bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Two Electron-Donating Substituents on Photochromism of Aryl Fulgide, 2-(2,6-Dimethyl-3,5-substituted benzylidene)-3-isopropylidenesuccinic Anhydride
Authors: Tomoda Akihiko , Kaneko Akira , Tsuboi Hideki , Matsushima Ryouka 
Published: July 2006

Abstract
Two electron-donating substituents (e.g. p-diethylaminostyryl) were introduced to an aryl structure of fulgide and photochromic performance was investigated. It was found that the strong electron-donating ability of the substituents caused a significant red shift of the colored form to the near-infrared region (λmax; 633 nm), resulting in a high molecular extinction coefficient (εmax; 24300 mol−1 cm−1). Furthermore, rapid reactions of both coloration and discoloration were observed; the quantum yields (φEC and φCE) were 0.65 and 0.052, respectively.
An Efficient and Practical Synthesis of l-α-Amino Acids Using (R)-Phenylglycinol as a Chiral Auxiliary
Authors: Inaba Takashi , Kozono Ichiro , Fujita Makoto , Ogura Katsuyuki 
Published: July 2006

Abstract
l-α-Amino acids including l-α-arylglycines were conveniently and stereoselectively synthesized via the α-amino carbonitriles given by the Strecker reaction of (R)-2-amino-2-phenylethanol with aldehydes and hydrogen cyanide. The stereoselectivity of these α-amino carbonitriles was thermodynamically controlled.
Synthesis of Non-Ester Pyrethroids Having a 1-Fluoro-1-methylethyl Group Using 1,2-Migration of an Aryl Group
Authors: Uneme Hideki , Okada Yoshiyuki 
Published: July 2006

Abstract
When 1,4-diaryl-4-methyl-1,3-pentanediol was treated with diethylaminosulfur trifluoride to introduce fluorine atoms into the central link, 1,2-aryl group migration products which have a 1-fluoro-1-methylethyl group were obtained as two diastereomers. Utilizing this migration, some non-ester pyrethroids possessing a 1-fluoro-1-methylethyl group were prepared. The reactivity of other fluorinating reagents is also discussed.
A Novel Synthesis of Allenic Lactones by Use of the [2,3]Sigmatropic Rearrangement of Cyclic Propargylsulfonium Ylides
Authors: Kido Fusao , Abiko Toshiya , Kato Michiharu 
Published: July 2006

Abstract
The [2,3]sigmatropic rearrangement of the cyclic propargylsulfonium ylides generated from ethyl 5-phenylthio-3-pentynyl and ethyl 6-phenylthio-4-hexynyl diazomalonates provided the novel allenic lactones, 2-ethoxycarbonyl-2-phenylthio-3-vinylidene-5-pentanolide and 6-hexanolide, respectively.
cis- and trans-Li[CoIII{l-tart(2–)-O1}2(en)2] Hydrate Separated from the Reaction Products of [CoIII(CO3)(en)2]+ with l-Tartaric Acid
Authors: Tomizawa Hiroshi , Harada Kazumasa , Miki Eiichi , Mizumachi Kunihiko , Ishimori Tatsujiro , Nakahara Masayoshi 
Published: July 2006

Abstract
The title compounds, trans(1) and cis(2) isomers, were isolated by means of QAE-Sephadex A-25 column chromatography from a reaction mixture of [Co(CO3)(en)2]Cl with l-tartaric acid. The crystal structure of 1 was determined by the X-ray diffraction study. The crystal is orthorhombic, space group C2221 with a = 12.008(1), b = 9.496(2), c = 18.524(4) Å, U = 2112.2(7) Å3, Z = 4, and final R = 0.0291. The two tartrate(2–) anions coordinate to the cobalt atom as a unidentate ligand in trans position each other. The two ethylenediamine rings are in the δδ gauche conformation. The lithium ion is tetrahedrally surrounded by two carboxylate oxygens of the tartrato(2–) ligands and two oxygens of the crystal waters. The compounds 1 and 2 were also characterized by UV-vis, NMR, and CD spectra.
Peroxidase-Catalyzed Chemiluminescence-Delay of Luminol for Determination of Traces of Copper(II)
Authors: Katayama Atsushi , Kamidate Tamio , Watanabe Hiroto 
Published: July 2006

