bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Condensation and Decomposition of Alkaline Earth and Phenyl Phosphoramidates with Acids
Authors: Sato Shoji , Takayanagi Takao , Watanabe Makoto 
Published: July 2006

Abstract
Alkaline earth and phenyl phosphoramidates were reacted with dried hydrogen chloride, acetic acid, and oxalic acid. The alkaline earth phosphoramidates other than the magnesium salt reacted with the acids to produce ortho- and polyphosphates, but did not react with them to make polyphosphates containing imino groups. The hydrolysis of the phosphoramidates to orthophosphate has been considered to be the initiation of the production of polyphosphates:
(Remark: Graphics omitted.)
where M stands for an alkaline earth metal ion. The formation of polyphosphates can be explained, for example, by this equation:
(Remark: Graphics omitted.)
where HA stands for acid. Magnesium phosphoramidate reacted with acetic acid and oxalic acid to produce orthophosphate, polyphosphates, and imidodiphosphate. The production of the imidodiphosphate can be indicated by the following equation:
(Remark: Graphics omitted.)
Studies on Mixed Chelates. XV. An ESR Investigation of Solvatochromic Copper(II) Complexes with Various N-Alkylated Ethylenediamines and β-Diketonates
Authors: Hoshino Naomi , Kodama Naoko , Fukuda Yutaka , Sone Kozo 
Published: July 2006

Abstract
ESR spectra were obtained for frozen solutions of copper(II) mixed chelate complexes, [Cu(diam)(dike)]ClO4, having various N-alkylated ethylenediamines (diam) and β-diketonate ligands (dike). The ESR g-factor (g⁄⁄) determined from apparently axial signals may be correlated by a decreasing function to pKa of dikeH or diam ligand for the series of [Cu(tmen)(dike)]+ or [Cu(diam)(acac)]+, respectively. On the other hand, the g⁄⁄ values gradually increased when the former series of complexes were dissolved in more strongly coordinating solvents, and a relationship was found between g⁄⁄ and Donor Number of the solvent. These trends are regarded as ligand substituent effect and solvent effect on the g⁄⁄ factor, and are analyzed using a crystal field model of a C2v symmetry.
The Base-Catalyzed Isomerization of the Bis(ethylenediamine-N-acetato)cobalt(III) Complex
Authors: Kawaguchi Hiroshi , Niiyama Ryuichi , Ama Tomoharu , Yasui Takaji 
Published: July 2006

Abstract
The isomerization reaction among six geometrical isomers of [Co(edma)2]+, which were all resolved into optically active isomers except for the achiral Ci-trans(O) isomer, has been studied in a basic aqueous solution. It has been found that the reaction is stereoselective and that the main reaction schemes may be described as follows: (1) ΛΔΛ(S,S)-C2-trans(O) \ightleftharpoons ΔΛΔ (R*,S)-C1-cis(O)\ightleftharpoons ΔΛ(R,R)-cis(O)trans(NH) \ightleftharpoons meso(R,S)-Ci-trans(O)→ΛΔΛ(R,R)[or ΔΛΔ(S,S)]-cis(O)trans(NH2) and (2) meso(R,S)-Ci-trans(O)←(+)504CD-mer→ΛΔΛ(S,S)-C2-trans(O). In each of the isomerization steps of (1), the inversion occurs at one of two secondary-N centers of the coordinated edma ligands. The rate of deuteration at the secondary-NH was also measured for all geometrical isomers; a linear relationship between the rates of the deuteration and isomerization was found. It was suggested that the isomerization of the [Co(edma)2]+ system proceeded through the deprotonated five-coordinated intermediates formed by Co–O bond-rupture in the conjugate-base forms.
Kinetic Study of the Polymerization of Styrene in the Presence of Various Organic Hydroperoxides
Authors: Komai Takeshi , Matsuyama Kazuo 
Published: July 2006

