bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Conformational Properties of Several 1,8-Diarylnaphthalenes
Authors: Ibuki Eiichi , Ozasa Shigeru , Fujioka Yasuhiro , Mizutani Hiroshi
Published: July 2006

Six new 1,8-diarylnaphthalenes, each having closely held parallel aromatic rings, were synthesized by a Kharash-type Grignard cross-coupling of arylmagnesium iodide and 1,8-diiodonaphthalene in the presence of N,N′-bis(1-methyl-3-oxobutylidene)ethylenediaminatonickel(II) as a catalyst. Among them, 1,8-di(1-naphthyl) naphthalene was obtained as cis and trans rotamers, caused by the restricted rotation at the 1,8-position. Interconversion between the rotamers on heating above their melting points was confirmed by differential scanning calorimetry. The proton magnetic resonance spectral studies of the 1,8-diarylnaphthalenes indicated the presence of a face-to-face arrangement of aromatic rings in the peri-position. Two new 8,8′-diaryl-1,1′-binaphthyls, each having two sets of closely held parallel aromatic rings, were isolated as minor coupling products. Trans-trans conformations were proposed for them on the basis of their thermal behavior. Several nickel(II) complexes were found to be effective catalysts for preparative Grignard cross-coupling reaction involving closely crowded geometry.
Direct Observation of the Rate for Cis→Trans and Trans→Cis Photoisomerization of Stilbene with Picosecond Laser Photolysis
Authors: Sumitani Minoru , Yoshihara Keitaro
Published: July 2006

The rates for direct cis→trans and trans→cis photoisomerizations of stilbene in solution were measured with a newly developed monitor light source for picosecond laser photolysis in the UV region. The rate constant of the trans→cis isomerization is 1.2×1010 s−1 in hexane at 295 K. The fluorescence decay rate constant of the S1 state of trans-stilbene has the same value. Thus, the decay of the S1 state is the rate limiting step and the lifetime of an intermediate perpendicular state (1p) has to be very short. The cis→trans isomerization is very fast and the half life of the excited cis-isomer is less than a few picosecond. These observations strongly indicate that the isomerization reaction proceeds through the potential surface of the singlet excited states.
Nickel(0) Catalyzed [2+2] Cross-addition of Bicyclo[2.2.1]heptene Derivatives with Electron-deficient Olefins
Authors: Takaya Hidemasa , Yamakawa Masashi , Noyori Ryoji
Published: July 2006

In the presence of bis(acrylonitrile)nickel(0) or bis(1,5-cyclooctadiene)nickel(0), exo-tricyclo[3.2.1.02,4]oct-6-ene cycloadds to acrylonitrile and methyl acrylate to give anti- and syn-3-cyano-exo,exo-tetracyclo[4.3.1.02,5.07,9]decane or the corresponding methoxycarbonyl derivatives. The cycloaddition with dimethyl maleate proceeds with retention of configuration. Benzonorbornadiene also enters into the 2+2 reaction, while endo-tricyclo[3.2.1.02,4]oct-6-ene, bicyclo[2.2.1]heptene, and 5-methylenebicyclo[2.2.1]heptene are unreactive. Origins of the observed selectivities in the catalyzed reaction are discussed.
Reactions of α,N-Diarylnitrones with O-Methyl Diphenylphosphinothioate and Oxidations of N-Alkylidene-2-hydroxyanilines with Silver Oxide. Preparation of Benzoxazoles
Authors: Yoshifuji Masaaki , Nagase Rihei , Inamoto Naoki
Published: July 2006

Reactions of α,N-diarylnitrones in the presence of O-methyl diphenylphosphinothioate at 150 °C gave 2-arylbenzoxazoles (3) in fairly good yields. Oxidation of N-alkylidene-2-hydroxyanilines with silver oxide afforded 2-alkenyl-, 2-alkyl-, or 2-arylbenzoxazoles (7 and 3) in good yields under mild reaction conditions (at room temperature). A plausible mechanism for formation of 3 and 7 has been discussed briefly.
An X-Ray Crystallographic Study on cis-trans Configurational Assignment to “cis-” and “trans-1,8-Terpins” and a Proposal of New Designation for Discriminating between the Configurational Isomers
Authors: Suga Takayuki , Hirata Toshifumi , Aoki Tadashi
Published: July 2006

The crystal structures of “cis-terpin” (terpin hydrate) and “trans-terpin” were elucidated by X-ray crystallography. This crystal structure elucidation showed that the hydroxyl group at C-1 and the 1-hydroxy-1-methylethyl group at C-4 are in cis and trans relationships in the “cis-” and “trans-1,8-terpin” molecules, respectively, similarly to the structures in solutions. A new designation for discriminating between the configurational isomers is proposed on the ground of the IUPAC Rule for Nomenclature.
Alkaline Hydrolysis of Propella-δ- and ε-lactones
Authors: Kakiuchi Kiyomi , Tobe Yoshito , Odaira Yoshinobu
Published: July 2006

Second-order rate constants for the alkaline hydrolysis of a series of propella-δ- and ε-lactones at 32.3 °C have been determined. The conclusion to be drawn from the kinetic data is as follows. In the case of propella-δ-lactones, the steric effect of the third ring on the hydrolysis plays an important role, whereas the hydrolysis of propella-ε-lactones is mainly governed by the steric effect attributable to the flexibility of the ε-lactone ring, and, on the contrary, the steric effect of the third ring is of no great consequence.
Coenzyme Models. 30. On the Unusual Spectroscopic Behaviors of Amphiphilic Flavins and 5-Deazaflavins
Authors: Shinkai Seiji , Harada Akiko , Manabe Osamu , Yoneda Fumio
Published: July 2006

