bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical Correlations of α-Santonin with (+)-Junenol and Acolamone
Authors: Niwa Masatake , Iguchi Masanobu , Yamamura Shosuke 
Published: July 2006

Abstract
The chemical transformation of the acetoxy ketone (5), which has previously been obtained from α-santonin, to (+)-junenol (1) and acolamone (3) has been carried out. In addition, isojunenol (2) was also derived from 5 via the trisubstituted olefin (9) which was obtained as the main product from the α- and β-oriented mesylates (8 and 11) on treatment with NaI in HMPA.
Influence of Anhydrous Hydrogen Fluoride on Hen Egg-White Lysozyme. II. Effects on Reduced Hen Egg-White Lysozyme
Authors: Aimoto Saburo , Shimonishi Yasutsugu 
Published: July 2006

Abstract
The influences of anhydrous hydrogen fluoride on reduced hen egg-white lysozyme were investigated under standard conditions for peptide synthesis. 1) Enzymatically fully active protein was recovered in poor yield (5%) from reduced hen egg-white lysozyme after treatment with hydrogen fluoride. 2) The yield (29–33%) was improved by addition of 1,4-butanedithiol or l-cysteine during treatment of reduced hen egg-white lysozyme with hydrogen fluoride. 3) Tetragonal crystals which were indistinguishable from those of native hen egg-white lysozyme were recovered after treatment of reduced hen egg-white lysozyme with hydrogen fluoride in the presence of 1,4-butanedithiol, anisole and amino acid derivatives. Thus, the original intact lysozyme could be recovered from an HF-solution of the reduced form.
Studies on the Reactions of Bis(acetylacetonato)platinum(II) with Lewis Bases. I. Reactions with Tertiary Phosphines Leading to a Complex Containing Carbon-Bonded Unidetate Acetylacetonato Ligand and Preparation of New Alkylplatinum Complexes
Authors: Ito Takashi , Kiriyama Takashi , Yamamoto Akio 
Published: July 2006

Abstract
Addition of tertiary phosphines (PR3) to [Pt(acac)2] (acac=acetylacetonato-O,O′) causes the rearrangement of one of the O-bonded chelate acac ligands to a C-bonded form giving [Pt(acac)(γ-acac)PR3] (γ-acac=acetylacetonato-C3) (PR3=PPh3, 1a, and P(C6H11)3, 2a). Complexes 1a and 2a were isolated and characterized by means of elemental analysis, infrared and 1H- and 13C-NMR spectroscopy. Some reactions involving complex 1 were investigated. The mechanism of formation of a diethylplatinum complex in the reaction of [Pt(acac)2] with Al(OEt)Et2 and PPh3 is discussed taking into account the rearrangement of the acac ligand from the O-bonded chelate to a C-bonded form.
Photoinduced One-Electron Reduction of 1-Benzyl-3-carbamoylpyridinium Chloride and 3,5-Bis(ethoxycarbonyl)-2,6-dimethylpyridine
Authors: Kano Koji , Matsuo Taku 
Published: July 2006

Abstract
Photolysis of 1-benzyl-3-carbamoylpyridinium chloride (BNA+) in aqueous solution in the presence of diethylamine and/or ethylenediaminetetraacetate gives the 6,6′-dimer (1), a coupled product of the pyridyl radicals generated by one-electron transfer from alkylamine to photoexcited BNA+. Thermal one-electron reduction of BNA+ either with zinc dust/copper sulfate or with magnesium powder in aqueous alkaline medium yields the 4,6′-dimer (2) together with a small amount of 1. In the case of 3,5-bis(ethoxycarbonyl)2,6-dimethylpyridine (HEox), the 2,2′-dimer (3) is formed as an initial photoreduction product, which is converted into the 4,4′-dimer (4) and 1,2-dihydropyridine (5) upon prolonged irradiation.
Carbonylation of Olefins, Alcohols, and Saturated Hydrocarbons Using Cu(CO)n+ and Ag(CO)2+ Catalysts in BF3–H2O
Authors: Souma Yoshie , Sano Hiroshi 
Published: July 2006

