Structural analysis of SNARE motifs from sea perch, Lateolabrax japonicus by computerized approaches

Three cDNA sequences encoding four SNARE (N-ethylmaleimide-sensitive fusion protein attachment protein receptors) motifs were cloned from sea perch, and the deduced peptide sequences were analyzed for structural prediction by using 14 different web servers and softwares. The "ionic layer" structure, the three dimensional extension and conformational characters of the SNARE 7S core complex by using bioinformatics approaches were compared respectively with those from mammalian X-ray crystallographic investigations. The result suggested that the formation and stabilization of fish SNARE core complex might be driven by hydrophobic association, hydrogen bond among R group of core amino acids and electrostatic attraction at molecular level. This revealed that the SNARE proteins interaction of the fish may share the same molecular mechanism with that of mammal, indicating the universality and solidity of SNARE core complex theory. This work is also an attempt to get the protein 3D structural information which appears to be similar to that obtained through X-ray crystallography, only by using computerized approaches. (C) 2007 Elsevier Ltd. All rights reserved.

Crystal structure of (5R,10R)-2,7-dibromo-3,8-dihydroxy-5,10-dimethoxy-5,10-dihydrochromeno[5,4,3-cde]chromene sesquihydrate, C16H12Br2O6 center dot 1.5H(2)O

C16H15Br2O7.5, orthorhombic, P2(1)2(1)2 (no. 18), a = 18.483(2) angstrom, b = 9.413(1) angstrom, c = 10.072(1) angstrom, V = 1752.3 angstrom(3), Z = 4, R-gt(F) = 0.083, wR(ref)(F-2) = 0.202, T= 293 K.

4-(2-Hydroxybenzylideneamino)-3-(1H-1,2,4-triazol-1-ylmethyl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C12H11N7OS, the dihedral angles made by the thione-substituted triazole ring with the other triazole ring and the benzene ring are 71.56 (2) and 47.89 (3)degrees, respectively. Inter- and intramolcular hydrogen-bond interactions stabilize the structure.

4-(2-fluorobenzylideneamino)-3-(1,2,4-triazol-4-ylmethyl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C12H10FN7S, the dihedral angles made by the plane of the thione-substituted triazole ring with the planes of the other triazole ring and the benzene ring are 74.55 (2) and 11.50 (3)degrees, respectively. The structure shows a number of N - H center dot center dot center dot N intermolecular hydrogen-bonding interactions, and weak C - H center dot center dot center dot S intra- and intermolecular interactions.

4-[3-(1,2,4-Triazol-1-yl)propionyl]phenyl 4-fluorobenzoate

In the title compound, C-18(14)3(3)H(FN)O, the dihedral angles made by the triazole ring with the plane of the central benzene ring and the p-fluorophenylcarbonyl group are 82.09 ( 2) and 82.05 (2), respectively. There are weak C-H...O intra- and intermolecular interactions in the crystal structure, which contribute to the stability.

2-(Benzotriazol-1-yl)-2-(alpha-hydroxybenzyl)-N-phenylthioacrylamide

In the title compound, C21H16N4OS, the dihedral angles between the planes of the benzotriazole and N-phenyl rings and the plane of the atoms that link these two rings are 79.56 (6) and 59.02 (5) degrees, respectively, while that between the two benzene rings is 64.12 (6) degrees. There are some inter- and intramolecular interactions in the crystal structure.

1-(4-fluorophenyl)-2-{4-phenyl-5-[(1H-1,2,4-triazol-1-yl) methyl]-4H-1,2,4-triazol-3-ylsulfanyl}ethanone

The crystal structure of the title compound, C19H15FN6OS, is stabilized by a weak intermolecular C-(HN)-N-... hydrogen-bond interaction.

4-(4-chlorobenzylideneamino)-3-(1H-1,2,4-triazol-1-ylmethyl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C12H10ClN7S, the dihedral angles made by the plane of the thione-substituted triazole ring with the planes of the other triazole ring and the benzene ring are 73.57 (3) and 46.65 (2)degrees, respectively. Inter-and intramolcular hydrogen bonds and pi-pi stacking interactions stabilize the structure.

5-[(1H-1,2,4-yriazol-1-yl)methyl]-4-(4-fluorobenzylideneamino)-2H-1,2,4-triazole-3(4H)-thione

In the title compound, C12H10FN7S, the dihedral angles made by the plane of the thione-substituted triazole ring with the planes of the other triazole ring and the benzene ring are 71.94 (3) and 40.10 (2)degrees, respectively. Inter- and intramolecular hydrogen-bond and pi-pi stacking interactions stabilize the structure.