Abstract
The polymerizations of styrene initiated by 2,2′-azobisisobutyronitrile have been carried out in the presence of various organic hydroperoxides, such as 1,1-dimethylethyl (Ia), 1,1-dimethylbutyl (Ib), and 1-methyl-1-phenyl-ethyl hydroperoxides (Ic) at 60 °C. The polymerization rate increased with the concentration of Ic, but became rather retarded with that of Ia and Ib. This phenomenon can be explained by the difference in the radical induced decomposition for the hydroperoxides. The hydroperoxide (Ic) decomposes with a radical displacement on the peroxide bond; however, Ia, and Ib, in addition to this reaction, decompose with the radical hydrogen abstraction of the hydroperoxyl group. The peroxyl radical formed (ROO·) subsequently gave rise to a primary radical termination.
Racemic Structure and Optical Resolution by Preferential Crystallization of Dl-Cysteine Salts of Substituted Benzenesulfonic Acids
Authors: Shiraiwa Tadashi , Tazoh Hirohide , Sunami Michio , Sado Yujin , Kurokawa Hidemoto 
Published: July 2006

Abstract
Infrared absorption spectrum, solubility, and thermodynamic analysis indicated that Dl-cysteine salts of benzenesulfonic acid (Dl-BA salt) and 4-ethylbenzenesulfonic acid (Dl-4-EB salt) are conglomerates at room temperature, but Dl-BA salt forms a racemic compound at the melting point. These Dl-salts were optically resolved by the preferential crystallization. As for Dl-4-EB salt, suitable conditions were estimated by the free energy of critical nucleation in supersaturated solutions. The successive preferential crystallization in ethanol at 20 °C was found to give D- and l-4-EB salts with optical purity of 97–100% in the resolution yield of 83–90%. Purification and following treatment with triethylamine gave optically pure D- and l-Cys’s.
Synthetic Studies of Amphotericin B. II. A Facile Synthesis of the C-1–C-12 Segments of the Amphotericin B Aglycon
Authors: Kinoshita Mitsuhiro , Morioka Masahiko , Taniguchi Masato , Shimizu Jun 
Published: July 2006

Abstract
3-Deoxy-1,2-O-isopropylidene-α-d-glycero-d-erythro-pentofuranose (11) was stereoselectively converted into the Witting salt 8 corresponding to the C-1–C-6 portion of amphotericin B aglycon (1) in 57% overall yield in 8 steps. The aldehydic segment 9 or 10 corresponding to the C-7–C-12 portion of 1 was also derived in 6 steps from 11 in 53 or 38% overall yield, respectively. Wittig condensation of 8 with 9 or 10 followed by four-step conversion afforded the C-1–C-12 segment, (3S,5R,8R,9R,11S)-1-O-t-butyldimethylsilyl-12-iodo-3,5:8,9-di-O-isopropylidene-11-O-[(2-methoxyethoxy)methyl]-1,3,5,8,9,11-dodecanehexol(4)or(2S,4R,5R,8R,10S)-1,2-anhydro-12-O-t-butyldimethylsilyl-4,5:8,10-di-O-isopropylidene-1,2,4,5,8,10,12-dodecaneheptol (5) in 26 or 15% overall yield from 11, respectively.
Horner–Emmons Olefination of 4-Hydroxy-2-oxoalkylphosphonates and Related Compounds: Applications to the Syntheses of (±)-Gingerol, (±)-Yashabushiketol, and (±)-Dihydroyashabushiketol
Authors: Tsuge Otohiko , Kanemasa Shuji , Nakagawa Norihiko , Suga Hiroyuki 
Published: July 2006

Abstract
Horner–Emmons olefination of 4-hydroxy-2-oxoalkylphosphonates, readily available by hydrogenation of 5-substituted 3-phosphinylmethyl-2-isoxazolines, gives mainly E-isomers of 1-hydroxy-4-alken-3-ones bearing a variety of substituents at the 1-position. Use of the combination of triethylamine (or DBU)+lithium bromide as a weak base on the O-unprotected phosphonates is favored. Similar olefinations on the isoxazolines, 2-oxo-3-alkenylphosphonates, and 4-alkoxy-2-oxoalkylphosphonates have been also examined. Their synthetic applications to (±)-Gingerol, (±)-Yashabushiketol, and (±)-Dihydroyashabushiketol are described.
Mechanism of the Pyrene-Sensitized Photolysis of N-(1-Naphthoyl)-O-(p-toluoyl)-N-phenylhydroxylainine
Authors: Sakurai Tadamitsu , Inomata Kensuke , Ishikawa Takayoshi , Inoue Hiroyasu , Hoshi Toshihiko , Okubo Jun 
Published: July 2006