Abstract
Olefins, alcohols, and saturated hydrocarbons reacted with carbon monoxide to give t-carboxylic acids in high yields using copper carbonyl and silver carbonyl catalysts at room temperature and in carbon monoxide at atmospheric pressure in BF3–H2O solutions. Dienes and diols also reacted with carbon monoxide to give mixtures of monocarboxylic acids, dicarboxylic acids and lactones. The concentration ratio of H2O/BF3 was maintained between 1 and 2 during the carbonylation reaction. There was no difference between the catalytic behavior of Cu(CO)n+ and that of Ag(CO)2+. The reaction rates for primary alcohols were very low in BF3–H2O, although they increased with the addition of H2SO4. The reaction rates for s-alcohol, t-alcohol and olefins in BF3-H2O remained unchanged upon the addition of H2SO4.
Luminescence of Pyridinols and Related Molecules
Authors: Kimura Ko , Nagai Ryo 
Published: July 2006

Abstract
Quantum yields of fluorescence and phosphorescence together with lifetimes at 77 K suggest that 2-pyridinol exists in the keto form in the excited states as well as in the ground state, and the lowest excited singlet and triplet states for 2-, 3-pyridinol, 2-methoxypyridine, and N-methyl-2-pyridone are (ππ*) states. The lowest triplet state for 4-pyridinol takes the keto form, and is assigned to (ππ*).
The Stability Constants of Nickel(II) Complexes with Chloride, Thiocyanate, Sulfate, Thiosulfate, and Oxalate Ions, as Determined by a Solvent Extraction Method
Authors: Murai Ryokichi , Kurakane Kiyoshi , Sekine Tatsuya 
Published: July 2006

Abstract
The stability constants of nickel(II) complexes in 1 mol dm−3 sodium perchlorate media were determined at 25 °C by means of a solvent extraction method. The values thus obtained for logβ1 and logβ2 are: 0.0 and no second complex (Cl−), 1.1 and 1.6 (SCN−), 1.0 and 1.4 (SO42−), 0.9 and 1.3 (S2O32−), and 3.7 and 6.6 (C2O42−), respectively.
A New Synthesis of α-Santalol
Authors: Sato Kikumasa , Inoue Seiichi , Takagi Yoshihiro , Morii Shigeki 
Published: July 2006

Abstract
A new synthesis of α-santalol (1) is described. 1-Benzyloxy-4-bromo-2-methyl-2-butene (6) was converted by the reaction with nickel carbonyl to the π-allylic nickel bromide complex (7), which reacted with (−)-π-bromotricyclene (8) to afford benzyl ether (2). The benzyl ether (2) was led to (1) (cis: trans=40: 60) by reductive cleavage of the benzyloxy group.
The Stereostructure of Acetylparabenzlactone and Its Conversion to a Lariciresinol-type Lactone
Authors: Niwa Masatake , Iguchi Masanobu , Yamamura Shosuke , Nishibe Sansei 
Published: July 2006

Abstract
Acetylparabenzlactone (1), an acetylation product of (−)-parabenzlactone (2), has been newly isolated from Parabenzoin trilobum Nakai, and the stereostructures of these two piperolignanolides have also been elucidated. Furthermore, the chemical conversion of 1 to a lariciresinol-type lactone (3) has been carried out.
The Photoelectrolytic Reaction of Chlorophyll–β-Carotene–Quinone Electrodes
Authors: Takahashi Fujio , Kikuchi Ryoichi 
Published: July 2006

Abstract
The NAD+ (nicotinamide adenine dinucleotide) reduction was carried out under illumination by using a platinum electrode coated with chlorophyll and quinone. Various quinones and β-carotene were used as components of the cathode layer to obtain a higher current density. The highest current density, 13 μA/cm2, was obtained in the case in which the cathode layer contained 0.01 μmol/cm2 of chlorophyll and the molar ratio of chlorophyll: chloranil : β-carotene was 1 : 1 : 2. The role of quinone and β-carotene in the cathode layer was discussed.
Studies on Lignoids in Lauraceae. II. Studies on Lignans in the Leaves of Machilus Japonica Sieb. et Zucc.
Authors: Takaoka Daisuke , Watanabe Keiko , Hiroi Mitsuru 
Published: July 2006