Synthesis and quantum-chemistry analysis on novel triazole compounds containing ester group

Nine novel triazole compounds containing ester group were designed and synthesized. Their structures were confirmed by elemental, H-1 NMR and IR analyses, and optimized by means of DFT (Density Functional Theory) method at the B3LYP/6-31G* level. Based on the quantum-chemical calculation results and the Pearson coefficients between FA and quantumchemical parameters, V, LogP, MR and E-HOMO are shown to be the important relative factors which affect FA of the title compounds.

大港油田复杂断块油气藏评价技术研究与应用

In this paper, in view of characteristics and appraisal difficulty of complicate fault block reservoir, based on the theory of reservoir geology, tectonic geology, sequence stratigraphy, logging geology and sedimentology, according to related multidisciplinary data, such as geological, geophysical, logging and testing, taking 3D seismic acquisition processing, delicate structure interpretation, fine reservoir prediction, reservoir engineering and logging evaluation as research methods, on the basis of comprehensive geologic research, innovative appraisal thinking of complicate fault block reservoir is probed into, reservoir evaluation technology series of different reservoirs were created, and appraisal circuit of complicate fault block reservoir was proposed. According to the research on main controlling factors of hydrocarbon and concentration and concealing laws of Dagang exploration area, family assemble patterns of complicate fault block reservoir were proposed firstly, such as twinning, juxtaposed, overlying, concurrent, connected in series and so on, so theory basement was provided to reservoir evaluation. Taking into account of difficulties of low signal to noise ratio and border identification of lithologic trap of complicate fault block reservoir, in the middle of seismic data acquisition, double focusing layout and optimization technology were adopted, geophysical model was set up, and best observation system was ascertained. During object processing, matching processing technology of removing time difference, phase difference, energy difference and frequency spectrum difference generated by different blazing and receiving elements was studied. Imagery, low amplitude structure and identification of subtle lithologic reservoir was interpreted reasonably. On the basis of characteristics and technical description analysis of structural, structural--lithologic and lithologic reservoirs, innovative appraisal thinking of these reservoirs was formatted, appraisal circuit of complicate fault block reservoir was proposed, and this method could be used in other similar oilfields

In-situ SAXS studies of the morphological changes of an alumina-zirconia-silicate ceramic during its formation

D Le Messurier, R Winter, CM Martin; J Appl Cryst 39 (2006) 589 Sponsorship: EPSRC, CCLRC, Pilkington

Investigation of catalyst effects in enantioselective copper- and rhodium-mediated transformations of α-diazocarbonyl compounds

This thesis describes the synthesis and reactivity of a series of α-diazocarbonyl compounds with particular emphasis on the use of copper-bis(oxazoline)-mediated enantioselective C–H insertion reactions leading to enantioenriched cyclopentanone derivatives. Through the use of additives, the enantioselectivity achieved with the copper catalysts for the first time reaches synthetically useful levels (up to 91% ee). Chapter one provides a comprehensive overview of enantioselective C–H insertions with α-diazocarbonyl compounds from the literature. The majority of reports in this section involve rhodium-catalysed systems with limited reports to date of asymmetric C–H insertion reactions in the presence of copper catalysts. Chapter two focuses on the synthesis and C–H insertion reactions of α-diazo-β-keto sulfones leading to α-sulfonyl cyclopentanones as the major product. Detailed investigation of the impact of substrate structure (both the sulfonyl substitutent and the substituent at the site of insertion), the copper source, ligand, counterion, additive and solvent was undertaken to provide an insight into the mechanistic basis for enantiocontrol in the synthetically powerful C–H insertion process and to enable optimisation of enantiocontrol and ligand design. Perhaps the most significant outcome of this work is the enhanced enantioselection achieved through use of additives, substantially improving the synthetic utility of the asymmetric C–H insertion process. In addition to the C–H insertion reaction, mechanistically interesting competing reaction pathways involving hydride transfer are observed. Chapter three reports the extension of the catalyst-additive systems, developed for C–H insertions with α-diazo-β-keto sulfones in chapter two, to C–H insertion in analogous α-diazo-β-keto phosphonate and α-diazo-β-keto ester systems. While similar patterns were seen in terms of ligand effects, the enantiopurities achieved for these reactions were lower than those in the cyclisations with analogous α-diazo-β-keto sulfones. Extension of this methodology to cyclopropanation and oxium ylide formation/[2,3]-sigmatropic rearrangement was also explored. Chapter four contains the full experimental details and spectral characterisation of all novel compounds synthesised in this project, while details of chiral stationary phase HPLC analysis and X-ray crystallography are included in the appendix.

