bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Structure of Trimethylphosphine-boron Trichloride by Gas Electron Diffraction
Authors: Iijima Kinya , Shibata Shuzo
Published: July 2006

The molecular structure of trimethylphosphine-boron trichloride (CH3)3P·BCl3 has been determined from gas electron-diffraction data. The structure parameters and uncertainties are rg(P–B)=1.941(16) Å, rg(B–Cl)=1.851(7) Å, rg(C–P)=1.800(4) Å, rg(C–H)=1.099(5) Å, rg(Cl…Cl)=3.022(5) Å, and rg(C…C)=2.936(10) Å. The potential barrier about the P–B axis is 3.8±0.7 kcal mol−1 in the gas phase. The data show that the molecular structure in the gas phase is nearly equal to that in the solid phase.
The Reaction of Recoil 35S Atoms with Organic Compounds. II. The Insertion Reaction of Recoil 35S Atoms into the C–H and C–C Bonds in Ethane in the Gas Phase
Authors: Niisawa Kazuhiro , Taki Ko
Published: July 2006

The sulfur atoms produced by the nuclear transformation of 35Cl(n,p)35S were allowed to react with gaseous ethane in the presence or in the absence of radical scavengers. The products were hydrogen sulfide, methanethiol, ethanethiol, dimethyl sulfide, and other sulfur-containing compounds. The yield of the C–H insertion product (ethanethiol) increased upon the addition of a small amount of the scavenger and then decreased with an increase in the amount of the scavenger to give a constant value, but the yield of the C–C insertion product (dimethyl sulfide) did not vary. The increase in the ethanethiol yield at low concentrations of the scavenger may be ascribed to a protective effect by the scavenger. By the addition of ethanethiol before thermal-neutron irradiation, the yield of ethanethiol was increased, but that of dimethyl sulfide was not increased, therefore the primary yield of ethanethiol could be determined. The spin state of the reactive sulfur atoms in the thermalinsertion reaction was also estimated to be the 3P state upon the addition of COS and C2H4.
Heteropolyanions of Methylarsonate and Dimethylarsinate: The Crystal Structures of Guanidinium Hexamolybdomethylarsonate Hexahydrate, (CN3H6)2[CH3AsMo6O21(H2O)6]·6H2O and Guanidinium Tetramolybdodimethylarsinate Monohydrate, (CN3H6)2[(CH3)2AsMo4O14(OH)]·H2O
Authors: Matsumoto Kazuko Y
Published: July 2006

The crystal and molecular structures of polymolybdo complexes of methylarsonate and dimethylarsinate have been determined by the X-ray diffraction technique. The crystal of (CN3H6)2[CH3AsMo6O21(H2O)6]·6H2O is trigonal, with the space group R3 and the cell dimensions of a=9.653(6) Å, α=87.01(15)°, and Z=l. The anion is an assemblage of six MoO6 octahedra and a tetrahedral CH3AsO3 group. The six MoO6 octahedra constitute a ring with alternate edge- and corner-sharing, and the tetrahedral CH3AsO3 group joins the anion, with its three oxygen atoms shared with the ring. Each molybdenum atom has two terminal oxygen atoms in the cis position and is coordinated by one water molecule. (CN3H6)2[(CH3)2AsMo4O14(OH)]·H2O crystallizes in the space group P21/c of the monoclinic system, with the cell dimensions of a=8.530(5), b=8.532(4), c=30.121(15) Å, β=95.50(16)°, and Z=4. The Mo4O14(OH) moiety in the [(CH3)2AsMo4O14(OH)]2− anion is formed with two face- and two edge-sharings of MoO6 octahedra into an almost flat rectangle. The oxygen atom located at the center of the anion and bonded to all the four molybdenum atoms is protonated and is, in fact, a hydroxyl group.
The Crystal Structure of Ethylenediaminebis[2-(aminomethyl)pyridine]-cobalt(III) Hexacyanocobaltate(III) Dihydrate
Authors: Sekizaki Masao , Utsuno Shunji
Published: July 2006

The crystal structure of ethylenediaminebis[2-(aminomethyl)pyridine]cobalt(III) hexacyanocobaltate(III) dihydrate, [Co(H2NCH2CH2NH2)(C5H4NCH2NH2)2][Co(CN)6]·2H2O, has been determined by the X-ray diffraction method and subsequently refined by a block-diagonal least-squares method to give R=0.050 for 5238 non-zero reflections. The crystals are triclinic with a space group P\bar1; a=9.034(2), b=17.267(2), c=8.395(2) Å, α=87.1(3), β=96.2(3), γ=104.6(3)°, and Z=2. The crystal is ionic, comprising the [Co(H2NCH2CH2NH2)(C5H4NCH2NH2)2]3+ cation and the [Co(CN)6]3− anion. The complex cation is a slightly distorted octahedron with three five-membered chelate rings in a lel conformation. The two pyridine nitrogen atoms occupy trans positions. Thus, the cation has an approximate twofold axis of rotation. The anion is also a distorted octahedron, with the coordination of CN− through the carbon atom. The cobalt atoms of the anions occupy the special positions. Two cations in the unit cell are connected by these anions through hydrogen bonds to form a three-dimensional network typical of an ionic crystal.
Photolysis of Water on Illuminated Strontium Titanium Trioxide
Authors: Yoneyama Hiroshi , Koizumi Masashi , Tamura Hideo
Published: July 2006

The photolysis of water was demonstrated in an illuminated strontium titanium trioxide suspension. Electrochemical mechanism takes place in the decomposition reaction.
Semiconducting Bis(dialkyldithiocarbamato)copper(III) Cation–TCNQ Radical Anion and –Bis(1,2-dicyano-1,2-ethylenedithiolato)nickel(III) Anion Salts: [Cu(S2CNR2)2]+TCNQ\ewdot and [Cu(S2CNR2)2]+-[Ni(S2C2(CN)2)2]− (R=Et, n-Pr, and n-Bu)
Authors: Yumoto Yoshiji , Tanaka Toshio
Published: July 2006

