bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereoselectivity of Diels–Alder Reactions of 6,7-Dioxabicyclo[3.2.2]nona-3,8-dien-2-one and 6,7-Diethoxycarbonyl-6,7-diazabicyclo[3.2.2]nona-3,8-dien-2-one
Authors: Takeshita Hitoshi , Mori Akira , Sugiyama Shigeru , Tsuda Tohru 
Published: July 2006

Abstract
A Diels–Alder reaction of 6,7-dioxabicyclo[3.2.2]nona-3,8-dien-2-one (2) with cyclopentadiene gave the cis-endo-[4+2] adduct and the trans-endo-[4+2] adduct. Their yields were improved when the reaction was carried out under high-pressure conditions. The reaction of 6,7-diethoxycarbonyl-6,7-diazabicyclo[3.2.2]nona-3,8-dien-2-one (3) gave the cis-endo-[4+2] adduct. Reactions of 2 and 3 with isobenzofuran and its 1,3-diphenyl derivative gave the thermodynamically-controlled exo-[4+2] adducts.
The Spectrophotometric Determination of Trace Vanadium with 3,4,5,6-Tetrachlorogallein
Authors: Mori Itsuo , Fujita Yoshikazu , Fujita Kinuko , Koshiyama Yozo , Tanaka Takeshi 
Published: July 2006

Abstract
As a solution of 3,4,5,6-tetrachlorogallein (T.Cl.gall) in a weakly acidic medium was easily decomposed by vanadium(V), a simple and sensitive spectrophotometric determination of vanadium by using the difference in absorbance at 385 nm between T.Cl.gall and T.Cl.gall-vanadium(V) solutions in the presence of hexadecylpyridinium chloride (HPC) and poly (N-vinylpyrrolidone) (PVP) was established. Under optimum conditions, vanadium could be determined in the range of 0–0.8 μg/10 cm3. The apparent molar absorptivity was calculated to be 7.0×105 dm3mol−1cm−1, with a Sandell sensitivity of 0.00006 μg cm−2, by the use of a decomposed T. Cl. gall solution in the presence of vanadium(V) at 385 nm. The recovery tests of vanadium added to prepared artificial water were examined; the results were a good agreement with the certified values (98.6–102.8%).
Substance P Analogs Containing Homoglutamine at Position 5 and 6
Authors: Uchida Yoshiki , Nishijima Miwako , Moro Tadashi , Sakura Naoki , Hirose Kyoko , Kontani Hitoshi , Hashimoto Tadashi 
Published: July 2006

Abstract
Six substance P (SP) analogs, in which the glutaminyl residue(s) at the position(s) 5 or/and 6 were replaced by homoglutamine (Hgn), were prepared using a novel Nα,Nca–(Boc)2–Hgn–OH by the solid phase method. The activity of the analogs was assayed on isolated guinea pig organs. Results indicate that the elongation of the methylene on glutaminyl residue(s) in SP enhances the activity on isolated guinea pig ileum.
Neurokinin B Analogs Substituted with Glycine
Authors: Hashimoto Tadashi , Moro Tadashi , Uchida Yoshiki 
Published: July 2006

Abstract
Four Neurokinin B analogs substituted with glycine at position 4, 5, 6, or 7 were synthesized by Merrifield’s solid phase method. Pharmacological property of the analogs is described. The results suggest that Phe6 and Val7 residues may be essential for intrinsic activity on smooth muscle.
The Diels–Alder Reactions of 2-Alkyl-5-methoxy-4-(p-nitrophenyl)oxazoles with Ethylenic, Acetylenic, and Azo-Type Dienophiles
Authors: Ibata Toshikazu , Nakano Shuji , Nakawa Hiroyuki , Toyoda Jiro , Isogami Yasushi 
Published: July 2006