Abstract
Delayed chemiluminescence (CL) was observed in the copper(II)-catalyzed oxidation of cysteamine with oxygen in the presence of horseradish peroxidase (HRP) and luminol. After preferential catalytic oxidation of cysteamine by both Cu(II) and HRP, a HRP-catalyzed luminol CL reaction was subsequently commenced with hydrogen peroxide accumulated from the catalytic oxidation. Thus, a delay time from the reaction initiation to a sharp flash of CL was observed. The HRP-catalyzed CL-delay of luminol was applied to the determination of Cu(II). The delay time was linearly correlated with the Cu(II) concentration over the range from the detection limit of 5.0 × 10−9 to 1.5 × 10−5 M. The detection limit of the present method is a factor of 30 times better than that of the conventional luminol CL method. The relative standard deviation of the delay time in five successive experiments was 3.2% at 1.0 × 10−7 M of Cu(II). The present method was highly sensitive compared to the conventional luminol CL method.
ESR Study of Active Oxygen Radicals from Photoexcited Semiconductors Using the Spin-Trapping Technique
Authors: Noda Hiroyuki , Oikawa Kazuo , Kamada Hitoshi 
Published: July 2006

Abstract
The ESR spin-trapping technique was used to detect active oxygen radicals by photoexcitation of powdery semiconductors (TiO2, WO3, CdS, and Fe2O3) in water and aqueous H2O2 solutions using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as spin trap. Superoxide ion (O2−), hydroperoxyl radical (·O2H) and hydroxyl radical (·OH) were detected under photoexcitation. The mechanism for the generation of active oxygen radicals is discussed referring to the energy band structures of the semiconductors and the redox potentials of the oxygen radicals.
Intercalation of a Trimethylammoniomethylated Calix[4]arene by Cu(II)-Montmorillonite
Authors: Kijima Tsuyoshi , Ohe Kaoru , Shinkai Seiji , Nagasaki Takeshi 
Published: July 2006

Abstract
The uptake of 5,11,17,23-tetrakis(trimethylammoniomethyl)-25,26,27,28-tetramethoxycalix[4]arene tetrachloride by Cu(II)-montmorillonite was examined at 25 °C. The mineral forms an intercalated phase in which the calixarene molecules are arranged as a 9.5 Å thick monolayer, with a cone-type conformation, with their cavity axes perpendicular to the silicate layers. Thermogravimetric and copper(II) release data suggest that the guest molecules are taken up in their tetra- and tri-valent forms during the initial and final uptake stages, respectively.
Synthesis, Characterization, and Properties of VIVO–Ln(III) (Ln = La, Pr, Eu, Gd, Tb) Complexes of N,N′-Bis(3-carboxysalicylidene)ethylenediamine
Authors: Sakamoto Masatomi , Ohsaki Masami , Yamamoto Koji , Nakayama Yusuke , Matsumoto Akira , Okawa Hisashi 
Published: July 2006

Abstract
Mononuclear oxovanadium(IV) and europium(III) complexes, [VO(H2fsaen)]·2H2O and [Eu(H2fsaen)(NO3)(H2On]·(5−n)H2O, and dinuclear oxovanadium(IV)–rare earth(III) complexes, [VOLn(fsaen)(NO3)(H2O)n]·(m−n)H2O (Ln = La, Pr, Eu, Gd, Tb), of N,N′-bis(3-carboxysalicylidene)ethylenediamine (H4fsaen) have been synthesized. Oxovanadium(IV) ion and europium(III) ion in the respective mononuclear complexes is bound at the O4-site of ligand, whereas in the VIVO–Ln(III) complexes VIVO ion is bound at the N2O2-site and Ln(III) ion at the O4-site. Based on the absorption and CD spectra, it is suggested that amino alcohols are specifically bound at the VIVO–Ln(III) heterometal center, through the nitrogen to the VIVO and through the oxygen to the Ln(III). The fluorescent spectral measurements reveal that the fluorescent bands of Eu(III) for the mononuclear Eu(III) complex are significantly quenched in the dinuclear VIVO–Eu(III) complex.
Vibrational and Rotational Raman Spectra of Trapped Hydrogen in Irradiated Ethanol Crystal at 77 K
Authors: Hase Hirotomo , Ishioka Kunie , Miyatake Yoko 
Published: July 2006