Abstract
The title hydroxylamine (NT) undergoes pyrene-sensitized photodecomposition to give rearrangement and fragmentation products. An analysis of linear Stern–Volmer plots, both for the sensitized photolysis of NT and for the fluorescence quenching of pyrene by NT, indicates the involvement of singlet pyrene in this photolysis. The observation of negligible effects of 1,3-cyclohexadiene and trans-stilbene as a triplet quencher on the reaction provides further supporting evidence for a singlet-pathway mechanism. A comparison of the relative state energies of NT and the sensitizer suggests the existence of a reactive singlet-exciplex intermediate formed between the singlet-state sensitizer and the ground-state NT. The results of solvent and micellar effects on the sensitized photolysis establish that electron transfer in the exciplex predominates in a polar solvent, and that in a nonpolar solvent energy transfer in this exciplex plays a major role in the reaction.
2-Amino-1-methyl-1H-imidazole-4,5-dione: Synthesis and the Dimroth Type Rearrangement to Creatone (2-Methyl-amino-1H-imidazole-4,5-dione)
Authors: Yamamoto Hiroshi , Ohira Chikara , Aso Toshiaki , Pfleiderer Wolfgang 
Published: July 2006

Abstract
Treatment of creatinine with BOC-ON gave 2-t-butoxycarbonylamino-1-methyl-1,5-dihydro-4H-imidazol-4-one, which was oxidized with mercury(II) acetate to the corresponding 1H-imidazole-4,5-dione. Deprotection of the amino group of this dione afforded the title compound 4, which in turn was shown to undergo a facile, Dimroth-type rearrangement under weakly acidic conditions to give creatone, thus proving 4 to be the key intermediate in the formation of creatone from various starting materials. The equilibria among these compounds are discussed.
The Study on Peptide and Protein Syntheses. Infrared Spectroscopic Conformational Analysis of Oligo-l-leucines Containing Only One d-Amino Acid Residue
Authors: Narita Mitsuaki , Honda Shinya , Umeyama Hiroshi 
Published: July 2006

Abstract
In order to investigate the influence of a d-amino acid residue on the conformational behavior of peptides and proteins, IR spectroscopic conformational analysis of oligo-l-Leus containing only one d-Ala or d-Val residue was performed in the solid state. For the estimation of their structures, a CPK model and Ramachandran map were very helpful. The d-amino acid residue is clearly inhibited to take the values of the backbone dihedral angles φ and ψ for β-sheet structures formed by l-amino acid residues, while it is allowed for the d-amino acid residue to take the values φ and ψ for helical structures formed by l-amino acid residues. The IR absorption spectroscopic analysis of samples after application of strong shear stress was also useful for the investigation. The effect of shear stress on β-sheet-like structure→helix conformational change is larger for oligo-l-Leus containing a d-Ala residue than those containing a d-Val residue, indicating that the d-Ala residue is more favorable in a helical structure than the d-Val residue. This tendency can be also easily confirmed using CPK model. The significance of this study was discussed in relation to protein synthesis and design of three-dimensional structures of peptides using d-amino acid residues.
Oxidation of Aliphatic Secondary and Benzylic Alcohols to Carbonyl Compounds by Peracetic Acid in the Presence of Sodium Bromide in Acetic Acid
Authors: Morimoto Takashi , Hirano Masao , Ashiya Hiroyuki , Egashira Hidetaka , Zhuang Xiumin 
Published: July 2006

Abstract
Alcohols were smoothly oxidized by peracetic acid in the presence of sodium bromide to give the corresponding carbonyl compounds in good yields.
First ESR Spectrum of a Selenoaminyl Radical
Authors: Miura Yozo , Tsumori Osamu 
Published: July 2006

Abstract
N-(o-Nitrophenylseleno)-3,5-di-t-butylphenylaminyl radical, generated by photolysis of N-(3,5-di-t-butylphenyl)-o-nitrobenzeneselenenamide in the presence of di-t-butyl peroxide, has been studied by ESR spectroscopy. The ESR parameters are compared with those for the corresponding sulfur analogue.
Crystal and Molecular Structure of Bis(benzylamine)bis(thiocyanato)cadmium(II), [Cd(SCN)2(C6H5CH2NH2)2]
Authors: Taniguchi Masahiro , Ouchi Akira 
Published: July 2006

