bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of Benzoylsulfene. V. The Reaction of Benzoylsulfene with Enamines
Authors: Tsuge Otohiko , Iwanami Sumio , Hagio Shigeru 
Published: July 2006

Abstract
The reaction of benzoylmethanesulfonyl chloride with enamines derived from cyclohexanone in the presence of triethylamine has been studied. The chloride reacted with 1-(1-morpholino)- and 1-(1-piperidino)cyclohexene in the presence of triethylamine, affording the corresponding acyclic sulfones. On the other hand, the reaction of the chloride with 1-(1-pyrrolidinyl)cyclohexene gave 2-benzoylmethanesuIfonylcyclohexanone and 2,3-dibenzoyl-2,3,4,5,6,7-hexahydrothianaphthene 1,1-dioxide. The latter compound, whose structure corresponded to the compound derived from the 2:1 adduct of benzoylsulfene and the enamine with the elimination of sulfur dioxide and pyrrolidine, reacted with hydrazine hydrate to give 1,4-diphenyl-5a,6,7,8,9,9a-hexahydrothianaphtheno[2,3-d]-pyridazine, which was then transformed into 3,4,6-triphenylpyridazine.
Calorimetric and Magnetic Studies of Crystalline and Glassy Bis[N-(3-methoxysalicylidene)isopropylamine]nickel(II)
Authors: Arai Naoto , Sorai Michio , Seki Syûzô 
Published: July 2006

Abstract
Thermal and magnetic properties of Ni(3-CH3O-SAL·iso-C3H7)2 were investigated by measuring thermograms, infrared and electronic spectra, heats of solution, magneitc susceptibilities, and heat capacities around glass transition temperature. In addition to the known paramagnetic crystalline phase III and the diamagnetic crystalline phase IV, two new crystalline phases (I and II) were discovered. Phase I was found to be paramagnetic, its molecular geometry being of a tetrahedral four-coordinated form like that of phase III, while phase II, similar to phase IV, is diamagnetic and has a square-planar four-coordinated form. Although the order of thermodynamic stability of these four crystalline phases was not determined, they were isolated stably at room temperature. The supercooled liquid and glassy states of this compound were realized for the first time by quenching the sample in the molten state. Unusual magnetic behaviors of these two states were satisfactorily accounted for by assuming an equilibrium between the diamagnetic and the paramagnetic species. In the supercooled liquid state, the paramagnetic species was partially converted into the diamagnetic one with decreasing temperature. Below the glass transition temperature Tg, however, this conversion process was prevented and the magnetic susceptibility obeyed apparently Curie’s law with a 26% paramagnetic content. The heat capacity measurement revealed a typical glass transition phenomenon at 297.5 K and the heat capacity jump at Tg was determined to be 172 JK−1mol−1. Detailed discussions were given for the relationship between molecular geometry and its associated magnetic property and also for the phase relationship between various phases.
A Molecular Orbital Calculation of Chemically Interacting Systems. Addition of Singlet Methylene to Ethylene
Authors: Fujimoto Hiroshi , Yamabe Shinichi , Fukui Kenichi 
Published: July 2006

Abstract
A semi-empirical self-consistent-field molecular orbital calculation of the addition of singlet methylene to ethylene was carried out on the basis of an isolated molecule approximation. The calculation was made with respect to two modes of approaches of methylene to ethylene which were proposed by Hoffmann. A calculation of the electron populations by use of the configuration interaction wave function showed that singlet methylene added to ethylene double bond in an electrophilic fashion with a quasi-synchronous formation of two σ bonds to yield cyclopropane. The present calculation revealed the important roles of the interaction between the highest occupied molecular orbital of ethylene and the lowest unoccupied molecular orbital of methylene and of the interaction between the highest occupied molecular orbital of methylene and the lowest unoccupied molecular orbital of ethylene, in interpreting the formation of new σ bonds between ethylene and methylene and the disappearance of the π bond of ethylene.
Photochemical Reactions of p-Benzoquinone Complexes with Aromatic Molecules
Authors: Arimitsu Satoshi , Tsubomura Hiroshi 
Published: July 2006