Abstract
The Diels–Alder reactions of 2-methyl- and 2-ethyl-5-methoxy-4-(p-nitrophenyl)oxazoles with N-methyl-, N-ethyl-, and N-phenylmaleimides gave endo- and exo-adducts. When the reactions were carried out in an acetonitrile solution containing a small amount of water as an impurity, N-substituted 3-hydroxy-2-(p-nitrophenyl)-4,5-pyridinecarboximides were obtained via the decomposition of the Diels–Alder adducts, while the methanol was eliminated. The decomposition might be catalyzed by contaminated water at the initial stage of the reaction. The adducts of N-phenylmaleimide and N-ethylmaleimide were shown to undergo the retro-Diels–Alder reaction on heating at 80°C to give the starting maleimides and oxazole. Diethyl azodicarboxylate and 4-phenyl-3H-1,2,4-triazole-3,5(4H)-dione gave the corresponding single adducts. A reaction with dimethyl acetylenedicarboxylate gave p-nitrobenzonitrile (10), dimethyl 2-methyl-5-methoxy-3,4-furandicarboxylate (11), and tetramethyl 3,5-epoxy-3-methoxy-5-methyl-1,4-cyclohexadiene-1,2,4,5-tetracarboxylate (12), although the expected adduct was not isolated. These products were explained on the basis of the Diels–Alder reaction, followed by the retro-Diels–Alder reaction, thus affording 10 and 11, which gave 12 upon cycloaddition with the second molecule of DMAD.
α,β-Epoxy Sulfoxides as Useful Intermediates in Organic Synthesis. III. A Novel Synthesis of α-Amino Ketones and α-Amino Aldehydes by Aminolysis of α,β-Epoxy Sulfoxides
Authors: Satoh Tsuyoshi , Kaneko Youhei , Sakata Kiichi , Yamakawa Koji 
Published: July 2006

Abstract
Aminolysis of α,β-epoxy sulfoxides, easily prepared from 1-chloroalkyl phenyl sulfoxides or chloromethyl phenyl sulfoxide and carbonyl compounds, with alkyl- or arylamines afforded α-amino ketones or α-amino aldehydes in good yields. Treatment of thus obtained α-arylamino ketones with weak Lewis acid led to 2,3-disubstituted indoles.
Fluorescence and Circular Dichroism Studies on Host–Guest Complexation of γ-Cyclodextrin Bearing Two 2-Naphthyl Moieties
Authors: Ueno Akihiko , Moriwaki Fumio , Osa Tetsuo , Hamada Fumio , Murai Koichi 
Published: July 2006

Abstract
Host–guest complexation of γ-cyclodextrin bearing two 2-naphthyl moieties (1) has been studied by circular dichroism and fluorescence spectroscopic methods. The exciton coupling band observed in the naphthalene 1La transition region shows that the two naphthyl moieties of 1 take a chiral orientation in the cavity. The guest binding of 1 changes the circular dichroism pattern, finally affording a negative band, but hardly influences the fluorescence pattern in which excimer emission is predominant. These phenomena suggest that a guest molecule is included in the cavity of 1 by extruding two naphthyl moieties from the cavity so as to make the moieties to act as hydrophobic caps. Dimethyl sulfoxide(DMSO) was found to be effective to change both fluorescence and circular dichroism patterns, increasing monomer-like emission and converting the exciton coupling pattern to a simple negative band. These results suggest that the two naphthyl moieties are not in proximal positions in DMSO-rich solutions.
Oxidation of Lipids, XII. Inhibition of Oxidation of Soybean Phosphatidylcholine and Methyl Linoleate in Aqueous Dispersions by Uric Acid
Authors: Niki Etsuo , Saito Mitsuo , Yoshikawa Yasuyuki , Yamamoto Yorihiro , Kamiya Yoshio 
Published: July 2006

Abstract
The activity of uric acid as a chain-breaking antioxidant was studied in the oxidations of methyl linoleate micelles and soybean phosphatidylcholine liposomes in aqueous dispersions at 37°C. Uric acid was found to act as a radical scavenger. Uric acid located in an aqueous phase could trap the radicals in an aqueous phase, but it could not scavenge radicals within the lipid region of micelles and liposomal membranes. The kinetics of the oxidations of lipids in aqueous dispersions inhibited by uric acid was discussed.
Oxidation of Lipids. XIII. Antioxidant Activities of α-, β-, γ-, and δ-Tocopherols
Authors: Niki Etsuo , Tsuchiya Jyunichi , Yoshikawa Yasuyuki , Yamamoto Yorihiro , Kamiya Yoshio 
Published: July 2006

