bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Pressure on the Diels-Alder Reaction
Authors: Seguchi Kazuyoshi , Sera Akira , Maruyama Kazuhiro 
Published: July 2006

Abstract
The effect of pressure on the Diels-Alder reaction was investigated. The observed activation volume was found to have a significant correlation with the activation free energy of the reaction. A correlation diagram between the activation volume and the activation free energy was proposed. By this diagram, the position of the transition state in the Diels-Alder reaction was discussed, and the activation volume was suggested to be a good diagnostic probe for the position of the transition state. The importance of the contribution of the volume contraction resulting from secondary orbital interaction to the apparent activation volume was pointed out.
Reaction of Sulfilimine and Sulfonium Ylide with Hydroxide or Methoxide Ion in Methanol
Authors: Furukawa Naomichi , Masuda Toshiaki , Yakushiji Masatoshi , Oae Shigeru 
Published: July 2006

Abstract
The reactions of dialkyl and alkyl aryl N-p-tosylsulfilimines with hydroxide or methoxide in methanol afforded either S-substitution products or Pummerer type products or a mixture of both, their distribution being dependent on the structure of the sulfilimine. From the results of analyses, the mechanisms of the formation of these products are discussed. A similar alkaline methanolysis of sulfonium ylides was also investigated.
The Allylic Rearrangement of Linalyl Acetate in the Medium of Acetic Acid, Propionic Acid, or Acetic Acid Containing Dioxane or Sulfuric Acid
Authors: Kogami Kunio , Kumanotani Ju 
Published: July 2006

Abstract
The mechanism of the allylic rearrangement of linalyl acetate in the medium of acetic acid, propionic acid, or acetic acid containing dioxane or sulfuric acid has been investigated. The nature of the carbonium-ion pairs generated from linalyl acetate in low-dielectric-constant solvents or in strong acids, and the behavior of the active intermediate in the transition state were postulated from the kinetic data as well as from the physicochemical properties and distributions of the products.
The Crystal Structure of Tetraiodo-p-benzoquinone
Authors: Kobayashi Hayao , Danno Takaaki , Shirotani Ichimin 
Published: July 2006

Abstract
The crystals of tetraiodo-p-benzoquinone-(iodanil) are monoclinic, with a space group of P21⁄c and with a=7.630(1), b=5.268(1), c=14.222(2) Å, β=113.07(2)°, and Z=2. The iodanil molecules are stacked to form columns along the b axis, with an interplanar distance of 3.694 Å.
Organic Photochemical Reactions. XXII. The Photoaddition of Methyl Pyruvate to Methyl-substituted Olefins
Authors: Shima Kensuke , Kawamura Teruo , Tanabe Koji 
Published: July 2006

Abstract
The irradiation of methyl pyruvate (III) and several methyl-substituted olefins (I) in acetonitrile gives allylic ethers (IV) as well as oxetanes (V) and alcohols (VI), Quenching studies suggest that IV and V are formed from the triplet state of methyl pyruvate, while VI is produced from the excited singlet state.
Microwave Spectrum, Structure and Dipole Moment of Ethanethiol. I. Trans Isomer
Authors: Hayashi Michiro , Imaishi Hisae , Kuwada Kazunori 
Published: July 2006

Abstract
The microwave spectra of trans-ethanethiol and its isotopic species were measured. The rs structure of the trans isomer was determined from the observed moments of inertia. The trans isomer has a symmetrical CH3group, the parameters for the CH2SH part of the molecule being approximately equal to those of methanethiol. The C-C bond length, found to be 1.529±0.006Å, is close to that of propane. The angle α(CCS), obtained as 108°34′±19′, is much smaller than that of analogous molecules. Discussion is given for this anomalously small α(CCS) angle. From the Stark shifts, the dipole moment of the trans isomer was determined to be μa=1.058±0.023, μb=1.146±0.002 and μtotal=1.560±0.032 D, an angle of 28°46′ being made with the bisector of the α(CSH) angle inclining towards the ethyl group. Since the dipole moment of methanethiol makes an angle of 18°30′ with the bisector of the α(CSH) angle, the increase of the angle with the bisector for ethanethiol was concluded to arise from the induction moment of the ethyl group. A brief description is given for the spectra due to the gauche isomer.
Fluorescence Depolarization Study of Hydrogen Bonded 1-Anthrol
Authors: Hamai Sanyo , Kokubun Hiroshi 
Published: July 2006