Abstract
From the leaves of Machilus japonica Sieb. et Zucc., four lignans were isolated; they have been found to be (+)-galbacin [1], (+)-galbelgin [2], (−)-licarin-B [4], and a new lignan, machilusin, whose structure can be described as [3a] or [3b].
The Reaction of Disodium Tetracarbonylferrate(–II) with Aldehydes
Authors: Yamashita Masakazu , Watanabe Yoshihisa , Mitsudo Take-aki , Takegami Yoshinobu 
Published: July 2006

Abstract
Disodium tetracarbonylferrate (–II) is an efficient catalyst for the dismutation of aromatic aldehydes to esters, 2RCHO→RCOOCH2R. Aliphatic ones give aldol-condensation products upon treatment with the ferrate. A successive reaction of the ferrate with an aldehyde, RCHO, and then with alkyl iodide, R’I, gives an ester, R’COOCH2R, after protonation. The mechanisms of these reactions are discussed.
Formation and Reactions of Alkoxydiaminosulfonium Salts
Authors: Minato Hiroshi , Okuma Kentaro , Kobayashi Michio 
Published: July 2006

Abstract
Ethoxydimorpholinosulfonium tetrafluoroborate and tetraphenylborate were prepared by ethylation of dimorpholino sulfoxide. They were readily hydrolyzed with water but did not react with methanol. In the reactions with nucleophiles, they acted as ethylating agent for β-picoline, triethylamine, diethylamine, methoxide ion, and chloride ion. When dimorpholino sulfide, 1-chlorobenzotriazole, and an alcohol were allowed to react at −80 °C, the main products were an alkyl chloride, dimorpholino sulfoxide, and morpholinium chloride. Alkoxydimorpholinosulfonium chloride was presumed to be the intermediate, which decomposed by an SN2-type nucleophilic attack of chloride ion on the alkyl group. When (+)-2-octanol was used, the 2-chlorooctane formed was of almost completely inverted configuration (enantiomeric excess, 97%). The yield of alkyl chlorides decreased in the order of methyl (80%), isopropyl (51), and t-butyl (20).
Coenzyme Models. VII. Micellar Catalysis of Acid-Catalyzed Hydration of 1-Dodecyl-1,4-Dihydronicotinamide
Authors: Shinkai Seiji , Ando Reiko , Kunitake Toyoki 
Published: July 2006

Abstract
The acid-catalyzed hydration reaction of 1-dodecyl-1,4-dihydronicotinamide was examined in cationic(CTAB) and anionic (SDS) micelles. The H3O+-catalysis(kH was negligibly small in the presence of the CTAB micelle and 225–521 M−1 s−1 in the presence of the SDS micelle, the difference being about 107-fold. The catalysis by carboxylic acids (kHA) was considerably suppressed in the CTAB micelle, but was promoted in the SDS micelle, suggesting the development of a cationic charge on a nitrogen atom of dihydropyridine at the rate-determining step. Brönsted plots for logkHA in the CTAB and SDS micelles vs. pKa of carboxylic acids gave straight lines with the slope of −0.8, the line for SDS being higher by two orders of magnitude than that for CTAB. These results indicate that a cationic charge (e.g., the lysine residue of alcohol dehydrogenase located very close to the bound NADH) may protect the NADH from hydration decay.
Regrioselectivity of Palladium(II)-Induced Intramolecular Cyclization of 2-(3-Methyl-2-butenyl)phenol
Authors: Hosokawa Takahiro , Yamashita Shinji , Murahashi Shun-Ichi , Sonoda Akio 
Published: July 2006

Abstract
Reaction of 2-(3-methyl-2-butenyl)phenol (1) with PdCl2 gives 2,2-dimethylchromene (3) and 2,2-dimethyl-4-methoxychroman (4) (six-membered products) predominantly, together with trace amounts of 2-isopropylbenzofuran (5) and 2-isopropenyl-2,3-dihydrobenzofuran (6) (five-membered products). The reaction involves attack of the oxygen atom of the phenoxyl group at 2- or 3-position of the allylic side chain. Addition of various sodium carboxylates to the reaction mixture changes the regioselectivity. In the presence of sodium salts of carboxylic acids bearing electron-releasing substituents, nearly equal amounts of five and six-membered products are formed. The presence of sodium salts of carboxylic acids bearing electron-withdrawing substituents results in the predominant formation of the six-membered products. These results are discussed en the basis of alternation of reactive Pd(II) species. Results obtained from 2-(2-butenyl)phenol (2) are also reported.
Gel Filtration of Aqueous Sodium Dodecyl Sulfate
Authors: Suzuki Hitoshi 
Published: July 2006