Abstract
The antioxidant activities of α-, β-, γ-, and δ-tocopherols were studied. They were all effective as antioxidant in the oxidations of methyl linoleate in homogeneous solution. When one of the four tocopherols was used alone, they were consumed at the same rate and they suppressed the oxidation for the same period. However, the stabilities of chromanyloxyl radicals derived from the corresponding tocopherols varied considerably and decreased in the order α&gt;β≅γ&gt;δ -chromanyloxyl radicals. α-Tocopherol reacts quite rapidly with β-, γ-, and δ-chromanyloxyl radicals to give α-chromanyloxyl radical and β-, γ-, and δ-tocopherols respectively. Accordingly, when the four tocopherols were used together, α-tocopherol was consumed first, then β- and γ-tocopherols were consumed, and δ-tocopherol began to decrease after most of α-, β-, γ-tocopherols were depleted.
Transformation between Lamellar and Nonlamellar Aggregates Formed with Synthetic Peptide Lipids
Authors: Murakami Yukito , Kikuchi Jun-ichi , Takaki Toshihiko , Uchimura Katsuya 
Published: July 2006

Abstract
The morphological behavior of various combinations of the following synthetic lipids was investigated in the aqueous dispersion state by means of electron microscopy, differential scanning calorimetry, and fluorescence polarization spectroscopy as well as by turbidity and X-ray diffraction measurements: N+C5Ala2Cn and N+(H)C5Ala2Cn as cationic, (SO3−)C5Ala2Cn as anionic, and QC5Ala2Cn as nonionic (n=14, 16). Aqueous dispersions of various combinations of cationic and anionic lipids at the equimolar ratio afforded nonlamellar aggregates, having highly ordered and three-dimensional network structure with repeating distances in the 70–130 Å range, above their phase transition temperatures (Tm). However, any slight loss of the fractional balance retained at the equimolar ratio led to the formation of bilayer aggregates. Under such conditions that allow the formation of nonlamellar aggregates, the high microscopic homogeneity of cationic and anionic lipid molecules was attained, originating from the intramembrane electrostatic interaction between cationic and anionic head moieties to form highly developed ion-pair clusters on the aggregate surface. Meanwhile, the nonlamellar phase appeared above Tm was spontaneously transformed into the normal bilayer phase below Tm as confirmed by electron microscopy and turbidity measurements. The nonlamellar phase was also characterized by the low-angle X-ray diffraction method and was consistent with the highly developed domain with the face-centered cubic lattice.
Studies on β-Turn of Peptides. XII. Synthetic Confirmation of Weak Activity of [d-Pro5,5′]-Gramicidin S Predicted from β-Turn Preference of Its Partial Sequence
Authors: Sato Kazuki , Kato Rika , Nagai Ukon 
Published: July 2006

Abstract
[d-Pro5,5′]-Gramicidin S was synthesized to confirm a prediction that d-d sequence at the corner position had low preference for β-turn. The analog showed much weaker activity than gramicidin S and also showed different CD spectra from those of gramicidin S. The results indicate that the analog can not take stable, gramicidin S-like, β-sheet conformation.
35Cl NQR and Ionicities of a Few N-Chloroimides
Authors: Nagao Yoshitaka , Katagiri Shigeyoshi 
Published: July 2006

Abstract
35Cl NQR frequencies were measured for N-chlorosuccinimide (NCS), N-chlorophthalimide (NCP), N,N′-dichlorobarbital (NDCB), sodium N,N′-dichloroisocyanurate dihydrate (Na-NDCI·2H2O) and N,N′,N″-trichloroisocyanuric acid (NTCI). The ionicities estimated by a 35Cl NQR study increased in the following order; NCS&lt;NCP&lt;NDCB&lt;Na-NDCI·2H2O&lt;NTCI. A linear relationship between the ionicities of chlorine atoms and the polarographic reduction potentials of N–Cl bonds was found. The ionicity was related to the reactivity.
Activity Coefficients of Dimethyl-β-cyclodextrin in Aqueous Solutions
Authors: Miyajima Koichiro , Mukai Takayo , Nakagaki Masayuki , Otagiri Masaki , Uekama Kaneto 
Published: July 2006

