction analysis shows that compound 1 is constructed by Keggin clusters grafted by binuclear nickel clusters, isolated HPPA and water molecules, while compound 2 consists of Keggin clusters grafted by binuclear zinc clusters and water molecules. Due to the selection of different transition metal (TM) ions, compounds 1 and 2 exhibit different structures and antitumor activities. Compound 1 possesses 0D structure and shows no antitumor activities. However, compound 2 possesses 1D structure and exhibits higher antitumor activities than its parent compound. The results show that introduction of different TM-PPA moieties onto the polyoxoanion surface can affect not only the final structures but also their antitumor activities.     

Assembly of an unprecedented metal-pipemidic acid complex modifying octamolybdates containing like DNA spiral chain

By introducing antibacterial drugs pipemidic acid into the octamolybdates, an unprecedented compound, [Zn(PPA)₂(H₂O)]₂·[Mo₈O₂₆]·3.5H₂O (1) (PPA = pipemidic acid), has been synthesized and characterized by routine physical methods. Single-crystal X-ray diffraction analysis reveals that the title compound contains the right- and left-double-stranded like DNA helical chains, which are assembled together via sharing the β-Mo₈ clusters forming the fascinating double intertwined inverted helices. The result of the antitumor activities shows that the title compound possesses higher antitumor activity and selectivity.     

Determination of pipemidic acid based on flow-injection chemiluminescence due to energy transfer from peroxynitrous acid synthesized on-line

A flow-injection chemiluminescence (CL) method for the determination of pipemidic acid is described. It is based on energy transfer from excited state peroxynitrous acid to pipemidic acid, in which the excited state peroxynitrous acid is synthesized on-line by the mixing of acid hydrogen peroxide with nitrite in a flow system and the CL is from two excited states of pipemidic acid. The proposed method allows the measurement of pipemidic acid over the range of 2.0×10^–7–2.0×10^–5 mol l^–1 . The detection limit is 6.3×10^–8 mol l^–1, and the relative standard deviation for 2.0×10^–6 mol l^–1 pipemidic acid (n= 9) is 0.9%. This method was evaluated by the analysis of pipemidic acid in pharmaceutical preparations.     

碳糊电极阳极吸附伏安法测定吡哌酸

吡哌酸（Pipmidic acid,简称PPA）,是吡喹酮类合成抗菌药物,目前的主要分析方法有分光光度法、交流示波滴定法、高效液相色谱法、阴极吸附溶出伏安法、单扫描示波极谱法、微分脉冲极谱法和循环伏安法。本文提出了在CPE上阳极吸附伏安法测定PPA的方法,并探讨了PPA在CPE上的伏安性质和电极反应机理。该法准确、简便、灵敏度高,应用于模拟尿样中痕量PPA的测定,得到满意的结果。     

New 3D two-fold interpenetrating polyoxometallate compounds built up of dititanium-substituted Keggin polyoxotungstates and transition metals

The unprecedented transition metals (TMs) bridged 1,4-dititanium(IV)-substituted Keggin-type polyoxotungstates K₃{M(H₂O)₄}₂PTi₂W₁₀O₄₀ · 8H₂O (M = Co^II (1), Ni^II (2), Mn^II (3)) have been synthesized and characterized by FT-IR, UV, element analyses, X-ray powder diffraction analyses,¹⁸³W NMR spectroscopy, cyclic voltammetry, TG and X-ray single-crystal analyses. It is the first time that Ti-containing polyoxotungstate [α-PTi₂W₁₀O₄₀]⁷⁻ fragments are linked by TMs based on novel Ti–O–M bonds, and it is the first example of a three-dimensional (3D) two-fold interpenetrating pure inorganic framework structure based on Keggin polyoxometallates and TMs.     

Chemiluminescence flow-through sensor for pipemidic acid using solid sodium bismuthate as an oxidant

A novel chemiluminscence (CL) flow-through sensor for pipemidic acid is described. It was based on the sensitizing effect of pipemidic acid on the CL oxidation of sulfite by sodium bismuthate in H₂SO₄ media. The solid-phase sodium bismuthate was mechanicially immobilized on the sponge rubber inside of the CL flow cell as CL oxidant. The calibration graph is linear in the range 0.1-10 μg/ml with a detection limit of 6.2×10⁻⁸ g/ml (3σ). A complete analysis could be performed in 1 min with a relative standard deviation (R.S.D.) of 2.5% for 2 μg/ml pipemidic acid (n=8). This method has been successfully applied to determine pipemidic acid in pharmaceutical preparation.     

pH-controlled assembly of two new supramolecular hybrid compounds based on Keggin polyoxotungstates

Two supramolecular compounds based on Keggin polyoxotungstates, (4,4′-H₂bpy){[Cu(4,4′-bpy)]₂[SiW₁₂O₄₀]} (1) and (4,4′-H₂bpy)₂[SiW₁₂O₄₀]·2H₂O (2) have been synthesized and characterized by elemental analyses, IR, UV, XPS spectra, TG analyses, and single crystal X-ray diffraction analyses. Compound 1 exhibits an infinite 1-D ladder like structure, which is further interconnected into a 3-D supramolecular framework via hydrogen bonding interactions. Compound 2 contains 4,4′-bipyridine (4,4′-bpy), pseudo-Keggin polyoxoanions [SiW₁₂O₄₀]^4?, and water molecules. Polyoxoanions together with water molecules in 2 construct a 3-D inorganic supramolecular network through O···O and O···Ow(1) interactions. The electrochemical behaviors and photocatalytic properties of 1 and 2 have been investigated.     