The title salts were synthesized. Segregated columnar structures of the salts are suggested from their electronic spectra and electrical resistivities; 104–105Ω cm range at 25 °C with activation energies of 0.24–0.33 eV as compact samples.
A Catalytic Effect of Amines on the Reaction of α-Toluenethiol with N,N′-Thiodiphthalimide
Authors: Abe Yasuo , Horii Toyokazu , Kawamura Shun-ichi , Nakabayashi Takeshige
Published: July 2006

In the presence of catalytic amounts of several amines, N,N′-thiodiphthalimide has been allowed to react with α-toluenethiol in benzene and dichloromethane giving N-(benzyldithio)phthalimide. N-(Benzyldithio)phthalimide has been obtained in excellent yields with 2,4-or 2,6-lutidine as the catalyst in benzene.
Reduction of Alloxan by Cyanide Ion. Isolation of Alloxan Radical Anion Salts and Alloxantin
Authors: Endo Takeshi , Kudo Akira , Okawara Makoto
Published: July 2006

Potassium or pyridinium salts of alloxan radical anion were isolated by the one-electron reduction of alloxan monohydrate with potassium cyanide or 1-benzyl 4-cyano-1,4-dihydronicotinamide at room temperature, respectively.
The Rate Constants for H and D-Atom Additions to O2, NO, Acetylene, and 1,3-Butadiene
Authors: Ishikawa Yo-ichi , Sugawara Ko-ichi , Sato Shin
Published: July 2006

Pulse radiolysis has been combined with Lyman-α absorption spectroscopy for the measurement of absolute rate constants for the addition reactions of H and D-atoms to oxygen, nitrogen monoxide, acetylene-d0 and -d2, and 1,3-butadiene at room temperature. The rate constants obtained with O2 and NO were in good agreement with the results previously reported and no H/D isotope effect was found. With acetylenes and 1,3-butadiene, the following rate constants were obtained (units of cm3 molecule−1 s−1): (3.8±0.4)×10−13 for H+C2H2; (2.6±0.2)×10−13 for D+C2H2; (3.8±0.2)×10−13 for H+C2D2; (2.5±0.2)×10−13 for D+C2D2; (8.5±1.5)×10−12 for H+1,3-C4H6; (7.5±0.6)×10−12 for D+1,3-C4H6. These results are compared to previous studies, and the H/D isotope effect discussed.
The Thermal Gas-phase Decomposition of Vinyl Bromide
Authors: Saito Ko , Yokubo Teiji , Fuse Tohru , Tahara Hiroyuki , Kondo Osamu , Higashihara Tetsuo , Murakami Ichiro
Published: July 2006

The thermal gas-phase decomposition of vinyl bromide in Ar has been studied behind reflected shock waves over the temperature range between 1300 and 2000 K and the density range of 5.2×10−6–3.8×10−5 mol cm−3 by monitoring the UV absorption of C2H3Br and the IR emission of HBr. The decomposition proceeds via the molecular elimination of HBr, and the unimolecular process is in the low-pressure region under the present experimental conditions. The low-pressure-limit rate constant was obtained as

k 2nd=1013.98±0.21exp{−(41.5±1.6 kcal mol−1)⁄RT} cm3 mol−1 s−1.

The collision efficiency factor, βc, was obtained as about 2×10−4, considerably lower than that of vinyl chloride.
An X-Ray Diffraction Study on the Structures of Bis- and Tris(ethylenediamine)zinc(II) Complexes in Solution
Authors: Fujita Tadao , Yamaguchi Toshio , Ohtaki Hitoshi
Published: July 2006

An X-ray diffraction study has been carried out at 25 °C for aqueous ethylenediamine(en) solutions of zinc(II) nitrate, the mole ratios, en/Zn, in the solutions being 2.252 and 3.204. In the former solution bis(ethylenediamine)zinc(II) complex existed as the main species, while in the latter tris(ethylenediamine)zinc(II) complex was predominant. The X-ray scattering data of the solution containing the bis-complex showed that four nitrogen atoms within the two ethylenediamine molecules were tetrahedrally coordinated to the zinc(II) ion at a distance of 2.131 (9) Å. The nonbonding Zn…C distance was also determined to be 2.89(2) Å. In the tris-complex in which the zinc(II) ion was coordinated with the six nitrogen atoms, the Zn–N and Zn…C distances were 2.276(5) Å and 3.00(1) Å, respectively. Raman spectra of the solutions supported the structures of the complexes.
Kinetics of the Ligand Substitution Reactions of the Copper(II) Chelates of 1-(2-Pyridylazo)-2-naphthol Analogs with EDTA
Authors: Wada Hiroko , Nakagawa Genkichi
Published: July 2006