Abstract
Rotaional depolarization of 1-anthrol fluorescence was studied in liquid paraffin. The molecular volume of 1-anthrol becomes large when it forms a hydrogen bonded complex. The molecular volume of the complex depends on the concentration of acceptor as well as the kind of acceptor. The molecular volume obtained by extrapolation to nil acceptor concentration increases with increasing size of acceptor molecule and is appreciably larger for amines than for ethers. The emitting species in the case of amines is 1-anthrolate ion pair whose strong dipolar nature may cause further interaction with excess amine molecules. It is probable that more than one molecule of amine participate in the rotating unit, leading to a large molecular volume. The rotational relaxation time was evaluated and found to depend on acceptor concentration. Two competitive effects occur by the increase in acceptor concentration, one shortening the relaxation time because of reduction of viscosity, and the other lengthening it because of molecular volume enlargement.
Chemistry of α-Haloaldehyde. VI. Reaction of 2-Chloro-2-methylpropanal with Benzoylacetonitrile in the Presence of Potassium Carbonate
Authors: Takeda Akira , Tsuboi Sadao , Sakai Takashi 
Published: July 2006

Abstract
The reaction of 2-chloro-2-methylpropanal with benzoylacetonitrile in aqueous K2CO3 has been studied. When 2-chloro-2-methylpropanal was added to a stirred suspension of benzoylacetonitrile in aqueous K2CO3, 2-hydroxy-3,3-dimethyl-4-cyano-5-phenyl-2,3-dihydrofuran (7) was obtained. The oxidation of 7 with CrO3gave α,α-dimethyl-β-cyano-γ-phenyl-Δβ,γ-butenolide (8). When benzoylacetonitrile was added to a suspension of 2-chloro-2-methylpropanal in aqueous K2CO3 stirred beforehand for 60 min, the reaction proceeded in a different manner to give the enol tautomer (9b) of 2,4-dibenzoyl-3-(α-hydroxyisopropyl)glutaronitrile (9a) at room temperature, and 2,2-dimethyl-3-(α-carbaminophenacyl)-4-cyano-5-phenyl-2,3-dihydrofuran (11) at 80–90 °C. The alkaline hydrolysis of the nitrile 9 conducted at 70 °C also afforded the amide 11. The nitrile 9 eliminated one mol of benzoylacetonitrile on treatment with H2SO4 to afford 2,2-dimethyl-3-hydroxy-4-cyano-5-phenyl-2,3-dihydrofuran (12). Chromic acid oxidation of 12 gave 2,2-dimethyl-3-oxo-4-cyano-5-phenyl-2,3-dihydrofuran (14), which can be derived from bullatenone in two steps. Structures of compounds 11, 12, and 14, which all possess 2,2-dimethyl-4-cyano-5-phenyl-2,3-dihydrofuran ring, have been confirmed and well correlated by both chemical transformations and spectral data.
Glass Formation in Multicomponent Phosphate Systems Containing TiO2
Authors: Kishioka Akira , Haba Masanori , Amagasa Michio 
Published: July 2006

Abstract
Glass formation was investigated in the Na2O–TiO2–P2O5, K2O–TiO2–P2O5, BaO–TiO2–P2O5,Na2O–BaO–P2O5, and Na2O–BaO–TiO2–P2O5 systems. In the Na2O–TiO2–P2O5 system, glass containing up to 45.5 mol% TiO2 was found to be formed at the composition of Na2O/P2O5=1, whereas in the K2O–TiO2–P2O5 system the glass formation was observed in a narrow region along the composition of K2O/P2O5=1 in a three-component diagram. In the BaO–TiO2–P2O5 system, only the glass containing about 10 mol% TiO2 as a maximum was obtained. In the Na2O–BaO–TiO2-P2O5 system, the region of glass formation extended with an increase of Na2O up to 30 mol%. These results suggested that a certain amount of Na2O is necessary for the formation of glass containing a large amount of TiO2 in the presence of BaO. The three-component diagrams of the Na2O–TiO2–P2O5 and Na2O–BaO–P2O5 systems indicated that the most favorable amount of Na2O for the glass formation in this four-component system is 27 to 28 mol%.
Reactions of Organoboranes with Ferric Chloride and Thiocyanate. Convenient Syntheses of Alkyl Chlorides and Thiocyanates from Olefins via Hydroboration
Authors: Arase Akira , Masuda Yuzuru , Suzuki Akira 
Published: July 2006