Study on ligation of copper complexes of the quinolone antibacterial drugs and octamolybdates POMs

By introducing different quinolone antibacterial drugs into the octamolybdates POMs, four new compounds, [Cu^II(L¹)₂(H₂O)₂]H₂[β-Mo₈O₂₆]·4H₂O (1), [Cu^II₂(L²)₄][δ-Mo₈O₂₆]·4H₂O (2), [Cu^II₂(L³)₂(H₂O)₂][β-Mo₈O₂₆] (3), [Cu^II₂(L⁴)₂(H₂O)₄][β-Mo₈O₂₆]·2H₂O (4) (where L¹ = Enrofloxacin; L² = Pipemidic Acid; L³ = Norfloxacin; L⁴ = Enoxacin), have been synthesized and characterized by routine physical methods and single crystal X-ray diffraction. In compound 1, isolated Cu-Enrofloxacin coordination subunits array the both sides of β-Mo₈O₂₆, forming 3D supramolecular structure via noncovalent interactions. And the Cu-Pipemidic Acid subunits covalently link δ-Mo₈O₂₆ to form 3D supramolecular structures via short interactions in 2. In 3, the Cu-Norfloxacin motif exhibits 1D chain structure, and the tetra-dentate β-[Mo₈O₂₆]⁴⁻ clusters interact with neighboring chains to construct a 2D sheet. Similar to that of 3, the Cu-Enoxacin subunit in 4 exhibits 1D chain structure, and the bi-dentate β-[Mo₈O₂₆]⁴⁻ clusters interact with neighboring chains to construct a 2D sheet. Due to the introduction of different drug molecules, the octamolybdates POMs exhibit different isomers and structures, which bring different properties. The antitumor activities of compounds 1-4 in vitro were studied by MTT experiments, and the results show that introduction of different drug molecules onto the polyoxoanion surface can affect their antitumor activities.     

两种结构钼磷酸的催化氧化行为

考察了Dawson与Keggin结构钼磷酸的催化氧化行为,并与结构特性进行了关联,结果发现,Dawson结构的杂多酸对氧化脱氢及插入氧反应均有更高的活性。     

Heteropoly acids of the Keggin type with N-substituted β-amminoethylphosphonic acids as coordinate center

Organophosphorus-heteropolytungstic acids of 1: 12 of P/W ratio, with N-substituted 2-amminoethylphosphonic acids R₂R’N⁺CH₂CH₂PO₃H⁻ (R = R’ = H; R′ = Me, R’ = H; R = R’ = Me; R = H, R ’ = Me₂CH; R′ = H, R’’ = CH₃(CH₂)₂CH₂) as coordinate centers were prepared, and characterized by means of elemental analysis, IR, UV spectroscopy, TG and DSC thermal analysis. The results indicate that these organophosphorous-HPAs possess Keggin type structure, and their stoichiometric formulation is R₂R’N⁺CH₂CH₂PO₃H⁻. W₁₂O₃₆.nH₂O. The organic side chain with the ammino-group R₂R’N⁺CH₂CH₂ ⁻ and the phosphono-group-PO₃H^- participate altogether in the formation of the primary structure of the heteropoly anion. In other words, the entirety of each compound R₂R ’N⁺CH₂CH₂PO₃H⁻ is as the core or coordinate center of the heteropoly anions. The number of crystal water in the HPA was affected obviously by the N-substituents of the organophosphonic acids.     

Synthesis and Characterization of Charge-transfer Complexes of Aminoethylphosphono-and Dimethylaminoethylphosphono-heteropolytungstic Acids of Keggin Type Structure

The charge-transfer complexes of heteropoly acids (HPA) possess special properties of light, electricity and magnetism, and have attracted widespread attention by researchers in the fields of functional materials and catalysis1. But until now, the electron acceptors of the charge-transfer complexes are the heteropolyanions with inorganic phosphoric acid, silicic acid etc. as the coordinate center2,3, the charge-transfer complexes of Keggin type structure of the organophosphonoheteropolytungs…     

Synthesis and antitumor activities of structure-related small molecular compounds of gambogic acid

Through simplifying the complicated skeleton of the natural product gambogic acid, two series derivatives of chromone and xanthone were synthesized and examined for their antitumor activities against several cancer cells in vitro by MTT method. The results showed that appropriate introduction of prenyl group to the small molecular compounds could elevate their antitumor activities. The structure-activities relationship of synthesized compounds certified that the bridgecore in gambogic acid was very important for keeping its antitumor activities.     