The rates of the substitution reactions of copper(II) chelates of metallochromic indicators such as 1-(2-pyridylazo)-2-naphthol (PAN, Hpan), 1-(2-thiazolylazo)-2-naphthol (TAN, Htan), 2-(2-pyridylazo)-4-methylphenol (PAC, Hpac), 2-(2-thiazolylazo)-4-methylphenol (TAC, Htac), 4-(2-pyridylazo)resorsinol (PAR, H2par), and 4-(2-thiazolylazo)resorcinol (TAR, H2tar) were determined. The rate laws can be written as −\fracd[CuL]dt=kedta′CuL [CuL][edta′] for PAN, TAN, PAC, and TAC in the pH range of 4 to 6.5, and −\fracd[(CuL)′]dt=(kedta′CuL[CuL]+kedta′CuHL[CuHL])[edta′], where [(CuL)′]=[CuL]+[CuHL], for PAR and TAR in the pH range of 3.5 to 6.5. In the pH range lower than 3.5 the laws are written as −\fracd[CuL]dt=(kedta′CuL[edta′]+kHCuL[H])[CuL] for PAN, and as −\fracd[CuHL]dt=(kedta′CuHL[edta′]+kHCuHL[H])[CuHL] for PAR and TAR. The rate constants (μ=0.1, 25 °C, at dioxane 2 vol% or 5 vol% (PAN and TAN) (dm3 mol−1 s−1)) are kedta′Cu(tan)=2.8×104, kedta′Cu(pac)=8.0×104, kedta′Cu(tac)=4×106, kedta′Cu(par)=2.0×103, kedta′Cu(tar)=6.3×104, kedta′Cu(Hpar)=1.2×104, kedta′Cu(Htar)=7.9×105, kHCu(pan)=6.5×10, kHCu(Hpar)=6.6×102, and kHCu(Htar)=1.2×104. The rate constants, kedta′CuL are inversely proportional to the basicities of the donor atoms of indicators. Thus, the rate of color change of thiazolylazo compound is larger than that of corresponding pyridylazo compound in the chelatometry of copper(II).
Alkylation of Bromocyclopropanes and Bromoarenes by Means of Dibutylcopperlithium and Alkyl Halides
Authors: Hiyama Tamejiro , Yamamoto Hajime , Nishio Koji , Kitatani Katuzi , Nozaki Hitosi
Published: July 2006

Treatment of bromocyclopropanes with excess dibutylcopperlithium in tetrahydrofuran at −48 °C gives the respective organocopper intermediates which upon quenching with excess alkyl halides afford alkylated cyclo-propanes with retention of the configuration. This process is applied to the synthesis of methyl cascarillate. Bromoarenes are also reduced with dibutylcopperlithium and allylarenes are prepared therefrom.
Cell Design for Simultaneous Measurement of Photoacoustic and Fluorescence Spectra
Authors: Kato Kenji , Sugitani Yoshinori
Published: July 2006

A simple and convenient sample cell has been designed for the simultaneous detection of photoacoustic and fluorescent signals. Spectral measurement of natural zircon, using the designed cell, is presented.
The Singlet-excitation-energy Migration in an Amorphous-state Film of 1,3-Di(9-carbazolyl)propane
Authors: Itaya Akira , Okamoto Ken-ichi , Kusabayashi Shigekazu
Published: July 2006

The singlet-excitation-energy migration in an amorphous film of 1,3-di(9-carbazolyl)propane(DCzP(a)) was studied by means of a fluorescene-quenching experiment. The results were compared with those of amorphous poly(9-vinylcarbazole)(PVCz) and poly[2-(9-carbazolyl)ethyl vinyl ether] (PCzEVE) films. The numbers of carbazolyl chromophores covered by a singlet exciton during the lifetime were in the following order: DCzP(a)>PCzEVE>PVCz.
Syntheses and Electrical Properties of α,α,α′,α′-Tetracyanodiphenoquinodimethane Complexes
Authors: Morinaga Minoru , Nogami Takashi , Mikawa Hiroshi
Published: July 2006

Two charge-transfer complexes of α,α,α′,α′-tetracyanodiphenoquinodimethane (TCNDQ), i.e., N-methylphenazinium (NMP)–TCNDQ, and N-methylquinolinium (NMQ)–TCNDQ, were synthesized. The electrical resistivities with pressed pellet samples were 7.1×108 Ω cm for NMP+TCNDQ− and 6.9×107 Ω cm for NMQ+TCNDQ−; they are thus much less conductive than the corresponding TCNQ, complexes.
Synthesis of t-2, t-3-Dicarboxy-r-1-cyclopentylacetic Acid
Authors: Obara Heitaro , Kimura Hiroshi , Suzuki Masanobu , Yamada Shigenobu
Published: July 2006

One of the four stereoisomers of 2,3-dicarboxycyclopentylacetic acid, the t-2, t-3, r-1-isomer, has been synthesized from (1RS, 5SR, 6SR)-6-ethoxycarbonylmethyl-3-oxabicyclo[3.3.0]octan-7-one in five steps.
Solution Equilibria of Histidine-containing Ternary Amino Acid–Copper(II) Complexes in 20 v/v% Dioxane–Water
Authors: Yamauchi Osamu , Takaba Toshikazu , Sakurai Takeshi
Published: July 2006

Equilibria of histidine-containing ternary amino acid–copper(II) systems have been investigated by potentiometric titration in acid–neutral solution in 20 v/v% dioxane–water containing 0.1 M KNO3 (1 M=1 mol dm−3) at 25 °C. The stability constants of the binary complexes of histidine (his) and other amino acids (A) with a polar or a nonpolar side chain (A: serine, threonine, homoserine, asparagine, glutamine, citrulline, glycine, alanine, or valine) and the ternary complexes Cu(his)(A) have been calculated by the method of nonlinear least-squares. The overall stability constants for CuA, CuA2, and Cu(his)(A) are higher than the values reported for the corresponding complexes in water, those for Cu(his) and Cu(his)2 remaining unaffected. The stability constants (logβ1110) for Cu(his)(A) are in the range 17.4–18.0, no difference in stability being observed between the diastereomers Cu(l-his)(l-A) and Cu(d-his)(l-A). Species distribution as a function of pH reveals that Cu(his)(A) predominates in the neutral region. The stability constants have been compared with various theoretical values and found to be higher than the statistically estimated ones.
Photochemical Transformations of 1,2-Diketones and Benzhydrylamine
Authors: Mehrotra Kailash Nath , Pandey Ganesh Prasad
Published: July 2006

