bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Reactions of Aromatic Anions with Quaternary Ammonium Ions in Ion Association-Nonionic Micellar Electrokinetic Chromatography
Authors: Takayanagi Toshio , Fushimi Kana , Motomizu Shoji 
Published: September 2002

Abstract
Reactions in ion association-nonionic micellar electrokinetic chromatography have been analyzed using mobility change in capillary electrophoresis. Several quaternary ammonium ions and aromatic anions were used as pairing cations and anions, respectively, and three kinds of nonionic surfactant were used to form micelles in an aqueous solution. The apparent electrophoretic mobility of the analyte anions decreased with increasing concentrations of nonionic surfactant and/or pairing cation. The equilibrium reactions participating in this electrophoresis system are binding of anions to nonionic surfactant micelle (KB), ion association of anions with pairing cation (Kass), and distribution of the formed ion associates to the nonionic surfactant micelle (KB,IA). The equilibrium constants were determined by non-linear least-squares analyses by applying the analyses to the mobility decreases. Equilibrium constants of KB and KB,IA for monovalent anions were found to be larger than those for divalent anions, and KB,IA values for each anions were larger than their KB values. The results obtained can be explained from distribution phenomena of analytes between aqueous and organic phases.
ORMOSIL Composite Phosphors Incorporated with Lanthanide Complexes
Authors: Li Hui-hui , Inoue Satoshi , Ueda Daisuke , Machida Ken-ichi , Adachi Gin-ya 
Published: September 2002

Abstract
Lanthanide complexes, [Eu(phen)2]Cl3 and [Tb(bpy)2]Cl3, were doped into organically modified silicate (ORMOSIL) matrices over a wide range of composition. The features and luminescence behavior of the resultant composite products were strongly dependent on the matrix composition. Transparent ORMOSIL composite phosphor disks were obtained under the optimized complex concentration and matrix composition, as well as with careful control of the drying process. Luminescence property varieties of the composites based on various matrix compositions were studied and interpreted from the viewpoint of local chemical environment around the doped complex molecules. Those for composite phosphors incorporated with [Eu(phen)2]Cl3 were additionally characterized by the 5D0-7F2 to 5D0-7F1 emission intensity ratio. Illustrative models of the lanthanide complex-containing sol-gel derived composites were proposed.
Practical Synthesis of [3-(2H3)Methyl]mevalonolactone and Incorporation Experiment of [3-(2H3)Methyl]mevalonolactone and [13C]Labeled Acetate in the Biosynthesis of Isoprenoidal Diether Lipids of Halophilic Archaea
Authors: Yamauchi Noriaki , Natsubori Yoshiaki , Murae Tatsushi 
Published: September 2002

Abstract
The biosynthesis of the saturated isoprenoid portion of membrane lipids of the halophilic archaea Natrinema pallidum was investigated. At first, a practical method for the synthesis of [3-(2H3)methyl]mevalonate was developed. Then, incorporation experiments of [3-(2H3)methyl]mevalonate into the lipid core indicated that the isoprenoid portion was derived from mevalonate. However, a [2-13C]acetate-incorporation experiment revealed a significant difference in the degree of 13C enrichment between the expected position from the mevalonate pathway, the CH2 groups (and at one terminal CH3 group) and the CH3 groups in the saturated isoprenoid chain. These results suggest that (1) the mevalonate pathway exists and is active, and (2) a part of acetoacetyl-CoA is not derived from an acetate in the biosynthesis of the isoprenoidal lipid-core of the archaebacterium.
Syntheses of Penta-O-benzyl-myo-inositols, O-β-L-Arabinosyl-(1 → 2)-sn-myo-inositol, O-α-D-Galactosyl-(1 → 3)-sn-myo-inositol, and O-α-D-Galactosyl-(1 → 6)-O-α-D-galactosyl-(1 → 3)-sn-myo-inositol
Authors: Koto Shinkiti , Hirooka Motoko , Yoshida Toyosaku , Takenaka Kazuhiro , Asai Chizuru , Nagamitsu Toshiki , Sakuma Hiroaki , Sakurai Michiyo , Masuzawa Shinichi , Komiya Mitsuo , Sato Tadaaki , Zen Shonosuke , Yago Kazuo , Tomonaga Fumiya 
Published: September 2002