Studies of ferrite, borosilicate and intercalation materials

This thesis is concerned with several aspects of the chemistry of iron compounds. The preparation (with particular emphasis on coprecipitation and sol-gel techniques) and processing of ferrites are discussed. Chapter 2 describes the synthesis of Ni-Zn ferrites with various compositions by three methods. These methods include coprecipitation and sol-gel techniques. The Ni-Zn ferrites were characterised by powder X-ray diffactometry (PXRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), Mössbauer spectroscopy and resistivity measurements. The results for the corresponding ferrites prepared by each method are compared. Chapter 3 reports the sol-gel preparation of a lead borosilicate glass and its addition to Ni-Zn ferrites prepared by the sol-gel method in Chapter 2. The glass-ferrites formed were analysed by the same techniques employed in Chapter 2. Alterations in the microstructure, magnetic and electronic properties of the ferrites due to glass addition are described. Chapter 4 introduces compounds containing Fe-O-B, Fe-O-Si or B-O-Si linkages. The synthesis and characterisation of compounds containing Fe-O-B units are described. The structure of [Fe(SALEN)]2O.CH2Cl2 (17), used in attempts to prepare compounds with Fe-O-Si bonds, was determined by X-ray crystallography. Chapter 4 also details the synthesis of three new borosilicate compounds containing ferrocenyl groups, i.e. [FcBO)2(OSiBut2)2] (19), [(FcBO)2(OSiPh2)2] (20) and [FcBOSiPh3] (21). The structure of (19) was determined by X-ray Crystallographic analysis. Chapter 5 reviews the intercalation properties of the layered host compound iron oxychloride (FeOCI). Intercalation compounds prepared with the microwave dielectric heating technique are also discussed. The syntheses of intercalation compounds by the microwave method with FeOCI as host and ferrocene, ferrocenylboronic acid and 4-aminopyridine as guest species are described. Characterisation of these compounds by powder X-ray diffractometry (PXRD) and M{ssbauer spectroscopy is reported. The attempted synthesis of an intercalation compound with the borosilicate compound (19) as guest species is discussed. Appendices A-E describe the theory and instrumentation involved in powder X-ray diffractometry (PXRD), scanning electron microscopy (SEM0, vibrating sample magnetometry (VSM), Mössbauer spectroscopy and electrical resistivity measurements, respectively. Appendix F details the attempted syntheses of compounds with Fe-O-B and Fe-O-Si linkages.

Chemistry of B1- and B10- boranes containing halogen or pseudohalogen groups

The research described in this thesis involved the chemistry of borane-species which contain one or more halide or pseudohalide groups. Both monoboron species e.g. [BH3X]- and "cluster" borane species e.g. [B10H9X]2- and I-Se B11H10 were studied. The first chapter is a review of the syntheses, properties and reactions of halide and pseudohalide species containing from one to ten boron atoms. Chapter Two is a theoretical investigation of' the electronic and molecular structures of two series of boranes i. e. [BH3X]- and [B10H9X]2- where X = H, CI, CN, NCS, SCN and N3. The calculational method used was the Modified Neglect of Differential Overlap (MNDO) method of Dewar et al. The results were compared where possible with experimental results such as the X-ray crystallographically determined structures of [BH3CI]- and [B10H10]2-. Chapter Three concerns halogenated selenaborane clusters and reports an improved synthesis of 12-Br-SeB11H10 and the first structural data for a simple non-metal containing selenaborane cage with the X-ray crystallographically determined structure of 12-1-SeB11H10. Finally, an indepth n.m.r. study of Se2B9H9 is also reported together with attempts to halogenate this compound. The last two chapters are based on single boron systems. Chapter Four concerns the synthetic routes to amine-boranes and -cyanoboranes from [BH4]- and [BH3CN]- substrates. This chapter discusses some difficulties encountered when polyamines were used in these reactions. The characterisation of an unusual ketone isolated from some of these reactions, the X-ray crystallographically determined structure of 4-dimethylamino-pyridine-cyanoborane and a new route to pyrazabole dimeric species are also discussed. The final chapter reports on work carried out at producing BH2X (X = H, CN) adducts of aminophosphines. Three routes were attempted to generate P-B and N-B bonded species with varying degrees of success. Some unusual products of these reactions are discussed including [Ph2(O) PPPh2 ] [Ph2NH]2, the structure of which was determined by X-ray crystallography.