Synthesis of monodispersed molecularly imprinted polymer particles for high-performance liquid chromatographic separation of cholesterol using templating polymerization in porous silica gel bound with cholesterol molecules on its surface

Monodispersed molecularly imprinted polymer particles selective for cholesterol were prepared by the copolymerization of styrene and divinylbenzene in the presence of template silica gel particles (particle size: 5 μm; pore size: 10 nm) functionalized with cholesterol on the surface, followed by dissolution of the cholesterol-bonded silica gel with a NaOH aqueous solution. Transmission and scanning electron micrographs of the molecularly imprinted polymer (MIP) particles revealed good monodispersity and porous structure. The MIP particles were packed into a high performance liquid chromatographic column, and its recognition ability of cholesterol was evaluated using cholesterol, cholesterol esters and fatty acid methyl esters by comparison with the non-imprinted polymer (NIP) particles prepared from styrene and divinylbenzene without cholesterol. The MIP particles showed a high affinity for cholesterol and cholesterol esters (K(MIP)'/K(NIP)' > 5.7).     

Novel one-pot synthesis of 5-alkenyl-15-alkynylporphyrins and their derivatisation to a butadiyne-linked benzoporphyrin dimer

5-Alkenyl-15-alkynylporphyrins have been obtained unexpectedly by [2 + 2] acid-catalyzed condensation of dipyrrylmethane and TMS propynal in addition to 5,15-dialkynylporphyrin, and the unsymmetrical porphyrin can be converted to a butadiyne-linked dimer by selective desilylation of the alkynyl TMS.     

Global existence and decay properties for a degenerate Keller-Segel model with a power factor in drift term

The following degenerate parabolic system modelling chemotaxis is considered:

(KS)     

Absolute stereochemistry of serricornin,the sex pheromone of cigarette beetle,as determined by the synthesis of its (4S,6R,7R)-isomer

The absolute stereochemistry of serricornin was determined to be (4S,6S,7S) by the synthesis of its (4S,6R,7R)-isomer using a carbohydrate synthon.     

ESR studies of a new phenoxyl-nitroxide hetero biradical

A new phenoxyl-nitroxide hetero biradical was prepared, and the nitrogen hyperfine splitting and g_iso-value of the biradical in toluene have been determined from its solution ESR spectrum.     

Ajugamarin,a new bitter diterpene from ajuga nipponensis makino

The structure of a new bitter neo-clerodane, ajugamarin, isolated from $\text{Ajuga nipponensis}$ Makino, has been elucidated by spectroscopic studies and confirmed by X-ray crystallographic analysis.     

Application of difference NOE-pumping NMR technique and cold-spray ionization mass spectrometry to identify a ligand binding with a protein receptor.

A difference diffusion-based NMR technique and cold-spray ionization mass spectrometry were employed as a solution-based approach for identifying a ligand binding with a protein receptor. The difference diffusion-based NMR technique, called difference NOE-pumping, can directly detect the ligand interacting with a protein receptor. This technique uses a simple pulse sequence and the diffusion filter can easily be optimized. The cold-spray ionization mass spectrometry (CSI-MS), a variant of electrospray ionization mass spectrometry (ESI-MS) operating at low temperature, has been applied to detect the ligand-receptor complex. The efficiency of these techniques for identifying binding ligands is demonstrated with the human serum albumin (HSA)-drug system.     

Fragmentation of tertiary cyclopropanol compounds catalyzed by vanadyl acetylacetonate

Tertiary cyclopropanol compounds react with a catalytic amount of vanadyl acetylacetonate in the presence of oxygen affording β-hydroxyketones and β-diketones. For 3-substituted-bicyclo[4.1.0]alkanols, peroxides are obtained, as are the β-hydroxyketones. Conversely, 2-ethoxycarbonylcyclopropyl silyl ethers produce ethyl γ-oxocarboxylate derivatives given the same reaction conditions.     

Conformational transitions of poly(β-benzyl L-aspartate)

Conditions that affect the conformation of poly(β-benzyl L-aspartate) in films have been studied. A slow transition from the left-handed to the right-handed α-helical form is observed under certain conditions in half-dried film cast from chloroform solutions and after exposure of amorphous films of the left-handed β-helical form to chloroform vapor. This transition is caused by adsorption of moisture. Thermal transitions of these films were examined by differential scanning calorimetry and infrared spectroscopy. The right-handed α-helices change to left-handed ω-helices around 140°C, and sharp exothermic peak is observed in this region for some films.     

Bicyclo[3.3.0]octenol as an effective tool for the determination of absolute configuration of chiral acids. The absolute configuration of aryl-t-butylacetic acid

(+)-endo-cis-Bicyclo[3.3.0]oct-7-en-2-ol gave good optical yields in the kinetic resolution of aryl-t-butylacetic anhydrice, establishing the absolute configuration of t-butyl-α-naphthylacetic acid as (S) - (+).