Structure of low concentrations of vanadium on TiO2 determined by XANES and ab initio calculations

The major local structure of low concentrations (1-3 wt% V) of vanadium on TiO2 was determined to have two terminal oxo groups and in total five oxygen coordination by means of vanadium K-edge XANES and ab initio calculations of XANES spectra.     

Synthesis, structure, and reaction of 1-alkynyl(aryl)-lambda3-bromanes

Reported here for the first time are the synthesis, structure, and reaction of hypervalent 1-alkynyl(aryl)-lambda3-bromanes. BF3-catalyzed ligand exchange on bromine(III) of p-trifluoromethylphenyl(difluoro)-lambda3-bromane with 1-alkynyl(trimethyl)stannanes in dichloromethane at -78 degrees C afforded 1-alkynyl(aryl)-lambda3-bromanes in good yields. Trimethyl(trimethylsilylethynyl)stannane gave silylethynyl-lambda3-bromane selectively. 13C NMR chemical shifts of acetylenic carbon atoms of alkynylbromanes are compared with those of alkynyl-lambda3-iodanes and explained in terms of the spin-orbit-induced heavy atom effects. The structure of tert-butylethynylbromane was established by a single-crystal X-ray analysis of its crown ether complex. The 1-alkynyl(aryl)-lambda3-bromanes serve as highly electron-deficient Michael acceptors and undergo tandem Michael-carbene rearrangements by the reaction with sulfonate anions, yielding 1-alkynyl sulfonates.     

Pericyclic reaction of ketenes with cascade reaction products of pyridine N-oxides and dipolarophiles. X-ray structures of the adducts and formation mechanism

The structures of the adducts derived from the reactions of substituted ketenes with dihydropyridine derivatives have been clarified by single crystal X-ray analyses and the formation mechanism is discussed on the basis of the reaction-path calculations by semiempirical and density functional theory (DFT) molecular orbital methods.     

Atropisomers of 1-(acyl or aroyl)-2-naphthylindolines. Isolation,X-ray crystal structure and conformational analysis

A series of pairs of stable diastereomeric atropisomers caused by restricted rotation around the Csp3-Csp2 bond of [2-(2-hydroxynaphthalen-1-yl)-3,3-dimethyl-2,3-dihydroindol-1-yl]-(3- or 4-substituted phenyl)-methanone or [2-(2-hydroxynaphthalen-1-yl)-3,3-dimethyl-2,3-dihydroindol-1-yl]-1-alkanone were isolated. The conformational analyses of the atropisomers were performed based on the X-ray crystallographic and (1)H-NMR spectral data. It became clear that rotation about the C2-naphthyl bond is restricted at room temperature, whereas the >NCO-Ar bond rotates freely.     

Electrochemical Aberrant Methylation Detection Based on Ferrocenyl Naphthalene Diimide Carrying β‐Cyclodextrin,FNC

Electrochemical detection of the specific gene carrying aberrant methylated cytosine was achieved by ferrocenyl naphthalene diimide carrying β‐cyclodextrin (β‐CD), FNC, coupled with the probe‐DNA‐immobilized electrode. The five CpG sites in a 24‐base sequence were selected as the target DNA on the CDH4 gene, which is associated with colorectal cancer. When methylated and unmethylated samples hybridized with the DNA probe (HS‐M24) immobilized on the electrode, an increased current signal was observed in the electrolyte containing FNC and correlated with the amount of target DNA. Furthermore, an increase in current (115 %) was observed when the PCR product of 105 bp was hybridized on the HS‐M24‐immobilized electrode, whereas a background level of current increase was observed in the case of unmethylated product. Such large discrimination ability might be due to the inter‐ and/or intra‐complex formation of ferrocene with β‐CD of FNC on the surface of the electrode.     