At room temperature in aqueous solution, isoalloxazines and 5-deazaisoalloxazines with 10- dodecyl substituent gave a well-resolved, three-banded Sl peak which has been believed to appear only in nonpolar solvents or in enzymic hydrophobic pockets where isoalloxazines and 5-deazaisoalloxazines become free of hydrogen-bonding effects. On the other hand, 3-methyl-10-ethylisoalloxazine and 5-deazaisoalloxazines with 10- ethyl or 10- octyl group did not give such a fine-structured Sl peak. We have found that (i) the fine structure disappears on the addition of organic solvents (ethanol>40 vol% or pyridine>20 vol%), (ii) the fine structure also disappears on the addition of surfactants (CTAB, Brij-35, and SDS) above the critical micelle concentrations, (iii) 10-dodecylisoalloxazine with hydrophilic 3-(thiazolinio)propyl group at 3-position has not the fine structure, and (iv) the fluorescent intensity of 3-methyl-10-dodecyl-5-deazaisoalloxazine is much weaker than that of 3-methyl-10-ethyl-5-deazaisoalloxazine in aqueous solution but these intensities become comparable above 40 vol% ethanol. These findings are consistently rationalized in terms of an aggregation-deaggregation equilibrium of amphiphilic flavin analogues, supporting that the fine structure in aqueous solution is due to the “stacking” association of (5-deaza)isoalloxazine nuclei, like that of dye molecules. The aggregation-deaggregation phenomenon is sensitively reflected by the reactivity: the reaction of 3-methyl-10-ethyl-5-deazaisoalloxazine and cyanide ion gave k2=1.27 M−1 s−1 in aqueous solution at 30 °C, whereas aggregated 3-methyl-10-dodecyl-5-deazaisoalloxazine did not react with cyanide ion. These findings have significant implications on the chemistry of flavoproteins, because the absorption spectra of enzyme-bound flavins and 5-deazaflavins have frequently been cited to discuss the flavin reactivities.
Infrared Study of 12-Molybdophosphoric Acid Reduced by Organic Compounds
Authors: Tsai Tian-hsi , Maruya Ken-ichi , Ai Mamoru , Ozaki Atsumu
Published: July 2006

Reaction of 12-molybdophosphoric acid with ethyl methyl ketone, crotonaldehyde, methacrylaldehyde, 1-butene, or 1,3-butadiene is enhanced by the presence of water, and leads to preferential decrease in ν(P–O) at 1060 cm−1 with preference over that in ν(Mo–O–Mo) at 880 cm−1, while the reaction with methanol is not dependent on the presence of water and results in rapid disappearance of ν(Mo–O–Mo) and retention of ν(P–O).
Recovery of Heavy Metals with Calcium Silicon Alloy. II. Recovery of Copper(II) Ions
Authors: Tokunaga Shuzo
Published: July 2006

In the 20.0-matom dm−3 Cu(II) solution of an initial pH of 4.0, more than 99% of it was removed by addition of calcium silicon alloy in ca. 5 min, and the pH decreased to below 2. The X-ray diffraction pattern of the solid reaction product indicated that the Cu(II) removal took place through reduction to metallic Cu. In the 1.0-matom dm−3 Cu(II) solution, the pH increased from 4.0 to above 9.0 in 30 min, which consequently maintained high removal for a long time. In the constant pH runs, relation of the equivalents of Ca and Si dissolved against that of Cu(II) ions removed showed that not only the Ca moiety but also the Si moiety participated in the reduction of Cu(II) ions. It is desirable to control pH value at 3.0 or higher, or to separate the solid phase from the liquid phase in the first 30–60 min in order to avoid excess dissolution of calcium silicon alloy and to attain high Cu(II) removal. Copper(I) oxide was formed in a solution of pH above ca. 5, which was in contact with the air. In a HNO3 solution, the removal decreased considerably. Sodium nitrate also caused strong interference with the removal which can be prevented by acidifying the solution with HCl to pH ca. 1. When Hg(II) or Cr(VI) ions are present, the Cu(II) removal tends to decrease depending on the amount of calcium silicon alloy added.
The Effect of Pressure on the Mutual Solubility of a Nonionic Surfactant–Water System
Authors: Kaneshina Shoji , Shibata Osamu , Nakamura Makoto
Published: July 2006

The cloud-point temperature (T) of an aqueous hexa(oxyethylene) dodecyl ether solution was determined as a function of the pressure (P) and the composition (x2). The volume (ΔV) and entropy (ΔS) changes for the separation of the surfactant phase from the water phase were estimated from the T-P-x2 relation. Both ΔV and ΔS were positive.
The Nafion-H-catalyzed Acylation of Thiophene with Acid Anhydrides
Authors: Konishi Hisatoshi , Suetsugu Kazuhiro , Okano Tamon , Kiji Jitsuo
Published: July 2006

The reaction of thiophene with acyclic acid anhydrides in the presence of Nafion-H (fluorocarbon resin sulfonic acid) afforded the corresponding 2-acylthiophenes in moderate yields. Acylation with cyclic acid anhydrides gave only low yields, however. The Nafion-H catalyst could be reused for the acylation with a little loss of activity.
The Enantioface-differentiating Methylation of the N-Benzylidene-Dl-phenylalanine Methyl Ester in the Presence of Chiral Lithium Amides
Authors: Yamashita Tetsushi , Mitsui Hitoshi , Watanabe Hiroyuki , Nakamura Nobuo
Published: July 2006

The asymmetric methylation of the N-benzylidene-Dl-phenylalanine methyl ester was carried out in the presence of lithium salts of secondary amines derived from (S)-proline. The lithium amides of poly(imino-1-isobutylethylene) and its corresponding low-molecular-weight model compound, derived from (S)-leucine, were similarly used in order to examine the polymer effects with regard to the stereoselectivity.
Hydrothermally Activated Silica–Alumina. II. Variations in Catalytic Activities for 1-Butene Isomerization and Polymerization, and in the Amount of Acid with Pretreatment Temperature
Authors: Furuyama Shozo , Murashita Osamu , Ichisaka Kotomasa , Morimoto Tetsuo
Published: July 2006

The technique of hydrothermal activation was used to prepare well-mixed and fully hydroxylated silica–alumina catalysts, SA-nMHT (n=13, 25, or 50 denotes the alumina content (wt%)). Their catalytic activities and cis/trans selectivities for the 1-butene isomerization (ki and c/t), the catalytic activities for the 1-butene polymerization (kp), the amount of acid (A), and the number of the surface hydroxyl group (NOH) were measured as a function of the degassing temperature (Td) over the 25–700 °C range; the following results were obtained: (1) ki changed prominently with Td and reached its maximum around 300 °C. (2) c/t was about 0.9 below 500 °C, but exceeded 1.2 at 700 °C. (3) kp increased till 300 °C and became constant above that temperature. (4) A was almost independent of Td above 100 °C. (5) NOH decreased from 11–15 (at 100 °C) to 0.5 group nm−2 (at 700 °C). An analysis of these data led to the conclusion that the SA-nMHT sample underwent the surface structural changes three times during the thermal dehydroxylation between 25 and 700 °C. The sequence of the structural change was sketched, and the different dependencies upon Td of ki, kp, and A were explained.
Molecular Structures of [2](2,5)(7,7,8,8-Tetracyanoquinodimethano)[2]paracyclophane and 14,17-Dimethoxy[2](2,5)(7,7,8,8-tetracyanoquinodimethano)[2]paracyclophane
Authors: Mizuma Takashi , Matsuura Hideaki , Kai Yasushi , Yasuoka Noritake , Kasai Nobutami
Published: July 2006