Abstract
The tail analysis of gel filtration was applied to a sodium dodecyl sulfate (SDS) solution using Sephadex G-50. This method is more simple and useful than the frontal analysis method formerly reported. The relative elution rate of SDS micelle, Rm, increased with an increase in the SDS concentration above CMC, reached a maximum near 16 mmol/l and then decreased up to 100 mmol/l. The application of the Laurent-Killander equation gave a micellar radius of 17.6 Å at CMC and 11.7 Å at the maximum Rm, corresponding to aggregation numbers of 35 and 80, respectively. The apparent decrease of Rm observed above 20 mmol/l was due to an structural change of the Sephadex gel caused by the addition of SDS. The micellar weight was estimated referring to a substance of known molecular weight; it was found to be constant in the region from 15 to 100 mmol/l SDS. The results of gel filtration of the SDS solution using CPG-10 as a gel column were similar to the case of Sephadex G-50; a micellar weight and an aggregation number of 25000 and 88, respectively, in the constant Rm range were obtained.
Proton Magnetic Resonance Spectra of Metal Ammine Complexes. VI. The trans-Effect in Cobalt(III) Amine Compounds as Studied by the Rate of Hydrogen-Deuterium Exchange
Authors: Sakaguchi Ushio , Maeda Koichi , Yoneda Hayami 
Published: July 2006

Abstract
The rate of the isotopic deuterium exchange has been measured for several cobalt(III) amine complexes in D2O. The substituents CN−, NO2−, and possibly SO32− decelerate the exchange of the amine protons trans to these ligands, leading in some cases to a smaller rate for these protons than for the cis ones. On the other hand, the trans-proton labilizing ligands include F−, Cl−, Br,−, H2O, CO32−, OCONH2−, N3−, CH3NH2, CH3COO−, and the malonate, fumarate, and oxalate ions. The above observation clearly indicates that the HD exchange rate can be a measure of the trans-effect of these ligand molecules.
Proton Magnetic Resonance Spectra of Metal Ammine Complexes. VII. Amine Proton Chemical Shifts in Bis(ethylenediamine)cobalt(III) Compounds
Authors: Sakaguchi Ushio , Yamazaki Shigeo , Yoneda Hayami 
Published: July 2006

Abstract
Amine proton chemical shifts have been measured for some cis-bis(ethylenediamine)cobalt(III) complexes in trifluoroacetic acid. The shifts can be explained quantitatively by the magnetic anisotropy of the central metal ion and by assuming fast conformational inversion of chelate rings. Discrepancy between the observed and the computed shift values is apparent, however, for the trans hydrogens of the cis-dicyano compound, which may be due to the ground-state trans-effect of the cyanide ion. The chemical shifts of amine protons of cis-tetraammine and cis-bis(trimethylenediamine)compounds have been briefly discussed.
Cyanoalkyl Complexes of Transition Metals. IV. Geometry and Spectroscopic Properties of Cyanomethyl Complexes of Palladium(II) and Platinum(II)
Authors: Suzuki Keinosuke , Ooyama Junichi , Sakurai Masami 
Published: July 2006

Abstract
A number of cyanomethyl complexes of palladium(II) and platinum(II) were prepared and characterized by proton nuclear magnetic resonance and infrared spectroscopy. It was shown that the methylene resonance, phenyl resonance, and a strong band at 550±5 cm−1 are acceptable criteria for deducing the geometry of the complexes MX(CH2CN)(PPh3)2 (M=Pd, Pt). The criteria allow us to assign the cis geometry to the bromo and iodo complexes of platinum(II) both of which showed an unusual methylene resonance. An approximately linear relationship holds between 2J(Pt–H) of trans-PtX(CH2CN)(PPh3)2 and that of trans-PtX(CH3)(PPh3)2 (X=Cl, Br, I, N3, NO2, NO3).
Epoxide Rearrangement. IV. Isomerization of Cyclohexene and 1-Methyl-cyclohexene Oxides over Solid Acids and Bases in Gas Phase
Authors: Arata Kazushi , Kato Kiyoshi , Tanabe Kozo 
Published: July 2006