Abstract
The reactions of trialkylboranes with ferric chloride and thiocyanate in an aqueous tetrahydrofuran solution give the corresponding alkyl chlorides and thiocyanates in good yields. It was found that two equivalents of ferric salts per alkyl group of organoborane are required, and not only the first alkyl group of trialkylborane but other alkyl groups are also used.
A New Method of Preparing Flavones
Authors: Kasahara Akira , Izumi Taeko , Ooshima Masatoshi 
Published: July 2006

Abstract
The reaction of the sodium salt of 2′-hydroxychalcones with palladium(II) salt led to the formation of flavones, accompanied by a small amount of flavanones. The reaction proceeds via a phenoxypalladation, followed by the elimination of a hydridopalladium(II).
Far Infrared Spectra and Internal Rotation of Ethyl Fluoride and Deuterated Species
Authors: Sugeta Hiromu , Adachi Yoshio , Miyazawa Tatsuo 
Published: July 2006

Abstract
Far infrared spectra were measured of ethyl fluoride CH3CH2F and deuterated species CH3CD2F, CD3CH2F, and CD3CD2F in the gaseous state. The potential barriers hindering the internal rotation were calculated with various models. Possibly because of isotope effects on structure relaxations due to torsional motion and to zeropoint motion of other vibrational modes, the observed potential barriers are slightly different among isotopic molecules; the threefold barrier is lowered on the deuteration of the methyl group. The absorption intensities of the four isotopic species were also measured. The intensity of the torsional vibration of the methyl group is nearly doubled on deuteration of the methyl group but is reduced on deuteration of the methylene group. The observed intensity ratios among isotopic species were in good agreement with the ratios calculated with the intensity theory of our previous study.
Spectroscopic Studies on Some Ketimines
Authors: Abu-Eittah R , Hamed M M 
Published: July 2006

Abstract
The electronic absorption spectra of some ketimines have been investigated using different solvents. Assignment of the obtained transitions was attempted. The N-substituted ketimines did not show a discrete band for the n–π* transition as was obtained with the unsubstituted molecules. Molecular orbital calculations were carried out using the PPP variant of the SCF-MO theory. Agreement between the calculated and experimental transition energies was satisfactory.
The Photoinduced Substitution Reaction of 4-Quinolinecarbonitrile
Authors: Hata Norisuke , Ono Isao , Suzuki Hiroshi 
Published: July 2006

Abstract
The photochemical reactions of 4-quinolinecarbonitrile with alcohol (ethanol, 1-propanol, 2-propanol, or t-butyl alcohol) resulted in the substitution of the 1- and/or 2-hydroxyalkyl group at the 2-position of a quinoline nucleus.
Determination of Conformations of Esters with the Use of Lanthanide Shift Reagents
Authors: Sakamoto Kazuhiko , Oki Michinori 
Published: July 2006

Abstract
Lanthanide shift reagents have been used for diagnosis of s-trans and s-cis conformations of esters. By taking a ratio of lanthanide-induced shift of (H)CH2C=O protons vs. [shift reagent]/[substrate] as a reference, relative ratio of (H)CH2O- of the s-trans form has been found to be almost unity, whereas that of the s-cis ca. 0.5.
An Ultrasonic Method for Determination of the Volume Change Due to Internal Rotation in 1,2-Dichloroethane
Authors: Aoi Masakatsu , Arakawa Kiyoshi 
Published: July 2006

