Design, syntheses and biological activity of novel ALS inhibitors (Ⅸ)——CoMFA of sulfonylureas and triazolopyrimidine-2-sulfonamides ALS inhibitors

Quantitative structure-activity relationships for herbicidal activity against rape of sulfonylurea and triazolopyrimidin-2-sulfonamide derivatives were examined three-dimensionally using comparative molecular field analysis (CoMFA). The CoMFA results show that the slopes in steric and electrostatic fields around the molecule were significant for both series in governing the potency variations in herbicidal activity. Based upon the successful superposition between the two series, the herbicidal activity was analyzable with a single equation for the combined set of compounds, which suggested that the two different series of compounds have a common region of the receptor site.     

Properties of meso-tetrakis (4- n -alkanoyloxyphenyl) porphyrin liquid crystal Co and Ni complexes

Six series of meso-tetrakis (4-n-alkanoyloxyphenyl) porphyrin Co and Ni complexes (12 kinds) were reported. Nine of the compounds were found to exhibit liquid crystal properties and display a hexagonal columnar discotic columnar (Col_h) phase. Molecular structure of all synthesized compounds was confirmed by IR, UV, MS, ¹H NIVR, and elemental analysis. These liquid crystalline compounds have been studied by cyclic voltammetry, luminescence, and surface photovoltage spectroscopy. Supported by the National Natural Science Foundation of China (Grant No. 59783001), the Natural Science Foundation of Shandong Province (Grant No. Y2006B41), the Foundation of Shandong Provincial Education Department (Grant No. J06A53), the Natural Science Foundation of Shandong University of Technology (Grant No. 2004KJM15) and Doctor Foundation of Shandong University of Technology     

Discussions about whether radioactive half life can be changed by mechanic motion

In this essay, some discussions and comments about the paper entitled “Can the decay rate of ³²P be changed by mechanic motion?” (Ding et al., Science in China Series B: Chemistry (Chinese version), 2008, 38(11):1035–1037) are given. It was strongly suggested that its experimental methods, data calculations and conclusion should be reconsidered. After the data were recalculated, the new results supported that the chiral mechanic motion could induce the changes of radioactive half life. Supported by the National Natural Science Foundation of China (Grant Nos. 20571085, and 20877099), Fund of the President of Chinese Academy of Sciences (Grant No. 0521021T04), 2005/2006 USA Li’s Foundation Merit Prize Fund, Fund of Graduate University of Chinese Academy of Sciences (Grant No. 065101HM03), and Fund of the Key Laboratory of Nuclear Analysis of the Institute of High Energy Physics of Chinese Academy of Sciences (Grant No. K129)     

Recent developments in intelligent biomedical polymers

Intelligent polymers or stimuli-responsive polymers may exhibit distinct transitions in physical-chemical properties, including conformation, polarity, phase structure and chemical composition in response to changes in environmental stimuli. Due to their unique 'intelligent' characteristics, stimuli-sensitive polymers have found a wide variety of applications in biomedical and nanotechnological fields. This review focuses on the recent developments in biomedical application of intelligent polymer systems, s...     

Sulfonate-based fluorescent probes for imaging hydrogen peroxide in living cells

Based on the mechanism of H₂O₂-mediated hydrolysis of sulfonates, two fluorescein disulfonates compounds (FS-1 and FS-2) were designed and synthesized as the highly selective and sensitive fluorescent probes for imaging H₂O₂ in living cells. The probes were detected with elemental analysis, IR, ¹H NMR and ¹³C NMR. Upon reaction with H₂O₂, the probes exhibit strong fluorescence responses and high selectivity for H₂O₂ over other reactive oxygen species and some biological compounds. Furthermore, the sulfonate-based probes, as novel fluorescent reagents, are cell-permeable and can detect micromolar changes in H₂O₂ concentrations in living cells by using confocal microscopy. Supported by the National Basic Research Program of China (Grant No. 2007CB936000), the National Natural Science Funds for Distinguished Young Scholar (Grant No. 20725518), Major Program of the National Natural Science Foundation of China (Grant No. 90713019), the National Natural Science Foundation of China (Grant No. 20875057), the Natural Science Foundation of Shandong Province, China (Grant No. Y2007B02), and the Science and Technology Development Programs of Shandong Province, China (Grant No. 2008GG30003012)     

Synthesis of Fréchet-type dendritic homotriptycenes

A rapid and efficient synthesis of novel dendrimer homotriptycenes is presented. The dendronized 9,10-dihydroanthracen-9-ols 4, having high electron densities in the benzene rings of the Fréchet-type dendrons, exhibited in the presence of acid a quantitative transannular ring closure to the corresponding dendritic homotriptycenes. The electron-donating Fréchet-type dendrons enabled the intramolecular FC alkylation by a regioselective 1,7-elimination of H2O.     

