bluuebunny/crossref_metadata_2025_split huggingface dataset:
An MO Calculation of the Reaction Path of a Symmetry-Disfavored 1,3-Sigmatropic Rearrangement
Authors: Minato Tsutomu , Inagaki Satoshi , Fujimoto Hiroshi , Fukui Kenichi 
Published: July 2006

Abstract
The path of suprafacial 1,3-sigmatropic rearrangement is studied with the INDO-CI and INDO LMO methods. The methyl migration has been found to be represented by successive 1,2-shifts with a biradicaloid transition state. The interaction between the singly occupied MO’s of allyl and methyl fragments is suggested to be responsible for the determination of the path. A subsidiary orbital also plays a part. On the other hand, the chlorine migration has been shown to be a direct 1,3-shift. The interaction between the lowest unoccupied MO of the allyl cationic part and the highest occupied MO of the remaining part, chloride anion, has been found to govern the path of chlorine migration. The lone pair electrons of the migrating fragment makes the successive 1,2-shifts quite unlikely in the 1,3-suprafacial chlorine rearrangements.
Determination of the 63P1→63P0 Transition Rate of Hg in CO and NO by a Modulation Technique
Authors: Horiguchi Hiroyuki , Tsuchiya Soji 
Published: July 2006

Abstract
In order to determine the branching ratio for Hg(63P1) deactivation to the 63P0 and 61S0 states in CO or NO, a modulation technique was utilized. The intensity of 253.7-nm radiation was modulated at a frequency in the range from 0.1 to 20 kHz, and the resulting a.c. component of the Hg(63P1 or 63P0) concentration was measured by monitoring the absorption of the 435.8- or the 404.7-nm emission line from an Hg discharge lamp. The lower detection limit of excited Hg atoms was 107 cm−3 in this experimental method. On the basis of the Hg(63P0) concentration relative to that of Hg(63P1) in an Ar+CO or NO mixture including information on the phase delay, the 63P1→63P0 transition rate could be determined; the 63P1→63P0 cross section was found to be 22.4 Å2 for CO and 7.1 Å2 for NO and the 63P0→61S0 cross section to be 1.80 Å2 for CO and 37 Å2 for NO at room temperature.
The Electron Capture by Bromobenzene in the γ-Radiolyses of Cyclohexane and 2,2,4-Trimethylpentane
Authors: Karasawa Hidetoshi , Kim Eung-Ryul , Sato Shin 
Published: July 2006

Abstract
The γ-radiolyses of cyclohexane and 2,2,4-trimethylpentane have been reinvestigated. Bromobenzene was used as the electron scavenger. The analysis of the G-values of benzene obtained at high concentrations of bromobenzene showed that the empirical formula proposed by Hummel for the electron scavenging
G=G_fi+G_gi{1-exp(-√‾αS)}
is better than that proposed by Warman et al. The values of Gfi+Ggi thus obtained were 3.7±0.3 for cyclohexane and 3.5±0.2 for 2,2,4-trimethylpentane. The bromobenzene-concentration dependence of the G-values of hydrogen and methane from 2,2,4-trimethylpentane was well explained by the hypothesis that the lifetimes of the 2,2,4-trimethylpentane ion for the decomposition are in the same order as the time needed for the geminate recombination.
Heat Capacities of Aqueous Solutions of Glutaric and Malonic Acids
Authors: Kawaizumi Fumio , Noguchi Tuneyuki , Miyahara Yutaka 
Published: July 2006

Abstract
Using a calorimeter composed of a Dewar vessel and a Beckmann thermometer, the specific heat capacities of aqueous solutions of glutaric and malonic acids were measured at 30 °C. Techniques for establishing the temperature gadient between the solution in the Dewar and the outer air bath were adopted. The partial molar heat capacities at infinite dilution were estimated assuming a relation of the form mφCp=bm+cm2. The contributions of the –CH2– and –COOH groups to the partial molar heat capacities in aqueous solution are roughly additive: for –CH2– a positive contribution and for –COOH a negative one. The Δ(=‾Cp2°–Cp2(pure state)) were also calculated and positive and negative values were obtained for Δ(–CH2–) and Δ(–COOH), respectively.
An Interpretation of Delayed Fluorescence Behavior of Naphthalene in Biphenyl Host in the Lower Temperature Region
Authors: Kusumoto Yoshihumi , Gondo Yasuhiko , Sato Hiroyasu , Kanda Yoshiya 
Published: July 2006

