bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation and Characterization of Pteridines from Pseudomonas ovalis
Authors: Suzuki Akira , Goto Miki 
Published: July 2006

Abstract
Four ribityllumazine compounds were isolated from the cultured medium of Pseudomonas ovalis. Three of them were characterized as 6-methyl-8-(1-d-ribityl)-2,4,7-trioxohexahydropteridine, 6-(3-indolyl)-8-(1-d-ribityl)-2,4,7-trioxohexahydropteridine and 6-(p-hydroxyphenyl)-8-(1-d-ribityl)-2,4,7-trioxohexahydropteridine by comparison with synthetic samples. The fourth compound, named putidolumazine, was supposed to be a new compound (2-carboxyethyl)-8-(1-d-ribityl)-2,4,7-trioxohexahydropteridine from its chemical and spectroscopic properties. This was confirmed from the identity of both natural and synthetic products.
Studies on the Interaction of Isocyanides with Transition-metal Complexes. VII. Insertion Reactions of Isocyanide into Alkyl-platinum Sigma Bonds
Authors: Yamamoto Yasuhiro , Yamazaki Hiroshi 
Published: July 2006

Abstract
The reactions of trans-iodobis(phosphine)aklylplatinum(II) compounds with isocyanide were carried out. The reactions of isocyanide with the methyl and benzyl derivatives of platinum(II) with triphenylphosphine or dimethylphenylphosphine gave salt-like complexes [trans-Pt(PR3)2(CNR′)CH3]I (1) (PR3=PPh3, PPhMe2; R′=C6H11, C(CH3)3). When 1 was refluxed in benzene or toluene, an insertion of isocyanide took place, affording trans-iodobis(phosphine)(1-cyclohexylimino)alkylplatinum(II). Two P-CH3 proton resonances were observed in the NMR spectrum of trans-Pt(PPhMe2)2I[C(CH3)=NC6H11], indicating that the two methyl groups on the same phosphorus atom are magnetically nonequivalent. It was deduced from this NMR behavior that all the iminoacyl complexes prepared have a five-coordinate structure.
Reactions of Tosylhydrazide Derivatives Having Olefinic Groups
Authors: Sato Tadashi , Homma Itomi 
Published: July 2006

Abstract
When α,β-unsaturated ketone tosylhydrazones (5) were heated in 85% aqueous acetic acid, a smooth decomposition was induced and β-tosylketones (4) were obtained in fair yields. Tosylhydrazones, devoid of an olefinic group in the specified position, failed to undergo the present reaction. When allyl halides (17) were reacted with the anion of tosylhydrazide in DMSO, substitution occurred on the N-1 of tosylhydrazide, unlike as in the case of the reaction of chlorides with tosylhydrazide in pyridine, which effected the substitution on N-2. On warming in acetic acid, these 1-allyltosylhydrazides (18) afforded olefins (19) in fair yields, with a complete allylic rearrangement. A concerted cyclic mechanism was proposed for the 5→4 and 18→19 reactions.
Studies of N-Sulfinyl Compounds. IV. The Reactions of N-Sulfinylanilines and -phenylhydrazines with Styrene Oxide
Authors: Tsuge Otohiko , Mataka Shuntaro 
Published: July 2006

Abstract
The reaction of p-substituted N-sulfinylanilines with styrene oxide in the presence of tetraethylammonium bromide gave the corresponding 1,2,4,5- and 1,2,4,6-tetraarylpiperazines, whose configurations were established on the basis of the NMR spectral studies. On the other hand, while a similar reaction of p-substituted N-sulfinylphenylhydrazines with the oxide in benzene gave the corresponding diaryl disulfide, diaryl sulfide, and p-substituted biphenyl, the reaction in acetonitrile did not give the biphenyl. The pathways for these reactions are suggested.
Cyclic Acetylenes. XIII. The Syntheses and Properties of p,p′-Bridged Cyclic Diphenyldiacetylenes
Authors: Kataoka Mutsuo , Ando Takashi , Nakagawa Masazumi 
Published: July 2006