Abstract
Electronic absorption spectra and ESR spectra have been measured for the photolyzed charge transfer complexes between p-benzoquinone and aromatic donors in low temperature matrices. When the p-benzoquinone complex with toluene or p-xylene was irradiated at 77°K, an electronic absorption spectrum attributable to the semiquinone radical was obtained together with that of the benzyl-type radical. The spectral shape and position of the former are somewhat different from those of the semiquinone radicals obtained by the photolysis of p-benzoquinone or hydroquinone. These differences indicate the presence of interaction between semiquinone and benzyl-type radicals. The ESR spectra obtained from these systems show that these radicals form pairs in the triplet (S=1) state. It is concluded that the radical pairs are produced as a result of intermolecular hydrogen atom transfer from the aromatic donor molecule to p-benzoquinone in the excited states of the CT complexes formed between them. The irradiations of various p-benzoquinone complexes were carried out in the wavelength regions corresponding to the lowest CT absorption bands at 77°K, and the reactivities were discussed in relation to the electronic structures and geometrical configurations of the CT complexes in the excited states. From the analysis of ESR spectra, the fine structure constant was evaluated for each of the radical pairs, from which the average distance between interacting unpaired electrons was calculated.
Photochemical Reaction of 9-Chloroacridine in Aerated and Deaerated Ethanol. II. Studies by Means of a Flash Technique
Authors: Nakamaru Katsumi , Niizuma Shigeya , Koizumi Masao 
Published: July 2006

Abstract
Studies were made on the transient species produced when the aerated and deaerated ethanol solutions of 9-Cl-acridine (9-Cl-A) are flashed. In the deaerated solution, triplet state of 9-Cl-A and a long-lived radical species of unknown structure were detected. It was established that the latter is produced by a reaction in the singlet excited state of 9-Cl-A (and possibly in the higher triplet (Tn−π*)) and that it produces biacridyl by a bimolecular reaction. In the aerated solution, another radical species of a long life of which structure is still unknown, was detected. It was established that this radical species reacts bimolecularly and produces acridone.
Binuclear Metal Complexes. IV. The Preparation and Properties of Binuclear Copper(II) Complexes of Schiff Bases Derived from 2,6-Diformyl-4-methylphenol and Glycine or Alanine
Authors: Okawa Hisashi , Kida Sigeo , Muto Yoneichiro , Tokii Tadashi 
Published: July 2006

Abstract
A new series of binuclear copper(II) complexes with different bridging groups, Fsal(=gly)2Cu2X (X=OH, Cl, Br) and Fsal(=ala)2Cu2X (X=Cl), were synthesized, Fsal(=gly)2 and Fsal(=ala)2 being the Schiff bases prepared by condensation of 2,6-diformyl-4-methylphenol with glycine and alanine, respectively. The copper(II) ions are bridged by the phenolic oxygen in the organic moiety and also the X. The properties of the complexes were studied by IR spectra, visible spectra, and magnetic susceptibility measurements at various temperatures. From the cryomagnetic data it was concluded that the effect of the bridging group X upon magnetic exchange interaction decreases in the order: OH&gt;Cl∼Br.
Studies on New Derivatives of 8-Quinolinol as Chelating Agents. II. Chelate Formation of Some Aminomethyl Derivatives Derived from 8-Hydroxyquinoline-2-carbaldehyde with Metal Ions
Authors: Hata Takehisa , Uno Toyozo 
Published: July 2006