Abstract
Temperature and concentration dependences of the delayed luminescence observed in the naphthalene (guest)–biphenyl (host) mixed crystal system have been studied. The presence of the temperature-independent delayed fluorescence (TIDF) and its significance in the evaluation of activation energy have also been confirmed in this system as in the case of the benzo[f]quinoline–biphenyl system previously reported, and the generality of the existence of TIDF as well as its significance in relation to activation energy has been suggested. In addition, some remarks have been made on the nature of TIDF and the decay behavior.
A Chlorine NQR Study of Trichloromethyl Derivatives. I
Authors: Hashimoto Masao 
Published: July 2006

Abstract
The chlorine NQR frequencies of several benzene derivatives with –CCl3 groups were measured at temperatures above 77 K. For all the compounds studied, the NQR signals of the –CCl3 groups were observed to fade out; the fade-out temperatures (Tf) were in the temperature range of 130–370 K. It was found that the most important factors involved in determining the Tf value are the intramolecular steric hindrance, hyper conjugation, and intermolecular interactions. In some compounds, an increase in the NQR frequency was found to be caused by the intramolecular steric hindrance.
The Microwave Spectrum of 1-Propanethiol
Authors: Ohashi Osamu , Ohnishi Mamoru , Tagui Akira , Sakaizumi Takeshi , Yamaguchi Ichiro 
Published: July 2006

Abstract
The microwave spectra of 1-propanethiol and its deuterated species (CH3CH2CH2SD) were measured in the frequency region from 8.5 to 35 GHz. Several a-type R-branch transitions for the ground and excited vibrational states of the normal species and for the ground state of the deuterated species were identified, and the following rotational constants in MHz were obtained: A=23429±653, B=2345.29±0.03, and C=2250.18±0.03 for the ground state of the normal species; A=24483±945, B=2346.30±0.04, and C=2253.91±0.04 for the excited state of the normal species, and A=21758±461, B=2306.71±0.03, and C=2217.79±0.03 for the ground state of the deuterated species. The spectrum assigned to the ground vibrational states has been attributed to the T–G rotational isomer, and the excited vibrational state has been ascribed to the –CH2–CH2– torsional motion.
Intrachain Charge-Transfer Complex in Ethanol Solution on a Polysarcosine Chain Having a Terminal Electron Donor and a Terminal Electron Acceptor Groups
Authors: Takagi Hiroaki , Sisido Masahiko , Imanishi Yukio , Higashimura Toshinobu 
Published: July 2006

Abstract
Polysarcosine having a terminal electron donating group (p-dimethylaminoanilide group) and a terminal electron accepting group (3,5-dinitrobenzoyl group) was synthesized. An ethanol solution of the polymer showed a distinct charge-transfer absorption band around 435 nm. With use of the extinction coefficient determined for the low-molecular-weight model compounds, the fraction of polymers forming an intrachain complex was evaluated to be about 0.08 for \barn=6 (\barn is the degree of polymerization of the polysarcosine chain). The fraction decreased with rise in temperature and increase in chain length. The fraction experimentally observed was considerably larger than that estimated from the Monte Carlo calculation on polysarcosine chain, indicating that the cyclic conformations are greatly stabilized by the intrachain charge-transfer interaction. Thermodynamic parameters were determined for the intrachain complex. The chain length dependence of the parameters in ethanol was the opposite of that obtained previously in a chloroform solution. The difference was explained in terms of the difference of the conformations of polysarcosine chain in chloroform and in ethanol solutions. This was evidenced by the NMR spectra recorded in the solvents.
The New Schizandrin-type Lignans, Kadsurin and Kadsurarin
Authors: Chen Yuh-Pan , Liu Rolan , Hsu Hon-Yen , Yamamura Shosuke , Shizuri Yoshikazu , Hirata Yoshimasa 
Published: July 2006

Abstract
Two new lignans, kadsurin and kadsurarin, were isolated from Kadsura japonica Dunal, and their structures were established. The stereostructures of the schizandrin-type lignans including their conformations were elucidated by measurements of intramolecular nuclear Overhauser effects.
Synthesis of Methyl-substituted 1-Cyclopentene-1-carboxylates and Related Compounds
Authors: Takeda Akira , Shinhama K\={o}ichi , Tsuboi Sadao 
Published: July 2006

