Synthesis and Insulin—sensitizing Activity of a Series of 2—Benzyl—1,3—dicarbonyl Derivatives

A series of 2-benzyl-1,3-dicabonyl derivatives was synthesized.Their insulin-sensitizing activity was evaluated in 3T3-L1 preadipocyte cells.Compounds3,26 and 27 were found to possess strong insulin-sensitizing activity in vitro and were selected for further hypoglycemic evaluation in vivo.     

Synthesis of 2-(imidazolylamino)benzothiazoles

Treatment of derivatives of 5-phenylthioureido-3H-imidazole-4-carboxylic acid with bromine afforded 2-(imidazolylamino)benzothiazoles.     

La2O3/MgO催化剂上的甲烷氧化偶联

研究了甲烷在La_2O_3/MgO催化剂上的氧化偶联。发现制备过等对催化剂的行为有显著影响。比较了催化剂的反应性能和体相结构,表明在MgO上存在着三种La_2O_3的状态:高分散La_2O_3是最活泼的;La(OH)_3不太活泼;而呈六方晶相的La_2O_3晶粒活性最低。在催化剂中加入Na_2CO_3和K_2CO_3可以改进催化剂的活性和选择性。还考察了反应条件如温度和空速的影响。     

Computation of cross sections for the F+H2(v=0,j=0) → FH(v′j)+H reaction by the hyperspherical method

Summary A quantum mechanical calculation of cross sections for the reaction F+H₂(v=0,j=0) FH(vj)+H has been performed on the T5A semiempirical potential surface using hyperspherical coordinates. State-to-state integral and differential cross sections converge rapidly with the number of components of the total angular momentum projection onto the axis of least inertia. Thev=3 differential cross section has a forward peak whose magnitude increases with energy whereas thev=2 differential cross section has a backward maximum, in qualitative agreement with cross-beam experiments. Thev=2 andv=3 rotational distributions are in rather good agreement with experiment, but not the vibrational branching ratios.     

The 2-(diphenylphosphino) ethyl group (DPPE) as a new carboxyl-protecting group in peptide chemistry

The use of the 2-(diphenylphosphino)ethyl group for carboxyl-protection of amino acids or peptides is described. This group is easily introduced by esterification using 2-(diphenylphosphino) ethanol in the presence of dicyclohexylcarbodiimide and 4-(dimethylamino)pyridine. These Dppe esters are stable under the standard conditions for peptide synthesis. Deprotection is carried out under mild conditions by quaternisation using methyl iodide followed by a β-elimination induced by fluoride ion or potassium carbonate.     

Determination of 1-aminocyclopropane-1-carboxylic acid in apple extracts by capillary electrophoresis with laser-induced fluorescence detection

A rapid and sensitive method for the determination of 1-aminocyclopropane-1-carboxylic acid (ACC) in apple tissues has been described. This method is based on the derivatization of ACC with 3-(2-furoyl)quinoline-2-carboxaldehyde (FQ), and separation and quantification of the resulting FQ-ACC derivative by capillary electrophoresis coupled to laser-induced fluorescence detection (CE-LIF). Our results indicated that ACC derivatized with FQ could be well separated from other interfering amino acids using 20 mM borate buffer (pH 9.35) containing 40 mM sodium dodecyl sulfate and 10 mM Brij 35. The linearity of ACC was determined in the range from 0.05 to 5 microM with a correlation of 0.9967. The concentration detection limit for ACC was 10 nM (signal-to-noise = 3). The sensitivity and selectivity of this described method allows the analysis of ACC in crude apple extracts without extra purification and enrichment procedure.     

Highly diastereoselective synthesis of bicyclo[4.2.0]octanone derivatives by the [2+2] photocycloaddition of chiral cyclohexenonecarboxylates to ethylene

The diastereoselective [2+2] photocycloaddition of a cyclohexenonecarboxylate containing (−)-8-(4-nitrophenyl)menthyl as a chiral auxiliary to ethylene gave the photocycloadduct, a bicyclo[4.2.0]octanone derivative, with a high degree of diastereoselectivity. A photoreaction, conducted in CH₂Cl₂ at −78 °C gave the corresponding photocycloadduct in 88% de. In the presence of Ti(OR)₄ or Me₃SnCl, the diastereoselectivity was increased up to 92% de.     

Electrochromic properties of WO<Subscript>3</Subscript> and WO<Subscript>3</Subscript>:P thin films

WO₃ and WO₃:P (5 mol% H₃PO₄) thin films were prepared using the sol-gel route and the electrochromic properties of the films were investigated using in situ spectroelectrochemical methods. The measurements were performed in propylene carbonate solution with 0.1 M LiClO₄ as electrolyte. During the cathodic polarization at –0.8 V a blue coloration is observed with a reversible variation between 14% and 84% of the transmittance at λ=633 nm. The kinetics for the bleaching process is faster for the WO₃:P film than for the undoped WO₃ film. Electronic Publication     

Synthesis and Structure of Dimolybdenum Carbonyl Thiolate Compound [Et4N]2[Mo2（CO）8（SC6H4—CH3—m）2]

1 INTRODUCTION In 1984, thiolate ligand was successfully introduced into molybdenum carbonyl compound by the reaction of Mo(CO)6 with [Et4N]SR( R = C6H5, But) in a moderate condition[1]. From then on, a series of dinuclear molybdenum(0) carbonyl thiolate compounds have been synthesized and characterized by using a variety of thiolate ligands in our research group. It was found that a planar Mo2S2 unit is in the compound [Et4N]2[Mo2(CO)8(SC6H4-CH_3-p)2][2] (2) and a "butterfly" t…