Abstract
The activity coefficients of aqueous solutions of dimethyl-β-cyclodextrin were measured by vapor pressure osmometry at 25, 35, and 45±0.1°C. The activity coefficient decreased with increase of concentration at each temperature. Both the excess enthalpy and the excess entropy were positive. The negative excess free energy originates from the large excess entropy term, indicating that dimethyl-β-cyclodextrin is a hydrophobic solute.
High-Resolution 13C NMR Spectra of trans-[CoIII(2,3-Alkanedione dioximato)2(pyridine)2]I Complexes in the Solid State
Authors: Kinoshita Setsuko , Wakita Hisanobu , Masuda Isao 
Published: July 2006

Abstract
High-resolution 13C NMR spectra of the title complexes showed two type signals based on the “packing effect” and the long-chain alkyl group of the dioximato ligand was found to be fixed near the axial pyridine ligand in the solid state.
A Practical Synthesis of 1,3-Diene Using Allyltriphenylsilane and Titanium Tetraisopropoxide
Authors: Ikeda Yoshihiko , Yamamoto Hisashi 
Published: July 2006

Abstract
A practical method for the stereoselective preparation of 1,3-dienes by the use of allyltriphenylsilane as a key reagent is described.
CD Spectra of Bis(2,4-dinitrophenyl) Derivatives of Acyclic Diamino Compounds Having Two Asymmetric Centers
Authors: Kawai Masao , Yamagishi Takahiro , Matsuura Taketoshi , Butsugan Yasuo , Nakashima Ruka 
Published: July 2006

Abstract
Chiroptical properties of bis(2,4-dinitrophenyl) derivatives of acyclic diamino compounds were discussed. The derivatives of diamines in which the two NH2-bearing carbons are asymmetric having the same chirality exhibited Cotton effects of much larger intensity than the corresponding diamine derivatives having only one asymmetric carbon atom. Relation between sign and magnitude of Cotton effect at the longest wavelength of bis(2,4-dinitrophenyl) derivatives and structure and stereochemistry of parent diamino compounds was summarized in a tabulated form.
Palladium-Catalyzed Coupling between Organic Halides and Organotin Compounds Involving C-N Unsaturated Bonds at the Reaction Centers
Authors: Kosugi Masanori , Koshiba Mamoru , Atoh Akira , Sano Hiroshi , Migita Toshihiko 
Published: July 2006

Abstract
Imidoyl chlorides were good substrates which can react with a variety of organotin compounds to give ketimines in the presence of a catalytic amount of palladium complex. Under similar conditions, C-tributylstannyl imines did not give the products except with 2-(tributylstannyl)benzothiazole, -benzoxazole, and 1-methyl 2-(tributylstannyl)imidazole. And N-tributylstannyl imines could not be utilized.
Precise Measurement of Ultrasonic Absorption in Micellar Solutions in the Frequency Range from 0.2 to 10 MHz
Authors: Kato Shigeo , Nomura Hiroyasu , Zielinski Ryszard , Ikeda Shoichi 
Published: July 2006

Abstract
A cylindrical resonator for the measurement of ultrasonic absorption has been designed. It was found that a newly designed resonator can determine the absolute value of the ultrasonic absorption coefficient of water at frequencies above 0.7 MHz. For aqueous solutions it has a sufficient resolution power down to 0.2 MHz by means of a reference measurement. Precise measurements of ultrasonic absorption were carried out for aqueous solutions of dodecyltrimethylammonium bromide using a newly designed resonator and two other previously reported resonators. The ultrasonic relaxation spectra show a single relaxation process within the investigated frequency range. The relaxation process can be ascribed to a “fast” relaxation related to the exchange of a surfactant between micelles and bulk solution. The kinetic parameters for the exchange process were estimated on the basis of Teubner’s theory.
Thermodynamic Study on Solvent Extraction of Alkali Metal Picrates with 18-Crown-6 into CHCl3
Authors: Takeda Yasuyuki , Tanaka Akio 
Published: July 2006

