Alkyltelluro Substitution Improves the Radical‐Trapping Capacity of Aromatic Amines

The synthesis of a variety of aromatic amines carrying an ortho‐alkyltelluro group is described. The new antioxidants quenched lipidperoxyl radicals much more efficiently than α‐tocopherol and were regenerable by aqueous‐phase N‐acetylcysteine in a two‐phase peroxidation system. The inhibition time for diaryl amine 9 b was four‐fold longer than recorded with α‐tocopherol. Thiol consumption in the aqueous phase was found to correlate inversely to the inhibition time and the availability of thiol is the limiting factor for the duration of antioxidant protection. The proposed mechanism for quenching of peroxyl radicals involves O‐atom transfer from peroxyl to Te followed by H‐atom transfer from amine to alkoxyl radical in a solvent cage.     

Synthesis and Insecticidal Evaluation of Novel N‐Pyridylpyrazolecarboxamides Containing Different Substituents in the ortho‐Position

In order to look for novel insecticides containing N‐pyridylpyrazole, ten novel pyrazolecarboxamides containing different ortho‐substituents in the aniline part were synthesized, and their structures were characterized by ¹H NMR, ¹³C NMR and HRMS. The single crystal structure of 10b was determined by X‐ray diffraction. Their evaluated insecticidal activity against oriental armyworm (Mythimna separata) indicated that all the compounds exhibited moderate insecticidal activities.     

Introduction of periodic boundary conditions into UNRES force field

In this article, implementation of periodic boundary conditions (PBC) into physics‐based coarse‐grained UNited RESidue (UNRES) force field is presented, which replaces droplet‐like restraints previously used. Droplet‐like restraints are necessary to keep multichain systems together and prevent them from dissolving to infinitely low concentration. As an alternative for droplet‐like restrains cuboid PBCs with imaging of the molecules were introduced. Owing to this modification, artificial forces which arose from restraints keeping a droplet together were eliminated what leads to more realistic trajectories. Due to computational reasons cutoff and smoothing functions were introduced on the long range interactions. The UNRES force field with PBC was tested by performing microcanonical simulations. Moreover, to asses the behavior of the thermostat in PBCs Langevin and Berendsen thermostats were studied. The influence of PBCs on association pattern was compared with droplet‐like restraints on the ββα hetero tetramer 1 protein system. © 2015 Wiley Periodicals, Inc.     

本征值方法在抗氧化剂定量构效关系研究中的应用

Antioxidants are of great interest because of their involvement in many important biological and industrial processes. It is meaningful to study their structure-antioxidant activity relationship (SAAR) and design novel, efficient and low-toxicity antioxidant. In this paper, Eigen Value Analysis (EVA), a 3-dimensional quantitative structure activity relationship (3-D QSAR) method, was employed to study antioxidant SAAR. Significant relational models were obtained with all the PLS cross-validate qcv^2 values being larger than 0.5, meaning that the models have sound predictive power. Compared with other QSAR methods, EVA possesses several advantages, especially that it does not need alignment. It should be believed that EVA will be an efficient approach to SAAR.     

An Unconventional Approach to Induce Liquid‐Crystalline Phases of Triazine‐Based Dendrons by Breaking Their Self‐Assembly into Dimers

Three triazine‐based dendrons ( 1 a – c ) were successfully prepared in 70–83 % yields. These newly prepared dendrons are found to be liquid crystalline (LC). Computational investigations on molecular conformations and dipoles of triazine‐based dendrons reveal that the substituent on the central triazine unit interrupts strong dipole or H‐bond interactions to avoid dimeric formation. The obtained dendrons, not favouring self‐assembly into dimers but showing LC behaviours, provides evidence for an approach contrary to the conventional method of inducing LC behaviours of dendrons by dimer or trimer formation, mostly through H‐bond interactions.     