The molecular structures of two [2.2]paracyclophanes containing a 7,7,8,8-tetracyanoquinodimethan (TCNQ) moiety as an electron acceptor have been determined by means of X-ray diffraction. The electron-donating moieties in these cyclopahnes are benzene (TCNQ-X) and p-dimethoxybenzene (TCNQ-X (OMe)2) rings. TCNQ-X crystallizes in a triclinic space group P\bar1 with two molecules per unit cell; a=9.772(2), b=18.477(4), c=6.569(1) Å, α=90.38(2), β=107.92(2), γ=100.32(2)°. The crystals of TCNQ-X(OMe)2 belong to the orthorhombic system; space group Fdd2; a=25.618(3), b=31.895(5), c=9.808(1) Å, Z=16. Both structures were solved by the direct method and refined by the block-diagonal least-squares procedure to R=0.088 (TCNQ-X) and 0.109 (TCNQ-X(OMe)2) for 3141 and 1695 non-zero rehections. In the two structures determined, the [2.2] paracyclophane skeleton has the usual structure; the benzene ring and six-membered ring of the TCNQ moiety have a boat form, and two C(CN)2 portions in the TCNQ moiety are bent down from the mean plane defined by the C(12), C(13), C(15), and C(16) atoms.
Phase Transitions in Tetramethylammonium Hexachloroplatinate(IV), -tellurate(IV), and -stannate(IV) as Studied by 35Cl NQR and Powder X-Ray Diffraction
Authors: Furukawa Yoshihiro , Prabhumirashi Laxman S , Ikeda Ryuichi , Nakamura Daiyu
Published: July 2006

The 35Cl NQR spectra of [(CH3)4N]2PtCl6, [(CH3)4N]2TeCl6, and [(CH3)4N]2SnCl6 were recorded in a temperature range between 77 and ca. 350 K. Below room temperature, the temperature dependence measurements of NQR frequencies for all of these complexes confirmed the presence of structural phase transitions reported very recently. From the experiments of DTA carried out above room temperature, structural phase transitions were located at 385, 351, and 365 K in the same order of the above complexes. The X-ray powder patterns taken in the highest-temperature phase of these complexes (at ca. 390 K) were well interpreted as arising from the K2PtCl6-type cubic structure with the lattice constant a0=12.828, 13.053, and 12.975 Å for the Pt, Te, and Sn complexes, respectively. In this phase of each complex, however, no NQR spectra were observed. The mechanism of the phase transitions detected is discussed in connection with the structure of these complexes.
The Polarization Characteristics and the Thickness of the Catalyst Layers in Fuel Cell Electrodes
Authors: Kenjo Tadao , Nakajima Noriyuki
Published: July 2006

The polarization characteristics of poly(tetrafluoroethylene)-bonded Raney nickel hydrogen- and silver oxygen-electrodes have been measured as a function of the thickness of the catalyst layer, and the polarization curves of these electrodes have been analyzed on the basis of the electrolyte film model. The observed polarization curves were divided into several segments and a linear polarization-current equation, derived from the model, has been applied to each segment. The performance of the electrodes approaches asymptotically to an upper limit with the thickening of the catalyst layers. The profiles of the faradayic current density across the electrode wall have been estimated for both electrodes. In contrast with the almost flat profiles of the Raney nickel electrodes, the current densities for the silver electrodes are localized on the liquid side of the electrodes; a thin area of the catalyst layer ranging from the electrode-face/electrolyte interface to 5.3×10−3cm distance sustains most of the load current at a polarization of 220 mV. The catalytic activities of both the silver and Raney nickel catalysts are enhanced with progression of the polarization while the resistivities of the electrolyte film maintained essentially constant. A slight surface oxidation for the Raney nickel and a surface reduction for the silver catalysts have been suggested as probable explanations for the enhanced catalytic activities observed.
129I Mössbauer Effect in Several π-σ Charge Transfer Complexes of Iodine
Authors: Sakai Hiroshi , Matsuyama Tomochika , Yamaoka Hitoshi , Maeda Yutaka
Published: July 2006

The 129I Mössbauer spectra at 16 K have been measured for the π-σ charge transfer complexes of iodine with benzene, coronene, perylene, and poly(p-phenylene). It is suggested that the benzene-iodine complex in benzene prepared by slow cooling consists of alternate benzene and iodine molecules with the six-fold axial symmetry. The Mössbauer spectrum for the coronene-iodine complex (1:1) shows only one chemical state of iodine. The acceptor orbital is described by only the σu-antibonding molecular orbital of iodine. The extent of charge transfer in the complex is estimated to be 0.06e− in the electronic ground state. In the poly(p-phenylene)-iodine complex the iodine exists as almost a free molecule, indicating that the interaction between the phenylene ring and iodine is very weak.
Conformational Changes of the Poly(α-l-glutamic acid)–Cu(II) Macromolecular Complexes in the pH Range 4–7. A Comparative Study by Means of Viscosity and Circular Dichroism
Authors: Masujima Tsutomu , Yamaoka Kiwamu , Hori Jin-ichiro
Published: July 2006

Intrinsic viscosity, [η], and far-UV circular dichroism, CD, were measured at 25 °C for poly(α-l-glutamic acid), poly(Glu), solutions in 7.5 mM and 150 mM NaCl in the presence and the absence of copper(II) ions over the pH range 4–7, where poly(Glu) undergoes two conformational transitions. The first is the well-known helixcoil transition and the second, which is followed by completion of the helix, was attributed to the formation of aggregates. The pH dependence of [η] and molar ellipticity was analyzed with the two-state model. The helixcoil transition can not be represented by the all-or-none process. The aggregation mode of helices is predominantly the side-by-side type in 7.5 mM NaCl, but probably a mixture of the side-by-side and the head-to-tail types in 150 mM NaCl. The hydrodynamic shapes of poly(Glu) and its Cu(II)-complexes were calculated with ellipsoid, cylinder, and straight chain element models. The so-called random-coil form is an extended-coil in 7.5 mM NaCl at higher pH. The poly(Glu) helix is probably slightly shortened as compared with the α-helix.
A Kinetic Study on the Conformational Change of Bovine Serum Albumin Induced by Sodium Dodecyl Sulfate
Authors: Takeda Kunio
Published: July 2006