Abstract
A simple method for determining the volume change, ΔV, in conformational isomerism from sound velocity has been worked out from the theory of binary mixtures. The method was applied for obtaining the volume change due to internal rotation in 1,2-dichloroethane. The sound velocity was measured with an ultrasonic interferometer. The method was found useful.
Acetoxythallation of Acetylenes and the Proto- and Halogenodethallation of the Products
Authors: Uemura Sakae , Tara Hideyuki , Okano Masaya , Ichikawa Katsuhiko 
Published: July 2006

Abstract
The trans acetoxythallation of alkylphenylacetylene with Tl(OAc)3 proceeds in acetic acid at 50–75 °C for 1–3 hr to give a mixture of two isomeric vinylthallium(III) compounds in 54–79% yields, 2-acetoxy-1-alkyl-2-phenyl- and 2-acetoxy-2-alkyl-1-phenylvinylthallium(III) diacetates [C6H5C(OAc)=C(R)–Tl(OAc)2 (1) and C6H5C(Tl(OAc)2)=C(OAc)R (2), where R=Me, Et, n-Pr, and n-Bu]. Protodethallation of 1 and 2 in refluxing acetic acid occurs with retention of configuration to afford C6H5C(OAc)=C(R)H (3) and C6H5CH=C(OAc)R (4), respectively. The reaction of 1 and 2 with NaBH4 in protic solvents at pH 6–7 also gives 3 and 4 with retention of configuration, where the hydrogen for replacement of thallium group comes almost completely (&gt;98%) from the solvent. 1 and 2 are relatively stable to water and dilute HCl, while they readily give ketones in alkaline condition. Halogeno-, cyano-, and thiocyanodethallations of 1 is conducted by reactions with the corresponding copper(II) or (I) salts in acetonitrile to give C6H5C(OAc)=C(R)X (X=I, Br, Cl, CN, and SCN) with retention of configuration. Bromodethallation of 1(R=CH3) by bromine gives C6H5C(OAc)=C(CH3)Br stereospecifically in pyridine (retention), while α,α-dibromopropiophenone is obtained in CS2 and acetonitrile.
Synthesis of Streptolidine (Roseonine, Geamine)
Authors: Kusumoto Shoichi , Tsuji Shinichi , Shiba Tetsuo 
Published: July 2006

Abstract
Streptolidine (roseonine, geamine) (1), a guanidino amino acid component of the streptothricin group antibiotics, was synthesized starting from d-ribose (8). The epimino compound (11b) was prepared from 8 in five synthetic steps. Azidolysis of 11b gave the arabino-type compound (12b), which in turn was converted to the key intermediate tribenzyloxycarbamido lactone (23b) by oxidation of C-1. The lactone 23b was rearranged to the free lactam (4) after deprotection, and then guanidinated with cyanogen bromide. The identity of the hydrolysis product of this guanidino lactam with natural streptolidine in all respects certified the proposed structure involving the steric configurations.
Enthalpies of Hydrogen Bond Formation between Diphenylamines and Dimethyl Sulfoxide
Authors: Hirota Minoru , Shinozuka Kazumasa , Hamada Yoshiki 
Published: July 2006

Abstract
Enthalpies of hydrogen bond formation for the diphenylamine–dimethyl sulfoxide systems were determined by infrared spectroscopic method. The ΔH values for 4-methoxy, 4-methyl, unsubstituted, 3-methoxy, 3-chloro, 3-nitro, and 4-nitro-diphenylamines are −9.6, −10.1, −11.1, −11.2, −12.8, −13.9, and −13.9 kJ mol−1, respectively. The substituent effects are discussed in relation with those on N–H stretching frequencies.
Reaction of Group IV Organometallic Compounds. XXXI. The Reaction of N-Trimethylsilyl- and -stannyl(diphenylmethylene)amine with Diketene
Authors: Suzuki Hiroharu , Matsuda Isamu , Itoh Kenji , Ishii Yoshio 
Published: July 2006