Abstract
A large amount of diene compounds was found to form in the isomerizations of cyclohexene and 1-methylcyclohexene oxides catalyzed by solid acids and bases in gas phase. The catalysts which were quite inactive in liquid phase showed unexpectedly high activities in gas phase, indicating the different catalytic actions.
Spectroscopic Study of Concentration Fluctuation and Intermolecular Interaction in Liquid
Authors: Fujiyama Tsunetake , Kakimoto Masao , Suzuki Tetsuo 
Published: July 2006

Abstract
The band widths of the infrared absorption spectra were observed for binary solutions of methyl iodide, methyl cyanide, chloroform, and carbon disulfide. The observed bands are: the v1 fundamental of chloroform in carbon disulfide and in carbon tetrachloride; the v2 fundamental of methyl iodide in methyl cyanide, nitromethane, benzene, carbon disulfide, and carbon tetrachloride; the 2v2 band of methyl iodide in methyl cyanide, and the v8 and 2v8 bands of methyl cyanide in methyl iodide. The concentration dependence of a band width was explained in terms of the concentration fluctuation. The theory was compared with the observed band widths, together with the light-scattering data. A fluctuation volume was related with the intermolecular interactions in these binary solutions.
Stereochemical Studies of Elimination Reactions of 2-Bromobutane and 2,3-Dibromobutane over Alkali-Ion Exchanged Silica Gels
Authors: Misono Makoto , Aoki Yukio , Yoneda Yukio 
Published: July 2006

Abstract
The stereochemistry (anti or syn mode) of elimination reactions of 2-bromobutane and 2,3-dibromobutane over alkali-ion exchanged silica gels (Li, Na, K, and Cs) was determined at 100–300 °C from the products of the diastereomeric isomers of each alkyl bromide. They were erythro- and thero-2-bromobutanes-3-d1 and meso- and dl-2,3-dibromobutanes. The steric course of dehydrobromination of 2-bromobutane changed nearly reversibly between syn and anti mode by the partial exchange of a surface proton with K+ or Cs+ ion, although the surface structure seemed to remain unchanged by the exchange procedure. On the other hand, the exchange with Na+ or Li+ ion did not change the steric course. Dehydrobromination of 2,3-dibromobutane proceeded by anti mode over Na-, K-, and Cs–SiO2, while SiO2 and Li–SiO2 were not active. The poisoning effect of acidic and basic reagents as well as the indicator test revealed that basic sites played important roles over K- and Cs–SiO2 where anti elimination prevailed, and that weakly acidic sites were responsible for syn elimination.
Studies of Fragment Ion Distribution and Reaction with a Charge Spectrometer. VIII. Fragmentation Processes of Various Alkyl Halides
Authors: Ikuta Shigeru , Yoshihara Kenji , Shiokawa Takanobu 
Published: July 2006

Abstract
The breakdown curves for C2H5X, n-C3H7X, and n-C4H9X (X=Cl, Br, and I) were obtained by the use of a double mass spectrometer of the perpendicular type. The charge exchange mass spectra for alkyl bromide and alkyl iodide are found to be similar, although those for alkyl chloride are somewhat different from these for bromide and iodide. According to the molecular orbital calculation, the difference of the electronic configuration between chloride and bromide or iodide is found to correspond to the difference of the breakdown curves. The results obtained in this study using larger molecules support our previous analysis on the breakdown processes in smaller molecules: (1) direct scission of the bond which has lost one electron by the charge exchange reaction, (2) electron redistribution, and (3) secondary decomposition (and those of higher order) from the primary fragments. In the case of alkyl chloride, formation of the ion CnH2n+ is ascribed to the elimination of HX from the molecular ion in its electronically ground but vibrationally excited state.
The Polymorphic Crystallization of TiO2 under Hydrothermal Conditions. I. The Effect of Phosphate Ions on the Selective Crystallization of Anatase
Authors: Izumi Fujio , Fujiki Yoshinori 
Published: July 2006