Stopped-flow measurements were made on the conformational change of bovine serum albumin induced by sodium dodecyl sulfate in a buffer solution containing 3.33 mmol/dm3 NaH2PO4 and 3.56 mmol/dm3 Na2HPO4 (pH 7.0, μ=0.014). The protein adopted a conformation with a smaller helical content than the original native state (helix to coil transition) upon the addition of the surfactant. The rate of transition depended strongly on the surfactant concentration. The results were compared with those of conformational changes of other proteins, in which a helical structure increased in the surfactant solution (coil to helix transition). It is noticeable that the value of the activation entropy is negative in the helix to coil transition, as compared with its positive and large values in the coil to helix transition. It seems that the binding of the surfactant to the protein causes the transition to only a particular conformation of the protein via each individual process.
Simultaneous Multielement Determination of Major, Minor, and Trace Elements in Soil and Rock Samples by Inductively Coupled Plasma Emission Spectrometry.
Authors: Tao Hiroaki , Iwata Yasuo , Hasegawa Tetsuya , Nojiri Yukihiro , Haraguchi Hiroki , Fuwa Keiichiro
Published: July 2006

A simple and convenient analytical method for simultaneous multielement determination of soil and rock samples has been investigated by inductively coupled plasma emission spectrometry. Spectral interferences due to major elements were examined in detail, and the correction coefficients for minor and trace elements were estimated for correction of matrix effects. The determinations of minor and trace elements as well as major elements could be performed without matrix matching of the standard solutions. The present method investigated has been applied to the analysis of various soil and rock samples, and the analytical results have been compared with those obtained by atomic absorption spectrometry.
A Cation-exchange Study of the Hydrolysis of Tracer Concentrations of Polonium(IV)
Authors: Suganuma Hideo , Hataye Itsuhachiro , Takashima Yoshimasa
Published: July 2006

A cation-exchange method was used for determining the average cationic charge of polonium species present in hydrolytic equilibrium in solutions. This method is based on measurements of the distribution ratio of polonium at a constant internal hydrogen-ion concentration of the cation-exchanger phase. In 1.0 mol dm−3 (H,Na)ClO4 and 1.0 mol dm−3 (H,Na)NO3 solutions at −log[H+]=1.0, tracer concentrations of polonium(IV) were found to exist in the mean chemical forms of Po(OH)3.430.53+ and Po(OH)2.83(NO3)0.600.57+, respectively. The formation of cationic polymerized species was also estimated in region of 4≤−log[H+] in a 1.0 mol dm−3 (H,Na)ClO4 solution.
The Reductive Coupling of Organic Halide Using Hydrazine and a Palladium Amalgam Catalyst. II. Homocoupling of Haloarene with Arylhydrazine
Authors: Nakajima Riichiro , Kinosada Masaji , Tamura Takashi , Hara Tadashi
Published: July 2006

The function of palladium chloride in the reaction of an arylhydrazine with a haloarene was found to differ from those of other metal salts; palladium chloride was reduced with arylhydrazine, and the palladium metal produced was again oxidized with haloarene to give palladium halide. Thus the reductive coupling of haloarene occurred in the presence of a catalytic amount of palladium chloride. Addition of mercury(II) chloride promoted this reaction. The reaction of o-, m-, and p-bromotoluene with the corresponding tolylhydrazine gave the corresponding bitolyl in 99, 112, and 115% yield, respectively, based on the haloarene.
Sesquiterpenoid Constituents of the Liverwort Frullania brotheri STeph.
Authors: Takeda Reiji , Ohta Yoshimoto , Hirose Yoshio
Published: July 2006

Two new sesquiterpene lactones, (+)-β-frullanolide and (+)-brothenolide, have been isolated from the liverwort Frullania brotheri STeph. One of them, (+)-brothenolide, has an allergenic property. The absolute structures of these lactones have been established by spectroscopic analysis and chemical transformation.
Sesquiterpenoid Constituents of the Liverwort, Ptychanthus striatus (LEhm. et LIndenb.) NEes
Authors: Takeda Reiji , Naoki Hideo , Iwashita Takashi , Mizukawa Kosei , Hirose Yoshio , Isida Toshimasa , Inoue Masatoshi
Published: July 2006

Four sesquiterpenoids, striatene, striatol, β-monocyclonerolidol and ptychanolide, were isolated from the liverwort Ptychanthus striatus (LEhm. et. LIndenb.)NEes. Their structures have been established by spectroscopic analysis and chemical transformation. Three of them, striatene, striatol and β-monocyclonerolidol, are interesting in terms of the evolution of the liverwort from the algae.
CD Spectra and Absolute Configurations of fac(a,b,c)-[Co(a)(b)(c)(1,4,7-Triazacyclononane)]n+ Complexes
Authors: Fujinami Shuhei , Hosokawa Takao , Shibata Muraji
Published: July 2006

Seventeen kinds of fac(a,b,NH3)-[Co(a)(b)(NH3)(tacn)]n+ complexes (a, b=CN−, NO2−, SO32−, NCS−, N3−, CH3COO−, H2O, OH−, Cl−, or Br−; tacn=1,4,7-triazacyclononane) have been prepared and optically resolved by column chromatography. The absolute configurations of these complexes have been determined by referring to the CD spectra of the related [Co(a)(gly)(tacn)]n+ complexes (a=CN−, NO2−, NCS−, N3−, or Cl−). It has been found that the signs of the Cotton peaks observed in the first absorption band region are closely related to the ligand field strengths of the unidentate ligands, and that the dominant Cotton peak is associated with the electronic transition which arises in the plane containing no ammonia molecule.
Syntheses of 5-Deoxy-, 5,4′-Dideoxy-, 5-Deoxy-5-epichloro-, and 5,4′-Dideoxy-5,4′-diepichlorokanamycin A
Authors: Miyake Toshiaki , Tsuchiya Tsutomu , Nishi Toshiyuki , Umezawa Sumio
Published: July 2006