Abstract
The reactions of new oxine derivatives with additional coordinative sites, 8-hydroxyquinoline-2-carbaldehyde, 2-(p-chlorophenylaminomethyl)-, 2-(naphthylaminomethyl)-, 2-(p-tolylaminomethyl)-, and 2-(o-hydroxyphenylaminomethyl)-8-hydroxyquinoline, and N,N′-bis(8-hydroxy-2-quinolylmethyl)ethylenedianiine (abbreviated as HQA, CAMHQ, NAMHQ, TAMHQ, PAMHQ, and BHQED respectively), with Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Mn2+, Mg2+, and Ca2+ were investigated by potentiometric and spectrophotometric methods. The stability constants of the metal chelates were determined in a 50 v/v % aqueous dioxane solution at 25°C. The stability constants of metal chelates of HQA, NAMHQ, CAMHQ, and TAMHQ with a ligand-to-metal ratio of 2:1 are lower than those of oxine. In these ligands, steric hindrance due to the aminomethyl group results in lower stability constants of the metal chelates. PAMHQ reacts as a terdentate ligand with Cu2+, Mn2+, Mg2+, and Ca2+to form 1:1 chelates by coordination with quinoline nitrogen and two phenolate oxygens. BHQED reacts with Cu2+, Co2+, Ni2+, Cd2+, and Mn2+ to form a protonated chelate, MHL+, in the acid region, while, in the neutral region, one proton is released from the protonated chelate to form a deprotonated chelate, ML, by coordination with six donor groups, namely, two imino and hydroxyl groups, and two quinoline nitrogens. BHQED acts as a sexadentate ligand to form the most stable chelates among these oxine derivatives.
Spectra and Keto-Enol Equilibrium of Benzoylacetanilides
Authors: Shawali Ahmad Sami A S , Naoum Magdi M , Ibrahim Saad A 
Published: July 2006

Abstract
A series of twelve monosubstituted benzoylacetanilides have been prepared by condensation of acetoacetanilide with substituted benzoylchlorides. IR and UV spectral data are presented and discussed. The benzoyl CO stretching frequencies were correlated with σ+ (\barv=34.97σ++1705; r=0.983). The effect of substituents in the benzoyl moiety on the keto-enol equilibrium, has also been investigated. The data were correlated by the equation: logK=0.865σ+−0.615; r=0.988.
Studies on Benzoquinolines [f] and [h]. Part I
Authors: Tiagi Rameshwar P , Joshi Bhuwan C 
Published: July 2006

Abstract
2-Chloro-4-methyl and 2-methyl-4-chloro-benzo[h]quinolines, 1-chloro-3-methyl- and 1-methyl-3-chlorobenzo[f]quinolines were converted into corresponding hydrazino derivatives. Structural studies of the hydrazino compounds and their derivatives were carried out. Chlorine atom in a position adjacent to nitrogen of the ring was found to be more reactive than in that away from nitrogen in benzo[f] and [h]quinolines. Cyclisation of hydrazino derivatives by nitrous and formic acids occurred at position 2 in 1-methyl-3-hydrazinobenzo[f]quinoline and at position 3 in the case of 2-hydrazino-4-methylbenzo[h]quinoline, respectively, while in the case of 1-hydrazino-3-methylbenzo[f]quinoline, at position 10 and in 4-hydrazino-2-methylbenzo[h]quinoline, at position 5, respectively.
The CNDO/2 Study of Barbararyl Cation and Its Isomeric C9H9+ Systems
Authors: Yoneda Shigeo , Winstein Saul , Yoshida Zen-ichi 
Published: July 2006

Abstract
The geometrical and electronic structures of C9H9+ systems have been studied applying CNDO-2 method. The calculated results are used to discuss the stabilities of the structures for C9H9+ system and their electronic states. It is suggested that the carbonium ion which has a D3h symmetry (IV) enjoys much stabilization energy, whereas bicyclo[3.2.2]nonatrienyl cation (I) is less stable than IV. The stability of IV can be explained by unusual delocalization of its electrons over the molecule.
Bromine Addition to Cyanonorbornene Derivatives
Authors: Kikkawa Sh\={o}ichi , Nomura Masakatsu , Uno Y\={o}ichir\={o} , Matsubara Masaaki , Yanagida Y\={u}ji 
Published: July 2006