Photolysis of a mixture of substituted 1,2-diketones and benzhydrylamine (in 1:2 mole ratio) in benzene gave N-benzhydrylidenebenzhydrylamine, N-(diarylmethyl)benzamides, acyloins (3), N-(arylmethylene)benzhydrylamines, and benzophenone separated by fractional crystallization and column chromatography. The products have been characterised by analytical and spectral (IR, UV, and NMR) data and the structural assignments confirmed by the comparison (IR spectra and undepressed mixed mp) with authentic samples. Acyloins (3) are precursors for N-(diarylmethyl)benzamides and N-(arylmethylene)benzhydrylamines. A tentative mechanistic route for the formation of products has been suggested.
Preparation of New Nitrogen-bridged Heterocycles. A Facile Synthetic Method of Pyrano[2,3-b]indolizinone Derivatives
Authors: Kakehi Akikazu , Ito Suketaka , Nakanishi Kazunori , Watanabe Kozo , Kitagawa Masahiko
Published: July 2006

Pyrano[2,3-b]indolizinone derivatives were formed in 18–98% yields by the reactions of 3-[bis(alkylthio)methylene]-2,3-dihydroindolizin-2-ones with various acetates in the presence of alkali. Dihydroindolizinones were readily obtained by the alkaline treatment of 1-[2,2-bis(alkylthio)-1-ethoxycarbonylvinyl]-2-ethylpyridinium iodides and -2-methylpyridinium iodides or by the S-alkylation of 3-[(alkylthio)mercaptomethylene]-1-phenyl-2,3-dihydroindolizin-2-ones with alkyliodides.
The Synthesis of 2-Imino-2,3-dihydro-1,3,4-selenadiazole Derivatives
Authors: Takahashi Masahiko , Kurosawa Michiyoshi
Published: July 2006

The reaction of phenacyl selenocyanate with arenediazonium chlorides afforded 3-aryl-5-benzoyl-2-imino-2,3-dihydro-1,3,4-selenadiazoles, which were then acetylated and nitrosated to give the corresponding 2-acetylimino and 2-nitrosoimino derivatives respectively.
High Temperature Hard Anodizing with Tartaric Acid–Oxalic Acid–Triethanolamine Bath
Authors: Fukuda Yoshio , Fukushima Toshiro
Published: July 2006

Tartaric acid does not produce uniform films on A6063 alloy (Al–Mg–Si). Uniform films are formed when oxalic acid is added to the tartaric acid bath, but hardness above Hv 400 cannot be obtained at a voltage below 100 V. When 1 mol dm−3 tartaric acid–0.4–0.6 mol dm−3 oxalic acid baths were adjusted with triethanolamine (0.26–0.54 mol dm−3) to pH 1.00 and 1.25, crack-free films with hardness above Hv 430 were formed at 40 °C in the range 65–85 V. The hardness of the film is independent of the anion content of the film, increasing with increase in the thickness of cell wall and lowering in porosity.
Studies of Spin Labeled Sodium Dodecyl Sulfate. I. Synthesis and Properties
Authors: Yamaguchi Takeo , Yamauchi Akira , Kimoto Eiji , Kimizuka Hideo
Published: July 2006

Nitroxide spin labeled surfactant, sodium salt of 2-ethyl-2-[9-(hydroxysulfonyloxy)nonyl]-4,4-dimethyloxazolidin-3-yloxyl, was synthesized and some properties of the compound were studied by means of ESR and conductivity measurements. From conductivity measurements it was found that the critical micelle concentration of the compound was 21.6 mmol kg−1 at 25.0±0.1 °C and the micelle consisted of a small number of labeled surfactant ions. The ESR spectra of the labeled surfactant were measured as a function of concentration and temperature. These spectra showed a typical pattern interpreted in terms of spin exchange. Regarding spin exchange as chemical reaction, second order rate constant was determined from the analysis of line width and compared with the values obtained by diffusion controlled model.
Structures and Properties of 5-Substituted Cytosines. II. The Crystal Structure of 5-Methylcytosine Hemihydrate
Authors: Takenaka Akio , Kato Masuhiro , Sasada Yoshio
Published: July 2006

The crystal structure of 5-methylcytosine hemihydrate has been determined by an X-ray analysis to investigate the substitution effect on the cytosine moiety. The space group is C2/c, with unit-cell dimensions a=17.832(4), b=8.261(2), c=10.641(3) Å, β=125.12(1)°, and Z=8. The hydrogen bonding scheme is quite different from that of cytosine, its monohydrate, 5-bromocytosine, and its dioxane hemi-solvate. This is ascribed to the packing effect of the methyl group. A comparison with the cytosine structure indicates some deviations in bond lengths and angles, which are due to the steric and electronic effects caused by methylation. The similar values of the C(2)–N(3)–C(4) angle in cytosine and 5-methylcytosine can be related to a resemblance of their pKa values.
Pseudo-sugars. 5. Synthesis of Dl-Validatol and Dl-Deoxyvalidatol, and Their Epimers
Authors: Ogawa Seiichiro , Toyokuni Tatsushi , Omata Masaji , Chida Noritaka , Suami Tetsuo
Published: July 2006

New cyclitols, validatol and deoxyvalidatol, derived by hydrogenolysis of antibiotic validamycin A, were synthesized as the racemates from readily available tri-O-acetyl-(1,3/2,4,6)-4-bromo-6-bromomethyl-1,2,3-cyclohexanetriol.
The Acid-catalyzed Reaction of the 2-Oxabicyclo[4.1.0]hept-3-en-5-one System: Isomerization from Homo-4-pyrones into 2-Furylacetone Derivatives
Authors: Yamaoka Hiroshi , Mishima Ikuhiro , Miyamoto Mitsuko , Hanafusa Terukiyo
Published: July 2006