5,4′-Dideoxy-5,4′-diepichlorokanamycin A has been synthesized from 1,3,6′,3″-tetrakis(N-benzyloxycarbonyl)-4″,6″-O-cyclohexylidenekanamycin A by treatment with sulfuryl chloride, followed by deblocking. Similar treatment of 2′,3′,4′,2″-tetra-O-acetyl-1,3,6′,3″-tetrakis(N-benzyloxycarbonyl)-4″,6″-O-cyclohexylidenekanamycin A gave 5-deoxy-5-epichlorokanamycin A. 5,4′-Dideoxykanamycin A and 5-deoxykanamycin A were synthesized from the corresponding 5,4′-diepichloro and 5-epichloro derivatives by reductive dechlorination with sodium metal in liquid ammonia or tributylstannane. The structures of these derivatives were confirmed by the 1H- and 13C-NMR spectroscopy.
Aryliminodimagnesium Reagents. VI. The Reactions with Conjugated Carbonyl Compounds. The Initial Coordination and the Electron-transfer in the Reactions of Organomagnesium Reagents
Authors: Okubo Masao , Yoshida Masatoshi , Horinouchi Kotomi , Nishida Hiroshi , Fukuyama Yoshinori
Published: July 2006

The reactions of aryliminodimagnesium reagents (ArN(MgBr)2) with benzylideneacetophenones, quinones, and benzils were examined. Among the product-distributions in the reactions with the enones and the α-diketones, some examples in which p-MeO-substituted substrates gave higher yields of condensation products were obtained. The results are in contrast with the product-distributions in the reaction of ArMgBr with Ar1COAr2 and that of ArN(MgBr)2 with Ar1NO2: p-Cl-Substituted substrates are advantageous for the formation of addition and/or condensation products. These reactions of the two organomagnesium reagents were classified into “coordination controlled” and “electron-transfer controlled” ones on the basis of the combination of electron-donating ability of reagents with the electron-accepting ability of substrates. The classification was illustrated also on the basis of the relative difference of the energy levels of HOMO’s and LUMO’s of the reactants.
The Mechanism of the Reaction of 3,5-Dinitrobenzonitrile with Sodium Methoxide in Methanol
Authors: Abe Takehiro
Published: July 2006

The reaction of 3,5-dinitrobenzonitrile in a methanolic solution containing a low sodium-methoxide concentration has been reinvestigated. The final product has been found to be methoxy(3,5-dinitrophenyl)methanimine, which is produced by a catalytic reaction. The reaction mechanism has been presented for the formation of the Meisenheimer complexes and the final product in the reaction system. The rate and thermodynamic stabilities for their formation have been discussed on the basis of the LUMO coefficients of 3,5-dinitrobenzonitrile and from the relative potential energies of their formation respectively, considering also the solvent effects.
The Disproportionate Constants of Mercurry(I) in Dilute Solutions. II
Authors: Sanemasa Isao , Kobayashi Toyohisa , Deguchi Toshio , Nagai Hideo
Published: July 2006

The equilibrium constants, Kd, of mercury(I) disproportionation have been measured by passing air containing mercury(0) vapor through mercury(I) solutions. At 15, 20, 25, 30, and 35 °C, the values of Kd were 1.3, 2.9, 5.2, 8.8, and 11×10−9 mol dm−3 respectively at μ=0.1 (NaClO4).
The Isotope Effects in the Reactions of Phenylcarbene with Alcoholic Matrices
Authors: Tomioka Hideo , Ozaki Yasuji , Izawa Yasuji
Published: July 2006

Product analysis studies on the reaction of phenylcarbene in deuterated alcoholic matrices at 77 K revealed that isotope effect on O–H (D) insertion is very small while substantial isotope effect was observed for C–H (D) insertion.
A Convenient Synthesis of 2-Phenylbenzo[b]thiopyrylium Perchlorates
Authors: Nakazumi Hiroyuki , Ueyama Tamio , Endo Takashi , Kitao Teijiro
Published: July 2006

2-Phenylbenzo[b]thiopyrylium perchlorates were conveniently prepared in good yields by reduction of 2-phenyl-4H-benzo[b]thiopyran-4-ones (thioflavones) with aluminium hydride, followed by treatment with acid in the presence of 2,3-dichloro-5,6-dicyano-p-benzoquinone.
Bromination of 4H-Cyclopenta[def]phenanthrenamines
Authors: Yoshida Masaaki , Minabe Masahiro , Ookawa Wataru , Suzuki Kazuo
Published: July 2006

Bromination of 4H-cyclopenta[def] phenanthren-1-amine, -2-amine, -3-amine, or -8-amine with bromine in chloroform took place at the 2-, 1-, 8-, or 9-position, respectively. The second bromine was introduced at the 8-, 3-, 2-, or 3-position. Similar regioselectivity was observed in the system of bromine in acetic acid–48% hydrobromic acid and of hydrobromic acid in dimethyl sulfoxide. The corresponding acetylamino compound was brominated at the same position as that of the parent amine.
Sesquiterpenoids in Cultured Cells of Liverwort, Calypogeia granulata INoue
Authors: Takeda Reiji , Katoh Kenji
Published: July 2006

Three new sesquiterpenoids, trinoranastreptene, 2-acetoxy-3-hydroxybicyclogermacrene and 3-acetoxy-2-hydroxybicyclogermacrene, were isolated from cultured cells of Calypogeia granulata INoue. Their structures have been established by spectroscopic analysis.
Synthesis of 2,2-Dimethyl-2H-pyran-fused Flavonols Using the Modified Algar-Flynn-Oyamada Reaction
Authors: Jain A C , Gupta S M , Sharma Anita
Published: July 2006

6-Acetyl-2,2-dimethylchromenes when separately condensed with p-anisaldehyde in the presence of ethanolic NaOH and subsequently oxidized with alkaline hydrogen peroxide without isolating the intermediate chalcones afforded the corresponding 2,2-dimethyl-2H-pyran-fused flavonols respectvely in good yield. Thus, flavonols having free 3-hydroxyl and fused with 2,2-dimethyl-2H-pyran can be synthesized easily.
On the Sorption Behaviour of Some Cations on Cobalt Hexacyanoferrate(III) Exchanger. Binary Separations of Rb+ and Cs+ on Columns
Authors: Jain Ajay K , Singh Rajpal , Bala Chand
Published: July 2006