Abstract
Concerning the studies on the effect of ring strain on the electronic spectra of cylcic acetylenes, a series of polymethylene ether derivatives of p,p′-dihydroxydiphenyldiacetylene (VIn, n=13, 14, 15, and 18) has been prepared by the oxidative coupling of p-hydroxyphenylacetylene polymethylene ethers (Vn, n=13, 14, 15, and 18) under a high dilution condition. A slight bathochromic shift accompanied by hypochromism was observed in the electronic spectra of VIn resulting from the increase of the ring strain. The same trend has been observed in the p,p′-bridged cyclic tolans. However, the bathochromic shift observed in the p,p′-series makes a contrast with the hypsochromic shift in the strained o,o′-bridged cyclic diphenyldiacetylene (I) and o,p′-bridged cyclic tolans (II). The NMR and IR spectra of VIn were discussed.
Cyclic Acetylenes. XIV. The Effects of Ring Strain on the Electronic Spectra of Cyclic Tolans and Cyclic Diphenyldiacetylenes
Authors: Toda Fumio , Ando Takashi , Kataoka Mutsuo , Nakagawa Masazumi 
Published: July 2006

Abstract
Characteristic features of the electronic spectra of o,o′-bridged cyclic diphenyldiacetylenes (In), o,p′-bridged cyclic tolans (IIn), p,p′-bridged cyclic diphenyldiacetylenes (IIIn) and p,p′-bridged cyclic tolans (IVn) are compared. The hyperchromism observed in the longest-wavelength absorption maxima (λmax) in the higher homologues of In, IIIn, and IVn as compared with the absorption intensities of the respective open-chain analogues is explained in terms of the coplanarity of the chromophore system, and the marked hypochromism observed in the lower homologues of these cyclic acetylenes is attributed to ring strain. The hypochromism observed in the series of IIn is ascribed to the superposition of the effects of ring strain and the twisting of phenyl groups. The bathochromic shifts of λmax with the increase of ring strain in the p,p′-bridged series (IIIn and IVn) are explained by the pronounced increase of the energy of the ground state of the strained molecule of this series. On the other hand, the hypsochromic shifts of λmax of o,o′-bridged series (In) are regarded as the result of the minor increase of energy of the ground state along with the increase of the ring strain.
The Preparation of 4′,6′-Di- and 2′,4′,6′-Tri-O-acetates of Theophylline Nucleosides of 3′-Deoxy-3′-nitro-β-d-galacto-, gluco- and mannopyranose
Authors: Nakagawa Toshio , Takamoto Tetsuyoshi 
Published: July 2006

Abstract
7-(3′-Deoxy-3′-nitro-β-d-glucopyranosyl)theophylline (1) was treated with acetic anhydride in the presence of boron trifluoride, perchloric or phosphoric acid as a catalyst to afford the corresponding 2′,4′,6′-tri-O-acetate (4) in 87, 60 and 48% yields, respectively. With galacto-isomer (2), tri-O-acetate (6) was obtained in a high yield by the use of phosphoric acid or a large excess of perchloric acid as a catalyst, while 4′,6′-di-O-acetate (5) was selectively prepared in 82% yield when a trace of perchloric acid was used. The similar preparation of 4′,6′-di- and 2′,4′,6′-tri-O-acetates (7 and 8) of manno-isomer (3) was also carried out in the presence of boron trifluoride and phosphoric acid, respectively. The positions of the acetyl groups in the diacetates 5 and 7 were unequivocally deduced from NMR data.
Studies of the Synthesis of Furan Compounds. XXIV. The Synthesis of 5-[2-(5-Nitro-2-furyl)-1-(4-nitrophenyl)vinyl]-1,3,4-oxadiazole and Its Related Compounds
Authors: Hirao Ichiro , Kato Yasuhiko , Hirota Toshiyuki 
Published: July 2006

Abstract
5-[2-(5-Nitro-2-furyl)-1-(4-nitrophenyl)vinyl]-1,3,4-oxadiazoles and -1,3,4-thiadiazoles have been prepared from 3-(5-nitro-2-furyl)-2-(4-nitrophenyl)acrylic acid. All of these compounds exhibited strong antibacterial activities against Staphylococcus aureus.
Electrochemical Reduction of Aza-heteroaromatic Compounds. IV. Stabilities of Neutral Free Radicals Electrolytically Derived from 1-Methylcyanoquinolinium Perchlorates
Authors: Kato Shozo , Nakaya Jun′ichi , Imoto Eiji 
Published: July 2006

