Molecular interactions between lipid bilayers and a water-soluble polymer

Molecular interactions between lipid bilayers (liposomes) and chondroitin sulfate C (CS), a water soluble polymer, have been investigated in terms of zeta-potential, particle size, microscopic-viscosity, microscopic-polarity of liposomes and permeability of calcein. Microscopic morphology is dramatically changed by the addition of CS to the positively charged liposomes (Pos.L), while it is not changed by the addition to uncharged liposomes (Unc.L) or negatively charged liposomes (Neg.L). The absolute value of the particle size of Pos.L increases with the addition of CS, while the zeta- potential of Pos.L decreases. Permeability of Pos.L decreases with an increase in the concentration of CS. Phase transition temperature of Pos.L is changed after the addition of CS. These values, however, are not changed for the other liposomes by the addition of CS. The results of gel filtration chromatography show that CS is absorbed on the Pos.L surface. Microscopic viscosity is also increased by the addition of CS to Pos.L due to the adsorption of CS.     

Enantioselective conjugate additions of organolithiums to BHA enoates mediated by A chiral ligand

The conjugate addition reactions of BHA alkenoates with organolithiums in toluene or toluene-hexane at −78 °C were mediated by the chiral ligands 1 and 2 to give the corresponding 3-substituted alkanoates in high ees and high yields. The two ligands are complementary each other, 1 is effective for phenyl- and vinyllithiums to give the adducts in 64–93% ee, while 2 is effective for butyl- and ethyllithiums to give the adducts in 91–99% ee.     

Formation of non-racemic E- and Z-olefins based on discrimination of enantiotopic carbonyl groups in α-diketones by a chiral phosphonate reagent

A chiral HWE reagent reacted with an alternative carbonyl group of meso-α-diketones of bicyclo[2.2.1] system to give non-racemic (Z)- and (E)-olefins, respectively.     

Unexpected formation of benzaldehydes by the reactions of dithioacetals derived from cinnamaldehydes with 2,3-dichloro-5,6-dicyano-p-benzoquinone in aqueous solvents

1,3-Dithianes 1 , 1,3-dithiolanes 2 , and diphenyl dithioacetals 3 derived from cinnamaldehydes reacted with 2,3-dichloro-5,6-dicyano-p-benzoquinone in aqueous solvents to give benzaldehydes 4 . Hydride transfer from 1–3 to 2,3-dichloro-5,6-dicyano-p-benzoquinone followed by hydrolysis and oxidative carbon-carbon bond cleavage would produce benzaldehydes 4 .     

Morphological and structural change of nano-pored alumina membrane above 1200 K

The transition and the change in pore morphology of a porous alumina membrane prepared by anodically oxidizing aluminum in sulfuric acid were studied mainly by TG-DTA, TMA, dilatometry and TEM. At ca. 1243 K, TMA showed an expansion followed by contraction; the CO₂ and SO₂ gases were quickly discharged, and the pore morphology of the as-prepared porous membrane (ca 150 mm-t, with pores ca 25 nm in diameter and containing ca 11% by mass of SO₂) showed an abrupt change, but the pores were retained to ca. 1573 K. Sulfur incorporated in the membrane was lost in two stages, i.e., at ca 1243 K and in a range up to 1373 K. Isothermal measurements revealed the complex crystallization of the amorphous phase into polycrystalline phase. This revised version was published online in August 2006 with corrections to the Cover Date.     

Novel alignment method of small molecules using the Hopfield Neural Network

Molecular alignment is an important step in three-dimensional quantitative structure-activity relationship (3D-QSAR) such as comparative molecular field analysis (CoMFA). A reasonable molecular alignment is necessary for building a 3D-QSAR model. In this paper, a novel method for molecular alignment using the Hopfield Neural Network (HNN) is introduced. Four kinds of chemical properties are assigned to each atom of a molecule. Then, those properties between two molecules correspond to each other using HNN. To validate our method, HNN was applied to 12 pairs of enzyme inhibitors cited from the Protein Data Bank (PDB). As a result, our method could successfully reproduce the real molecular alignments obtained from X-ray crystallography.     

Diversity-oriented synthesis of tamoxifen-type tetrasubstituted olefins

A general synthetic scheme for tamoxifen-type tetrasubstituted olefins based on the novel Cu-catalyzed carbomagnesation across alkynyl(2-pyridyl)silane has been developed. A wide array of electronically and structurally diverse tetrasubstituted olefins can be prepared in a regiocontrolled, stereocontrolled, and diversity-oriented manner. Noteworthy features are that (i) the three aryl groups, which are believed to be important (essential) for anti-estrogenic activity, can be varied at will because they all stem from readily available aryl iodides, and (ii) any stereo- and regioisomers can, in principle, be prepared by simply changing the applying order of aryl iodides into the sequence.     

Adsorption properties of activated carbon from waste newspaper prepared by chemical and physical activation

Adsorption properties of activated carbons prepared from waste newspaper by chemical and physical activation were investigated using water vapor, ammonia, methane, and methylene blue (MB) as adsorbents. The water vapor adsorption isotherms show type V behavior and the maximum vapor adsorption of the chemically and physically activated products is about 1050 and 450 ml/g, respectively. The higher water vapor adsorption of the chemically activated products is attributed to the higher specific surface area (S(BET)) and greater hydrophilic activity (arising from the surface oxygen-containing functional groups) than in the physically activated products. The adsorption of ammonia and methane was measured by temperature-programmed desorption (TPD). NH(3) adsorption is found to be higher in the chemically activated product than in the physically activated product while methane adsorption is slightly higher in the physically activated products even though these have lower S(BET) values. In the MB adsorption, the chemically activated products show higher adsorption (390 mg/g) than the physically activated product. These results are suggested to be related to the surface characteristics.     

One Dimensional Face-to-Face Stacking of Anderson–Evans [Cr(OH)6Mo6O18]3− Polyoxometalate Anion: Synthesis, Structure, and Physical Properties of (BEDT-TTF)4[Cr(OH)6Mo6O18]⋅2H2O

The synthesis, structural and magnetic characterizations of a new charge transfer salt (BEDT-TTF)₄[Cr(OH)₆Mo₆O₁₈]2H₂O based on the planar paramagnetic Anderson–Evans polyoxometalate are reported. Structural parameters: T=293 K, triclinic (P ), a=5.9545(2) Å, b=16.3767(6) Å, c=21.8643(6) Å, =110.829(2)°, =91.262(2)°, =98.129(1)°, Z=1, R=0.0540. The crystal structure is characterized by a face-to-face stacking of the anions giving rise to a one-dimensional inorganic chain which develops along the a direction. The organic layers contain two crystallographically independent BEDT-TTF dimers that form alternating stacks along the b direction. This organic chain is perpendicular to the inorganic chains. The charges on BEDT-TTF dimers are deduced to +1.2(1) and +1.7(1) on the basis of the intramolecular bond lengths. The EPR spectrum at 2.5 K is characterized by the superposition of BEDT-TTF⁺ and [Cr^III(OH)₆Mo₆O₁₈]^3– signals. The static susceptibility can be fitted by the Curie–Weiss law down to 1.9 K and the magnetic moment at 300 K is estimated to 4.21 _B , suggesting the uncorrelated spin system with BEDT-TTF⁺ (S=1/2) and Cr^III (S=3/2) ions. This interpretion is consistent with the charge disproportionation on BEDT-TTF dimers along the stack, which is supported by the refined molecular structure and is closely related to the insulating behavior (<10^–9Scm^–1 at RT).