Sorption behaviour of Ag, Cs, Rb, Co(II), Zn(II), and Fe(III) ions at low concentration (0.2 mmol) is studied in different concentrations of nitric acid and ammonium nitrate on cobalt hexacyanoferrate(III) exchanger. logKdvs. log concentration plots show that the sorption of these ions is not followed through ion exchange mechanism, only. In case of Rb+ and Cs+, a very low Kd is observed at high concentration of nitric acid (>5 mol dm−3) thereby showing the possibility of their elution on columns. For various other ions, such as Ba, Sr, Mn, Hg(II), Mg, Cd, Ca, Pb, Ni, La, and Th, the Kd values are almost zero. Thus the binary separation of Rb+ and Cs+ from a number of ions on the columns of this exchanger has been carried out.
X-Ray Diffraction Study of Mixing States in the Carbon Tetrachloride Solutions of Methanol and Pentane
Authors: Tanaka Masami , Nishikawa Keiko , Tohji Kazuyuki , Fujiyama Tsunetake
Published: July 2006

A simple method has been proposed for estimating the state of mixing in a binary solution directly from the radial distribution function. The method has been applied to the estimation of the size of the cluster or aggregate in a binary solution of methanol and carbon tetrachloride. Pure liquid carbon tetrachloride and a binary solution of pentane and carbon tetrachloride have also been studied as reference systems. The number of methanol molecules which form a cluster in the solution at the volume ratio of 8.5(CCl4):1.5(CH3OH) has been estimated to be about 18, which is in good agreement with an estimate by light scattering.
The Conversion of CH3OH into Olefins over Al2O3–Cr2O3 Treated with CF3Cl
Authors: Kurosaki Akito , Okazaki Susumu
Published: July 2006

A mixed oxide of Al and Cr having an atomic ratio(Al/Cr) of around 9 showed catalytic activity for the conversion of CH3OH into olefins and aromatic compounds after treatment with CF3Cl at 450 °C. The mixed oxide treated with CF3Cl adsorbed a considerable amount of NH3, even at temperatures as high as 500 °C. Analyses of the compositions on the surface layer by using XPS showed that the F component was predominantly bound to Al, not to Cr. Strong acid sites related to the less crystallized AlF3 seemed to be able to promote the conversion of CH3OH.
Effect of Adsorption of Potassium Iodide on Catalytic Activity of Plate-type Raney Nickel
Authors: Yoshino Tomio , Abe Tuneyo
Published: July 2006

An experimental investigation was made of the adsorptive activity of Raney nickel catalyst toward potassium iodide over a wide KI concentration range and of the change with KI adsorption of hydrogenating activity toward unsaturated alcohol and ketone. Adsorbed amounts of K+ and I− ions were determined by potentiometry and radioactivity measurement. The adsorptive activity vs. I− concentration relation yields a definitive break at equilibrium concentration 5.5×105 mol dm−3 (surface coverage 26%), the adsorption features in the lower and higher ranges relative to the break point being approximately represented by Freundlich’s and BET equations, respectively. Adsorption sites effective for I− ion in the Freundlich region disappear almost completely when the catalyst is preheated at 600 °C. The surface coverage causing the hydrogenation activity to decrease by 50% is 3% for allyl alcohol and 0.3% for 2-butanone. With allyl alcohol, however, even such a catalyst as has preadsorbed ca. 5-monolayer amount of I− ions possesses a 33% residual activity, though catalyst coverages over 26% result in only a little decrease in activity. These results suggest that the adsorption sites in the Freundlich region may function as strong catalytically active centers for the hydrogenation, which are unstable to heating.
Suppression of Electroreductive Dimerization of Benzaldehyde by Addition of α-Cyclodextrin
Authors: Matsue Tomokazu , Tasaki Chikako , Fujihira Masamichi , Osa Tetsuo
Published: July 2006

The effect of α-cyclodextrin (α-CD) on the electroreduction of benzaldehyde was investigated. The reduction in aqueous system produces benzyl alcohol and 1,2-diphenyl-1,2-ethanediol (hydrobenzoin, dimerization product). The addition of α-CD caused the decrease in the yield of hydrobenzoin. This suppression effect was observed both in the controlled potential and controlled current electrolyses. This is accounted for by the retardation of the dimerization rate between the neutral radicals, since inclusion of substrate provides severe steric hindrance around the reaction site. The addition had only a small influence on the stereochemistry of hydrobenzoin formed by the dimerization.
The Molecular Structure of Bromo(ethyl)[(−)-sparteine]magnesium(II), a Catalyst for the Asymmetric-selective Polymerization of Racemic Methacrylates
Authors: Kageyama Hiroyuki , Miki Kunio , Tanaka Nobuo , Kasai Nobutami , Okamoto Yoshio , Yuki Heimei
Published: July 2006

The molecular structure of EtMgBr-(−)-sparteine, which initiates asymmetric (enantiomer) selective polymerization of racemic methacrylates, has been determined by means of X-ray diffraction. The crystal is orthorhombic, space group P212121, a=11.278(2), b=14.112(3), c=11.746(2) Å, Z=4. The structure was established by the heavy atom method and refined by the block-diagonal least-squares procedure: R=0.100 for 1272 non-zero reflections. The Mg atom is tetrahedrally coordinated by the Et group, Br and two N atoms of the (−)-sparteine.
The Low Lying Electronic States of Dichloromaleic Anhydride
Authors: Ishibashi Yoshimi , Shimada Ryoichi , Shimada Hiroko
Published: July 2006

The polarized Raman and infrared spectra of dichloromaleic anhydride were studied and the assignments of the normal vibrations were reinvestigated based on the polarization behaviors of the spectral bands and on the normal coordinate calculation. Using the assignments the vibrational structure of the phosphorescence spectrum was analyzed and the phosphorescence lifetime was also measured. These results indicate that the lowest triplet state of this molecule is a 3(π, π*) state perturbed by closely located 3(n, π*) states. The near ultraviolet absorption and phosphorescence excitation spectra were measured and four absorption bands due to 3(n, π*)←1A1, 1A2(n, π*)←1A1, 1B1(n, π*)←1A1, and 1A1(π, π*)←1A1 transitions were found. The polarization experiment made on the 1A2(n, π*)←1A1 absorption suggests that this transition borrows the intensity from the 1A1(π, π*)←1A1 transition.
Circular Dichroism Spectra and Racemization of Two Geometrical Isomers of the (2-Aminoethanesulfenato-S,N)[tris(2-aminoethyl)amine]cobalt(III) Ion
Authors: Kojima Masaaki , Fujita Junnosuke
Published: July 2006