Abstract
Two-step conversions of myo-inositol into (±)-2,3,4,5,6- and 1,3,4,5,6-penta-O-benzyl-myo-inositols are described. Starting from these monohydroxy derivatives of myo-inositol, O-β-L-arabinopyranosyl-(1 → 2)-sn-myo-inositol from Japanese green tea [SENCHA], Camellia sinensis, and O-α-D-galactopyranosyl-(1 → 3)-sn-myo-inositol (galactinol) as well as its homolog, O-α-D-galactopyranosyl-(1 → 6II)-galactinol, were synthesized by way of the in situ activating glycosylation procedure.
Exploration of the Role of Phenylalanine in the Thrombin Receptor Tethered-Ligand Peptide by Substitution with a Series of Trifluorophenylalanines
Authors: Matsushima Ayami , Fujita Tsugumi , Okada Kazushi , Shirasu Naoto , Nose Takeru , Shimohigashi Yasuyuki 
Published: September 2002

Abstract
The thrombin receptor-tethered ligand SFLLRNP (abbreviation formed by one letter amino acid codes expressing Ser-Phe-Leu-Leu-Arg-Asn-Pro) consists of the Phe-2 residue essential for the receptor activation. In order to explore the molecular characteristics of this Phe-2-phenyl, a series of trifluorophenylalanines [(F3)Phe] was incorporated into this S/Phe/LLRNP for evaluation of their ability to induce the human platelet aggregation. A complete set of (F3)Phe in the L-configuration, namely, (2,3,4-F3)Phe, (2,3,5-F3)Phe, (2,3,6-F3)Phe, (2,4,5-F3)Phe, (2,4,6-F3)Phe, and (3,4,5-F3)Phe, was prepared from trifluorobenzyl bromides and diethyl acetamidomalonate. S/(2,3,4-F3)Phe/LLRNP was equipotent to S/Phe/LLRNP, while (2,4,5-F3)Phe-containing analog was almost twice as potent as those. (2,4,6-F3)Phe-analog exhibited about a half of the activity of S/Phe/LLRNP. (3,4,5-F3)Phe-, (2,3,5-F3)Phe-, and (2,3,6-F3)Phe-analogs were very weak. The analysis of these assay results suggested that Phe-2-phenyl of SFLLRNP is in the edge-to-face CH/π interaction with the receptor aromatic group, utilizing the Phe-2-phenyl edge along with benzene hydrogens at position 2-3 or 5-6. The computer-assisted semi-empirical molecular orbital calculations by MOPAC showed that the fluorine atom decreases the electron density of its ortho, meta, and para hydrogens, and thus increases their acidity more strongly in that order. All these suggested that H → F replacements reinforce the edge-to-face CH/π interaction to enhance biological activity. The H → F replacement on the Phe-phenyl group was found to render an effective structural examination; i.e., to identify the hydrogens in the CH/π interaction, and to intensify the CH/π interaction.
Flavin Receptors. Effect of the Acidity of Melamine Derivatives Bearing a 2-Arylguanidinium Ion on 6-Azaflavin Binding in Chloroform
Authors: Moriya Hideki , Kajiki Takeshi , Watanabe Shigeki , Kondo Shin-ichi , Yano Yumihiko 
Published: September 2002

Abstract
The pKa's of melamine derivatives bearing a 2-arylguanidinium ion and their binding constants for 6-aza-10-dodecylisoalloxazine (6-azaflavin) were nicely correlated with the Hammett σ of the substituents. However, the rates of the oxidations of N-benzyl-1,4-dihydronicotinamide (BNAH) and dithiothreitol (DTT) by 6-azaflavin were not affected by the substituents of the receptors in CHCl3.
Interactions of a Dye and a Solvent with Poly(N-isopropylacrylamide) Gel in Relation to Its Phase-Transition Behavior
Authors: Murase Yasuyuki , Onda Tomohiro , Tsujii Kaoru , Tanaka Toyoichi 
Published: September 2002

