bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reinvestigation of the Nitration of Ethylmesitylene and n-Propylmesitylene. Revision of Early Works.
Authors: Suzuki Hitomi , Sawaki Mikio , Sakimoto Reiji 
Published: July 2006

Abstract
Ethylmesitylene reacts with fuming nitric acid in dichloromethane at −50°C to give mononitroethyl-mesitylene, 3,5-dimethyl-4-ethylbenzyl nitrate, 2-nitro-3,5-dimethyl-4-ethylbenzyl nitrate and a dinitroethyltri-methylcyclohexenone, while on nitration with mixed acid it yields mono and dinitro derivatives as the major products, together with minor quantities of 2-nitro- and 2,6-dinitro-3,5-dimethyl-4-ethylbenzyl nitrates, diphenyl-methanes, and unidentified nitro-carbonyl compounds, possibly nitrobenzaldehydes. Similar results are obtained from the nitration of n-propylmesitylene. If the hydrocarbons are nitrated by adding into a large excess of the nitrating agent, the major product is 2,6-dinitro-3,5-dimethyl-4-alkylbenzyl nitrate soon after the reaction, or 2,6-dinitro-3,5-dimethyl-4-alkylbenzaldehyde when the mixture is left to stand at room temperature. The nitro compound melting at 123°C, obtained by Smith and Kiess from the nitration of ethylmesitylene and described as trinitro-4-ethyl-o-xylene, is identified as 2,6-dinitro-3,5-dimethyl-4-ethylbenzyl nitrate. An uncharac-terized nitration product (mp 135°C) from n-propylmesitylene, obtained by Töhl and Tripke, is found most likely to be 2,6-dinitro-3,5-dimethyl-4-n-propylbenzyl nitrate (mp 139–140°C).
Location of the Sulfate Groups in κ-Carrageenan from Gigartina Tenella
Authors: Hirase Susumu , Watanabe Kyoko 
Published: July 2006

Abstract
Location of the sulfate groups in κ carrageenan from G. tenella has been re-investigated by adapting the method, which was devised by Bouveng for locating the acetyl groups in hemicellulose. In this method, the sulfate groups were replaced by methyl groups through a series of reactions consisting of blocking the free hydroxyl groups with phenylcarbamoyl groups, removing the sulfate groups and methylating the newly formed hydroxyl groups. The blocking substituents were then removed, and the positions of the methoxyl groups were investigated by the standard method. The results have shown, in accordance with the conclusion based on the methylation data, that one forth of the 1,4-linked 3,6-anhydro-d-galactose residues are 2-sulfated and that the 1,3-linked d-galactose residues are 4-sulfated. No evidence was obtained to indicate the presence of d-galactose 2,6-disulfate, which had been presumed by other workers. The problem concerning the acyl migration of the blocking groups during the process has also been discussed.
Reactions of Tris(acetylacetonato)manganese(III) and Bis(acetylacetonato)-manganese(II) with Ethylenediamine and Other Primary Amines
Authors: Nishikawa Yoshinori , Nakamura Yukio , Kawaguchi Shinichi 
Published: July 2006

Abstract
Tris(acetylacetonato)manganese(III) reacts with ethylenediamine (L2) and other primary amines (L) in organic solvents at room temperature producing Mn(acac)2L2. The same Mn(II) complexes were also prepared quantitatively by reactions of Mn(acac)2(H2O)2 with amines. Besides the usual hexa-coordinate monomeric complex, allylamine gave a dimeric compound [Mn(acac)2(CH2=CHCH2NH2)]2, which is the first example of the binuclear manganese(II) complex of acetylacetone. The stoichiometry of the redox reaction between Mn(acac)3 and ethylenediamine was established and discussed in connection with the initiation mechanism of vinyl polymerization.
The Infrared Spectra of Addition Compounds of Hydrogen and Deuterium Cyanides with Boron Tribromide
Authors: Kanesaka Isao , Hase Yoshiyuki , Kawai Kiyoyasu 
Published: July 2006