Optically active trans(t-N,S)(t) and cis(t-N,S)(p) isomers of [Co{S(O)CH2CH2NH2}(tren)]2+ (tren=tris(2-aminoethyl)amine; t-N= tertiary amine nitrogen) were prepared, and their circular dichroism spectra were compared with those of Δ(S or R)- and Λ(S or R)-[Co{S(O)CH2CH2NH2}(en)2]2+ and two geometrical isomers of [Co(R-pn)(tren)]3+ (R-pn=(R)-1,2-propanediamine) and [Co(S-dmbn)(tren)]3+ (S-dmbn=(S)-3,3-dimethyl-1,2-butanediamine). Racemization or epimerization of these sulfenato complexes was studied in aqueous solutions with ionic strength of 1.0 (NaClO4) in the pH and temperature ranges of 3.65–8.8 and 24.0–40.0 °C, respectively. The rates of p- and t-isomers of the tren complex are proportional to concentrations of the complex, but independent of pH, the latter isomer accompanying some decomposition during the course of racemization. The first-order rate constants of the p- and t-isomers are 9.92×10−5 and ca. 1.2×10−6 s−1 at 30.0 °C, respectively. No epimerization takes place in the en complexes under the same experimental conditions. The difference in rate of racemization or epimerization of these sulfenato complexes seems to be related closely to the crowding around the S=O group of the complex.
Mixed-ligand Palladium(II) Complexes Containing O,O′-Chelated β-Diketonate and η3-Carbon-bonded Ethyl 3-Oxobutanoate Anions. Preparation and Reactions with Some Lewis Bases
Authors: Yamada Kurumi , Baba Shigeru , Nakamura Yukio , Kawaguchi Shinichi
Published: July 2006

Novel palladium(II) complexes [Pd(β-dik)(η3-etac)] (5), in which anions of a β-diketone and ethyl 3-oxobutanoate coordinate to the central metal atom by the O,O′-chelation and the η3 carbon bonding, respectively, were prepared by the reactions of a dinuclear complex [PdCl(η3-etac)]2 with thallium (I) β-diketonates in benzene or acetone at room temperature. Reactions of 5 with Lewis bases (L) such as triphenylphosphine, diethylamine, propylamine and benzylamine were investigated. In almost all reactions, only the η3-carbon-bonded ester ligand in 5 was converted into a terminal-carbon-bonded one to afford complexes [Pd(β-dik)(etac-C4)L]. The bonding modes for the ligands in these products as well as in 5 were determined by means of IR and 1H and 13C NMR spectroscopy.
Solvent Effects on the Extraction of Gallium(III) with Decanoic Acid
Authors: Yamada Hiromichi , Imai Shozo , Takeuchi Eiichi
Published: July 2006

Extraction of gallium(III) with decanoic acid (HA) in several solvents was carried out at 25 °C and at an aqueous ionic strength of 0.1 mol/dm3(NaClO4). Organic solvents used are toluene, chlorobenzene, 1,2-dichloroethane, and 1-octanol. Extracted species differs from solvent to solvent: Ga6A18(H2O)w for toluene, Ga3A9 for chlorobenzene, GaA3 and Ga3A9 for 1,2-dichloroethane and GaA2(OH), Ga2A4(OH)2 and Ga2A6 for 1-octanol. The less polar the solvent, the more extensive is the polymerization of the extracted species.
Reactions of Chloro[4-[2-(methylthio)anilino]-3-penten-2-onato-O,N,S]palladium(II) with Carbanions and Pyridine Derivatives
Authors: Hiraki Katsuma , Onishi Masayoshi , Hayashida Minoru , Kurita Kyogo
Published: July 2006

A Schiff base, 4-[2-(methylthio)anilino]-3-penten-2-one (Hmtap), prepared from acetylacetone and 2-(methylthio)aniline, reacted with Na2[PdCl4] in the presence of sodium ethoxide to give [PdCl(mtap-O,N,S)] (1). Complex 1 was treated with carbanions formed from dimethyl malonate, methyl cyanoacetate, and malononitrile in the presence of sodium methoxide to afford the corresponding (disubstituted methyl)palladium(II) complexes, [Pd(CHYY′)(mtap-O,N,S)] (Y,Y′=COOMe and/or CN). On the other hand, 1 reacted with Tl(acac) to yield an O,O′-chelating complex, [Pd(mtap-N,O)(acac)], in which the mtap moiety served as a bidentate ligand. Moreover, 1 reacted with 2,2′-bipyridine (bpy) and 4-(dimethylamino)pyridine (dmapy) in the presence of NaClO4·H2O to give [Pd(mtap-N,O)(bpy)]ClO4 and [Pd(mtap-O,N,S)(dmapy)]ClO4, respectively. These complexes are characterized by means of elemental analysis and IR and NMR spectroscopy.
A Convenient Method for the Synthesis of Adenylyl-(2′–5′)-adenylyl(2′–5′)-adenosine Using 3′-O-Benzoyladenosine Derivatives
Authors: Takaku Hiroshi , Ueda Souichi
Published: July 2006

N 6,3′-O-Dibenzoyladenosine was prepared by treating 2′,3′-O-(dibutylstannylene)-N6-benzoyladenosine with benzoyl chloride in methanol. The trimeric adenylyl-(2′–5′)-adenylyl-(2′–5′)-adenosine was synthesized in a good yield using N6,3′-O-dibenzoyladenosine as the starting material via the phosphotriester approach.
Oxygen Promoted Addition of 1,3-Dioxolane to Electron-deficient Alkenes
Authors: Watanabe Yoshihisa , Tsuji Yasushi , Takeuchi Ryo
Published: July 2006

1,3-Dioxolane reacted with electron-deficient alkenes, such as diethyl maleate, maleic anhydride, diethyl fumarate and fumaronitrile, under an oxygen atmosphere or in air to give 1:1 adducts in good to excellent yields. The presence of oxygen promoted the reaction. The reaction appears to be characteristic of 1,3-dioxolane. Methylal and ethylal did not react with diethyl maleate under the same conditions.
Pseudo-sugars. VIII. Synthesis of Dl-1-Epivalidamine and Related Compounds
Authors: Ogawa Seiichiro , Oya Masayuki , Toyokuni Tatsushi , Chida Noritaka , Suami Tetsuo
Published: July 2006