Abstract
The binding of a dyestuff and the sorption of a solvent to a polymer gel have been studied in relation to the phase-transition behavior of the gel. Binding or sorption isotherms of a dye (erythrosine B) and a solvent (benzyl alcohol) to a polymer gel (poly(N-isopropylacrylamide) : NIPA) were measured and found first to be Langmuir- and BET-type curves, respectively. A single Langmuir-type adsorption isotherm and the superposition of the two isotherms of the dye were fit for the collapsed (40 °C) and swollen states (25 °C) of the gel, respectively. The phase-transition behavior of the NIPA gel was not affected at all by binding of the dye, but was highly altered by the addition of benzyl alcohol. A reentrant-type phase transition of the NIPA gel was observed with increasing concentration of benzyl alcohol at 25 °C. It is quite interesting to note that the gel shrinks when the concentration of the solvent inside the gel attains its solubility limit (ca. 0.4 mol dm-3), and swells again when it reaches the solubility in the bulk solution phase (outside the gel). At the stage of re-swelling, the solution in the gel interior consists of almost pure benzyl alcohol. These results indicate that the NIPA gel shows a selective sorption of benzyl alcohol, and separates it from its aqueous solutions.
The Role of Deltorphin II Phenylalanine Residue in Binding to the δ Opioid Receptor
Authors: Honda Takeshi , Shirasu Naoto , Chuman Yoshiro , Okada Kazushi , Fujita Tsugumi , Nose Takeru , Shimohigashi Yasuyuki 
Published: September 2002

Abstract
Deltorphin II is a peptide ligand specific for the δ opioid receptor. In order to elucidate the role of Phe3 in binding to the δ opioid receptor, we synthesized a series of analogs in which Phe3 was replaced by various amino acids such as Ala, cyclohexylalanine (Cha), fluorophenylalanines, and other alkyl-side chain amino acids (Val, Leu, and norleucine (Nle)). It was found that [Cha3]deltorphin II and [Nle3]deltorphin II retain almost a full receptor binding affinity. The results indicated that the Phe3-phenyl group of deltorphin II can be substituted by the alkyl groups such as cyclohexyl and propyl in the interaction with the δ receptor.
New Organogelators Bearing Both Sugar and Cholesterol Units: an Approach toward Molecular Design of Universal Gelators
Authors: Amaike Masato , Kobayashi Hideki , Shinkai Seiji 
Published: September 2002

Abstract
The gelators of organic solvents are classified into two categories on the basis of their basic intermolecular forces: hydrogen-bonded or nonhydrogen-bonded. To utilize these two interactions cooperatively for organogel formation we newly synthesized seven gelators (1—7) and two reference compounds (8 and 9) which have both a cholesterol moiety and a saccharide moiety within one molecule. The solubility of 1—7 changed drastically from totally insoluble one to very soluble one depending on the saccharide absolute configuration. In general, the gelator became very insoluble when it includes many equatorial OH groups, whereas it became very soluble when it includes many axial OH groups. Gelators 2 and 5 bearing two equatorial OH groups and one axial OH group acted as good gelators and in several cases the sol-gel phase-transition temperatures (measured in a sealed tube) were higher than the boiling points. The SEM observations of the xerogels established that the stable gels contain the entangled fibrous network. These results indicate that a very stable organogel can be designed by a cooperative coagulative effect of a cholesterol-cholesterol interaction and a saccharide-saccharide interaction.
Rhodium-Catalyzed Enantioselective Michael Addition of (1-Cyanoethyl)phosphonate: Synthesis of Optically Active Phosphonic Acid Derivatives with Phosphorus-Substituted Quaternary Asymmetric Carbon Center
Authors: Sawamura Masaya , Hamashima Hitoshi , Ito Yoshihiko 
Published: September 2002