Abstract
Three isomers of 1-methylcyanoquinolinium perchlorates were reduced by controlled potential electrolysis for one-electron transfer, and the reduction products were identified in order to clarify their reduction mechanisms and the effect of the cyano group on the stabilities of cyanoquinolinyl radicals. The 1-methyl-4-cyanoquinolinyl radical was stable enough to survive at room temperature under anaerobic conditions. The 1-methyl-2- and 1-methyl-3-cyanoquinolinyl radicals were short-lived and were subsequently dimerized to the 1,4-dihydrotype. The 1-methyl-4-cyanoquinolinyl radical was autoxidized to 1-methyl-4-cyanoquinolinium salts in an electrolyte solution and to 1-methyl-4-cyano-2-quinolone in an ethanol solution.
Iminodithiocarbonates. III. Reactions with Some Electrophiles and the Structural Effect on Nucleophilic Reactivities and Basicities
Authors: Ueno Yoshio , Nakai Takeshi , Okawara Makoto 
Published: July 2006

Abstract
With a view toward demonstrating the structural effect on the reactivity of iminodithiocarbonates, the reactions of some electrophilic reagents with the following four iminodithiocarbonates have been studied; 2-methylimino-(IVa) and 2-phenylimino-1,3-dithiolane (IVb) and S,S′-dimethyl-N-methyl-(Va) and S,S′-dimethyl-N-phenyliminodithiocarbonate (Vb). Cyclic IVa and its N-ethyl homologue reacted with an equimolar amount of phenyl isocyanate at room temperature giving 1:2 cycloadducts. However, the other imino compounds (IVb, Va, and Vb) did not react at all even at elevated temperature. All these imino compounds reacted with acid chlorides to afford the corresponding N-acyliminium salts which could, in some cases, be isolated; however the rate of formation of the salts varied significantly with the structure of the imino compound. Some reactions with alkyl halides and phenyl isothiocyanate were also attempted. From the present results and those previously obtained on their reactions with epoxides and with ketenes, it has been concluded that the nucleophilic reactivity of the imino compounds increases in the order Vb&lt;Va&lt;IVb&lt;IVa. Furthermore, it was found that the basicity of the imino compounds increased in the order Vb&lt;IVb&lt;Va&lt;IVa. The observed ring effect and N-substituent effect on the reactivity and basicity of the imino compounds are discussed in connection with similar effects on the stability of closely related tri(hetero)carbonium ions, i.e., bis(alkyl thio)-dialkylaminocarbonium ion (I).
Relative Reactivities in the Addition of Free Trichloromethyl Radicals to Substituted Styrenes. An Attempt to Separate Polar and Resonance Effects
Authors: Sakurai Hideki , Hayashi Shun-ichi , Hosomi Akira 
Published: July 2006

Abstract
Relative reactivities in dibenzoyl peroxide-catalyzed addition of bromotrichloromethane to nine nuclearsubstituted styrenes have been investigated with unsubstituted styrene. The effect of meta substituents upon the relative rates was correlated with the simple Hammett equation using either σ or σ+ constants. The relative rates of para-substituted styrenes, however, did not obey the simple Hammett relation, with the results best explained on the basis of polar (ρσ+) and resonance (ED) terms. All para substituents examined increase the reactivity.
log(k⁄kH)=ρσ++ED
The ED term shows a striking correlation with logQ, of the corresponding para styrene in Alfrey-Price′s Q-e scheme of free-radical copolymerization. That the polar term originates in charge-transfer interactions between the olefin and the electrophilic trichloromethyl radical and can be expressed by ρσ+ is further supported by the evidence that charge-transfer energies of substituted styrenes showed good correlation with σ+. Factors influencing the reactivity have been discussed.
Some Oxidation and Reduction Products of 4-Acetyltropolone and Its Methyl Ethers
Authors: Nozoe Tetsuo , Takase Kahei , Shimizu Kohei , Yasunami Masafumi 
Published: July 2006