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.     

含有甘氨酸的Keggin型杂多蓝的合成和抗艾滋病毒(HIV-1)活性研究

采用控制电位电解方法,制得8种含有甘氨酸的Keggin型钨系杂多蓝配合物．通过IR,UV-vis,^H NMR,^183W NMR,XPS等方法对其结构进行了表征．这类化合物具有较强的抗碱解能力．在MT4细胞内,对合成化合物进行了抗艾滋病毒(HIV-1)活性及毒性测定,发现该类化合物的抗艾滋病毒(HIV-1)活性随着还原电子数增多有增强的趋势,其中含有甘氨酸的十二钨锗酸4电子杂多蓝(代号HPBG-110)有较高的治疗指数(TI)．初步的试验结果表明：该类化合物的抗HIV-1活性作用是在病毒感染早期,通过抑制艾滋病毒(HIV-1)在靶细胞表面吸附而发挥作用的．     

过氧钛钨硅杂多配合物的合成、表征及催化活性

合成了过氧钛钨硅杂多酸盐α-M6-mHm[SiW11(TiO2)O39].xH2O和α-M10-mHm[SiW9(TiO2)3O37].xH2O(M=K, TBA), 用IR, UV吸收光谱,极谱-循环伏安, 183W NMR, XPS和XRD等测试方法对其性质、结构进行研究。结果表明, 它们都是具有Keggin结构的过氧杂多配合物,TiO2基的引入将其极谱半波电位提高至-0.3V以上, 它们对顺丁烯二酸的H2O2环氧化反应具有显著高的催化活性。     

Synthesis,antibacterial activity and docking studies of substituted quinolone thiosemicarbazones

Abstract

Fifteen 2-quinolone thiosemicarbazone derivatives of which eleven were new, were synthesized at room temperature. The key intermediate was the quinolone carbaldehyde, from which thiosemicarbazones were formed by the reaction of thiosemicarbazides with the aldehyde moiety. The structures of the synthesized compounds were elucidated by 1D and 2D-NMR spectroscopy and mass spectrometry. The synthesized compounds showed antibacterial activity with MBCs in the range 0.80 to 36.49?mM against Staphylococcus aureus, Staphylococcus aureus Rosenbach (MRSA), Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli and Salmonella typhimurium. The best activity was seen when a larger halogen such as chlorine and bromine were substituted at C-6 on the quinolone scaffold and when a planar phenyl group was present on the thiosemicarbazone moiety. Activity was reduced when a smaller fluorine atom was present at C-6 or when a methyl group was attached to the thiosemicarbazone. This group of compounds showed a high negative binding affinity, which suggested promising antimcrobial activity. The 6-chloro derivative with a phenyl group on the thiosemicarbazone had the greatest negative binding affinity.     

硅烷偶联剂改性SBA-15固载Keggin型杂多酸催化合成柠檬酸三丁酯

以3-(甲基丙烯酰氧)丙基三甲氧基硅烷(MEMO)表面改性的介孔分子筛SBA-15为载体,制备了一系列介孔分子筛/硅烷偶联剂@杂多酸复合催化剂SBA-15/MEMO@HnXW12O40(X=P⁵+,Si⁴⁺,B³⁺;n=3,4,5),并利用FTIR、P-XRD、TEM、N2吸附-脱附对其结构进行表征。以SBA-15/MEMO@HnXW12O40(X=P⁵⁺,Si⁴⁺,B³⁺;n=3,4,5)为负载型杂多酸催化剂对柠檬酸三丁酯的催化合成进行研究,分别考察了酸醇摩尔比、催化剂用量、反应温度、反应时间对催化合成柠檬酸三丁酯酯化率的影响,并获得合成柠檬酸三丁酯的最佳工艺条件。结果表明:当负载型硅钨酸催化剂的负载量为50%、催化剂用量为3.8%、酸醇摩尔比为1∶4、反应温度为140℃、反应时间为6 h、环己烷用量为5 mL时酯化率可达97.56%,重复使用7次后酯化率仍可达62.67%。     

CdS纳米棒/酞菁氧钛复合光导体的光电导性能

采用以溶剂热方法合成的CdS纳米棒与酞菁氧钛复合制备的复合光导体,在570nm光照下其光电导性能明显提高,将质量分数为5%的CdS纳米棒与TiOPc复合使光敏性能提高32%.电子结构的数据和表面光电压谱分析结果表明,复合体系中存在从CdS纳米棒到TiOPc的光致空穴转移,TiOPc因被CdS纳米棒敏化而表现出高的光电导性能.