Synthesis of 2-phenylbenzofuran derivatives as testosterone 5 alpha-reductase inhibitor

A series of 2-phenylbenzofuran derivatives with a carbamoyl, alkylamino, or alkyloxy group at the 5 or 6 position of the benzofuran ring were synthesized and evaluated for rat and human testosterone 5 alpha-reductase inhibitory activities in vitro. Against rat enzyme, the carbamoyl derivatives had more potent inhibitory activities than the alkylamino or alkyloxy derivatives, and the 6-carbamoyl derivatives tended to be more potent than the 5-carbamoyl derivatives. Against human enzyme, the 6-substituted derivatives had more potent inhibitory activities than the 5-substituted derivatives. The 6-carbamoyl and 6-alkylamino derivatives tended to show stronger inhibitory activities against human type 1 enzyme than against type 2 enzyme, but they were not largely selective.     

Molecularly imprinted polyethersulfone microspheres for the binding and recognition of bisphenol A

BPA-imprinted polyethersulfone (PES) microspheres for the binding and recognition of bisphenol A (BPA) were fabricated by means of a liquid-liquid phase separation technique. The imprinted novel PES microspheres had a porous structure with a skin layer, under which was followed by a finger-like structure. The recognition experiments with the BPA-imprinted microspheres were carried out by applying the microspheres to various BPA solutions. In water, high binding amounts of BPA were observed in the range of 19-42 μmol/g capacity, but the recognition was low in the BPA water solution. With the increase of the concentration in BPA solution, the binding amounts and the recognition coefficient increased. However, 1,4-butylene glycol/water media showed high recognition of the imprinted microspheres with a low binding capacity of BPA. In addtion, with the increase of the BPA amounts in the PES solution used to prepare the imprinted microspheres, the specific recognition sites increased, and the recognition ability increased. Evidence revealed that microsphere recognition was effective for BPA due to the binding to specific recognition sites [S]_(sites). The imprinted microspheres showed the selectivity for BPA in the wine including BPA and other organic compounds. Charge transfer and special cavities could be employed to explain the mechanism.     

Distribution of 67Ga-citrate in 3'-methyl-4-dimethylaminoazobenzene-induced hepatoma of rats

The distribution of 67Ga-citrate in the hepatoma of rat induced by 3'-methyl-4-dimethylaminoazobenzene was studied. 67Ga uptake ratio resected specimen, autoradiography and histological specimen were compared each other. 67Ga uptake ratio of the tumor was increased 1.6 to 7.2 times (average 4.4) to control group. Regardless of the size of the tumor, macroautoradiographically observed distribution of 67Ga-citrate in the hepatoma was higher in the peripheral zone than in the central zone. Histologically the degeneration of tumor cell was low or absent in the peripheral zone of tumor, whereas it was intense in the central zone. 67Ga-citrate was highly accumulated in the zone which the degeneration was low or absent. We, however, could not demonstrate the site where 67Ga-citrate was incorporated.     

Photoinduced Atom Transfer Radical Addition/Cyclization Reaction between Alkynes or Alkenes with Unsaturated α-Halogenated Carbonyls

We have developed a photochemical ATRA/ATRC reaction that is mediated by halogen bonding interactions. This reaction is caused by the reaction of malonic acid ester derivatives containing bromine or iodine with unsaturated compounds such as alkenes and alkynes in the presence of diisopropylethylamine under visible light irradiation. As a result of various control experiments, it was found that the formation of complexes between amines and halogens by halogen-bonding interaction occurs in the reaction system, followed by the cleavage of the carbon–halogen bonds by visible light, resulting in the formation of carbon radicals. In this reaction, a variety of substrates can be used, and the products, cyclopentenes and cyclopentanes, were obtained by intermolecular addition and intramolecular cyclization.     

Formation of interpenetrated spherulites based on miscible crystalline polymer blends

The morphology and formation process of interpenetrated spherulites of poly(butylene succinate)/poly(vinylidene choloride‐co‐vinyl chloride) (PBSU/PVDCVC) blends were investigated by confocal laser scanning microscopy (CLSM). CLSM images showed that the dense fibrils of PBSU spherulites penetrated into the sparse PVDCVC spherulites. For a blend with PBSU content 50% and crystallization temperature T_c = 368 K, the simultaneous growth of PBSU and PVDCVC spherulites was observed. After PBSU fibrils collided with PVDCVC spherulites, they kept growing through PVDCVC spherulites. For a blend with PBSU content 30% and T_c = 363 K, PBSU started to nucleate after PVDCVC spherulites filled the whole space.