Abstract
The crystal and molecular structure of the title complex was determined by means of a single-crystal X-ray diffraction method. A crystal of CdC16H18N4S2, F. W. 442.8, is monoclinic, with the space group of P21⁄n, a=27.390(19), b=5.7709(8), c=5.8733(9) Å, β=90.35(3)°, U=928.3(7) Å3, Z=2, Dm=1.57(3), Dx=1.58 Mg m−3, and μ(Mo Kα)=1.59 mm−1. The cadmium(II) atom is hexa-coordinated being ligated with two thiocyanato (SCN) sulfur atoms, as well as with two SCN and two benzylamine nitrogen atoms, where the respective pairs of the same kinds of atoms are all in transconfiguration. Each cadmium atom is at the center of symmetry, and the coordination structure around the atom is symmetric. The metal atoms are lined along c-axis, and the pair of the neighboring metal atoms are doubly bridged by SCN ions, although the bridges are a little weaker than the other same type adducts.
The Thermally-Controlled Chemoselective Reduction of 5H-Pyrrolo[3,4-b]pyridine-5,7(6H)-dione with Sodium Borohydride
Authors: Goto Takehiko , Saito Minoru , Sato Ryu 
Published: July 2006

Abstract
The title reaction produced either 2-(hydroxymethyl)nicotinamide or 6,7-dihydro-7-hydroxy-5H-pyrrolo[3,4-b]pyridin-5-one as the major product at room temperature or −20 °C, respectively, along with the corresponding regioisomers as minor products. These novel compounds were converted to known compounds in order to establish their isomeric structures.
Synthesis of Novel Bis-Crown and Double-Armed Crown Ethers Having the 18-Crown-6 Residue
Authors: Naemura Koichiro , Iwasaka Hiroshi , Chikamatsu Hiroaki 
Published: July 2006

Abstract
The 18-crown-6 derivative possessing two hydroxyl groups was prepared from the Diels–Alder adduct of 1,7-(1,2-ethanediylidene)-18-crown-6 with dimethyl 2-butynedioate. By using the crown ether as the key intermediate, novel bis-crown and double-armed crown ethers having the 18-crown-6 residue were synthesized, and their abilities to extract metal picrates were investigated.
Ortho-Selective Alkylation of Phenols with Symmetric Sulfides and Sulfuryl Chloride
Authors: Sato Kikumasa , Inoue Seiichi , Miyamoto Osamu , Ikeda Hiroshi , Ota Tomomi 
Published: July 2006

Abstract
Sulfuryl chloride has been shown to be useful activator for sulfides in the selective preparation of ortho-alkylated phenols via [2,3]sigmatropic rearrangement. By this process, ortho-alkylated phenols have been prepared with various symmetric sulfides in good yields. The rearrangement products having 3-chloropropyl or 3-methyl-3-butenyl moiety have been converted into 2H-1-benzopyran derivatives.
Electroreduction of m-Hydroxybenzoic Arid. Preparation of m-Phenoxybenzyl Alcohol for the New Insecticide Ethofenprox
Authors: Oi Ryu , Shimakawa Chitoshi , Shimokawa Yasushi , Takenaka Shinji 
Published: July 2006

Abstract
The electroreduction of m-hydroxybenzoic acid was examined from both mechanistic and technical points of view, and a practical route to m-phenoxybenzyl alcohol has been developed.
AlBr3 Group Reorientation in NaAl2Br7 and KAl2Br7 Studied by Means of 81Br, 27Al NQR and 27Al NMR
Authors: Yamada Koji , Okuda Tsutomu , Ichiba Sumio 
Published: July 2006