Abstract
The addition reactions of endo-5-cyanonorbornene, trans-endo,exo-5,6-dicyanonorhornene, cis-endo-5,6-dicyanonorbornene, and cis-exo-5,6-dicyanonorbornene with bromine have been studied. The assignments of the configurations of bromine adducts were determined mainly on the basis of the NMR spectra. As to trans-endo,exo-5,6-dicyanonorbornene, reaction mixtures have been found to contain trans and exo-cis adducts. The reaction conditions involving the proportions of these isomers and a rationale for the formation of the exo-cis adduct are discussed. cis-endo-5,6-Dicyanonorbornene and cis-endo-5,6-dicyanonorbornene gave the exo-cis adduct and the trans adduct respectively. The stereochemistry of bromine atoms may be explained in terms of a steric factor. A kinetic study showed that these addition reactions in solution in acetic acid obey the second-order rate law and that the magnitudes of the rate constants are in the order; cis-exo-5,6-dicyanonorborne&gt;trans-endo,exo-5,6-dicyanonorbornene&gt;cis-endo-dicyanonorbornene.
Asymmetric Hydrogenation of C=O Double Bond with Modified Raney Nickel. XXI. The Effect of Water on the Asymmetric Activity of the Catalyst
Authors: Ninomiya Toshio 
Published: July 2006

Abstract
The effect of water added to the hydrogenation system of methyl acetoacetate was investigated on catalysts modified with l-amino acids, their derivatives, and d- or l-hydroxy acids. In the absence of water, catalysts modified with all l-amino acids except l-serine and l-proline gave methyl ds(−)-3-hydroxybutyrate, and in the presence of water all the catalysts modified with l-amino acids gave methyl ls(+)-3-hydroxybutyrate. On the other hand, the catalysts modified with l- or d-hydroxy acids were not affected by the addition of water and gave an ls(+) or ds(−) hydrogenation product respectively. In the presence of water, the catalyst modified with the l-valine methyl ester gave an ls(+) product, while the catalysts modified with N-acetyl l-amino acids were not affected by water. As a whole, it was concluded that water added to the hydrogenation system affected the amino group of the modifying reagent on the catalyst surface, which might play an important role in the asymmetric control of the substrate approaching the catalyst surface. The water in the hydrogenation system also promoted the hydrogenation rate, regardless of the modifying reagents.
Asymmetric Hydrogenation of C=O Double Bond with Modified Raney Nickel. XXII
Authors: Ninomiya Toshio 
Published: July 2006

Abstract
The state of the amino acid molecule used as a modifying reagent on a catalyst surface was investigated. From the relationship between the asymmetric activities of the catalysts modified with l-valine and its derivatives and the stability constants of the nickel chelates of l-valine and its derivatives, it was concluded that l-valine adsorbs like a ligand of the chelate on the catalyst surface. This conclusion was also supported by the finding that the asymmetric activity of the catalyst modified with the nickel l-valine chelate was higher than those of the catalysts modified with l-valine and its derivatives. Also, the asymmetric activities of the catalysts modified with l-histidine, l-serine, and l-proline, and with the nickel chelates of the above three l-amino acids were discussed on the basis of the stability constants of the nickel chelates of the above three l-amino acids, it was concluded that two conditions at least are necessary for the modifying reagent to be effective; it must adsorb stably on the catalyst surface, and it must have a structure affording effective asymmetric control of the substrate.
Structure and Reactivity of Organic Ions in Gas-Phase Radiolysis. III. The Benzenonium Ions Formed by the Reactions of CH5+ and C2H5+ Ions from Methane with o-Xylene
Authors: Yamamoto Yukio , Takamuku Setsuo , Sakurai Hiroshi 
Published: July 2006

Abstract
The gas-phase radiolysis of mixtures of o-xylene and excess methane has been studied at room temperature as a function of methane pressure and the added NO and NH3 in order to investigate the reactions of CH5+ and C2H5+ ions from methane with o-xylene. It has been suggested that the proton transfers from these ions to o-xylene result in the isomerization to m-xylene via an intermediate σ complex, dimethylbenzenonium ion, and that a part of the C2H5+ ions is added to o-xylene leading to the formation of two isomers of dimethylethylbenzene. The proposed mechanism of the methane-sensitized isomerization of o-xylene to meta isomer has been supported by the observation that both m-xylene-d0 and m-xylene-d1 were formed in the radiolysis of a mixture of o-xylene and methane-d4. The isotope effect (kH/kD) on the proton loss from the dimethylbenzenonium ion was roughly estimated to be 1.8±0.4. Group migration of intermediate a complexes was discussed.
Asymmetric Hydrogenation of C=O Double Bond with Modified Raney Nickel Catalyst. XXIII
Authors: Ninomiya Toshio 
Published: July 2006