Abstract
The treatment of methyl-substituted 1-chloro-2-oxo-1-cyclohexanecarboxylic esters (7a–e) with anhydrous Na2CO3 in refluxing xylene gave the corresponding methyl-substituted 1-cyclopentene-1-carboxylic esters (1a–e). Several intermediates important in the synthesis of natural products, such as 4,4-dimethyl-1-cyclopentene-1-carbaldehyde (9), 5-methyl-1-cyclopentene-1-carbaldehyde (12), α-(3-methyl-1-cyclopentenyl)propionic acid (16), and ethyl 2-methyl-3-oxo-1-cyclopentene-1-carboxylate (17), have been prepared starting from esters 1e, 1d, 1b, and 1a, respectively.
ESR Studies of N-(Arylthio)-t-butylaminyls
Authors: Miura Yozo , Asada Hidetsugu , Kinoshita Masayoshi 
Published: July 2006

Abstract
It was found that N-(arylthio)-t-butylaminyls (2) are easily generated by the photolysis of N-t-butylbenzene-sulfenamides (1). The ESR spectra of 2 were split into a 1 : 1 : 1 triplet by the interaction with the nitrogen nucleus (11.70–11.89 G), and each of the triplet was further split by the ring protons (ao-H: 0.89–1.07 G). The g-values of 2 lie in the range from 2.0068–2.0073. The radicals persist in benzene and it appears that they are not sensitive to the atmospheric oxygen.
Inositol Derivatives. 10. Isopropylidenation of 1,2-O-Cyclohexylidene-myo-inositol Derivatives and Preparation of Unaccessible Blocked Inositols
Authors: Ogawa Seiichiro , Oki Shuichi , Kunitomo Hideo , Suami Tetsuo 
Published: July 2006

Abstract
Isopropylidenation of 1,2-O-cyclohexylidene-myo-inositol and its 3-O-tosyl- and 3-O-benzoyl derivatives with 2,2-dimethoxypropane in N,N-dimethylformamide in the presence of acid catalyst gave the corresponding 4,5- and 5,6-O-isopropylidene derivatives. Selective benzoylation of 1,2-O-cyclohexylidene-4,5-O-isopropylidene-myo-inositol with benzoyl chloride in pyridine gave mainly the 3-O-benzoate, whereas with benzoic anhydride the 6-O-benzoate. Several unaccessible blocked inositols were prepared by displacement reaction of the protected sulfonyl derivatives with sodium benzoate.
Catalytic Behavior of Sulfonium Trihalides in the Low-temperature Liquid-phase Oxidation of Tetralin
Authors: Ohkubo Katsutoshi , Aoji Teruo , Yoshinaga Kohji 
Published: July 2006

Abstract
Homogeneous oxidation of nonpolar tetralin catalyzed by sulfonium trihalides was found to proceed via a radical chain mechanism in which the trihalide catalysts promoted the reaction through the activation of molecular oxygen.
The Reactions of Several Anilides with Phosphoryl Chloride
Authors: Fukuda Masahiro , Okamoto Yoshiki , Sakurai Hiroshi 
Published: July 2006

Abstract
Chloroacetanilide and p-methylchloroacetanilide reacted with phosphoryl chloride to give 2-chloromethyl-3-chloro-4-anilinoquinoline and 2-chloromethyl-3-chloro-4-(p-toluidino)-6-methylquinoline respectively. In the case of propionanilide, 2-ethyl-3-methyl-4-anilinoquinoline was obtained when the reaction was carried out at 20–30 °C. On the other hand, when the reaction temperature was raised to 80–100 °C, N-(1-chloro-1-propenyl)-N,N′-diphenylacetamidine was obtained.
Reaction of Camphene with Chloroacetic Acid and the Synthesis of 2-(8-Camphenyl)ethanol
Authors: Kishimoto Takao , Ishihara Hiroshi , Matsubara Yoshiharu 
Published: July 2006