Abstract
81Br NQR spin-lattice relaxation times for MAl2Br7 (M=Na and K) were measured from 77 to 373 K and the reorientational activation energies of the AlBr3 groups about Al–Br(bridge) axes were determined. In the case of NaAl2Br7, the reorientation of the AlBr3 group was also confirmed by a motional narrowing effect of the 27Al NMR using a single crystal. In order to examine the effect of the reorientation on the Al site, 27Al NQR frequencies in NaAl2Br7 were observed as a function of temperature by a SEDOR technique. The asymmetry parameter (η) of the electric field gradient (efg) tensor was found to increase at one of the two Al sites with the onset of the reorientation.
The Influence of Molecular Conformation on the Electronic Relaxation Processes. Complex Formation in the Ground State and Triple Fluorescences of 6-Acetoxyspiro[aceanthyrylene- 2(1H),9′(10′H)-anthracene]-10′-one
Authors: Fujii Tsuneo , Hirano Masahiro , Uno Yoshihiro , Suzuki Satoshi , Hirakawa Kiyoichi 
Published: July 2006

Abstract
The absorption spectra of 6-acetoxyspiro[aceanthyrylene-2(1H),9′(10′H)-anthracene]-10′-one(2) in cyclohexane, dichloromethane, and chloroform have been observed. The absorption spectra have been also observed as a function of concentration of chlorinated methanes in mixtures with cyclohexane. It was revealed that 2 forms a ground state complex with chlorinated methanes. The equilibrium constants for the ground-state complex formation with dichloromethane and chloroform were determined to be 0.14 and 0.17 mol−1 dm3, respectively. The fluorescence and fluorescence excitation spectra of 2 have been obtained as a function of excitation wavelengths and emission wavelengths in cyclohexane and chlorinated methanes. The spiro compound emits structured fluorescence(FM) in cyclohexane. On the other hand, three types of fluorescence bands (FM, FC, and FE) were observed in chlorinated methanes. The FC and FE bands are both structureless and their peak wavenumbers are 20800 and 18700 cm−1. The quenching of fluorescence quantum yield and lifetime were treated by Stern–Volmer kinetics considering the complex formation in both the ground and the excited states of the system. Based on the experimental findings, the origins of FM, FC, and FE bands are explained by the complex formation between 2 and chlorinated methanes in the ground state and exciplex formation in the excited state.
Shock Tube Studies of the Oxidation of Acetylene in Fuel-Rich Mixtures
Authors: Koike Tohru , Morinaga Kihei 
Published: July 2006

Abstract
The oxidation of C2H2 in fuel-rich mixtures was studied in the temperature range 1600–2500 K by a shock-tube technique combined with UV absorption spectroscopy. The absorption profile, attributed to both an increase of C4H2 and a decrease of C2H2, could be modeled with a reaction mechanism comprising 38 elementary reactions. The progress of the oxidation was found to be greatly influenced by the pyrolysis steps of C2H2.
A High-Resolution Solid-State 13C NMR Study of the Secondary Structure of Branched (1→3)-β-d-Glucans from Fungi: Evidence of Two Kinds of Conformers, Curdlan-Type Single-Helix and Laminaran-Type Triple-Helix Forms, as Manifested from the Conformation-Dependent 13C Chemical Shifts
Authors: Saitô Hazime , Tabeta Ryoko , Yoshioka Yûko , Hara Chihiro , Kiho Tadashi , Ukai Shigeo 
Published: July 2006

Abstract
The high-resolution 13C NMR spectra of a variety of fungal branched (1→3)-β-d-glucans were recorded in a DMSO solution and a lyophilized solid in order to gain an insight into the primary and secondary structures in relation to their gel-forming property. We found that all the five lyophilized branched (1→3)-β-d-glucans examined so far, except lentinan, exhibit the laminaran-type triple-helix form, as established by the close resemblance of the 13C NMR spectra among them. On the contrary, lentinan taking the curdlan-type singlehelix conformation was readily converted to the triple-helix form by lyophilization after having been dissolved in a 8M urea solution (1M=1 mol dm−3) and dialysis against distilled water. This finding should be compared with the similar conformational change of curdlan: the conversion by this procedure was at most 50%; annealing at 150°C, followed by slow cooling, was essential for a complete conversion. This treatment did not induce the reverse conformational change from the triple helix to the single helix. The differential behavior of gelformation between the linear and branched (1→3)-β-d-glucans was explained in terms of the molecular conformations in the solid and gel states.
Mutarotation of α-d-Glucose over Several Al2O3 Catalysts
Authors: Ozawa Sentaro , Nakatani Jiro , Sato Masanori , Ogino Yoshisada 
Published: July 2006