Abstract
The ultraviolet spectra of acetylacetone and methyl acetoacetate adsorbed on evaporated nickel film modified with amino or hydroxy acid were measured. The spectroscopic data suggested that the adsorbed species of acetylacetone was affected by the modifying pH, that the interaction between acetylacetone and the hydroxy acid was different from that between acetylacetone and the amino acid, and also that methyl acetoacetate, similar to acetylacetone, chemisorbed with a pseudo aromatic ring on the nickel surface. Consequently, the above results strongly support the theory that in the asymmetic hydrogenation, the substrate, acetylacetone or methyl acetoacetate, approaches the catalyst surface in a form like a pseudo aromatic ring, that it is asymmetrically controlled by the modifying reagent adsorbed on the catalyst surface, and, further, that the ease of the adsorption of the substrate onto the catalyst determines the rate of asymmetric hydrogenation.
Thermolysis and Photolysis of Benzopinacol Dicarboxylates
Authors: Shirafuji Tamio , Yamamoto Yasusi , Nozaki Hitosi 
Published: July 2006

Abstract
Thermal decomposition of benzopinacol dicarboxylates (I) results in the cleavage of the central carbon-carbon bond to afford benzhydryl esters (II) and benzophenone (III). Benzopinacol diacetate (Ia) in benzyl alcohol-benzene solution produces benzyl acetate via ionic reaction path, whereas Ia in THF-benzene or in toluene gives radical products such as 2-diphenylmethylenetetrahydrofuran and bibenzyl, respectively. Photolysis of I proceeds in the similar manner as thermolysis to afford II and III. The ester II is further decarboxylated photo-chemically to give 1,1-diphenylalkane, diphenylmethane, and 1,1,2,2-tetraphenylethane. The photochemical solvent incorporation of II proceeds in both radical and ionic sense. Such dual nature of the reaction products in thermolysis and photolysis of I and of the photodecarboxylation of II is explained in terms of the intimate ion-radical pair hypothesis proposed by Walling.
Synthesis of Some Nucleoside Analogs of Substituted 1,2,3-Triazole
Authors: Makabe Osamu , Fukatsu Shunzo , Umezawa Sumio 
Published: July 2006

Abstract
1-(β-d-Ribofuranosyl)-1,2,3-triazole-4-carboxamide (4) and 4-amino-1-(β-d-ribofuranosyl)-1,2,3-triazole-5-carboxamide (7) have been synthesized as an approach to obtain bioisosteres of pyrazomycin, an antiviral agent. The synthesis has been accomplished by condensation of blocked triazoles with tri-O-benzoyl-d-ribofuranosyl chloride in the presence of mercuric cyanide in nitromethane. UV spectral studies revealed the orientation of N-glycosidation in the substituted triazoles.
A Salt Effect on the Reaction of Zinc Carbenoid
Authors: Kawabata Nariyoshi , Noda Shigeyoshi , Yamashita Shinzo 
Published: July 2006

Abstract
Bicyclo[4.1.0]heptane (norcarane) was obtained as the major product of the reaction of cyclohexene with diethylzinc and methylene iodide. In the presence of lithium halide or magnesium halide, however, the yield of norcarane considerably decreased. Large amounts of n-propyl and n-butyl iodides were formed which was interpreted in terms of an insertion mechanism, viz., insertion of zinc carbenoid into the carbon-iodine bond of ethyl and n-propyl iodides.
N,N,N′,N′-Tetramethylethylenediamine-Copper Salt-catalysed Coupling of Aryl Grignard Reagents with Alkyl and Aralkyl Halides
Authors: Onuma Kazuhiko , Hashimoto Harukichi 
Published: July 2006