Abstract
Camphene (1) reacts with chloroacetic acid (2) or its polymer, polyacetoxamer; α-chloro, ω-carboxy in the presence of potassium bromide at reflux temperature to give the 2,2-dimethyl-exo-3-hydroxynorbornane-endo-3-propanoic acid lactone and the 2,2-dimethyl-endo-3-hydroxynorbornane-exo-3-propanoic acid lactone in a 50% yield. The synthesis of 2-(8-camphenyl)ethanol from 1 was simplified by utilizing this reaction.
The Intramolecular Cyclization Reaction of Unsaturated Acid with Palladium(II) Salt
Authors: Kasahara Akira , Izumi Taeko , Sato Kazuhiro , Maemura Mitsugi , Hayasaka Tomohide 
Published: July 2006

Abstract
The stoichiometric reaction of sodium salts of 3-butenoic acid, 3-pentenoic acid, 4-pentenoic acid, and 4-hexenoic acid with lithium tetrachloropalladate(II) affords 2-buten-4-olide, 4-methyl-2-buten-4-olide (2b), 2b, and 4-ethyl-2-buten-4-olide respectively. Similarly, the reaction of 2-styrylbenzoic acid with palladium(II) salt leads to the formation of 3-phenylisocoumarin.
Electronic Structures of Meso-ionic Azapentalenes Studied by X-Ray Photoelectron Spectroscopy
Authors: Ohta Toshiaki , Yoshida Masayuki , Kuroda Haruo 
Published: July 2006

Abstract
X-Ray photoelectron spectra of meso-ionic azapentalenes were observed in the solid phase. The charge distributions in these molecules were investigated by using the observed chemical shifts of core-electron levels, employing Siegbahn’s electrostatic potential model and the results of CNDO/2 calculations.
Kinetics of the Oxidation of Ethylenediaminetetraacetato and Aqua Complex of Dimeric Molybdenum(V) by the μ-Hyperoxo-bis[pentaamminecobalt(III)] Ion in Aqueous Perchloric Acid Solution
Authors: Sasaki Yoichi 
Published: July 2006

Abstract
Kinetics of the oxidation of double-bridged Mo(V) complexes, [Mo2O4(edta)]2− (H4edta=ethylenediaminetetraacetic acid) and [Mo2O4(aq)]2+ with [(NH3)5CoO2(−)Co(NH3)5]5+ has been studied in aqueous perchloric acid solution at 25–50 °C. The oxidation of [Mo2O4(edta)]2− is characterized by the electron transfer within the ion-pair formed between the two reactants. The first order rate constants for the electron transfer process (ke) are independent of [H+] ([H+]=0.05–0.1 M; I=0.1–2.0 M) (M=mol dm−3). At 40 °C and I=0.1 M, ke is equal to (1.34±0.08)×10−3 s−1 and the corresponding activation parameters are ΔH\eweq=28±4 kcal mol−1 and ΔS\eweq=18×11 cal K−1 mol−1. The rate of oxidation of [Mo2O4(aq)]2+ is independent of the oxidant concentration and accelerated by halide ions and Mo(VI). The rate-determining step is the formation of a single-bridged Mo(V) dimer (A) prior to electron transfer. The first order rate constants for the formation of A (k1) are reciprocally dependent on [H+] ([H+]=0.5–2.0 M; I=2.0 M). k1 is (4.3±0.3)×10−6 s−1 at 25 °C and for [H+]=1.0 M. The difference in the oxidation mechanism of the two complexes has been discussed in terms of the charge of the complex, stabilization of the Mo2O4-unit by the ligands, and the role of coordinated water.
The Chemistry of Phenalenium Systems. XXIII. Syntheses and Properties of Cyclohepta[cd]phenalen-6-one and the Cyclohepta[cd]phenalenium Ion
Authors: Yamamoto Kagetoshi , Kayane Yutaka , Murata Ichiro 
Published: July 2006

Abstract
The syntheses of cyclohepta[cd]phenalen-6-one (8) and the cyclohepta[cd]phenalenium tetrafluoroborate (1) are reported. As expected, it is apparent that in the transition from 10,11-dihydrocyclohepta[cd]phenalen-6-one to the fully conjugated ketone 8, all the vinyl protons move downfield by 0.22 to 0.53 ppm. The plausible explanation suggests that these shifts arise from deshielding due to the existence of a diamagnetic ring current induced in the 14π periphery of 8. In accord with theoretical prediction, the cation 1 is extremely stable. The substantial thermodynamic stability of 1 is reflected to its pKR+ of 8.4. The ion 1 can be regarded as a perturbed [15]annulenium ion weakly coupled with a localized central vinyl crosslink.
Syntheses of 4-Phenylcoumarins Containing a Dimethylpyran Ring
Authors: Matsui Takanao , Nishimura Shinji , Nakayama Mitsuru , Hayashi Shûichi , Fukui Kenji 
Published: July 2006