Abstract
Trapped hydrogen molecules were produced in γ-irradiated ethanol crystal at 77 K and their Raman spectra of Q- and S-branches were observed at 77 K for the first time. Relative scattering intensities of the bands due to p-H2 (Q1 (0), S0 (0)) and o-H2 (Q1(1)), S0(1)) were measured and compared with the reported results of solid normal hydrogen.
Halogenation Using Quaternary Ammonium Polyhalides. XXXII. Dichlorination of Aromatic Acetyl Derivatives with Benzyltrimethylammonium Tetrachloroiodate
Authors: Kakinami Takaaki , Urabe Yasuaki , Hermawan Irwan , Yamanishi Hiroko , Okamoto Tsuyoshi , Kajigaeshi Shoji 
Published: July 2006

Abstract
The reaction of aromatic acetyl derivatives with 2 molar amounts of benzyltrimethylammonium tetrachloroiodate in acetic acid at 70 °C for several hours gave dichloroacetyl derivatives in good yields.
Triphenylselenonium Salts as Effective Phase-Transfer Catalysts
Authors: Kondo Shuji , Shibata Akihiro , Kunisada Hideo , Yuki Yasuo 
Published: July 2006

Abstract
Triphenylselenonium salts work as highly efficient phase-transfer catalysts for nucleophilic substitution reaction of octyl bromide and addition reaction of dichlorocarbene to olefins.
Effects of Pd Dispersion on the Catalytic Activity of Pd/SiO2 for Ethylene Hydroformylation
Authors: Takahashi Nobuo , Tobise Tatsushi , Mogi Isao , Sasaki Makoto , Mijin Akihiko , Fujimoto Toshiyuki , Ichikawa Masaru 
Published: July 2006

Abstract
In ethylene hydroformylation over Pd/SiO2 catalysts with 17–85% Pd-dispersion, the turnover frequency for propionaldehyde formation increased with the Pd dispersion, particularly in the region of higher dispersion, suggesting the responsibility of atoms at the corners and at edges on the surface of Pd metal particles for this reaction.
Heterogeneous Amine Catalyst Grafted on Amorphous Silica: An Effective Organocatalyst for Microwave-promoted Michael Reaction of 1,3-Dicarbonyl Compounds in Water
Authors: Hagiwara Hisahiro , Inotsume Sachiyo , Fukushima Masakazu , Hoshi Takashi , Suzuki Toshio 
Published: July 2006

Abstract
Michael addition of a 1,3-dicarbonyl compound to an α,β-unsaturated carbonyl compound was effectively catalyzed by heterogeneous N,N-diethylaminopropylated silica gel (NDEAP) in water under microwave heating. The reaction condition was mild, practical, and environmentally benign. The sustainable nature of the catalyst was exemplified by re-use up to 5 times.
Mesophase Control of Mesoporous Silica Thin Films by Vapor-phase Preparation
Authors: Tanaka Shunsuke , Hillhouse Hugh W 
Published: July 2006

Abstract
Highly ordered mesoporous silica thin films with c2mm rectangular and R3m rhombohedral symmetry have been synthesized on a silicon substrate by a vapor-phase method using PEO106–PPO70–PEO106 triblock copolymer as a templating agent.
Oligonucleotide-bound Eu(III) as a Probe for Microenvironments at Specific Site in DNA
Authors: Sumaoka Jun , Kojima Yuki , Komiyama Makoto 
Published: July 2006