Synthetic and Structural Studies of 1,8‐Chalcogen Naphthalene Derivatives

Four novel 1,8‐disubstituted naphthalene derivatives 4 – 7 that contain chalcogen atoms occupying the peri positions have been prepared and fully characterised by using X‐ray crystallography, multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular distortion due to noncovalent substituent interactions was studied as a function of the bulk of the interacting chalcogen atoms and the size and nature of the alkyl group attached to them. X‐ray data for 4 – 7 was compared to the series of known 1,8‐bis(phenylchalcogeno)naphthalenes 1 – 3 , which were themselves prepared from novel synthetic routes. A general increase in the E???E′ distance was observed for molecules containing bulkier atoms at the peri positions. The decreased S???S distance from phenyl‐ 1 and ethyl‐ 4 analogues is ascribed to a weaker chalcogen lone pair–lone pair repulsion acting in the ethyl analogue due to the presence of two equatorial S(naphthyl) ring conformations. Two novel peri‐substituted naphthalene sulfoxides of 1 , Nap(O?SPh)(SPh) 8 and Nap(O?SPh)₂ 9 , which contain different valence states of sulfur, were prepared and fully characterised by using X‐ray crystallography and multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular structures were analysed by using naphthalene ring torsions, peri‐atom displacement, splay angle magnitude, S???S interactions, aromatic ring orientations and quasi‐linear O?S???S arrangements. The axial S(naphthyl) rings in 8 and 9 are unfavourable for S???S contacts due to stronger chalcogen lone pair–lone pair repulsion. Although quasi‐linear O?S???S alignments suggest attractive interaction is conceivable, analysis of the B3LYP wavefunctions affords no evidence for direct bonding interactions between the S atoms.     

Mononuclear Co(III), Ni(II) and Cu(II) complexes of 2‐(2,4‐dichlorobenzamido)‐N'‐(3,5‐di‐tert‐butyl‐2‐hydroxybenzylidene)benzohydrazide: Structural insight and biological assay

A series of mononuclear metal complexes of Co(III), Ni(II) and Cu(II) with 2‐(2,4‐dichlorobenzamido)‐N′‐(3,5‐di‐tert‐butyl‐2‐hydroxybenzylidene)benzohydrazide ( LH ₃ ) have been synthesized and characterized using various physico‐chemical, spectroscopic and single crystal X‐ray diffraction techniques. Structural studies of [Co( LH )( LH ₂ )]·H₂O ( 4 ) revealed the presence of both amido and imidol tautomeric forms of LH ₃ , resulting in a distorted octahedral geometry around the Co(III) ion. [Ni( LH )(H₂O)]·H₂O ( 5 ) and [Cu( LH )(H₂O)]·H₂O ( 6 ) are isomorphous structures and crystallize in the monoclinic P2₁/c space group. The crystal structures of 4 , 5 and 6 are stabilized by hydrogen bonds formed by the enclathrated water molecules, C‐H···π and π···π interactions. Complexes along with the ligand ( LH ₃ ) were screened for their in vivo anti‐inflammatory activity (carrageenan‐induced rat paw edema method) and in vitro antioxidant activity (DPPH free radical scavenging assay). Metal complexes have shown significant anti‐inflammatory and antioxidant potential.     

4‐Hydroxy‐3‐carboxycoumarin as an efficient building block for new ruthenium(II) complexes: synthesis,characterization, antibacterial,antioxidant and anti‐inflammatory activities

A new 4‐hydroxy‐3‐carboxycoumarin ligand and its ruthenium(II) complexes ( 1 – 5 ) have been synthesized, characterized and screened for their in vitro antibacterial activity against a range of Gram‐positive and Gram‐negative bacteria. In addition, compounds 1 – 5 were investigated for antioxidant activities using superoxide radical, 2,2‐diphenyl‐1‐picrylhydrazyl radical and hydroxyl radical scavenging assays, in which most of them displayed significant antioxidant activities. Furthermore, compounds 1 – 5 were evaluated for anti‐inflammatory activity using indirect haemolytic and lipoxygenase inhibition assays and revealed good activity. The new complexes were characterized using spectroscopic methods in addition to elemental analysis.     

Symmetry‐Breaking Transitions in SmCu1+δAs2—χPχ(δ = 0 — 0.2, χ = 0 — 2). Effect of P and Additional Cu Atoms on Crystal Structures and Magnetic Properties