Abstract
Three isomers of 2H,8H-benzo[1,2-b: 3,4-b′]dipyran and 2H,8H-benzo[1,2-b: 5,4-b′]dipyran, were synthesized by dehydrogenation of the dihydrobenzodipyran derivatives using DDQ or NBS and by dehydration of the secondary alcohol prepared by reduction of 4-phenylcoumarin derivatives bearing dihydropyranone ring with sodium borohydride.
Synthesis and 13C NMR Spectra of endo-5-(4-Imidazolyl)bicyclo[2.2.2]oct-endo- and exo-2-yl trans-Cinnamates
Authors: Utaka Masanori , Akiyama Mamoru , Takeda Akira 
Published: July 2006

Abstract
The Synthesis of endo-5-(4-imidazolyl)bicyclo[2.2.2]oct-endo- and exo-2-yl trans-cinnamates was carried out starting from 2-butyn-1,4-diol. The key intermediate, endo-5-(4-imidazolyl)bicyclo[2.2.2]octan-2-one, was obtained by oxidation of endo-5-(4-imidazolyl)bicyclo[2.2.2]oct-2-ene with palladium chloride, the oxidation being stereo- and regiospecific. The mode of 2,5 disubstitution and endo, exo stereochemistry were determined by means of 13C chemical shifts of the bicyclo[2.2.2]octane framework.
The Isolation and Structure of Toxic Principles, Milliamines A, B, and C, from Euphorbia Millii
Authors: Uemura Daisuke , Hirata Yoshimasa 
Published: July 2006

Abstract
Toxic compounds were isolated from Euphorbia Millii Ch. des Moulins (Euphorbiaceae). The structure of the milliamines was established from chemical and spectral evidence. Furthermore, the acute toxicity of milliamine A was examined.
Synthesis of Corticotropin Peptides. XIV. The Synthesis of Two Octadecapeptides Corresponding to the Amino Acid Sequence 22–39 of Porcine and Human Corticotropins
Authors: Watanabe Kunio , Inouye Ken 
Published: July 2006

Abstract
The syntheses are described of two octadecapeptides, H–Val–Tyr–Pro–Asn–Gly–Ala–Glu–Asp–Glu–Leu–Ala–Glu–Ala–Phe–Pro–Leu–Glu–Phe–OH (Ip) and H–Val–Tyr–Pro–Asn–Gly–Ala–Glu–Asp–Glu–Ser–Ala–Glu–Ala–Phe–Pro–Leu–Glu–Phe–OH (Ih), corresponding to a tryptic fragment (positions 22–39) of porcine corticotropin (αp-ACTH) and that of human hormone (αh-ACTH), respectively. The porcine pep tide and the corresponding human peptide are prepared simultaneously by an identical synthetic procedure except for the introduction of amino acid residue in position 31. Synthetic peptide Ip is compared with the authentic αp-ACTH (22–39), which has been isolated from a tryptic hydrolysate of natural αp-ACTH, in terms of chemical and physicochemical properties to establish their identity. These data as well as those obtained with human peptide Ih prove the satisfactory synthesis of the two octadecapeptides.
Synthesis of Amino Compounds under Phase Transfer Conditions
Authors: Nakajima Yosuke , Kinishi Ryo-ichi , Oda Jun’ichi , Inouye Yuzo 
Published: July 2006

Abstract
The phase transfer process was applied to the reaction of organic bromides with azide anion. The reduction of intermediary azide derivatives gave the corresponding amino compounds, benzylamine, glycine, alanine, butyrine, and serine in fairly good yields. Effective catalytic activity was demonstrated by the difference in chemical yields in the case of methyl bromoacetate and ethyl α-bromopropionate. In order to examine the role of phase transfer catalyst, two bromohydrins (methyl β-hydroxy-α-bromopropionate and styrene bromohydrin) were subjected to the present reaction. Methyl β-hydroxy-α-bromopropionate afforded serine exclusively in the presence of 18-crown-6 and tetrabutylammonium bromide, but in the absence of the catalyst a mixture of serine and isoserine was obtained. A different regioselectivity was observed in the case of styrene bromohydrin.
Hydration of Aza-aromatic Aldehydes. I. Isolation of the Solid Hydrates and the Thermodynamic Properties in Dimethyl Sulfoxide
Authors: Abe Kazuhisa , Hirota Minoru , Takeuchi Isao , Hamada Yoshiki 
Published: July 2006