Abstract
The chemical properties of the acetyl side-chain of 4-acetyltropolone and its methyl ethers in relation to some oxidizing and reducing reagents were examined. The selenium-dioxide oxidation of one of the methyl ethers afforded a glyoxyloyl derivative in its hydrate form. The catalytic reduction of 4-acetyltropolone gave a mixture of 4-(1-hydroxyethyl)- and 4-ethyltropolones. The reduction of two isomeric methyl ethers with sodium borohydride gave 4-(1-hydroxyethyl)-2-methoxy- and 6-(1-hydroxyethyl)-2-methoxytropones respectively, from which two isomeric methyl ethers of 4-ethyltropolone were prepared in pure states.
Adsorption of Benzoic Acid on Gold in Perchlorate Solutions
Authors: Katoh Koichi , Schmid G M 
Published: July 2006

Abstract
The adsorption of benzoic acid from solutions of 10−2 to 10−5 m on gold electrode surface in perchlorate solutions of pH 1–4 was studied from differential capacity data obtained by a single pulse method. Strong adsorption is observed in the more acidic solutions. This points to predominant adsorption of benzoic acid molecule, rather than benzoate anions, possibly due to the π-electron interaction. At pH 1, benzoic acid replaces four water molecules. This interprets the flat adsorption of benzoic acid molecule on the gold electrode and the π-electron interaction with free electron of the metal surface. The standard free energy of adsorption Δ\barG° is −10.4 kcal/mol.
Steric Effects in Azo Compounds. The Electric Dipole Moments and the Absorption Spectra of Azobenzene Derivatives
Authors: Yamamoto Shunzo , Nishimura Norio , Hasegawa Shigeo 
Published: July 2006

Abstract
The electric dipole moments of trans-4-N,N-dimethylaminoazobenzene and its derivatives, and the absorption spectra of azobenzene derivatives and their conjugate acids have been measured. The dipole moment and the intensity of the π–π* band are clearly reduced by introduction of methyl groups into ortho positions to azo group. The twisting angle of the benzene rings with respect to the azo group has been estimated for 2,2′-disubstituted azobenzenes and their conjugate acids by means of the Braude equation. From the spectral intensity and transition energy, it was concluded that the conjugate acids are generally more susceptible than the bases to the steric effect.
Vibrational Analysis of the 2400–2800 Å Bands of 1,2,3- and 1,3,5-Trimethylbenzenes in Vapour Phase
Authors: Verma V N , Nair K P R , Rai D K 
Published: July 2006

Abstract
The near ultraviolet absorption spectra of 1,2,3- and 1,3,5-trimethylbenzenes have been photographed in vapour phase at different vapour pressures on a Q-24 Zeiss Medium Quartz Spectrograph. Assuming C2v symmetry for the 1,2,3- and D3h symmetry for the 1,3,5-isomer, tentative assignments of the observed bands have been made in terms of various ground state and excited state fundamentals. The respective vibrational modes have also been suggested.
Photomicroscopic Observation of Dispersion State of Droplets in Flowing Emulsion
Authors: Suzuki Kazushige , Watanabe Takehiko 
Published: July 2006

Abstract
The viscosity of dilute emulsion with disperse phase of volume fraction φ=0.005–0.06 was measured, and the dispersion state of emulsion droplets under shear was observed with a photomicroscope. Oil components used were aromatic hydrocarbons, i.e., benzene, o-xylene, and toluene, and saturated hydrocarbons, i.e., cyclohexane, decaline, n-hexane, etc. As emulsifier, Arlacel 60 or Arlacel 83 was used for W/O type emulsion and Tween 20 for O/W type one. For the W/O type emulsions of aromatic hydrocarbon of low emulsifier concentration (0.2%), Einstein’s equation could be applied to the viscosity at a high rate of shear in the range of φ below 0.02, in spite of the presence of aggregates of droplets in the flowing emulsion. When φ becomes 0.04–0.06, the deviation from Einstein’s equation was large. In the case of higher emulsifier concentration (1%), the deviation from Einstein’s equation was noticeable even for φ=0.01, when Arlacel 60 was used as stabilizer. The results may be brought about by the increase of effective volume fraction of disperse phase owing to the inclusion of continuous phase liquid in aggregates. In the case of W/O type emulsions of saturated hydrocarbon and O/W type ones, irrespective of the kind of oil phase liquid, the aggregates were completely redispersed into primary droplets at a high rate of shear, and Einstein’s equation could be applied.
Stereochemical Studies of Monoterpene Compounds. X. Intramolecular Interaction of Oxirane and Cyclopropane Rings with a Hydroxyl Group
Authors: Watanabe Satoru , Suga Takayuki , Shishibori Tsuyoshi , Matsuura Tamon 
Published: July 2006