Abstract
By attaching Eu(III)/β-diketone complex covalently to oligonucleotide, microenvironments at a specific site in DNA have been probed. The conjugate efficiently emits luminescence, since coordination of water to the Eu(III) is competitively inhibited by the internal phosphodiester groups. In the presence of complementary DNA, however, this inhibition is diminished because of rigidity of double-stranded DNA and the emission becomes much weaker. The emission intensity is also affected by other environmental changes.
Modification of Highly Dispersed Cerium Oxides on Silica with Highly Dispersed Titanium Oxides as a New Photocatalyst Design for Nonoxidative Direct Methane Coupling
Authors: Yuliati Leny , Itoh Hideaki , Yoshida Hisao 
Published: July 2006

Abstract
Modification of ceria-based photocatalyst with titanium oxide resulted in formation of highly dispersed cerium and titanium oxides on silica, where both species exhibited photoactivities for nonoxidative direct methane coupling. A new design of photocatalyst was proposed here.
Photoinduced Release of Fluorescent Probe in the Presence of Target DNA: Synergetic Effect of Two Types of Oligonucleotides with Indolequinone–Coumarin Conjugate and Flavin Photosensitizer
Authors: Tanabe Kazuhito , Tachi Yukihiro , Okazaki Arimichi , Nishimoto Sei-ichi 
Published: July 2006

Abstract
We have synthesized and evaluated two types of functionalized oligodeoxynucleotides (ODNs) that can release a fluorescent coumarin probe via co-hybridization with a target DNA base sequence and subsequent photoirradiation. Photoirradiation of flavin-bearing ODN in the presence of a counterpart ODN with indolequinone–coumarin conjugate and a target complementary DNA strand gave rise to the efficient release of coumarin with a multiple turnover as a result of intermolecular flavin-photosensitized reduction of indolequinone–coumarin conjugate, while the release of coumarin was considerably suppressed in the absence of the target DNA. Concomitant with this photoreaction, we could observe intense fluorescence emission from the sample solution photoirradiated with the target DNA, but weak fluorescence from a control solution without the target DNA.
Synthesis and Characterization of Dimetallostannafluorenes
Authors: Saito Masaichi , Shimosawa Masakazu , Yoshioka Michikazu , Ishimura Kazuya , Nagase Shigeru 
Published: July 2006

Abstract
The reaction of 9,9-bis(p-methoxyphenyl)-9-stannafluorene with lithium or potassium gave the corresponding dimetallostannafluorene, as evidenced by NMR spectral analysis and a trapping experiment.
Self-assemblage of Single/Multiwall Hollow CeO2 Microspheres through Hydrothermal Method
Authors: Zhang Youjin , Hu Qixiu , Fang Zhiyong , Cheng Tao , Han Kaidong , Yang Xiaozhi 
Published: July 2006

Abstract
Novel single/multiwall hollow CeO2 microspheres were synthesized by self assemblage through hydrothermal method without any surfactant, the shells of which were consisted of CeO2 nanoparticles with mean size of 70 nm. The influence of the molar ratio of urea to Ce(NO3)3·6H2O on the morphology of the products was investigated and the formation mechanism of single/multiwall hollow CeO2 was proposed.
Approaches to rotary molecular motors
Authors: Hawthorne M. Frederick , Ramachandran Bhaskar M. , Kennedy Robert D. , Knobler Carolyn B. 
Published: July 2006

Abstract
Interest has recently intensified in the search for molecular motors and actuators capable of delivering useful work to nanodevices under the control of electrochemical or photochemical power sources. While many of these man-made molecular machines are designed to deliver rectilinear motion, very few are proposed for the controlled delivery of rotary motion on the time scale characteristic of intramolecular rearrangements. The adaptation of commo-bis-dicarbollide metallacarborane structures to the possible design and synthesis of such rotary molecular motors is now under investigation. Progress toward this goal will be reported.
Syntheses and chemistry of bis- and tris-mercaptoborates
Authors: Shore Sheldon G. , Hamilton Ewan J. M. , Kultyshev Roman G. , Leung Hoitung T. , Yisgedu Teshome 
Published: July 2006