Abstract
Asymmetric Michael addition of diethyl (1-cyanoethyl)phosphonate with vinyl ketones or acrylaldehyde in the presence of 0.01 molar amount of a rhodium catalyst prepared in situ from Rh(acac)(CO)2 and a trans-chelating chiral diphosphine ligand (R,R)-(S,S)-2,2′′-bis[1-(diphenylphosphino)ethyl]-1,1′′-biferrocene (PhTRAP) in benzene at 3 °C gave optically active phosphonates having a phosphorus-substituted quaternary asymmetric carbon center with high enantiomeric excesses (92—93% ee) in high yields. The Michael addition product from acrylaldehyde was converted into an optically active (1-aminoalkyl)phosphonic acid derivative.
Reactivities of Stable Rotamers. XLIII. Diazotization of 2-Methyl-2-(1,2,3,4-tetrachloro- and 1,4-dimethoxy-9-triptycyl)propylamine Rotamers
Authors: Oki Michinori , Yoshida Satoshi , Taguchi Yasushi , Minato Ichiro , Nobuoka Koji , Fukada Norihiro , Toyota Shinji , Tanaka Toshimasa , Tanaka Yasuhiro , Yamamoto Gaku 
Published: September 2002

Abstract
The title amines were prepared from the corresponding rotamers of carboxylic acids via azides and isocyanates. Diazotization of these amines with isopentyl nitrite and organic acids commonly afforded olefins, that are derived from Wagner-Meerwein type rearrangement of the intervening cation followed by deprotonation. Other products included a cyclic compound derived by the attack of the carbocation on an unsubstituted benzeno bridge and esters derived from the acid which was used for diazotization. These two compounds are the products from the cation prior to the rearrangement. The sc-tetrachloro compound afforded the esters of the organic acids as almost an exclusive product and the sc-dimethoxy compound afforded a cyclized compound which is derived from the nucleophilic reaction of the 1-methoxy group with the cation, followed by demethylation of the resulting oxonium ion. These features are attributed to the strong interaction of the 1-substituent with the intermediate carbocations. In agreement with this interpretation, the formation of the corresponding ester is decreased with decreasing the nucleophilicity of the acid used for the diazotization of the sc-tetrachloro compound.
Catalytic Asymmetric Hydrogenation of α-(Acetamido)acrylates Using TRAP Trans-Chelating Chiral Bisphosphine Ligands: Remarkable Effects of Ligand P-Substituent and Hydrogen Pressure on Enantioselectivity
Authors: Kuwano Ryoichi , Sawamura Masaya , Ito Yoshihiko 
Published: September 2002

Abstract
The catalytic asymmetric hydrogenation of α-(acetamido)acrylates was carried out with the rhodium complexes prepared from [Rh(cod)2]BF4 and trans-chelating chiral bisphosphine ligands, (S,S)-2,2′-bis[(R)-1-(dialkylphosphino)ethyl]-1,1′-biferrocenes [(R,R)-(S,S)-TRAPs]. In the reaction of β-unsubstituted or β-monosubstituted α-(acetamido)acrylates [(E)-RCH=C(NHAc)CO2Me], the selectivity for (R)-hydrogenation product increased with decreasing steric demand of the substrate β-substituent and the ligand P-substituent as well as decreasing hydrogen pressure. The selectivity for the (R)-product in the reaction with EtTRAP-rhodium catalyst at 60 °C and 0.5 kg cm-2 of hydrogen pressure was as follows: R = H, 96% ee; R = Me, 92% ee; R = Ph, 77% ee; R = i-Pr, 57% ee. The remarkable steric and pressure effects caused a dramatic reversal of enantioselectivity in the reaction of methyl 2-(N-acetylamino)cinnamate (R = Ph). For example, the selectivity of 87% (R) with EtTRAP at 60 °C and 0.1 kg cm-2 of hydrogen pressure has reversed to 92% (S) with i-BuTRAP at 15 °C and atmospheric hydrogen pressure. Hydrogenation of the β,β-disubstituted α-(acetamido)acrylates proceeded smoothly at 15 °C and atmospheric hydrogen pressure with high enantioselectivity in favor of the 2S-isomers when EtTRAP or BuTRAP was employed as the chiral ligand.
Diastereoselective Aldol and Reformatsky Reactions of α-Halo Carbonyl Compounds and Aldehydes Mediated by Titanium(II) Chloride
Authors: Kagayama Akifumi , Igarashi Koji , Shiina Isamu , Mukaiyama Teruaki 
Published: September 2002