Abstract
The intramolecular interaction of oxirane and cyclopropane rings with a hydroxyl group in the alicyclic α,β-epoxy-, β,γ-epoxy-, and cyclopropyl alcohols was investigated by means of the infrared spectroscopy. cis-α,β-Epoxyalcohols (II, IV and V) showed a free hydroxyl band, an interacted hydroxyl band with a C–O bond of the oxirane ring, and/or a band due to a O–H···O hydrogen bond, whereas trans-epoxyalcohols (I and III) showed only a free hydroxyl band. The interaction between the hydroxyl group and a C–C bond of the oxirane ring was likely to be absent. β,γ-Epoxyalcohols revealed a hydroxyl band interacting with lone-pair electrons of the oxirane oxygen, in addition to a free hydroxyl band. The O–H··· cyclopropane interaction was found with 2-(1-methylcyclopropyl)-5-methylcyclohexanols (VII and VIII). The correlation of the infrared spectra with the conformation of the interacting groups is also discussed.
The Protonation of Aromatic Hydrocarbon Radical Anions. II. Interpretations of the Rate Constants in Terms of HMO Calculations
Authors: Hayano Shigeo , Fujihira Masamichi 
Published: July 2006

Abstract
The rates of the protonation of aromatic hydrocarbon radical anions with water in dimethylformamide (DMF)-water mixtures were measured by means of the decay of the visible absorption maxima of radical anions with time. The rates were found to be greatly accelerated by the increasing water content in DMF-water mixtures. This behavior suggests that the negative charge is much more localized in the transition state than in the original radical anion. The rate constants in DMF could be obtained by extrapolation. The correlation of these rate constants to the molecular structure of radical anions was discussed on the basis of the results of HMO calculations. This correlation and the solvent effect could be interpreted by means of the charge-transfer mechanism.
Tritium Fractionation on the Crystal Growth of Sodium Sulfate Decahydrate from Its Tritiated Aqueous Solution
Authors: Tanaka Haruhiko , Negita Hisao 
Published: July 2006

Abstract
The fractionation of tritiated water (HTO) was examined during the crystallization of sodium sulfate decahydrate, Na2SO4·10H2O, from a slightly supersaturated solution which contained a trace amount of tritium. No appreciable fractionation of HTO was found to occur in the crystallization under both stirred and unstirred conditions. The factors which may influence the degree of the fractionation were generally considered in connection with the studies by deuterated water. It was suggested that virtually all of the water of crystallization in sodium sulfate decahydrate should come from free water in its aqueous solution, and should integrate into the crystal in accordance with the volume-diffusion model. This model was supported also by the energetical consideration of the sodium ion in the crystallization.
81Br Nuclear Quadrupole Resonance of Modifications of Titanium Tetrabromide
Authors: Okuda Tsutomu , Furukawa Yoshihiro , Negita Hisao 
Published: July 2006

Abstract
81Br NQR of titanium tetrabromide has been observed at temperatures between −196°C and 35.5°C, and its Zeeman effect has been measured at room temperature. The cubic form of titanium tetrabromide shows two resonance lines, as has been reported previously; their temperature coefficients change from positive to negative when the temperature is raised. The bond angles, ∠Br–Ti–Br, are in the range of 108.7° to 110.3°. The asymmetry parameters are 2.0 and 2.5%. On the other hand, the monoclinic form shows four resonance lines; 39.175, 39.184, 39.454, and 39.800 MHz at 11°C. The temperature coefficient of the lowest line is positive at the lower temperature, whereas those of the remainder are negative. The bond angles, ∠Br–Ti–Br, are found in the range of 108.8° to 110.1°. The asymmetry parameters are 1.2, 4.6, 2.1, and 3.5% for the bromine atoms in the order of increasing resonance frequencies. The ionic and double-bond characteristics of the Ti–Br bond in both forms are about 60 and 16%. These findings suggest that, in titanium tetrabromide. the crystal field has little effect on the molecular shape, the bond character, and the asymmetry parameter.
The Crystal Structure of the 2 : 3 Complex of Zinc Phthalocyanine and n-Hexylamine
Authors: Kobayashi Takashi , Ashida Tamaichi , Uyeda Natsu , Suito Eiji , Kakudo Masao 
Published: July 2006