Abstract
The preparation and chemistry of bis- and tris-mercaptoborates based on closo-B12 and closo-B10 structures is described. These species undergo a number of reactions such as halogenation and alkylation without changing the closo-borane core. Addition of the third dimethylsulfide substituent to the closo-boranes is thought to proceed via an unusual cationic intermediate.
Recent developments in the chiral synthesis of homoallylic amines via organoboranes
Authors: Ramachandran P. Veeraraghavan , Burghardt Thomas E. 
Published: July 2006

Abstract
Among the plethora of protocols for the preparation of chiral homoallylic amines, the use of boron-based reagents remains relatively undeveloped. However, the recent advances in the use of α-pinene-based versatile reagents for the synthesis of such amines confirmed that very high enantioselectivity and outstanding diastereoselectivity can be readily achieved. Addition of the "allyl"boron reagents to various N-substituted imines provided the desired amine products in high yields and high to very high ee. The discovery that an addition of 1.0 equiv of methanol or water to the "allyl"boration reaction with N-masked imines is critical allowed for higher yields and noticeably improved ee. The use of N-aluminoimines, which are not only easy to prepare by a partial reduction of nitriles, but are also relatively stable for both enolizable and non-enolizable substrates, considerably expanded the scope of the reactions. In this review, the developments in the syntheses of chiral homoallylic amines using organoboranes, with the particular accent on the reagent-controlled reactions, are summarized. Additionally, the novel methodology for the crotyl- and alkoxyallylboration of imines using trialkylboron "ate" complexes is described.
Pharmacologically active boranes
Authors: Jabbour Adel , Smoum Reem , Takrouri Khuloud , Shalom Eli , Zaks Batia , Steinberg Doron , Rubinstein Abraham , Goldberg Israel , Katzhendler Jehoshua , Srebnik Morris 
Published: July 2006

Abstract
Novel methods are described for the preparation of alkyldimethylamine cyanoboranes and β-hydroxylalkyldimethylamine cyanoboranes by C-lithiation of trimethylamine cyanoboranes followed by reaction with alkyl halides, aldehydes, and ketones. Lithiation of the monobromo derivatives of amine cyanoboranes led to the synthesis of the first examples of diborane derivatives of amine cyanoboranes. Bromo derivatives of amine cyanoboranes and amine carboxyboranes have been synthesized by new simple and efficient methods. Amine fluorocyanoboranes and amine fluorocarboxyboranes, new classes of compounds, have been prepared from the bromo precursors by fluorine/bromine exchange using fluorinating reagents such as AgF and Et3N.3HF. Eight different derivatives of oxazaborolidines were synthesized and evaluated for their affect on Streptococcus mutans viability, adhesion, and biofilm formation using 3[H]-thymidine labeled bacteria, and fluorescent stained bacteria. This is the first reported antibacterial activity of this class of compounds. The minimal inhibitory concentration (MIC) values ranged from 0.26 to 10 mM. Structure-activity relationship was observed. The B-butyl moiety of the oxazaborolidines contributed an anti-adhesion effect for all derivatives, while its effect diminished when the boron atom was incorporated in a fused heterocyclic ring. The B-phenyl group induced bacterial adhesion in all tested compounds. In a separate study for boronated saccahrides and enzymatic inhibition, the complex formation between N-butylboronic acid and a series of monosaccharides was investigated by 1H, 13C, and 11B NMR spectroscopy and gas chromatography-mass spectrometry (GC-MS). Then, a series of boronic acid compounds with protease inhibition properties were prepared. The effect of added mono-, di-, and polysaccharides on the inhibitory activity of these compounds was studied. Potassium organotrifluoroborates were found to be reversible competitive inhibitors of α-chymotrypsin and trypsin. Based on 19F NMR, it was speculated that they inactivate the enzymes as a result of the formation of hydrogen bonds between fluorine atoms of the inhibitors and the serine protease.
Standards, calibration, and guidelines in microcalorimetry. Part 2. Calibration standards for differential scanning calorimetry* (IUPAC Technical Report)
Authors: Della Gatta Giuseppe , Richardson Michael J. , Sarge Stefan M. , Stølen Svein 
Published: July 2006