Dl-1-Epivalidamine has been synthesized starting from the dianhydro compound derived from Dl-1,2,3-tri-O-acetyl-(1,3/2,4,6)-4-bromo-6-bromomethyl-1,2,3-cyclohexanetriol. Dl-7-Amino-7- deoxy-1-epivalidamine, which is considered to be a homolog of 2-deoxystreptamine, has also been prepared.
Regio-controlled Prenylation and Geranylation of 3-Furylmethylmagnesium Bromide. Selective Syntheses of 3-Substituted Furanoid and 2-Substituted 3-Methylfuranoid Terpenes
Authors: Araki Shuki , Butsugan Yasuo
Published: July 2006

Coupling reactions of 3-furylmethylmagnesium bromide with prenyl and geranyl diethyl phosphates gave 2-substituted 3-methylfurans, rosefuran and sesquirosefuran, as the main products. When the reactions were carried out in the presence of a catalytic amount of copper(I) iodide, normal coupling occurred and 3-substituted furans, perillene and dendrolasin, were formed in good yields. The related naturally occurring 3-substituted thiophene, 3-(4-methyl-3-pentenyl)thiophene, was also synthesized from 3-thienylmethylmagnesium bromide and prenyl diethy phosphate.
The Preparation of (C6H11)3Sb(OH)Y and Their Infrared Spectra
Authors: Kawasaki Yoshikane , Yamamoto Yasushi , Wada Masanori
Published: July 2006

Tris(cyclohexyl)hydroxoantimony(V) compounds, (C6H11)3Sb(OH)Y, Y=Cl, Br, CH3COO, and NO3, were prepared by the hydrolysis of μ-oxo-bis[tris(cyclohexyl)haloantimony(V)], [(C6H11)3SbX]2O, in a mixed solvent of acetone and water(7:3) or by a reaction of silver salts with [(C6H11)3SbX]2O in the same solvent. When Y=Cl and Br, the dehydration of the hydroxo compounds, giving the μ-oxo compounds, [(C6H11)3SbY]2O, occurred readily. However, when Y= CH3COO and NO3, the hydroxo form is stable. In the IR spectra of these hydroxo compounds in dichloromethane solution, the ν(O–H) band was observed at ca. 3630 cm−1 and the ν(Sb–O) band, at 565–513 cm−1. The hydrolysis of several μ-oxo compounds, [R3SbY]2O, R=CH3, C2H5, i-C3H7, C6H5, and p-CH3C6H4, Y=Cl, Br, CH3COO, and NO3, in a water-saturated dichloromethane solution was studied by using the IR spectra. All the compounds were hydolyzed in this solvent, but only the starting μ-oxo compounds were recovered from this solution.
Syntheses of Acyclic Polyethers Containing a Ferrocene Nucleus and Its Extraction Ability
Authors: Akabori Sadatoshi , Ohtomi Michiko , Sato Masaru , Ebine Seiji
Published: July 2006

Acyclic polyethers (7) (containing a ferrocene nucleus in both terminal sites) were synthesized by a one-pot reaction of 1,1′-diacetoxyferrocene with halide. Also, ferrocene derivatives (11) having polyethylene glycols were synthesized by the reaction of potassium salt of hydroxyferrocene with dihalide in DMF. On the addition of alkali metal thiocyanate in methanol, a hypsochromic shift and an increasing intensity of the absorption band at 438 nm were observed in ferrocene-containing polyethers 7, suggesting the complexing of 7 with cations. However, a similar spectral change could not be observed in 11. 7a extracts silver and thallium ions most effectively, the extraction efficiency of several metal cations being in this order: Ag+>Tl+>Cs+>K+>Li+>Na+.
Hydroxymethylation and Alkoxymethylation of Methacryloguanamine
Authors: Seo Toshihiro , Abe Kenji , Kakurai Toshio
Published: July 2006

The reaction of 2-amino-4-(substituted amino)-6-isopropenyl-1,3,5-triazines (methacryloguanamine) with formaldehyde gave several new monomers having hydroxymethyl groups in satisfactory yields. These monomers were easily converted into the corresponding alkyl ethers with methanol. Their melting points and solubilities were affected considerably by the species and the number of substituted groups. Especially, tetrakis(hydroxymethyl)methacryloguanamine and its methoxymethyl derivative were readily soluble in water and nonpolar solvents, respectively. The former was polymerized and crosslinked smoothly to yield a insoluble polymer. Copolymerization of the latter with methyl methacrylate, however, gave soluble polymers, formed flexible and tough films. Similarly, the reactive polymers were prepared from polymers containing guanamine structure by hydroxymethylation followed by etherification.
Persistent Nitrogen-centered Free Radicals, N-(Arylthio)-3,5-di-t-butylphenylaminyls. The Reactions with Phenols
Authors: Miura Yozo , Yamamoto Akifumi , Kinoshita Masayoshi
Published: July 2006

The reactions of N-(4-chlorophenylthio)-3,5-di-t-butylphenylaminyl (1) with phenols were examined. The reaction with 2,6-dimethyl- and di-t-butylphenols gave 2,6-dimethyl- and di-t-butyl-p-benzoquinone 3,5-di-t-butylphenylimines, respectively, in excellent yields. In the reaction with unsubstituted phenol, 2,6-bis[N-(4-chlorophenylthio)-3,5-di-t-butylphenylamino]-p-benzoquinone 3,5-di-t-butylphenylimine was obtained in 32–56% yields. On the other hand, the reactions with p-substituted phenols such as p-cresol, p-t-butylphenol, and 2,4-di-t-butylphenol, gave phenols which were substituted by 1 at the ortho-positions to the OH group. Furthermore, the reactions with o-cresol, 2,6-di-t-butyl-p-cresol, and 1-naphthol were examined. On the basis of these results, plausible mechanisms for the reactions are presented.
A New Synthesis of Triphenodithiazines and Triphenodithiazinequinoes
Authors: Nishi Hisao , Hatada Yuichi , Kitahara Kiyoshi
Published: July 2006

A new class of 6,13-bis(arylamino)triphenodithiazines has been synthesized by condensing chloranil with arylamines followed by the reaction of the resulting 2,5-bis(arylamino)-3,6-dichloro-1,4-benzoquinones with zinc 2-aminobenzenthiolates (4) in the presence of a base in Methyl Cellosolve. On the other hand, the reaction of 2,5-dianilino-3,6-dichloro-1,4-benzoquinone (3a) with 4 in DMF proceeded unexpectedly to give 7,14-dihydro-6,13-triphenodithiazinequinones by eliminating the anilino groups of 3a.