Design, synthesis and bioactivity of novel ALS inhibitors (V)

By means of the X-ray diffraction method, quantum pharmacology analysis and quantitative structure-activity relationships (QSAR) analysis, the structure-activity relationships of the herbicidal sulfonylureas and fused heterocyclic sulfonamides were systematically studied. The results showed that the structure-activity relationships of these two kinds of herbicides were identical and that the heterocyclic ring and sulfonyl moiety in the molecules were their pharmacophores which likely bind in the same receptor sites of acetolactate synthase (ALS). According to these results, the initial model of these two kinds of herbicides binding with the receptor was put forward. Project supported by the National Natural Science Foundation of China (Grant No.29472056).     

Chiral assembly of achiral pseudoisocyanine with D- and L-phenylalanine

Supramolecular chirality and molecular self-assembly are important and interesting phenomena in living and non-living systems.In this work,supramolecular chirality of achiral pseudoisocyanine(PIC) J-aggregates was successfully induced by D-,L-phenylalanine(Phe) and other amino acids in NaCl solution.The chiral J-aggregates showed a characteristic,induced circular dichroism(ICD) in the visible region of J-band chromophore which depends on the absolute configuration,concentration and side groups of α-amino ac...     

3D-QSAR and docking studies of estrogen compounds based on estrogen receptor β

Close attention has been paid to estrogen compounds because these chemicals may pose a serious threat to the health of humans and wildlife. Estrogen receptor (ER) exists as two subtypes, ERα and ERβ. The difference in amino acids sequence of the binding sites of ERα and ERβ might lead to a result that some synthetic estrogens and naturally occurring steroidal ligands have different relative affinities and binding modes for ERα and ERβ. In this investigation, comparative molecular similarity indices analysis...     

Synthesis and cationic selectivity studies of novel calix[4]arene derivatives containing heteroatom at the lower rim

A series of calixarene derivatives 2―5 containing heteroatom at the lower rim have been synthesized. 1H NMR studies and crystallographic structures demonstrated that the calix[4]arene derivatives adopted cone conformations. Their cationic binding abilities and selectivities towards heavy and tran- sition metal ions have been evaluated by solvent extraction of aqueous metal picrates. The obtained results indicated that the introduction of nitrogen, sulfur, and/or phosphor atoms to the calix[4]arene framework could effectively enhance their binding ability and selectivity for heavy and transition metal ions, such as Pb2 or Ag .     

Host-guest complexes of a water soluble cucurbit[6]uril derivative with some dications of 1,ω-alkyldipyridines: <Superscript>1</Superscript>H NMR and X-ray structures

Interactions between a symmetrical tetramethyl-substituted cucurbit[6]uril (host: TMeQ[6]) and 1,ω-alkylenedipyridine (ω = 2, 4, 6, 8, 10) dicationic guests were investigated using ¹H NMR spectroscopy and single crystal X-ray crystallography. In these inclusion complexes, combined cavity and portal binding in TMeQ[6] were observed, and the length of the bridged alkylene was found to play an important role not only in balancing the overall hydrophilic/hydrophobic interaction between the host and the guest, but also in defining the structure of the resulting inclusion complexes. For the guest 1,2-ethylenedipyridine (Edpy), TMeQ[6] includes a positively charged pyridine ring of Edpy to form an unsymmetrical inclusion complex; for the guest 1,4-butylenedipyridine (Bdpy), TMeQ[6] includes a positively charged pyridine ring of Bdpy, but the different competitive interactions in and between the related inclusion complexes could lead to a fast exchange between the hosts and guests. For the guests with longer bridge chains, such as 1,6-hexamethylenedipyridine (Hdpy) or 1,8-octylenedipyridine (Odpy), a stable pseudorotaxane inclusion complex is formed by combining the hydrophobic cavity and the outer portal dipole-ion interactions. However, for 1,10-decatylenedipyridine (Ddpy), the two TMeQ[6] host molecules include the two end pyridine rings of Ddpy and form a dumbbell inclusion complex. Supported by the National Natural Science Foundation of China (Grant Nos. 20662003 & 20767001), the International Collaborative Project of Guizhou Province (Grant No. 2007400108), the Science Technology Fund of Guizhou Province (Grant No. J-2008-2012) and the Natural Science Youth Foundation of Guizhou University (Grant No. 2007-005)     

New bienzymatic strategy for glucose determination by immobilized-gold nanoparticle-enhanced chemiluminescence

Bienzymatic biosensor for the determination of glucose by flow injection chemiluminescence (CL) detection was proposed. Hybrids of gold nanoparticles (GNPs) and chitosan were chosen as the immobilization matrix of glucose oxidase (GOD) and horseradish peroxidase (HRP) to fabricate the biosensors with silane-pretreated glass microbeads. After the enzyme catalyzing oxidation of glucose in GOD biosensor, the produced H₂O₂ flowed into HRP biosensor to react with luminol. The doped GNPs in chitosan were found to enhance the classical CL reaction of luminol-H₂O₂-HRP. The CL enhancement was investigated in detail by CL and UV-visible spectrum. Under the optimized experimental conditions, glucose could be determined in a linear range from 0.01 to 6.0 mmol/L with a detection limit of 5.0 μmol/L at 3σ. The accuracy of the proposed method was examined by detecting the glucose level in four clinical serum samples from hospital. The proposed method provides a new alternative to determine glucose. Supported by the Natural Science Foundation of Shandong Province (Grant No. Q2007B03), the Doctoral Fund of Qingdao University of Science and Technology (Grant No. 0022141), and the National Natural Science Foundation of China (Grant No. 20775038)     