Abstract
In the presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA) and a small amount of copper salt, phenyl- and p-tolylmagnesium bromides react with alkyl or benzyl halide to give cross-coupling products in benzene or in a benzene-diethyl ether solvent. Among the alkyl iodides, normal iodides are most reactive, while secondary iodides do not react under our conditions. As copper salts, CuCl, CuCl2, CuCl2(TMEDA), and CuBr are all efficient for catalysis. This newly-developed catalytic system of TMEDA-copper salt is thought to be useful for the syntheses of polyalkyl-substituted aromatic hydrocarbons. As the reaction mechanism, the intermediate formation of TMEDA-coordinated organocopper(I) species and the nucleophilic displacement is proposed.
The Synthesis and Reaction of Monohalogeno-t-butyloxycarbonylamino Acids
Authors: Ohnishi Takanobu , Sugano Hiroshi , Miyoshi Muneji 
Published: July 2006

Abstract
Monohalogeno-t-butyloxycarbonylamino acids (XBOC-amino acids) were synthesized by the use of the corresponding chloroformates in a basic aqueous solution. Several dipeptides containing XBOC-amino acid were also prepared. The cleavage of the XBOC group was successfully carried out not only under some acidic conditions, but also by heating in methanol or ethanol. In order to demonstrate the usefulness of this group in peptide synthesis, Z–Gly–Lys(Z)–Gly–OEt was synthesized via BrBOC–Lys(Z)–Gly–OEt, which had been treated by hot ethanol. Side reaction during the synthesis of XBOC-amino acids will also be described.
A Simple Protecting Group Protection-Purification “Handle” for Polynucleotide Synthesis. II.
Authors: Tajima Kiyohiko , Hata Tsujiaki 
Published: July 2006

Abstract
A new method for the synthesis of oligonucleotides by employing a protecting group protection-purification “handle” was investigated. It was found that 3′-O-acetylthymidylyl(5′→3′)thymidine 5′-phosphor[p-N,N-dimethylamino]anilidate (NpTpTOAc) was prepared in 65% yield from thymidine 5′-phosphor[p-N,N-dimethylamino]anilidate (NpT) and 3′-O-acetylthymidine 5′-phosphate (pTOAc) in the presence of triisopropylbenzenesulfonyl chloride (TPS). The NpTpTOAc was selectively isolated by the use of Dowex 50W-X2 and Amberlite IR-45 resins. After treatment of NpTpTOAc with 80% acetic acid, pTpTOAc was obtained in 60% yield based on pTOAc. Similarly, trinucleotide derivative, pTpTpTOAc, was isolated in 31% yield based on pTpTOAc.
Total Syntheses of Carbohydrates. I. Dihydroxyacetone and Dl-Erythrulose
Authors: Ando Takashi , Shioi Sachiko , Nakagawa Masazumi 
Published: July 2006

Abstract
An improved method of preparation of halopropargyl alcohol is described. Hydration of halopropargyl alcohol followed by hydrolysis gave dihydroxyacetone which was identified as its dibenzoate. 2-Butyne-1,4-diol was converted into acetoxymethyl vinyl ketone. 1,4-Diacetoxy-3-bromobutan-2-one obtained by the addition of acetyl hypobromite to the vinyl ketone was treated with silver acetate to yield tri-O-acetyl-Dl-erythrulose. Hydrolysis of the triacetate afforded Dl-erythrulose which was identified as phenylhydrazone.
The Nuclear Magnetic Resonance Spectra of 2-Formylaminopyridine and 2-Formylamino-γ-picoline
Authors: Enomoto Nobuko , Kondo Michio 
Published: July 2006

Abstract
The NMR spectra of 2-formylaminopyridine and 2-formylamino-γ-picoline have been recorded under various conditions. At low temperatures, these compounds were found to exist in two forms. In these two forms, the chemical shifts of the ring proton-3 differ much from each other because of the difference in the orientation of the formylamino group, which has a large magnetic anisotropy. The difference in the chemical shifts of the formyl protons in the two forms are too large to be explained by the anisotropic shielding effect of the pyridine-ring currents. At higher temperatures, the signal coalescence of these protons in two forms have been observed. The molecular structures of these compounds have been concluded to be planar.