The monocyclopropanation of 4-pyrones with dimethyloxosulfonium methylide, using a dimethyl sulfoxide hexamethylphosphoric triamide medium in place of neat dimethyl sulfoxide, gave homo-4-pyrone derivatives, which were then rearranged into the 2-furylacetone derivatives, along with hydra ted triketones or the dehydrated naphtho[2,1-b]furan derivative, by means of strong acid catalysis at room temperature.
An X-Ray Photoelectron Spectroscopic Study of Several Hydroxy Azo Compounds
Authors: Yoshida Tooru
Published: July 2006

The tautomerism of several solid hydroxy azo compounds has been examined by X-ray photoelectron spectroscopy. It has been found that the proportion of enol and keto tautomers may be readily estimated from the relative intensities of the two peaks in the O(1s) electron spectrum which corresponds to the protonated and deprotonated oxygen atoms. The resonance structures of the sodium salt of 1-phenylazo-2-naphthol and 5-phenylazo-8-quinolinol have been discussed on the basis of the N(1s) and O(1s) electron binding energies.
The Isomerization of 1-Butene over the ReO3 Catalyst
Authors: Yamaguchi Tsutomu , Tsuda Nobuo , Tanabe Kozo
Published: July 2006

The catalytic activity of the single crystals of ReO3 was examined by using the isomerization of 1-butene as a test reaction. The results indicate that there are two types of surfaces: one is sensitive to the introduction of hydrogen, and the other is not.
The Polarographic Reduction of Various Ammonium Cations in Hexamethylphosphoric Triamide
Authors: Sakura Yachiko , Nakata Ryuji , Fujinaga Taitiro
Published: July 2006

The reductions of tetradecylammonium, tetradodecylammonium, benzyldimethyl(tetradecyl)ammonium, and ammonium ions were examined in hexamethylphosphoric triamide. The reduction behavior of these ions was found to be a function of the size and the charge of the cation of the supporting electrolytes.
Selective Decarboxylation of 1-Methyl-4,5-imidazoledicarboxylic Acid
Authors: Takahashi Kazuyuki , Mitsuhashi Keiryo
Published: July 2006

The selective decarboxylation of 1-methyl-4,5-imidazoledicarboxylic acid was carried out in various solvents. 1-Methyl-5-imidazolecarboxylic acid was obtained by heating in acetic or propionic anhydride, whereas 1-methyl-4-imidazolecarboxylic acid was obtained in N,N′-dimethylformamide, N,N′-dimethylacetamide, or N-methylpyrrolidone or by pyrolysis. The reaction mechanism is discussed.
Asymmetric Synthesis of Aspartic Acid by Hydrogenation of Optically Active 1,4-Oxazine Derivative
Authors: Tamura Minoru , Harada Kaoru
Published: July 2006

The asymmetric hydrogenation of an optically active heterocyclic compound, (R)-3-methoxycar-bonylmethylene-5-phenyl-3,4,5,6-tetrahydro- 2H-1,4-oxazin-2-one(2), was studied. The compound 2 was hydrogenated with several catalysts, and was converted into optically active aspartic acid. The configuration of the resulting aspartic acid proved to be (S), and the optical yield was in the range 19–170%.
Coordinative Role of Alkali Cations in Organic Reactions. IV. Benzoylation, Phenacylation, and Benzylation of Kojic Acid
Authors: Poonia Narinder S , Arora Ashok k , Bajaj Amritlal V
Published: July 2006

Using kojic acid (5-hydroxy-2-hydroxymethyl-4-pyrone) as a substrate, the title reactions were carried out with various alkali metal hydroxides. Whereas phenacylation (with KOH or NaOH) and benzylation (with KOH, NaOH, or LiOH) are possible only on the phenolic hydroxyl, benzoylation can be carried out selectively as well as collectively on both the hydroxyl group (in 80% aq EtOH). The results were discussed in terms of the interactive role of alkali cations with the substrate.
The Thermal Cycloaddition of Dispiro[2.2.2.2]deca-4,9-diene to Isolated Carbon-Carbon Multiple Bonds
Authors: Shibata Tohru , Tsuji Takashi , Nishida Shinya
Published: July 2006

The cycloadditions of dispiro[2.2.2.2]deca-4,9-diene (1) to isolated carbon-carbon multiple bonds have proceeded in two different modes, giving dispiro[2.2.4.2]dodeca-4,11-diene and tricyclo[6.4.0.03,6]dodeca-2,7-diene derivatives. Mono- and 1,2-disubstituted olefins and acetylenes gave the former adducts, whereas 1,1-disubstituted olefins gave the latter, as the major products. Evidence for the intermediacy of biradicals is provided. The observed difference in the mode of the cycloaddition is explained in terms of the stereoelectronic and/or steric effects in the transition state for the cyclization of the intermediate. The addition of 1 to tetracyanoethylene (TCNE) in wet acetone has proceeded via a zwitterionic intermediate(s), giving a 1:1:1 adduct of 1, TCNE, and water.
Vinyl Polymerization. 393. Radical Polymerization of Vinyl Monomer Initiated by Aliphatic Aldehyde
Authors: Ouchi Tatsuro , Murayama Noriyuki , Imoto Minoru
Published: July 2006

The homogeneous polymerization of methyl methacrylate (MMA) initiated with butanal (PrCHO), pentanal (BuCHO), and hexanal (C5H11CHO) was carried out in dioxane. It was found that the rate of polymerization can be expressed by Rp=k[MMA]1.5[RCHO]0.5. The polymerization was confirmed to proceed through a radical mechanism. Overall activation energies, when PrCHO, BuCHO, and C5H11CHO were used, were estimated to be 37.2, 36.3, and 36.0 kJ mol−1, respectively. Instead of MMA, many kinds of vinyl monomer were applied. Various methacrylates and acrylates could be polymerized, but not styrene and acrylonitrile. The effect of solvent on the rate of polymerization was studied.
A Valence Structural Study of the Electronic Structure of S2N2
Authors: Fujimoto Hiroshi , Yokoyama Takashi
Published: July 2006

A valence structural analysis of S2N2 has been performed within the framework of the INDO approximation. The fractional double-bond character has been suggested to be the consequence of the interaction between nonionic and ionic structures, counterbalanced in part by the overlap repulsions in the ring.
SOLUBILITIES OF METALLIC CYANIDES
Authors: Masaki Kosaku
Published: July 2006

(1) Ionic conductance of CN− was determined.