Abstract
The mutarotation of α-d-glucose to β-d-glucose has been studied at 25±0.1 °C using five kinds of alumina as catalysts. Two kinds of alumina with measurable surface basicities have exhibited high catalytic activities while the others with little surface basicities have exhibited low activities. Thus, the surface basic sites have been considered to be responsible for the catalytic activity observed. Any of crystal structures, surface areas, pore structures, and surface elemental compositions have no relation to the catalytic activity. It has also been revealed that the kinetics of the reaction is explained by a surface reaction mechanism
α+1 \undersetKα\ightleftharpoons αad \oversetk1\undersetk2\ightleftharpoons βad \undersetKβ\ightleftharpoons β+1,
where 1, Kα, Kβ, k1 and k2 denote the active site, the adsorption equilibrium constant for α, the adsorption equilibrium constant for β, the rate constant for the surface forward reaction, and the rate constant for the surface backward reaction, respectively, and the subscript ad denotes an adsorbed state. The result of kinetic analysis has revealed that Kβ&gt;Kα, indicating that the adsorption of β-glucose is stronger than that of α-glucose. This also supports the view that the surface basic sites are responsible for the catalytic activity.
Reaction of Allyl Phenyl Ether over Various Liquid Metal Catalysts
Authors: Ozawa Sentaro , Sasaki Yoshiki , Ogino Yoshisada 
Published: July 2006

Abstract
Allyl phenyl ether has been reacted over various kinds of liquid metal catalysts (Sn, Ga, In, Tl, Pb, Cd, Bi, Zn) and without catalysts in the temperature range of 320–500 °C. Phenol (PN), 1,5-hexadiene (HD), benzofuran (BF), and o-allylphenol (o-AP) together with small amounts of unknown compounds have been found in the condensable products. The results of correlation among the conversion for PN, HD, and BF as well as the results of kinetic simulation of the products distribution have revealed that only the o-AP formation is catalyzed by the liquid metal. A clear compensation effect between the frequency factor and the activation energy has been found for the o-AP formation reaction, suggesting that a radicalic high energy and high entropy transition state is involved in the catalysis. A good correlation between the methyl group-catalyst metal bond energy and kinetic parameters of the o-AP formation reaction has also supported the radicalic transition state model.
Interaction between Dodecyltrimethylammonium Chloride and DNA
Authors: Shirahama Keishiro , Takashima Koji , Takisawa Noboru 
Published: July 2006

Abstract
Binding of dodecyltrimethylammonium cation to calf thymus DNA was studied by using the surfactant-selective electrode as a function of added electrolyte concentration at various temperatures. Binding is highly cooperative and biphasic. An abruptly occurring binding attains a slight shoulder within a very narrow equilibrium concentration range followed by a further augmentation in binding, as the equilibrium concentration is increased. Temperature caused relatively small shift in binding isotherm, but a distinct inversion point was found around 27 °C. Above this temperature the isotherm shifts to the left and then to the right below it. Analogous binding studies as above were repeated with heat-denatured DNA, which binds the surfactant with higher intrinsic affinity but less cooperatively than the intact DNA. A fluorescent probe, pyrene, was employed to assess the microenvironmental polarity of pyrene in DNA before and after surfactant binding. The surfactant–DNA complex has a hydrophobic region akin to ordinary micelle.
Molecular Structure of the exo-Diels–Alder-Adduct of 5-Methoxy-2-methyl-4-(p-nitrophenyl)oxazole with N-Methylmaleimide
Authors: Ibata Toshikazu , Toyoda Jiro , Tamura Hatsue , Ogawa Kazuhide 
Published: July 2006

Abstract
The molecular structure of the exo-Diels–Alder adduct of 5-methoxy-2-methyl-4-(p-nitrophenyl)oxazole with N-methylmaleimide was determined by X-ray analysis. The crystals are triclinic, space group P\bar1, with a=9.160(2), b=11.182(2), c=8.816(1) Å, α=92.39(1), β=116.47(1), γ=100.60(1)°, Z=2, Dx=1.455 Mg m−3, Dm=1.458 Mg m−3, μ(Cu Kα)=9.76 cm−1. The configuration of the exo-adduct is consistent with that predicted on the basis of the NMR data.