Abstract
The infrared spectra of addition compounds of hydrogen and deuterium cyanides with boron tribromide have been measured in the frequency region from 4000 to 200 cm−1, and the normal frequencies have been proposed on the basis of the C3υ symmetry for four isotopic compounds, HCN·10BBr3, HCN·11BBr3, DCN·10BBr3, and DCN·11BBr3. The force constants have been calculated on the assumption of a modified Urey-Bradley force field, and the shift of the vibrational frequencies by the coordination has been discussed.
Studies of Mixed Cyano Cobalt(III) Complexes. IV. Preparation and Characterization of trans(O,X)-[Co(X)(aminoacidato)(diethylenetriamine)]+ Complexes with X=CN−, NO2−, or Cl−
Authors: Ohkawa Kuwako , Fujita Junnosuke , Shimura Yoichi 
Published: July 2006

Abstract
A series of new kinds of mixed cobalt(III) complexes, trans (O,X)-[Co(X) (aminoacidato) (diethylenetriamine)]Y, have been prepared and characterized by visible and ultraviolet, circular dichroism, and proton magnetic resonance spectroscopy for X=CN−, NO2−, and Cl−; aminoacid=glycine, α-aminoisobutyric acid, l-alanine, l-valine, l-threonine, and l-proline; and Y=Br−, Cl−, or ClO4−. The proton magnetic resonance spectra of the cyano mixed complexes show the existence of new conformational isomers, endo and exo forms, which concern the ligand CN− and the hydrogen atom attached to the central nitrogen atom of the meridionally coordinated diethylenetriamine ligand.
Convenient Quadratic Formulas for the Two-center Coulomb Repulsion Integrals in the Semiempirical LCAO-MO Method and the Significance of the Pariser-Parr Approximation
Authors: Gondo Yasuhiko , Kanda Yoshiya 
Published: July 2006

Abstract
The coefficients in the Pariser-Parr-type quadratic formulas for the two-center Coulomb repulsion integrals encountered in the planar as well as the non-planar conjugated systems have been expressed as linear functions of the effective nuclear charges of the 2p atomic orbitals involved. The formulas thus obtained are applicable to those conjugated systems consisting of carbon, nitrogen, and oxygen atoms, and may well be useful in variable electronegativity self-consistent field calculations on these systems. With some illustrative applications to spin densities and phosphorescent-state energies, it has been shown that the Pariser-Parr approximation gives better results than the Nishimoto-Mataga one, although the latter is successful in the prediction of electronic transitions within the singlet manifold. Incidentally, this was also the case for the phosphorescent-state zero-field splittings (Y. Gondo and Y. Kanda, This Bulletin, 43, 3943 (1970)). The electric dipole moments have also been discussed.
Equilibrium of Urea Synthesis. II.
Authors: Inoue Shigeru , Kanai Kazumichi , Otsuka Eiji 
Published: July 2006

Abstract
In the preceding paper (This Bulletin, 45, 1339 (1972)) it was reported that the existence of the maximum equilibrium conversion was not due to the experimental method. For this phenomenon, we have presented the following interpretation. While NH4CO2NH2 is converted to urea and water, it dissociates into NH3 and CO2 in the solution (not in the gas phase), and the degree of the dissociation increases exponentially as the temperature becomes higher, while the conversion to urea gradually increases. Therefore, at a certain temperature, the equilibrium conversion reaches its maximum value. Although it is nearly impossible to prove analytically the dissociation of NH4CO2NH2 in the solution, we are sure of it from the following facts: 1) The dissociation of NH4-CO2NH2 is a great endothermic reaction, even under the conditions of urea synthesis. 2) The value of NH3/CO2which gives the minimum equilibrium pressure at a usual temperature is not always equal to 2.0, but varies with the temperature. 3) The effect of H2O/CO2 on the equilibrium pressure varies with the temperature; that is, when the temperature is lower than about 200°C, an increase in H2O/CO2 reduces the equilibrium pressure, but when the temperature is higher than 200°C, an increase in H2O/CO2 makes the equilibrium pressure higher.
Least-Squares Determination of Molecular Structures from Gaseous Electron-Diffraction Data. II. Polynomial Expression of Background
Authors: Shibata Shuzo 
Published: July 2006