Abstract
Highly diastereoselective aldol reactions of α-bromo ketones with several aldehydes were successfully carried out by using a combination of titanium(II) chloride and copper or sodium iodide in dichloromethane-pivalonitrile at low temperature. Similarly, Reformatsky reactions of α-bromo thioester with aliphatic aldehydes proceeded to afford β-hydroxy thioesters in good yields under mild conditions.
Interaction Mode of H397A Mutant Carboxypeptidase Y with Protein Substrates Analyzed by the Surface Plasmon Resonance
Authors: Nakase Hiroshi , Jung Giman , Ueno Hiroshi , Hayashi Rikimaru , Harada Yoshinori 
Published: September 2002

Abstract
In order to study the substrate binding mode and subsite properties of carboxypeptidase Y (CPY), the dissociation and association constants, KD and KA, of its catalytically inactive mutant, H397A, were determined by surface plasmon resonance with protein substrates, i.e., α-casein, RCM-RNase A, RCM-lysozyme, and RCM-BSA. KD values obtained for four substrates were in a range of 10-8 to 10-7 M, being equal to Km values of catalytically active wild-type CPY for the same protein substrates. These results suggest that the acylation step is a rate-limiting step in the CPY-catalyzed hydrolysis of protein substrates. Small substrates like N-acylated dipeptides gave Km values in a range of 10-4 to 10-2 M, considerably smaller than those for protein substrates, suggesting the presence of additional subsites in addition to S1′ and S1 in the substrate binding pocket of CPY.
Synthesis of Optically Active 2-Methylchroman Derivatives and Application to Chiral Dopants for Nematic Liquid Crystals
Authors: Shitara Hiroaki , Aoki Yoshio , Hirose Takuji , Nohira Hiroyuki 
Published: September 2002

Abstract
Chiral 2-methylchroman-2-carboxylic acid derivatives were prepared as new chiral dopants for nematic liquid crystals. The starting material, optically active 6-benzyloxy-2-methylchroman-2-carboxylic acid, was newly synthesized as a rigid core structure and resolved by a diastereomeric salt formation method. Its absolute configuration was determined by comparing its circular dichroism spectrum with that of the commercially available (S)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid derivative. The helical twisting power of the new dopants was determined and the relationship between their functional groups and flexible terminal structures was studied.
Rotational Isomerism Involving an Acetylenic Carbon II : Effect of 1-Halogen Substituents on Rotamer Population and Rotational Barrier around C(sp)-C(sp3) Bonds in Bis(9-triptycyl)ethynes
Authors: Toyota Shinji , Yamamori Takao , Makino Toshiaki , Oki Michinori 
Published: September 2002

Abstract
A series of (1,4-dimethyl-9-triptycyl)(1-halo-9-triptycyl)ethynes were synthesized to examine the effect of halogen substituents on the rotational isomerism about C(sp)-C(sp3) bonds. The kinetic and thermodynamic data of the isomerization between the ap and sc rotamers were determined by the total lineshape analysis and the intensity of the 1H NMR signals, respectively. The rotational barriers are enhanced with the steric size of halogen atoms from 11.6 (F) to 17.3 (I) kcal mol-1, and there is a linear correlation between the barrier height and van der Waals radius of the 1-substituent. Although large halogen atoms decrease the ratio of the sterically congested sc form, its population tends to be larger than that expected from the steric effect. This finding is attributable to the C-H…X(halogen) interactions between the 1-Me and X groups in the sc form. The possibility of the weak interactions is discussed on the basis of molecular structures optimized by the MM2 calculations.
The Ion-Exchange Property of Some Layered Inorganic Materials with Potassium Ion, Rubidium Ion and Cesium Ion, and Selective Cesium Ion-Exchange of Synthetic Mica
Authors: Suzuki Noriko , Yamamoto Daisuke , Anaguchi Noriko , Tsuchiya Hiroko , Aoki Kumi , Kanzaki Yasushi 
Published: September 2002