Abstract
The hydrothermal growth of anatase has been investigated at 480–650 °C and 500–1000 atm. Only rutile was formed in KF solutions. On the other hand, anatase was found to crystallize in solutions containing 5 wt% KF+0.1–10 wt% K2HPO4 at temperatures up to 600 °C, accompanied by small amounts of K2Ti6O13 on the addition of 5–10 wt% of K2HPO4. The optimum growth conditions were: mineralizer solution, 5 wt% KF+1–2.5 wt% K2HPO4; temperature, 550–600 °C; pressure, 1000 atm. Anatase crystals were found as irregular aggregates of dipyramidal grains, blue and transparent. Individual crystals grown at a low supersaturation were characterized by well-developed {101} and {103} faces. The observed habit agrees with the expectations based on Hartman’s PBC theory. The presence of phosphate ions favored anatase formation in NH4F solutions as well, and the retrograde solubility of TiO2 was observed. The reaction scheme for anatase formation has been proposed. The polymorphic crystallization of TiO2 under hydrothermal conditions has been shown to be greatly affected by the complexing anions, such as fluoride or phosphate, in mineralizer solutions.
Substituent Effects in the Ionization of trans-2-Substituted Cyclopropanecarboxylic Acids
Authors: Kusuyama Yoshiaki , Ikeda Yoshitsugu 
Published: July 2006

Abstract
The ionization constants of trans-2-substituted cyclopropanecarboxylic acids were determined in water and 50% aqueous ethanol at 25 °C. The substituent effects thus obtained were interpreted by the use of the four parameter equations presented by Yukawa and Tsuno. The transmitting resonance effect of trans-cyclopropylene is about a quarter that of trans-vinylene and a half that of p-phenylene.
Photochemical Reaction of 9,10-Phenanthrenequinone with Hydrogen Donors. Behavior of Radicals in Solution as Studied by CIDNP
Authors: Maruyama Kazuhiro , Otsuki Tetsuo , Naruta Yoshinori 
Published: July 2006

Abstract
Behavior of radicals produced in the photochemical reaction of 9,10-phenanthrenequinone was investigated by use of CIDNP and ESR technique. By comparison of the sign of CIDNP signals in formation of and in decomposition (photochemical or thermal) of adducts, the rearrangement of adducts, e.g., from the 1,2-adduct to 1,4-adduct and vice versa, was proposed. Although the adducts are stable enough to isolate in general, they decomposed photochemically or thermally to give the mixture of 9,10-phenanthrenediol (or its quinhydrone), the dehydrogenated dimer of hydrogen donor, and others as minor product.
Lumiflavin-sensitized Photooxygenation Accelerated by Adenine. II. The Photolysis of 14C-labeled Reactants
Authors: Yoshimura Akio , Kato Shunji 
Published: July 2006

Abstract
Radioactive tryptophan, histidine, methionine, and guanine were photolyzed in the presence of lumiflavin either with or without adenine, and the reaction products were compared chromatographically. Adenine accelerated these lumiflavin-sensitized photooxygenation reactions, and no effect of adenine on the reaction products was shown.
Ligand Isotopic Exchange Kinetics of Tris(acetylacetonato)titanium(IV) Perchlorate in Acetonitrile
Authors: Nishizawa Masato , Kido Hiroaki , Kinoshita Isamu , Soma Yoshikuni , Saito Kazuo 
Published: July 2006

Abstract
The rate of isotopic exchange between tris(acetylacetonato)titanium(IV) ions and acetylacetone-14C3 in enol form is measurable at −20 °C in acetonitrile. Water, free ligand and a strong acid catalyse the exchange.
C-13 NMR Chemical Shifts and Charge Densities of Substituted Thiophenes—The Effect of Vacant dπ Orbitals
Authors: Osamura Yoshihiro , Sayanagi Osamu , Nishimoto Kichisuke 
Published: July 2006

Abstract
The effect of vacant dπ orbitals on the charge distributions of heteroatomic systems containing sulfur and halogens is discussed. From an appropriate estimation of the Coulomb and resonance integrals associated with the vacant dπ orbitals, a linear relationship is obtained between charge density and C-13 chemical shift. For a discussion of the reactivity for electrophilic substitution of thiophene, the contribution of dπ orbitals of sulfur atom should be taken into account.