Abstract
A new least-squares method has been devised for interpreting electron-diffraction data by comparison of an experimental background with a calculated background. The former is derived from an experimental total intensity by assuming a molecular model. The latter is approximated by a polynomial function. A computer program is written to refine structural parameters of a molecule so as to yield a smooth background. The characteristic of the present method is that it does not need any bias depending upon human judgement throughout an analysis. The distinctive features of the procedure are discussed, and the application of this method to structure determination of several molecules is also described.
Mössbauer Effect of 119Sn in Tetracarbonylcobalt Derivatives of Tin(IV) Halides
Authors: Ichiba Sumio , Katada Motomi , Negita Hisao 
Published: July 2006

Abstract
The 119Sn Mössbauer effect was studied in tetracarbonylcobalt derivatives of tin(IV) halides, XnSn[Co-(CO)4]4−n, where X=Cl, Br or I, and n=0∼4. The isomer shift in each halogen series increased as the halogen atom was successively replaced by the Co(CO)4 group. The values of the isomer shift were between those of tin(IV) halides and XSn[Co(CO)4]3 and did not change lineraly with the number of halogen atoms. The values of the quadrupole splitting were smaller than those of the corresponding organotin halides, XnSnR4−n, and attained their maximum at dihalides. From the Mössbauer parameters, the chemical bonds in the compounds, especially the Sn-Co bond, were discussed.
Fluorescence Emission in the Gas Phase of Several Aromatic Hydrocarbons
Authors: Nakajima Akira 
Published: July 2006

Abstract
The fluorescence and excitation spectra of several condensed aromatic hydrocarbons were measured in the gas phase at low pressures. The emission from the second excited singlet state (S2 emission) could be observed with some of the compounds studied, in which the first weak absorption band is located close to the second much stronger band. The relative yield of the S2 emission always increased with the increase in the excitation wave number. It has been shown that the occurrence of the S2 emission can be explained in a qualitative way by the state densities and the radiative rates. In coronene, an emission to be regarded as originating from the third excited singlet state was observed.
Activation Analysis of Arsenic, Copper, and Antimony in Sea Water
Authors: Gohda Shiro 
Published: July 2006

Abstract
Arsenic, copper, and antimony in sea water were determined by the thermal neutron activation analysis. Convenient pre- and post-irradiation procedures were proposed and some samples were analyzed. Arsenic, copper, and antimony were collected by the cocrystallization with thionalide, and were irradiated for 30 min in the neutron flux of 2×1013 n/cm2/sec. After the thionalide complex was decomposed with nitric acid, the copper and antimony were separated from the arsenic by precipitating with oxine, and the arsenic in the filtrate was coprecipitated with ferric hydroxide. Gamma-ray spectra were obtained and the decays of the 0.44–0.67 MeV photo peak of 64Cu plus 122Sb and the 0.55 MeV peak of 76As were followed. The arsenic, copper, and antimony contents in sea water were estimated to be 1.12–1.71 μg As/l, 1.49–3.35 μg Cu/l, and 0.22–0.57 μg Sb/l.
Spectrophotometric Studies and Analytical Applications of Vanadium(IV) Chelates with 4-(2-Pyridylazo)resorcinol and 1-(2-Pyridylazo)-2-naphthol
Authors: Mushran S P , Prakash Om , Verma J R 
Published: July 2006

Abstract
Oxovanadium(IV), VO2+, gives sensitive colour reactions with 4-(2-pyridylazo)resorcinol (ε=2.54×104 at λmax 550 nm) and 1-(2-pyridylazo)-2-naphthol (ε=1.02×104 at λmax 560 nm). The composition of the complexes VO2+: PAN or PAR was established by the continuous variations, mole ratio, and Asmus straight line methods. Lambert-Beer’s law range, Ringbom optimum range, pH stability range, photometric error, and stability constant values were also evaluated.
The Preparation of Bis(dimethylglyoximato)nitrosylcobalt(II) and its Conversion into the Nitro Complex
Authors: Tamaki Motonori , Masuda Isao , Shinra Koichiro 
Published: July 2006