Abstract
The ion-exchange property of sodium difluorotetrasilicate, Na-TSM, with potassium, rubidium and cesium ions was investigated in addition to two other typical layered inorganic materials. The selectivity sequence of Na-TSM was Cs+ &gt; Rb+ &gt; K+ and the selectivity difference of Na-TSM was highest among the examined layered materials. It was found from a chemical analysis that cesium ion-exchange participated in magnesium ions, which is a lattice component of Na-TSM, in addition to an ordinary ion-exchange reaction with the interlayer sodium ions. The exchange of cesium ions with magnesium ions was found to be stoichiometric, and was expected to be an ideal ion-exchange reaction. It was a peculiar phenomenon only on Na-TSM. Once cesium ions were exchanged in a Na-TSM lattice, they were hardly released, due to a reverse ion-exchange with sodium ions. The highest selectivity difference and tight binding of cesium ions were interpreted by an ion-exchange with lattice magnesium ion as well as decreased dehydration, which resulted in the interlayer gallery height.
Synthesis and Characterization of Titanium-Containing Mesoporous Silica by a Non-Hydrothermal Microwave Method
Authors: Belhekar Anagha , Agashe Mangala , Soni Hirji , Sathaye Shivaram , Jacob Nalini , Thundimadathil Jyothi 
Published: September 2002

Abstract
We report on a new method for preparing mesoporous silica and titanium-containing mesoporous silica using microwave (MW) synthesis under non-hydrothermal conditions. The materials were characterized by XRD, nitrogen adsorption, UV-vis and FTIR techniques, and compared with a sample prepared by the conventional method. A single peak at 2θ = 2.4° in the XRD pattern showed the formation of mesoporous silica. A typical isotherm, characteristic of a mesoporous material where pore filling occurred at p/p0 in the range of 0.2—0.3 was obtained for nitrogen sorption. UV-vis diffused reflectance spectra showed bands at 210—220 nm and a shoulder at 270 nm, indicating the presence of Si-O-Ti bonds for titanium-containing mesoporous silica. This new method has been observed to have inherent advantages over reported methods, such as instant start up, a short heating time and low cost. These mesoporous titanosilicates prepared using a microwave heat energy source are active in the oxidation of 2,6-diisopropylphenol (DIPP) and 2,6-di-t-butylphenol (DTBP) with hydrogen peroxide as an oxidant.
Dye-Sensitized Photocells with Meso-Macroporous TiO2 Film Electrodes
Authors: Ito Seigo , Ishikawa Keiji , Wen Ching-Ju , Yoshida Shoichiro , Watanabe Tadashi 
Published: September 2002

Abstract
Meso-macroporous anatase TiO2 films, described in a previous work, have been used for the first time as electrodes for dye-sensitized photoelectrochemical cells. The mesopores provide a large surface area that is favorable for efficient light absorption, and the macropores serve as pathways for diffusion of electroactive agents (EAAs). Although the introduction of macropores led to an improvement in the magnitude of the short-circuit photocurrent (Jsc), electron recombination on the SnO2 substrate surface at the bottom of the macropores deteriorated the open-circuit voltage (Voc). This unfavorable process has been depressed by applying a thin (200 to 300 nm) TiO2 film between the meso-macroporous film and the SnO2 substrate, to obtain finally a dye-sensitized photoelectrode with a Voc nearly identical with, and a Jsc superior to, the values for a conventional porous TiO2 film electrode.
Formation of Cylindrical-Shaped Coordination Polymer by Self-Assembling of 2, 2, 4, 4, 6, 6-Hexakis(4-pyridylmethoxy)-2λ5, 4λ5, 6λ5-cyclotri(phosphazene) with Silver Nitrate
Authors: Itaya Tomoyuki , Inoue Kenzo 
Published: September 2002

Abstract
The self-assembling of 2, 2, 4, 4, 6, 6-hexakis(4-pyridylmethoxy)-2λ5, 4λ5, 6λ5-cyclotri(phosphazene) (PyPN) and AgNO3 in DMSO gives a white rod-shaped coordination polymer. FT-IR and X-ray absorption fine structure spectra, X-ray diffraction data, and elemental analysis showed that the coordination polymer takes a cylindrical structure and is laterally packed into a hexagonal arrangement.