Abstract
Crystals of the 2 : 3 complex of zinc-phthalocyanine and normal hexylamine were studied. They are monoclinic, space group P21⁄c, with cell dimensions a=12.40, b=15.76, c=20.05, β=93.2° and there are four phthalocyanine and six hexylamine molecules per cell. The phthalocyanine molecule is not planar and the central zinc ion is displaced from the plane by 0.48 Å toward the nitrogen atom of the amine. Zinc ion is of a square pyramidal five coordination. There are two bonding states for the amine in the complex crystal. One is weakly bonded and can be easily released from the lattice and the other is strongly bonded and coordinated directly to the zinc ion. None of the atomic parameters of these amines except those of the coordinating nitrogen were exactly determined.
Studies of Peptide Antibiotics. XXV. Synthesis of an Immediate Precursor of Gramicidin S
Authors: Makisumi Satoru , Matsuura Shuji , Waki Michinori , Izumiya Nobuo 
Published: July 2006

Abstract
A linear decapeptide, HCO-d-Phe-Pro-Val-Orn-Leu-d-Phe-Pro-Val-Orn-Leu-NHCH2CH2OH, which has been identified as an immediate precursor of gramicidin S was synthesized in order to define the physical and biological properties of this peptide. The synthetic product possessed practically no antibacterial activity against any of the microorganisms tested, though the optical rotatory dispersion feature of this peptide was quite similar to that of gramicidin S. Stability of the terminal blocking groups of this peptide to the action of hydrogen chloride in methanol was also discussed.
Rare-Gas-Sensitized Radiolysis of Toluene
Authors: Yamamoto Yukio , Takamuku Setsuo , Sakurai Hiroshi 
Published: July 2006

Abstract
The Ar-, Kr-, and Xe-sensitized radiolyses of toluene was studied at room temperature in the gas phase. The discussion was concentrated on the formation of three isomers of methyldiphenylmethane (MDPM), which, it had been suggested in a previous paper on the direct radiolysis of toluene, were formed by the ion-molecule reaction of C7H7+ ions. The sensitization effect on the MDPM formation was extremely large in the case of Ar, and decreased in the order of Ar, Kr, and Xe. These results were explained in terms of charge transfer from these rare gases to toluene, resulting in the formation of the C7H7+ ions. The isomer distribution of MDPM’s in the raregas-sensitized radiolysis was considered on the basis of the reaction mechanism proposed previously. The sensitization effect on the formation of other products was also discussed briefly.
A Simple Relation among the Energy Differences between Conformers of XH2C-CH2Y, C6H11X, C6H11Y, and trans-1,2-C6H10XY
Authors: Fujimoto Etsuko , Kozima Kunio , Takeoka Yoshiko 
Published: July 2006

Abstract
By measuring the infrared intensities, the energy differences between two conformers have been determined for bromocyclohexane, iodocyclohexane, trans-1-bromo-2-chlorocyclohexane, 1-bromo-2-chloroethane, ethylene bromohydrin, and ethylene iodohydrin in dilute solutions, and for cyclohexanol, trans-2-chlorocyclohexanol, ethylene chlorohydrin, and ethylene bromohydrin in vapors.
It was ascertained that the following relation holds for the energy differences:
Et−Eg=(Eaa−Eee)−(Ea−Ee)−(Ea′−Ee′).
Here Et−Eg is the energy difference between the trans and the gauche isomer of XH2C–CH2Y, Eaa−Eee is that between the aa- and the ee-isomer of trans-1,2-C6H10XY, and Ea−Ee and Ea′−Ee′ are those between the a- and the e-isomers of C6H11X and C6H11Y respectively, where X is a halogen and Y is a halogen or the O–H group.