Abstract
Linear 1/1 adducts and oxazinone derivative were obtained by the reaction of N-trimethylsilyl- and -stannyl(diphenylmethylene)amine; Ph2C=N–MMe3 (M=Si, Sn) with diketene. Consecutive demetallation reaction by ethanethiol for the organostannyl 1/1 adduct, and by methanol for the organosilyl 1/1 adduct gave a piperidine derivative and an oxazinone derivative, respectively.
The Reaction of Alkyl Halides with Mercuric Thiocyanate
Authors: Watanabe Nanao , Okano Masaya , Uemura Sakae 
Published: July 2006

Abstract
The reaction of secondary and tertiary alkyl halides with mercuric thiocyanate in less-polar solvents e.g., n-hexane, di-n-butyl ether, and 1,2-dichloroethane) was found to afford predominantly N-alkylation products, alkyl isothiocyanates, in contrast to the reaction with potassium salt in DMF. Especially, from t-butyl bromide, α-phenethyl bromide and benzhydryl chloride, the corresponding pure isothiocyanates were obtained in good yields. A most probable reaction mechanism is suggested, based on the relative rate data, the stereochemical result of the reaction with optically active α-phenethyl bromide, and the well-known catalytic effect of silver or mercury salt in SN1 reaction.
Kinetics of Ligand Isotopic Exchange of Tris(acetylacetonato)gallium(III) and Related β-Diketonato Complexes in Tetrahydrofuran
Authors: Chatterjee Chinmoy , Matsuzawa Kazuyo , Kido Hiroaki , Saito Kazuo 
Published: July 2006

Abstract
The rate of isotopic exchange of tris(acetylacetonato)gallium(III)[Ga(acac)3] and acetylacetone-14C(Hacac) in tetrahydrofuran (THF) is expressed by the formula R=[complex](k1+k1+[H2O]+k3[Hacac]) and the k1, k2, and k3 are ≤2×10−6 s−1, 0.31×10−3 M−1s−1 and 0.71×10−4 M−1 s−1, at 0 °C, respectively. The activation enthalpies and entropies are 18±2 and 19±2 kcal-mol−1, and −13±6 and −20±6 cal·K−1 mol−1, for k2 and k3 respectively. Trichloroacetic acid gives acid catalysis. A dissociative mechanism through an intermediate containing a unidentate ligand is suggested. The isotopic exchange rate decreases in the sequence In&gt;Ga&gt;Al for a given β-diketonato complex, and with increase in pKa of the β-diketone for given central metal ions.
The Thermal Reactions of Azido-1,3,5-triazines
Authors: Kayama Ryuichi , Hasunuma Shigeru , Sekiguchi Shizen , Matsui Kohji 
Published: July 2006

Abstract
Azido-s-triazines containing –Cl, –OCH3, and –N(CH3)2 groups were synthesized, and their thermal reactions with some hydrocarbons were investigated with respect to the reaction products and the reaction kinetics. With non-olefinic hydrocarbons the reactions were found to proceed via a nitrene inteimediate; in the reactions with cyclohexane, cydohexylamino-s-triazines and amino-s-triazines were obtained. On the other hand, with olefinic hydrocarbons the reactions took place via a. bimolecular mechanism involving a formation of an intermediate of the triazoline type; in the reactions with cyclohexene, cyclohexenylamino-s-triazines were obtained along with amino-s-triazines; In both cases, the yields of alkylamino and alkenylamino-s-triazines increased with the electron-withdrawing power of the substituents in the s-triazine nucleus.
The Synthesis of 2,4-Dehydrohomoadamantane
Authors: Yamaguchi Ryohei , Katsushima Takeo , Kawanisi Mituyosi 
Published: July 2006