Abstract
Differential scanning calorimeters (DSCs) are widely used for temperature, heat capacity, and enthalpy measurements in the range from subambient to high temperatures. The present recommendations describe procedures and reference materials (RMs) for the calibration of DSCs. The recommendations focus on the calibration of the response of the instrument and on the estimation of the measurement uncertainty. The procedures for temperature, enthalpy, and heat-flow rate calibration are given in detail. Calibration on cooling has also been considered. Recommended RMs are listed, and the relevant properties of these materials are discussed.
β-Carotene and angiogenesis
Authors: Dembińska-Kieć Aldona , Malczewska-Malec Malgorzata , Polus Anna , Kieć-Wilk Beata , Grzybowska Joanna , Stachura Jerzy , Dyduch Grzegorz , Pryjma Julian , Skrzeczyńska Joanna , Langman Thomas , Bodzioch Marek , Partyka Łukasz , Schmitz Gerd 
Published: July 2006

Abstract
Carotenoids and retinoids modulate growth and differentiation of a variety of cell types and are fundamental regulators of development. Endothelial cells play an important role in angiogenesis, which is essential for organogenesis and tissue remodeling, but also inflammatory response or carcinogenesis. Binding to the retinoid (RARs) or rexinoid (RXRs) receptors, all-trans-RA, 13-cis-RA, 9-cis-RA, and synthetic retinoids and rexinoids showed antiangiogenic properties in several models. However, the role of β-carotene in endothelial cell function and angiogenesis is still poorly characterized. Although in our experiments, β-carotene used in nontoxic concentrations (up to 3 μM) had no detectable effect on the proliferation or apoptosis of HUVECs or umbilical-cord-blood-derived endothelial progenitors; β-carotene did not change the tubulogenic activity of cells in an in vitro angiogenesis model, but it potently activated the migration of endothelial and progenitor cells. β-Carotene also promoted the development of microcapillaries in a matrigel plug injected subcutaneously into mice. The analysis of microarray data from endothelial cells revealed that β-carotene modified the expression of genes involved in activation of chemotaxis, cell/cell and cell/matrix adhesion, matrix reorganization, G-protein-regulated intracellular signaling as well as genes involved in the rapid remodeling of the actin cytoskeleton. We conclude that physiological levels of β-carotene stimulate early steps of angiogenic activity of endothelial cells by activation of cellular migration as well as matrix reorganization and reduction of cell adhesion.
Distribution and metabolism of dietary carotenoids in humans as a criterion for development of nutritional supplements
Authors: Khachik Frederick 
Published: July 2006

Abstract
There are approximately 40-50 carotenoids in commonly consumed fruits and vegetables in a typical U.S. diet. These can be divided into carotenoid epoxides, mono- and dihydroxycarotenoids, hydrocarbon carotenoids, and carotenol acyl esters. However, among these, only a selected group of carotenoids are routinely found in human plasma, breast milk, major organs, and ocular tissues. In addition, several carotenoid metabolites have also been isolated and characterized from human plasma, tissues, and ocular tissues. The proposed metabolic transformation of carotenoids in humans will be discussed. Dietary carotenoids and their metabolites have been implicated in the prevention of cancer, cardiovascular disease, and age-related macular degeneration (AMD). An approach for the development of a nutritional supplement that is based on the distribution of carotenoids and their metabolites in humans will be discussed.
Reactive intermediates in aqueous ozone decomposition: A mechanistic approach
Authors: Fábián István 
Published: July 2006

Abstract
This paper provides a detailed account of recent developments in the mechanistic interpretation of aqueous ozone decomposition. Experimental complications with collecting reliable kinetic information for this system are illustrated via a few examples. Classical and comprehensive data treatment methods are compared, and an advanced kinetic model is presented on the basis of simultaneous evaluation of about 60 kinetic traces recorded at 260, 430, and 600 nm. These are the wavelengths of the absorbance maxima of O3, O3
-, and CO3
-, respectively. The model is used to explore specific features of the initiation sequence, the role of reactive intermediates, and the carbonate ion inhibition. It is also demonstrated how a complex kinetic model can be validated by studying the system under specific experimental conditions.