(2) The activities, i.e. solubilities of cyanides of cadmium, zinc, nickel, and cobalt were calculated.
ON THE ESSENTIAL OIL OF TAIWANIA CEDAR
Authors: Kafuku Kinzo , Kato Ryo
Published: July 2006

1. The wooden chips of Taiwania Cryptomerioides, Hayata, gives on steam distillation 0.23% of an oil, consisting chiefly of sesquiterpene and sesquiterpene alcohol.

2. The sesquiterpenes in the oil are chiefly cadinene, with a little humulene and caryophyllene.

3. From the cadinene, a new oxidation product C12H22O2 (m.p.=142°–143°) was obtained.

4. The sesquiterpene alcohol in the oil, to which the authors suggest the name “taiwanol,” closely resembles cadinol of Semmler and Jonas. From cadinol no crystalline phenyl urethane could be obtained, but in case of taiwanol, it affords a crystalline pheyl urethane melting at 134°–135°, and furthermore, it gives a neutral oxidation product (m.p. 170°) if oxidized with permanganate in acetone solution.
Enzymatic Reactions in Aqueous-Organic Media. XVII. Optical Resolution of Amino Acid Esters by Enzymatic Hydrolysis in Organic Solvents
Authors: Tomiuchi Yoshimasa , Ohshima Kouji , Kise Hideo
Published: July 2006

Enantiospecific hydrolysis of Dl-tyrosine ethyl ester was carried out using α-chymotrypsin (CT) as a catalyst in organic solvents, and l-tyrosine was obtained with high optical purity. Activity and enantiospecificity of CT were found to be greatly altered by water content in the reaction media, and generally high enantiospecificity was observed at low water contents. Many of natural and unnatural amino acid esters were resolved by hydrolysis in organic solvents using CT, subtilisin Carlsberg, or subtilisin BPN′ as catalysts.
Improved Synthetic Methods of Firefly Luciferin Derivatives for Use in Bioluminescent Analysis of Hydrolytic Enzymes; Carboxylic Esterase and Alkaline Phosphatase
Authors: Toya Yoshiaki , Takagi Masaharu , Kondo Tadao , Nakata Hisao , Isobe Minoru , Goto Toshio
Published: July 2006

Improved synthetic methods of firefly luciferin derivatives, such as 6-O-alkanoylluciferins and 6-O-phosphonoluciferin, are described. These derivatives proved to be useful as substrates for the bioluminescent assay of hydrolytic enzymes such as carboxylic esterase and alkaline phosphatase. The synthetic methods previously reported gave fairly low yields because of direct derivatization of unstable luciferin itself and are difficult to be applied to large-scale synthesis because of unavoidable HPLC purification. We first modified the hydroxyl group of 2-cyano-6-hydroxybenzothiazole and then condensed the resulting stable products with d-cysteine to give the appropriate derivatives in good yields without HPLC purification. 6-O-Phosphonoluciferin was unstable as free acid form but stable as its sodium salt.
A Novel Ring Transformation of 3a,5,6a-Triaryl-3,3a-dihydro-2H-furo[3,2-b]pyrrole-2,6(6aH)-diones into 3-Aroyl-2,5-diarylpyrrole Derivatives
Authors: Mataka Shuntaro , Suzuki Hiroshi , Uehara Kazuko , Tashiro Masashi
Published: July 2006

Under aqueous conditions dimethylamine, piperidine, and triethylamine catalyzed the ring-transformation reaction of triaryl-2H-furo[3,2-b]pyrrole-2,6(6aH)-diones (1), giving benzoylhydroxy-1-pyrrolines 2, which afforded benzoylpyrroles 3 upon acid-catalyzed dehydration. The lactone-ring-opened amides 6 were obtained in the reaction of 1 with methylamine, pyrrolidine, piperidine, and perhydroazepine at room temperature in ethanol. Pyrrolidine and piperidine produced pyrrolecarboxamides 7 when the reaction was carried out in aqueous ethanol under reflux. Amides 6 afforded 7 upon treatment with the amines under the above-mentioned conditions.
Synthetic Study on Lipoteichoic Acid of Gram Positive Bacteria. I. Synthesis of Proposed Fundamental Structure of Streptococcus pyogenes Lipoteichoic Acid
Authors: Fukase Koichi , Matsumoto Takahiro , Ito Naoko , Yoshimura Takuya , Kotani Shozo , Kusumoto Shoichi
Published: July 2006

Synthetic study on Streptococcus pyogenes lipoteichoic acid (LTA) which was reported to induce nontoxic TNF is described. The proposed fundamental structure of LTA was constructed by coupling of the glycolipid part with the poly(glycerol phosphate) (PGP) part and subsequent deprotection. The PGP part was prepared by a simple repeating procedure using the phosphoramidite method for the construction of 1,3-phosphodiester-linkage. The glycolipid part was synthesized using appropriate glycosyl fluorides as donors, where the p-nitrobenzyl group was successfully applied to temporary protection of a hydroxyl function.
Spectroscopic Analysis and Geometry Assignment of the Minimum Energy Conformations of 2-Phenoxypyridines and Diphenyl Ethers
Authors: Uno Bunji , Kawakita Toshio , Kano Kenji , Ezumi Kiyoshi , Kubota Tanekazu
Published: July 2006