Crystal structures of the compounds SmCu_1+δAs_2—χP_χ (δ = 0 — 0.2, χ = 0 — 2) undergoing symmetry‐breaking transitions and SmCuP_2.3 have been investigated by the X‐ray single crystal and powder methods. While the phases SmCuAs₂ through SmCuAs_1.22P_0.78 retain the tetragonal HfCuSi₂ structure (P4/nmm space group), the compounds SmCuAs_1.11P_0.89 through SmCuAs_0.56P_1.44 adopt the GdCuAs_1.15P_0.85—type structure (Pmmn space group), an orthorhombic variant of the HfCuSi₂‐type. Further distortion follows in SmCuAs_0.33P_1.67 through SmCuP_2.3, the powder patterns of which were indexed in the P2/n space group (P2/c in a standard setting). According to Landau theory the transitions from tetragonal SmCuAs_1.22P_0.78 to orthorhombic SmCuAs_1.11P_0.89 and from orthorhombic SmCuAs_0.56P_1.44 to monoclinic SmCuAs_0.33P_1.67 can be continuous. Introducing extra copper into some of the orthorhombic arsenophosphides restabilizes tetragonal phases (0 < δ ≤ 0.2) with the P4/nmm symmetry, and the reverse transition Pmmn → P4/nmmcan be continuous. Inserting copper atoms into monoclinic SmCuP₂ yields the SmCu_1+δP₂ phosphides with Cmmm symmetry, and this transition is first‐order. Single crystals of SmCu_1.05As_1.67P_0.33, SmCu_1.07As_0.85P_1.15 and SmCu_1.15P₂ have been prepared using iodine as a mineralizing agent. Their structures have partially occupied Cu sites around the square As/P or P layers and they are a stuffed variant of the HfCuSi₂ structure for SmCu_1.05As_1.67P_0.33 (P4/nmm, a = 3.9163(6), c = 9.932(2)Å), a stuffed GdCuAs_1.15P_0.85 structure for SmCu_1.07As_0.85P_1.15 (Pmmn, a = 3.859(1), b = 3.862(1), c = 9.852(3)Å) and a CeCu_1.12P_1.97‐type structure for SmCu_1.15P₂ (Cmmm, a = 5.453(3), b = 19.511(10), c = 5.439(3)Å). The P net in SmCu_1.15P₂ is broken into rectangular units. The results of magnetic measurements for SmCuAsP are reported.     

Identification of Hypoxic Cells Using an Organotellurium Tag Compatible with Mass Cytometry

Mass cytometry (MC) offers unparalleled potential for the development of highly parameterized assays for characterization of single cells within heterogeneous populations. Current reagents compatible with MC analysis employ antibody‐metal‐chelating polymer conjugates to report on the presence of biomarkers. Here, we expand the utility of MC by developing the first activity‐based probe designed specifically for use with the technology. A compact MC‐detectable telluroether is linked to a bioreductively sensitive 2‐nitroimidazole scaffold, thereby generating a probe sensitive to cellular hypoxia. The probe exhibits low toxicity and is able to selectively label O₂‐deprived cells. A proof‐of‐concept experiment employing metal‐bound DNA intercalators demonstrates that a heterogeneous mixture of cells with differential exposure to O₂ can be effectively discriminated by the quantity of tellurium‐labeling. The organotellurium reagents described herein provide a general approach to the development of a large toolkit of MC‐compatible probes for activity‐based profiling of single cells.     

Screening free radical scavengers in Xiexin Tang by HPLC‐ABTS‐DAD‐Q‐TOF/MS

Xiexin Tang (XXT) is a traditional Chinese medicine (TCM) that has been used in herbal clinics for more than 1800 years. Many studies have shown that XXT has therapeutic effects on patients with arteriosclerosis owing to its antioxidant activity. However, there is little information about the relationship between the chemical composition of XXT and its antioxidant activity. In this study, the HPLC‐ABTS‐DAD‐Q‐TOF/MS method, which can simultaneously identify individual components and rapidly screen for antioxidant compounds, was used to screen and identify antioxidant components in XXT. The 15 compounds identified were gluco‐syringic acid, adenine, gallic acid, biflorin, cularine, 6‐C ‐arabinose‐8‐C ‐glucose‐chrysin, 6‐C ‐glucose‐8‐C ‐arabinose–chrysin, baicalin, rhein‐8‐O‐β ‐d ‐glucopyranoside, coptisine, epiberberine, jatrorrhizine, norwogonin, 5,7,2′‐trihydroxy‐6‐ methoxyflavone and baicalein. In addition, the data showed that the antioxidant activity of peaks 4, 6, and 11 was lower in XXT than in its constituent herbs, while the activity of peaks 1, 2, 3, 5, 7, 8, 10, 12, 13, 14 and 15 was higher in XXT. Compound 5 had the strongest antioxidant activity in XXT, while compound 1 showed the strongest antioxidant activity among its constituent herb. The differences between antioxidant activities of major components of XXT and those of its constituent herbs might be due to the interaction of crude drugs that changes the solubility of active components during the decoction process. The results show that the HPLC‐ABTS‐DAD‐Q‐TOF/MS method can successfully combine on‐line mass spectrometry with activity detection system. It is a useful tool for the rapid detection and identification of antioxidants, and for quantitative analysis of individual antioxidants in complex mixtures such as plant extracts. Furthermore, this method does not require extensive extract purification and fraction collection.     