Abstract
The preparation of diamagnetic CoII(dmgH)2NO (dmgH=dimethylglyoximato monoanion) is reported. The complex shows the IR absorption band of NO at 1641 cm−1, indicating a neutral NO ligand in the complex. The IR and electronic spectra are consistent with the structure of the penta-coordinate, the square-pyramidal configuration of the complex. In the presence of oxygen and water, the complex is oxidized rapidly (NO→NO2−, Co(II)→Co(III)) and converted into CoIII(dmgH)2NO2·OH2. During the reaction, a complex formulated as [CoII(dmgH)2NO·OH2] [CoIII(dmgH)2NO2]·2H2O is obtained. It is considered that, in the complex, the Co(II) is bound with the Co(III) through a NO bridge. The assignments of the IR spectra have been made using 15NO and 15NO2.
The Characterization of Oligomeric Iron(II)-tetraoxime Complexes
Authors: Backes Joseph , Masuda Isao , Shinra Koichiro 
Published: July 2006

Abstract
Several polymeric iron(II) chelates with tetraoxime ligands,
CH3C(NOH)C(NOH)–\overset(α)CH2–\overset(β)CH2–(CH2)n–\overset(β)CH2–\overset(α)CH2–C(NOH)C(NOH)CH3,
where n=2 and 6, were characterized. They show a ligand-to-iron molar ratio of 1 : 1, corresponding to a planar arrangement of the ferrous ion and the four oxime nitrogens; two pyridine or methylpyridine substituents are axially coordinated to the central metal ion. The complexes are diamagnetic in the solid state, and their absorption spectra closely resemble those of the monomeric ferrous dimethylglyoxime compounds. The molecular weight, determined in a pyridine solution by vapor-pressure osmometry (2800 for –(CH2)2– and 3100 for –(CH2)6–), corresponds to 5 or 6 Fe–N4 units within the polymer chain. An NMR investigation including tetraoxime ligands with both aliphatic and aromatic linkages, as well as the corresponding chelates, shows that the protons in the α or in the β position to the oxime groups do not undergo any shift upon chelation. The electronic spectral data and NMR data provide no evidence that the Fe(II) chelate rings within the polymer chain are affected by one another.
The Polarography of N,N′-Ethylenebis(acetylacetoniminato) and N,N′-Ethylene bis(salicylaldehydeiminato) Complexes of Cobalt(III), Nickel(II), and Copper(II) in an N,N′-Dimethylformamide Solution
Authors: Kodama Mutsuo , Fujii Yuki , Sakurai Mitsuo 
Published: July 2006

Abstract
The polarographic behavior of N,N′-ethylenebis(acetylacetoniminato) (baen) and N,N′-ethylenebis(salicylaldehydeiminato) (bisaen) complexes of cobalt(III), nickel(II), and copper(II) in DMF solutions was studied thoroughly. At the dropping mercury electrode, these metal complexes give well-defined cathodic waves corresponding to the reduction of metal(II) to metal(I). A careful and systematic study of the polarographic behavior of β-cis and trans cobalt(III)-baen and -bisaen complexes of the general formulae: CoZY1−a and CoZX21−2b, and that of nickel(II)- and copper(II)-baen complexes, revealed that the unusual stability of the metal(I)-baen and -bisaen complexes can be ascribed mainly to the stable square-planar nature of baen and bisaen. The effect of the replacement of the ligand by the halogen atom was also investigated.
Effect of Ring Size on the Mass Spectral Fragmentation of Cyclic Sulfoxides
Authors: Tamagaki Seizo , Oae Shigeru 
Published: July 2006

Abstract
Mass spectra of six cyclic sulfoxides were determined in order to study the effects of ring size on the rate of OH-elimination from molecular ions. The ratios of the rates for the OH loss, [M+–OH]/[M+], are: trimethylene sulfoxide: 0.23/tetramethylene sulfoxide: 0.06/pentamethylene sulfoxide: 0.24 /hexamethylene sulfoxide: 1.21/9-thiamonoxybicyclo[3.3.1]nonane: 3.14/7-thiamonoxybicyclo[2.2.1]heptane: 0.02. These findings were explained in terms of the difference in the closest approaching distance between the sulfinyl oxygen and the β- or γ-hydrogen atoms. Geometry of the ionized molecular ions appears to be an important factor in determining these ratios. The loss of HSO was also disucssed.
Structure and Reactivity of Small Ring Compounds. IV. Photochemistry of Spirocyclopropyl Ketones
Authors: Sonoda Akio , Moritani Ichiro , Miki Jo , Tsuji Takashi , Nishida Shinya 
Published: July 2006