Abstract
Enthalpy (ΔHex) and entropy changes (ΔSex) for overall extractions of alkali metal (Na, K, Rb, and Cs) picrates with 18-crown-6 (18C6), and those (ΔHD,L and ΔSD,L) for distribution of 18C6 itself were determined between CHCl3 and water, all the extracted complexes being 1:1:1 complexes. The ΔHex and ΔSex values of 18C6 for all the alkali metals are negative. The ΔHD,L and ΔSD,L values of 18C6 are both positive. Enthalpy (ΔHex′) and entropy changes (ΔSex′) for ion-pair extractions of 18C6-alkali metal ion complexes with picrate anions were calculated. All the ΔHex′ and ΔSex′ values are negative except for ΔSex′ value of Na (positive). The ion-pair extractions were discussed from the thermodynamic point of view.
Reaction Mechanism of Cathodic Crossed Coupling of Acetone with Unsaturated Compounds in Acidic Solution
Authors: Koizumi Toshio , Fuchigami Toshio , Kandeel Zaghloul El-Shahat , Sato Norio , Nonaka Tsutomu 
Published: July 2006

Abstract
It was confirmed that the cathodic crossed coupling of acetone with unsaturated compounds in aqueous sulfuric acid could proceed smoothly, when the compounds which had radical-acceptable double bonds and were adsorbed on a mercury cathode were used. From this fact, it was concluded that the coupling occurs via the addition of a radical intermediate formed by the one-electron reduction of acetone to the double bonds on the cathode surface. Possibility of the addition of an anionic intermediate derived from acetone was excluded by no occurrence of the coupling of acetone with a polar acetylenic triple bond compound adsorbed on the cathode.
Interaction of Poly[S-(2-carboxyethyl)-l-cysteine] with Cationic Surfactants
Authors: Maeda Hiroshi , Tanaka Yoriko , Ikeda Shoichi 
Published: July 2006

Abstract
The induction of the β-structure of fully ionized poly[S-(2-carboxyethyl)-l-cysteine] in solution markedly depended on the kind of head group of cationic surfactants; it occurred by the addition of dodecylammonium chloride (DAC) but not by the addition of dodecyldimethylammonium chloride (DDAC) or dodecyltrimethylammonium chloride (DTAC), as concluded based on circular dichroism spectra. The induction of the β-structure by DAC was not inhibited by raising ionic strength of the medium but was enhanced when the polypeptide concentration was increased. The polypeptide took the β-structure in the precipitates produced by the addition of any one of these three surfactants, as indicated by the infrared absorption (IR) spectra. Intensity of a characteristic absorption band of carboxylate group around 1570 cm−1 for the complex with DDAC was vanishingly weak, while those with DAC and DTAC were medium and strong, respectively. The precipitates were solubilized in the presence of excess amount of surfactants. In the solubilized solution, the β-structure was again found in the case of DAC, irrespective of the polypeptide concentration, but it was found only at high polypeptide concentrations in the case of DDAC.
Solvent Effects on Extraction of Aluminum(III), Gallium(III), and Indium(III) with Decanoic Acid
Authors: Yamada Hiromichi , Hayashi Hisao , Fujii Yukio , Mizuta Masateru 
Published: July 2006

Abstract
Extraction of aluminum(III) and indium(III) with decanoic acid in 1-octanol was carried out at 25 °C and at an aqueous ionic strength of 0.1 mol dm−3 (NaClO4). Monomeric and tetrameric aluminum(III) decanoates and monomeric indium(III) decanoate are responsible for the extraction. From a comparison of the present results with those obtained from the previous works, the polymerization of the extracted species was found to be more extensive in benzene than in 1-octanol, and the metal decanoates were highly polymerized in the following order in both solvents: Al&gt;Ga&gt;In.
Pseudo-Sugars. XIV. Synthesis of Sweet-Tasting Pseudo-β-Dl-fructopyranose
Authors: Suami Tetsuo , Ogawa Seiichiro , Takata Makoto , Yasuda Kuninobu , Takei Kiyoshi , Suga Atsuo 
Published: July 2006

Abstract
Pseudo-β-Dl-fructopyranose was synthesized from Dl-1,2-di-O-acetyl-(1,3/2)-3-bromomethyl-5-cyclohexene-1,2-diol by a six steps reaction: Dehydrobromination, epoxidation, acetolysis, reduction, and deacetylation, in overall yield of 4.8%. Pseudo-β-Dl-fructopyranose was found to be nearly as sweet as d-fructose which is the most sweet sugar known in naturally occurring carbohydrates.
A Novel Friedel-Crafts Type Reaction of 2-Chlorothiophene with Some Active Aromatic Compounds
Authors: Sone Tyo , Yokoyama Ryoji , Okuyama Yohko , Sato Kazuaki 
Published: July 2006