Abstract
A synthesis of 2,4-dehydrohomoadamantane (I) is described. a) The UV irradiation of a solution of 4-homoadamantene (IV) in xylene containing a small amount of methanesulfonic acid under nitrogen gave a 2: 1 mixture of I and IV after 7 day; this mixture afforded pure I in a 40% isolation yield. b) The oxidation of 4-homoadamantyl hydrazone (XI) by Pb(OAc)4, NiPO, and MnO2 (active) gave a 7–11: 1 mixture of I and IV respectively. It was observed that the ratio of I to IV depends on the reaction temperature, and that the oxidation of XI by Pb(OAc)4 at −78 °C gave thirty times as much I as IV. The addition of MeOH as a proton source reduced the ratio of I to IV in the cases of NiPO and MnO2. The Bamford-Stevens reactions of 4-homoadamatyl tosylhydrazone (II) were effected in aprotic as well as in protic solvents. The ratio of I to IV was inverted under aprotic and protic conditions. The selectivities in the oxidation of XI and the Bamford-Stevens reactions of II were explained by considering the conformations of 4-homoadamantyIidene (XII) and the 4-homoadamantyl cation (VIII).
Determination of the Optical Purity of Amino Acids by Complex Formation. Determination of Optimum Condition for Rotational Measurement
Authors: Fujii Yuki 
Published: July 2006

Abstract
A new method has been established for the determination of the optical purity of a small amount of amino acids (alanine, valine, leucine, and glutamic acid). The method utilizes the fact that when an optically active amino acid is dissolved in an alkaline solution of K[Co(acac2en)(gly)2], the solution shows much larger optical rotation than the free amino acid in the visible region. 1/50 to 1/100th the amount of an amino acid (about 0.1– 0.05 grams) suffices for the determination of optical purity as compared with that needed in the usual method. The optimum conditions for measurement are: wavelength, 500 nm; pH, 10.00; time required to establish the substitution equilibrium, 6–8 hours; concentration of the complex, (4–5)×10−3 mol l−1; concentration of amino acid, (2–1)×10−2 mol l−1
The Selectivity Evaluation of an Ion-selective Electrode with a Liquid Membrane by Electrode Response to a Foreign Ion
Authors: Jyo Akinori , Torikai Masanori , Ishibashi Nobuhiko 
Published: July 2006

Abstract
The potential responses of liquid-membrane electrodes to foreign ions were examined. The electrode response obeyed the Nikolsky equation when the selectivity for the foreign ion was nearly equal to or higher than that for the objective ion and when the concentration of the foreign ion in the sample solution was sufficiently higher than that of the ion-exchanger in the liquid membrane. The Nikolsky equation, however, did not hold for the response when the selectivity for the foreign ion over the objective ion was extremely low or when the concentration of the sample was not so high. Such a non-ideal response was ascribed to the variation in the ionic composition at the membrane-solution interface caused by the ion-exchange. From the measurement of the electrode potential under conditions when the response obeyed the Nikolsky equation, the selectivity coefficient for the foreign ion over the objective ion could be obtained successfully as an intrinsic value of the electrode membrane. The selectivity value thus obtained was in good agreement with the value estimated from the Sandblom-Eisenman-Walker theory on the electrode selectivity. The additivity of the membrane potential was also described.
Binuclear Copper(II) Propionate Complexes with N-Arylsalicylideneamines
Authors: Tokii Tadashi , Emori Shuji , Muto Yoneichiro 
Published: July 2006

Abstract
Two copper(II) propionate complexes with N-arylsalicylideneamines have been prepared. The magnetic and spectral properties of these complexes indicate that they have a carboxylate-bridged binuclear structure.
Synthesis of Methyl Isobutyl Ketone from Acetone and Hydrogen Catalyzed by Palladium Supported on Zirconium Phosphate
Authors: Watanabe Yoshiaki , Matsumura Yoshito , Izumi Yusuke , Mizutani Yukio 
Published: July 2006

Abstract
The one-step synthesis of methylisobutyl ketone from acetone and hydrogen was investigated by using palladium supported on zirconium phosphate, a bifunctional catalyst. Effects of reaction variables on both the conversion of acetone and the selectivity of methylisobutyl ketone were examined. The experiments were carried out with a continuous flow unit at 110–140°C and 7–25 kg/cm2 over a range of liquid hourly space velocity of acetone for 2–15 hr−1 with a mole ratio of hydrogen to acetone in the range 0.2–1.45. Under these conditions, the conversion of acetone was 20–40%, the selectivity of methylisobutyl ketone being as much 90–97 mol%. It is suggested that the one-step reaction proceeds via a consecutive mechanism.