Abstract
The photochemical transformations of a series of spriocyclopropyl ketones (1–4) have been investigated in dilute n-hexane solutions. Spirocyclopropyl ketones 1 and 2 give mainly the ’Type I’ photoproducts of cycloalkanones, i.e., 1-(2′-propenyl)cyclopropanecarboxaldehyde (5, 34%) and 1-(3′-butenyl)cyclopropanecarboxaldehyde (7, 37%), respectively, in marked contrast to the usual photochemical cleavage of cyclopropyl ketones. Ethylidenecycloalkanones are not detected, but their hydrogenated derivatives, 2-ethylcycloalkanones, are produced in a small amount.
The photoreaction of 1 has been found to be quenched by piperylene, so that it is highly probable that the reaction products are derived from the n-π* triplet states of the ketones.
The irradiations of nonconjugated spiroketones 3 and 4 afford ring-enlarged 4-methylenecycloalkanones, 9 and 10, respectively.
Studies on the Voges-Proskauer Reaction. II. The Structure of a Pigment from the Diacetyl Reaction of 1-Benzyl-1-methylguanidine
Authors: Nishimura Tamio , Yamazaki Chiji , Ueno Tetsuro , Kitajima Shinichi , Ishige Koichi 
Published: July 2006

Abstract
A pigment formed in the diacetyl reaction of 1 -benzyl-1 -methylguanidine was isolated as reddish purple prisms. The reduced pigment was colorless and rapidly converted back to the original pigment on exposure to the air. On the basis of IR, NMR, and mass spectral evidence, the structures of the pigment and the reduced one were established to be 2-(N-benzyl-N-methylamino)-4-methyl-5-(1-oxo-1,2-dihydro-2-naphthylidenemethyl)-imidazole and 2-(N-benzyl-N-methylamino)-4-methyl-5-(1-hydroxy-2-naphthylmethyl)imidazole, respectively.
Isomerism of the Metal Complexes containing Multidentate Ligands. I. Geometric and Optical Isomers of the Bis(diethylenetriamine)-cobalt(III) Ion
Authors: Yoshikawa Yuzo , Yamasaki Kazuo 
Published: July 2006

Abstract
Three possible isomers of bis(diethylenetriamine)cobalt(III) halide were isolated by column chromatography on ion-exchange cellulose and Sephadex, and the mer- and u-facial isomers were completely resolved by column chromatography on SE-Sephadex. These isomers were studied by electronic, infrared, and PMR spectroscopy, and the absolute configuration of the u-facial isomer was assigned on the basis of the circular dichroism spectrum.
Imidothiocarbonates. V. Preparations and Properties of Novel Azomethine Ylides and Thiocarbonyl Ylides from Sulfur-contained Heterocycles
Authors: Ueno Yoshio , Okawara Makoto 
Published: July 2006

Abstract
Preparations and properties of some novel azomethine ylides and thiocarbonyl ylides containing 1,3-dithiolanium moiety have been studied. Azomethine ylides, 3a, b, and c, were prepared by deprotonation of 2-(N-methyl-N-phenacyl)amino-(2a), 2-(N-p-nitrobenzyl-N-methyl)amino-(2b), and 2-(N-carbethoxymethyl-N-methyl)amino-1,3-dithiolanium salt (2c), respectively. Azomethine ylides 3a, b reacted with benzaldehydes to give 1,3-dipolar cycloadducts which are new class of spiro orthocarbonates, otherwise it is difficult to obtain. Elimination of ethylene sulfide from the spiro orthocarbonates easily occurred to give thiocarbonyl compounds. In the absence of dipolarophiles, 3a cyclized intramolecularly to give 1,3-oxazoline-2-thione derivative. Formation of the thiocarbonyl ylides by deproptonation of 2-phenacylthio-1,3-oxazolium and 2-p-bromophenacylthio-1,3-dithiolanium salts, and their different cyclization to spiro compounds were also studied. Reaction of thiocarbonyl ylides 16 with p-nitrobenzaldehyde afforded p-nitrochalcone. Mechanisms of these interesting reactions and their synthetic utility were discussed.
Methylene Analogs of Cyclobutenedione. IV. The Reaction of 3,4-Bis(diphenylmethylene) cyclobutanedione Monoacetal and Its Derivatives with Methanolic Potassium Hydroxide
Authors: Toda Fumio , Ooi Nobuhiro 
Published: July 2006