The conformational preferences of 2-phenoxypyridines and diphenyl ethers were determined by minimum-energy optimization using the method of ab initio molecular orbital calculations with STO-3G basis sets, and by spectral measurements and their analyses based on CNDO/S-CI calculations. The o,o-disubstituents of the methyl groups to diphenyl ether and 2-phenoxypyridine, i.e., 1,3-dimethyl-2-phenoxybenzene and 2-(2,6-xylyloxy)pyridine, respectively, prefer a symmetric skew conformation. The conformation of unsubstituted diphenyl ether (1a) is nonrigid with a dihedral angle, about 90°, of two phenyl rings at room temperature. Spectral observations at 77 K have provided evidence for this conclusion. On the other hand, 2-phenoxypyridine (2a) has been found to possess sufficient internal barriers to stabilize the two aromatic rings in a skew form. The weak nuclear repulsion, compared with that in 1a, would mainly contribute to stability in the skew form. The characteristic 1La band observed for 2a is attributed to the configuration interaction of the n–π* excited state to the 1La states in the skew form.
Hydrates of Organic Compounds. XVII. The Effect of Cations on the Formation of Hydrates of Poly(tetraisopentylammonium acrylate)
Authors: Nakayama Haruo , Yamada Ryoichi
Published: July 2006

A thermal analytic method using a differential scanning calorimeter was applied to binary mixtures of water with a series of poly(tetraisopentylammonium acrylates) whose cation was partially substituted by such cations as Na+, (n-C3H7)4N+, and (n-C4H9)4N+ (Cx[(i-C5H11)4N]1−xPA; C=Na, (n-C3H7)4N, and (n-C4H9)4N; x = 0.1–0.9; PA=one unit of a polyacrylate anion). It was found that (1) when C=Na, the formation of a hydrate solid is possible, even in a system of x = 0.9, though both the dissolution temperatures and the amounts of heat absorbed to melt the hydrate solid decreased with increasing x; (2) the effect of the (n-C3H7)4N+ ion was essentially similar to that of the Na+ ion, except that the temperature at which the ice phase began to melt decreased pronouncedly with increasing x; and (3) in the case of the [(n-C4H9)4N]x[(i-C5H11)4N]1−xPA system it was concluded that the solid phase was essentially a (i-C5H11)4NPA hydrate when x was smaller than about 0.4, a (n-C4H9)4NPA hydrate when x was larger than about 0.7 and some intermediate hydrate phase when x was around 0.5.
Chemical State Analysis of Sn–Sb–O Solid Surfaces by Auger Electron Spectroscopy: Differentiation of Sb(III) and Sb(V)
Authors: Komiyama Masaharu , Yoshii Mikio , Ogino Yoshisada , Ono Takehiko
Published: July 2006

Chemical state analysis of Sn–Sb–O solid surfaces was performed by means of Auger electron spectroscopy (AES). Differential and numerically integrated AE spectra were curve-fitted using standard spectra obtained from pure substances. The fitting revealed, for the first time, the possibility of differentiating two antimony oxide components, Sb(III) and Sb(V), by AES. Using the AE spectral parameters obtained for these two chemical states, a correlation between the Sb AE peak positions and the average Sb oxidation number was constructed and it was applied for the determination of the average Sb oxidation state in Sn–Sb mixed oxide systems.
Synthetic and Spectroscopic Studies of Some Lanthanoid Metal Complexes of 2-Acetylpyridine Nicotinoylhydrazone
Authors: Rao Thatavarthi Ramalingeswar , Srivastava Madhu Rani
Published: July 2006

Lanthanoid metal (Ln) complexes of the types, [Ln(Hapnh)2Cl2]Cl·nH2O and [Ln(apnh)3] have been prepared by reacting 2-acetylpyridine nicotinoylhydrazone (abbreviated to Hapnh) with hydrated lanthanoid metal chlorides. These complexes have been characterized by elemental analysis, molar conductance, magnetic susceptibility, electronic, infrared, NMR, and mass spectral studies. Various spectral parameters have been calculated from the electronic spectra of praseodymium(III), neodymium(III), samarium(III), and dysprosium(III) complexes while the neodymium(III) complexes have been subjected to detailed investigations with respect to the hypersensitive band profile and its oscillator strength’s dependence on temperature and pH. On the basis of IR and NMR spectral studies, Hapnh is believed to act as a neutral tridentate species in the adduct complexes and as a uninegative tridentate one in the neutral complexes. Electrical conductance data indicate 1 : 1 electrolytic nature of the adducts and nonelectrolytic nature of the neutral complexes. On the basis of these studies, eight- and nine-coordination numbers have been proposed around Ln(III) in the [Ln(Hapnh)Cl2]Cl·nH2O and [Ln(apnh)3] respectively.
Chromatographic Separation of α-Amino Acids on Antimony(V) Phosphate–Silica Gel ‘G’ Plates from Some Synthetic Mixtures and Drug Samples
Authors: Varshney Krishna Gopal , Khan Asif Ali , Maheshwari Sanjiv Mohan , Gupta Upma
Published: July 2006

Thin-layer chromatography of α-amino acids has been performed on the antimony(V) phosphate-silica gel ‘G’ plates in different aqueous, nonaqueous, and mixed solvent systems. The study has resulted into the separation and determination of amino acids from their mixtures of the same type such as acidic from acidic, and neutral from neutral. Separations of basic amino acids from neutral and acidic amino acids have also been made. The method has been utilized for the quantitative separation of amino acids from two drugs namely ‘Astymin Forte’ and ‘Santevini (Plus)’.
A New Synthesis of 5-Substituted 3-Methyl-2-phenylthio-2-penten-5-olides
Authors: Su Huiwen , Shirai Kozo , Kumamoto Takanobu
Published: July 2006