Abstract
2-Chlorothiophene (1) was found to easily react with certain active aromatic compounds (2) in the presence of AlCl3 under mild conditions, yielding the corresponding 2-arylthiophenes (3) and 5-chloro-2,2′-bithienyl (5) as the main products. With compounds more reactive than 1, the formation of 3 predominated. Reactions of 1 with aryl alkyl ethers, for example, afforded the corresponding 3 in 44–83% yields in one step.
Asymmetric Addition of Hydrogen Cyanide to Substituted Benzaldehydes Catalyzed by a Synthetic Cyclic Peptide, Cyclo((S)-phenylalanyl-(S)-histidyl)
Authors: Kobayashi Yoshiyuki , Asada Shoichi , Watanabe Ichigen , Hayashi Hiroaki , Motoo Yoshiyuki , Inoue Shohei 
Published: July 2006

Abstract
Using cyclo((S)-phenylalanyl-(S)-histidyl) as catalyst, optically active cyanohydrins from substituted benzaldehydes with p-methyl, m-methyl, o-methyl, m-methoxyl, or m-phenoxyl group were obtained with optical yield of 82–33%. For the asymmetric cyanohydrin synthesis, nonpolar solvent such as benzene or carbon tetrachloride was advantageous, while no asymmetric synthesis took place in methanol or dimethyl sulfoxide.
Raman and Solid State NMR Study on an Inclusion Compound of Aspartame with Cyclodextrin
Authors: Takahashi Shin-ichiro , Suzuki Ei-ichiro , Amino Yusuke , Nagashima Nobuya , Nishimura Yoshifumi , Tsuboi Masamichi 
Published: July 2006

Abstract
A crystal of inclusion compound of Aspartame (α-l-aspartyl-l-phenylalanine methyl ester, APM) with β-cyclodextrin (β-CD) was obtained from their aqueous solution. The Raman spectrum of this crystal indicates some differences from the spectral sum of APM and β-CD. An analysis of these spectral differences suggests that the phenyl moiety of APM is included in the cavity of β-CD in the inclusion compound. In addition, a Raman spectroscopic study of APM with 15N-substitution and N-deuteration indicates that the peptide backbone of APM undergoes some conformational change on APM going into the inclusion compound. Solid state 13C CP MAS- and gated-decoupling MAS–NMR spectra for the inclusion compound indicate that the phenyl ring rotates at a higher frequency than 270 MHz, that the Phe Cβ and phenyl ring Cl move at the frequency of about 270 MHz, and that the molecular motion of the other parts of APM occurs at lower frequency than 270 MHz.
Improved Optical Resolution of (±)-1,2-Diphenylethylenediamine
Authors: Saigo Kazuhiko , Kubota Naomi , Takebayashi Shoko , Hasegawa Masaki 
Published: July 2006

Abstract
(±)-1,2-Diphenylethylenediamine (DPEDA) was efficiently resolved by the fractional crystallization of its diastereomeric salts with optically active mandelic acid. 1H-NMR spectrum of N-monoacylated DPEDA with an optically active derivatizing agent showed that DPEDA thus obtained was optically pure.
Effective Rotational Temperatures of N2+ (X) Produced by Electron-Impact Ionization on N2
Authors: Kawazumi Hirofumi , Uchida Tuneaki , Ogawa Teiichiro 
Published: July 2006

Abstract
The laser-induced fluorescence of molecular ions, N2+ (X, 2Σg+), was measured under the controlled electron-impact ionization of N2 in the thermal gas jet. The effective rotational temperature of N2+ (X) increased from 320±5 K to 367±15 K for the incident electron energy from 750 eV to 17 eV.
α,β-Epoxy Sulfoxides as Useful Intermediates in Organic Synthesis. IV. A Novel Synthesis of α-Acetoxy Ketones from α,β-Epoxy Sulfoxides
Authors: Satoh Tsuyoshi , Motohashi Shigeyasu , Yamakawa Koji 
Published: July 2006

Abstract
The treatment of α,β-epoxy sulfoxides, prepared from 1-chloroalkyl phenyl sulfoxides with ketones or aldehydes, with cesium acetate in dimethyl sulfoxide in the presence of lead tetraacetate afforded α-acetoxy ketones in moderate to good yields.