Abstract
The reaction of 2,2-dimethoxy-3,4-bis(diphenylmethylene)cyclobutanone (II), 2,2-dimethoxy-3,4-bis(diphenylmethylene)cyclobutanol (III), 2-hydroxy-3,4-bis(diphenylmethylene)cyclobutanone (IV), and 2-methoxy-3,4-bis(diphenylmethylene)cyclobutanol (VIII) with methanolic potassium hydroxide was studied. The three methoxy compounds, II, III, and VIII, afforded the ring-opened products, methyl 4,4-dimethoxy-2-diphenylmethylene-3-diphenylmethylbut-3-enate (X), 4,4-dimethoxy-2-diphenylmethylene-3-diphenylmethyl-but-3-enal (XIII), and 4-methoxy-2-diphenylmethylene-3-diphenylmethylbut-3-enal (XVI) respectively. However, the ketoalcohol IV afforded the enolizable cyclobutenedione, 3,4-bis(diphenylmethyl) cyclobutenedione (XXI).
The Photolysis and Thermolysis of Ethyl Azidoformate in the Presence of Ketones
Authors: Hiyama Tamejiro , Taguchi Hiroaki , Fujita Shinsaku , Nozaki Hitosi 
Published: July 2006

Abstract
The photochemical decomposition of ethyl azidoformate (I) in an acetone solution gives the nitrene adduct, oxazirane II, whereas the thermolysis of the solution gives a C–H insertion product, III. The photolysis of I in cyclohexanone gives an α-insertion product, IX, while the thermolysis affords a β-insertion product, X, and an oxazole, XIII, in addition to IX. The multiplicity of the reactive species is examined in terms of the heavy-atom effect.
Mass-spectral Fragmentation of 3-(5-Nitro-2-furyl)-1,2,4-triazoles
Authors: Kato Yasuhiko , Hirao Ichiro 
Published: July 2006

Abstract
The mass spectra of 3-(5-nitro-2-furyl)- (I), 5-methyl-3-(5-nitro-2-furyl)- (II), 5-ethyl-3-(5-nitro-2-furyl)-(III), and 5-trideuteriomethyl-3-(5-nitro-2-furyl)-l,2,4-triazole (IV) and their 1-acetyl, 1-trideuterioacetyl, and 1-propionyl derivatives were examined. The mother compounds, I-IV, gave the most prominent molecular ions and showed the same fragmentation pattern. The molecular ions undergo two modes of cleavages; one is the elimination of NO (1) and CO (2), followed by the loss of C2H2 (3), thus giving the M−84 ions which include the 5-substituents of the triazole ring, while the other is the loss of NO2–CO, which directly gives rise to the fragment M−74 ions. The 1-acyl derivatives gave extremely weak molecular ion peaks. In the first step of the fission of the molecular ions, the elimination of an acyl group occurred, with the rearrangement of a hydrogen atom, thus giving rise to prominent ions. These ions correspond to the molecular ions of the mother compounds, I–IV, and are expected to show a similar fragmentation pathway. The fragmentation of these compounds was also considered to occur in view of the existence of meta-stable ion peaks. The meta-stable peaks appearing at the transition of the loss of NO are flat-topped, releasing kinetic energy of 0.78±0.04 eV.
The Synthesis of an Etiojervane Analog of Corticosterone.
Authors: Masamune Tadashi , Orito Takako 
Published: July 2006

Abstract
The synthesis of C-nor-D-homo-17-epicorticosterone 21-acetate (1) from jervine (3), which possesses the corticosterone configuration at each of the ring junctions, is described. Etiojerv-5-ene-3β,11β-diol-17-one (4), obtained by a seven-step process from 3, was subjected to the Darzens reaction and afforded glycidic ester (7), which was converted by treatment with boron trifluoride into olefin (9). Catalytic hydrogenation followed by reduction with lithium aluminum hydride gave rise to tetraol (15), which was isolated as the acetonide (16). After Oppenauer oxidation of 16, acid hydrolysis and subsequent partial acetylation, the resulting monoacetate (19) was oxidized with dicyclohexylcarbodiimide in dimethylsulfoxide to give compound 1. Spectral and chemical evidence are presented for configurational assignment to both the compound and the synthetic intermediates.