Abstract
The covalent hydration forming geminal diol is shown to be general in six-membered aza-aromatic aldehydes substituted by a formyl group at ortho or para-position to the nitrogen atom, and the equilibrium constants and thermodynamic quantities of the reaction are determined by NMR spectroscopic measurements. The results are compared with those of their hemiacetal formation. In several cases, solid monohydrates are isolated and identified.
The Cycloaddition of Dispiro[2.2.2.2]deca-4,9-diene with the Styrene Derivatives. The Syntheses and Spectral Properties of the [4.2]Paracyclophane Derivatives
Authors: Shibata Tohru , Tsuji Takashi , Nishida Shinya 
Published: July 2006

Abstract
The thermal cycloaddition of dispiro[2.2.2.2]deca-4,9-diene 1 with the styrene derivatives has afforded [4.2]paracyclophane derivatives, 3. A reaction mechanism by way of the biradical intermediates, involving the initial homolytic cleavage of the cyclopropane ring in 1 followed by the addition to the styrene molecule, is proposed. In the reaction of 1 with styrene, and methyl α-phenylacrylate, the yields of 3 were improved with the dilution of the reactants, while in the reaction with trans-stilbene, no appreciable dependence on the reactant concentration was observed. The mass spectra of the substituted [4.2]paracyclophanes show a predominant fragmentation to the substituted p-xylene-α,α′-diyl (or elements thereof) ion radical. [4.2]Paracyclophane exhibited a temperature-dependent NMR spectrum which could be ascribed to the rapid equilibration between two structurally equivalent conformers. Bulky substituents on C-1 and C-2 shifted the equilibrium to one side.
Induced Circular Dichroism Spectra of Cobalt(III) Complexes in a Chiral Medium Containing (+)589-Diethyl Tartrate
Authors: Taniguchi Yutaka , Hidaka Jinsai , Shimura Yoichi 
Published: July 2006

Abstract
The induced circular dichroism (CD) spectra of 21 achiral or racemic cobalt(III) complexes have been measured in a chiral medium containing (+)589-diethyl tartrate in the region of the first d-d transition bands. The absolute value of the molar circular dichroism (Δε) observed for these complexes is in the range of about 0.04–0.3 cm−1 mol−1 dm3. The induced CD spectra of the racemic complexes show a different pattern from the natural CD spectra of their resolved enantiomers. The observed induced CD spectra have been discussed in relation to the stereochemistry of the complexes.
Pressure Effect on the Base Hydrolysis Rate of [Co(NH3)5Cl]2+ in a Carbonate Buffer
Authors: Kitamura Yoichi 
Published: July 2006

Abstract
The pressure effect on the base hydrolysis reaction rate of [Co(NH3)5Cl]2+ in a 0.0133 M Na2CO3–0.0200 M NaHCO3 buffer solution was measured up to 1500 kg cm−2 (M=mol dm−3). The activation volume (ΔV\eweq) was found to be 33.4 ml mol−1. This value is consistent with that expected from the Dcb mechanism.
INDO-UHF-CI Calculations of the Electronic Structure of Formaldehyde–Hydrogen Systems
Authors: Mizutani Kimiko , Izumi Toyoo , Matsumoto Shiro 
Published: July 2006

Abstract
The electronic structures were calculated for the ground and several excited states of systems composed of a formaldehyde molecule and a hydrogen atom at various relative positions by means of an INDO-UHF-CI method, in order to elucidate the hydrogen-abstracting process of excited carbonyl compounds. The results were presented and discussed by means of the adiabatic potential energy curves, by means of configuration analysis using the various states of the non-interacting component species as reference, and by means of electron-density maps. The results showed in a concrete way that the process may proceed through an intermediate charge-transfer state, and the electron-density maps had features suggesting an attractive force acting on the positively charged hydrogen atom.