Treatment of long‐term stored DNA—Comparison between different methods to obtain high‐quality material

Long‐term stored DNA can be sometimes the only source of genetic material of an organism that does not exist anymore, but a research interest still persists. However, there is a lack of information about useful methods to improve quality from such type of material. In this study, we compared four different protocols using DNA samples collected in 1998. Fresh DNA was also tested aiming to check the differences between these two material types. Sixteen samples of each DNA type treated with phenol‐chloroform with PEG 5.0%, silica‐gel membrane spin column, PEG 7.5%, and glass‐fiber matrix spin column were submitted to spectrophotometer measurements, electrophoresis, PCR, and RFLP‐PCR to assess the best method concerning yield, quality, and purity. Based on the results, purification with PEG 7.5% was considered the best method to treat aged DNA samples. In addition to the efficiency, this protocol has low cost. Analyzing the data, we also conclude that long‐term stored DNA may be considered a reliable and potential resource for future molecular studies.     

Synthesis of 8‐hydroxyquinolium chloroacetate and synthesis of complexes derived from 8‐hydroxyquinoline,and characterization,density functional theory and biological studies

8‐Hydroxyquinolium chloroacetate ( L¹ ) was synthesized and characterized. The results suggest that L¹ loses ethyl chloroacetate ion on coordination at low pH (2–5) and consequently it behaves as 8‐hydoxyquinoline ( L² ). Cu²⁺, Co²⁺, Pt⁴⁺, Pd²⁺, Au³⁺, Ag⁺ and Nd³⁺ complexes derived from L² have been synthesized and characterized using spectral, magnetic and thermal measurements. L² acts as a neutral bidentate ligand in the case of Cu²⁺, Co²⁺, Pt⁴⁺, Pd²⁺ and Nd³⁺ complexes and as a mononegative bidentate ligand in the case of Au³⁺ and Ag⁺ complexes. Octahedral geometry is proposed for Cu²⁺, Co²⁺ (grey) and Pt⁴⁺ complexes and square‐planar for Co²⁺ (green), Pd²⁺ and Au³⁺ complexes. The bond lengths, bond angles, chemical reactivities, binding energies and dipole moments for all compounds were evaluated using density functional theory and molecular electrostatic potential for L¹ . Superoxide dismutase radical scavenger‐like activity and cytotoxic activity of the complexes towards HepG2 liver cancer cells has been screened. Cytotoxicity measurements show that Ag⁺ and Pd²⁺ complexes have the highest cytotoxic activity while L¹ , Cu²⁺, Co²⁺ (grey), Co²⁺ (green), Pt⁴⁺ and Nd³⁺ complexes have no cytotoxic activity. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis of polymethacrylate derivatives having sulfated maltoheptaose side chains with anti‐HIV activities

Anti‐HIV (human immunodeficiency virus) active polymethacrylates having pendant sulfated oligosaccharides were synthesized, and the relationship between structures and biological activities of the polymethacrylates was examined. Acetylated 1‐O‐methacryloyl maltoheptaoside (MA‐AcM7) was polymerized with AIBN as an initiator to give polymethacrylates having a pendant acetylated maltoheptaose in every repeating unit, poly(MA‐AcM7)s. After hydroxyl groups were recovered by deacetylation, the polymethacrylates having maltoheptaose units, poly(MA‐M7)s, were sulfated to give polymethacrylates having sulfated maltoheptaose side‐chains, poly(MA‐SM7)s, with degrees of sulfation of 1.1 to 2.7 (maximum, 3.0). These polymethacrylates including sulfated oligosaccharides exhibited low anti‐HIV activities represented by the 50% protecting concentration (EC₅₀) in the range of 15–62 μg/mL and low blood anticoagulant activities around 10 unit/mg (standard dextran sulfate, 22.7 unit/mg). The anti‐HIV activity increased with increasing degree of sulfation to reach EC₅₀ of 15–16 μg/mL. In addition, copolymerization of MA‐AcM7 with methyl methacrylate (MMA) and subsequent sulfation gave polymethacrylates consisting of various proportions of highly sulfated maltoheptaose and MMA units. It was revealed that the anti‐HIV activity increased with decreasing proportion of the sulfated oligosaccharide moiety and that a copolymethacrylate having 22 mol % of sulfated maltoheptaose units (DS = 3.0) had a high anti‐HIV activity in the EC₅₀ of 0.3 μg/mL. The blood anticoagulant activity increased slightly from 9 to 18 unit/mg with decreasing proportion of the sulfated maltoheptaose units. These results suggested that the biological activities were influenced strongly by the spatial distance between sulfated oligosaccharide substituents in the polymethacrylate main chain. Distinction and conformation of the oligosaccharide side chains also played an important role. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 789–800, 1999