Bio-rational design of photosystem II inhibitors (VIII)

Molecular modeling of acrylates (acrylamides) with Dl protein ofPisum sativum is presented. Studies show that the binding force mainly includes H-bond interaction, Van der Waals and π-ring stacking interaction. It was found that SER 268 in Dl protein might be an important binding site. It is important for high inhibitory activity of compounds whether an electronegative atom in alkyl of ester linkage could make H-bond interaction with SER 268 in Dl protein. Thus some new acrylates (acrylamides) were designed and synthesized. Bioassay indicated that these new compounds showed expected Hill reaction inhibitory activity. Project supported by the National Natural Science Foundation of China (Grant No. 29702006) and the special fund of Nature Science of Tianjin.     

Synthesis,structure and nonlinear optical properties of two novel two-photon absorption chromophores

Two triphenylamine-based derivatives that can be used as two-photon absorption chromophore,tris{4-[4-(3-trifluoromethyl-3-oxopanoyl)]phenyl}amine (1) and tris{4-[4-(3-phenyl-3-oxopanoyl)] phenyl} amine (2) were successfully synthesized and fully characterized by elemental analysis,IR,1H NMR and MS. The single crystal X-ray diffraction analysis showed that the molecules possess D-(π-A)3 structures. One-and two-photon absorption and fluorescence in various solvents were experimentally investigated. A data rec...     

Facile synthesis of small crystal ZSM-5 zeolite by acid-catalyzed hydrolysis of tetraethylorthosilicate

Small crystal zeolites ZSM-5 with sizes of 150–300 nm were synthesized using the colloidal silicate precursors as the silica source created by the acid-catalyzed hydrolysis of tetraethylorthosilicate with tetrapropylammonium bromide as the structure-directing agent within a short crystallization time of 20–35 h. The precursors and final products were detected by XRD, SEM, ICP and DLS. Supported by the National Natural Science Foundation of China (Grant No. 20776069), Key Natural Science Foundation for Universities of Jiangsu Province (Grant No. 06KJA53012), and Program for Changjiang Scholars and Innovative Research Team in University (Grant No. PCSIRT 0732)     

Electrochemical sensing of ATP with synthetic cyclophane as recognition element

A new electrochemical sensor for ATP with synthetic cyclophane stably attached onto single-walled carbon nanotubes (SWNTs) as the recognition elements is described. UV-vis and cyclic voltammetric results demonstrate that ATP may interact with the synthetic cyclophane recognition elements to form a stable adduct mainly through electrostatic, π-π stacking and donor-acceptor interactions. Such interactions eventually lead to a decrease in the peak currents of the cyclophane recognition elements attached onto t...     

Comparative molecular field analysis (CoMFA) of new herbicidal sulfonylurea compounds

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Removal of nitrate from groundwater by heterotrophic denitrification using the solid carbon source

Removal of nitrate from groundwater was investigated using biodegradable meal box(BMB) and poly(ε-caprolactone)(PCL) as carbon source and biofilm carrier.The experimental results show that nitrate in groundwater can be effectively removed using BMB and PCL as carbon source.Denitrification rates supported by BMB and PCL were 52.80 and 42.77 mg(NO3-N)/(m2h),respectively,at 30 ℃ and pH 7.5.The pH value of effluent ranged from 7 to 8,and NO2-N concentration was less than 0.1 mg/L.Compared with BMB,PCL could dec...     

Theoretical study on the charge transport properties of triphenylene discogens with a phenylpropionyloxy or 3-phenylpropenoyloxy side chain

Charge transport is one of the most important properties in organic materials. Charge transport properties of triphenylene discogens with a phenylpropionyloxy or 3-phenylpropenoyloxy side chain have been investigated computationally on the basis of semi-classical Marcus theory. The results show that three triphenylene derivatives have high charge mobility. Title compounds have much better electronic mobility than the triphenylene. The triphenylenes containing 3-phenylpropenoyloxy have better hole mobility, but smaller electronic mobility than the triphenylenes with phenylpropionyloxy. For the triphenylene discogens with a phenylpropionyloxy, the longer the alkloxy chains, the better the positive charge transfer rate, but the smaller the negative charge transfer rate. Supported by the National Natural Science Foundation of China (Grant No. 50673069), the Research Foundation of Education Bureau of Sichuan Province, China (Grant No. 07ZA093), and Scientific Research Foundation of Sichuan Normal University for Innovation Groups ( Grant No. 025156)     

A novel family of diarylethene-phthalocyanine dyad systems for nondestructive data processing

A novel family of diarylethene (DTE)-phthalocyanine (Pc) dyad systems were designed and synthesized. It was found that the significant change in the extension of the linear π-conjugation of DTE when irradiated by 254 nm UV light directly made the absorption of the Q-band of phthalocyanine decrease. Detecting the absorption changes of the Q-band would not induce the reversible photochromic reaction. Therefore, non-destructive readout was feasible based on the spectral changes of the Q-band when such materials were used as storage media.