Dienolate 11, which was produced from 3-methyl-2-phenylthio-2-butenoic acid (1) and two equivalents of LDA, reacted with aldehydes or ketones to give 5-alkyl-3-methyl-2-phenylthio-2-penten-5-olides (12) in good yields.
Crystal and Molecular Structure of 3,6-Dioxograyanotoxin I
Authors: Sato Mamoru , Katsube Yukiteru , Katai Masaaki , Katakawa Jun’ichi , Tetsumi Tadahiro
Published: July 2006

The structure of 3,6-dioxograyanotoxin I ((14R)-14-acetoxy-5,10,16-trihydroxygrayanotoxane-3,6-dione) is based on four rings with various conformations. The mutual ring junction of the molecule is the same as that of grayanotoxin I.
A Study on the Preferential Solvation of Ions in Mixed Aqueous Binary Solvent Systems Using the Scaled Particle Theory
Authors: Das Bijan
Published: July 2006

The free energies of transfer of electrolytes from water to ethylene glycol (EG)–water, 2-methoxyethanol (ME)–water and 1,2-dimethyoxyethane (DME)–water mixtures have been calculated at 25 °C using the scaled particle theory in conjunction with the Born charging equation. The predicted values of transfer free energies have been compared with the corresponding experimental values in order to gain insight into the preferential solvation of ions by water molecules in these solvent mixtures. The results from the present theoretical analysis indicate that in the cosolvent–water mixtures the ease of preferential solvation of electrolytes by water molecules increase in the order DME–water < ME–water < EG–water.
Photocurrent Response of Polyaniline Film Electrode
Authors: Komura Teruhisa , Sakabayashi Hironobu , Takahashi Koshin
Published: July 2006

The photoelectrochemical behavior of polyaniline (PA) film was investigated in acidic aqueous solutions. In the presence of NO3− in the solutions, a large cathodic photocurrent was observed at lower potentials than 0.1 V vs. Ag/AgCl. The dependence of the current quantum efficiency at −0.1 V on the wavelength of light indicated that the photocurrent was due to the absorption of ultraviolet light by the reduced film of PA. The variations in potential and spectrum of the reduced film under open-circuit conditions confirmed the transformation of PA from a reduced state to a radical cation state with the ultraviolet irradiation. In conclusion, the cathodic photocurrent at −0.1 V could result from the photo-induced oxidation of the reduced PA film by NO3−. A film resistance-potential relationship was examined in connection with the pH dependence of the photoresponse of PA. The potential giving a minimum resistance at a given pH shifted to lower potentials with increasing pH. It can be presumed that a maximum in the photocurrent–pH curve arises from the increase in the ease of oxidation of the reduced film with an increase in pH.
The Polarized Absorption Spectrum of 1,3-Diphenyl-1,2-propadiene: Interaction between Mutually Perpendicular Equivalent π-Electronic Systems
Authors: Okubo Jun , Shimazaki Takayasu , Sato Shin-ichi , Shinozaki Hiraku
Published: July 2006

The polarized UV absorption spectrum of 1,3-diphenyl-1,2-propadiene (DPA) was measured in a stretched polymer film at 101 K, and the polarization directions of the electronic absorption bands were determined. Pariser–Parr–Pople (PPP) calculations extended to three dimensions were performed, and the position, intensity, and polarization of each absorption band of DPA were obtained from the calculations. The observed 289.8 and 265.2 nm bands polarized along the longer molecular axis were assigned to the calculated S1←S0 and S3←S0 transitions, respectively, and the 237.1 nm band along the shorter molecular axis was assigned to the S4←S0 transition. The results of configuration analysis indicate that the second transitions (at 260.5 nm) of two styrenes, whose π-electronic systems are perpendicular to each other, contribute equally to the third and fourth transitions observed at 265.2 and 237.1 nm of DPA. In addition, it was clarified that the first absorption band of DPA corresponding to Parity’s forbidden transition was intensified by an increase of the ionization energy of the sp hybridized carbon atom in the allenic moiety.
Generation of the α-Sulfinyl Carbenoid from α-Chloro Sulfoxides: A New Method for One-Carbon Homologation of Ketones to α-Sulfinyl Ketones
Authors: Satoh Tsuyoshi , Hayashi Yasumasa , Mizu Yasuhiro , Yamakawa Koji
Published: July 2006

Treatment of 1-chloroalkyl phenyl sulfoxides with a base gave carbenoids rather than free carbenes. The carbenoids were successfully used in a new method for homologation of ketones to α-sulfinyl ketones. Treatment of the carbanion of chloromethyl phenyl sulfoxide with ketones gave the adducts, α-chloro β-hydroxy sulfoxides, in nearly quantitative yields. The adducts were treated with excess lithium diisopropylamide to give one-carbon homologated α-sulfinyl ketones via α-sulfinyl β-oxido carbenoids in moderate to good yields. This type of reaction was found not to occur with the corresponding sulfones.
Stereoselective Synthesis of Antifungal Agent threo-2-(2,4-Difluorophenyl)-3-methylsulfonyl-1-(1H-1,2,4-triazol-1-yl)-2-butanol (SM-8668)
Authors: Saji Ikutaro , Tamoto Katsumi , Tanaka Yoshihiro , Miyauchi Hiroshi , Fujimoto Koji , Ohashi Naohito
Published: July 2006

The stereoselective synthesis of antifungal agent threo-2-(2,4-difluorophenyl)-3-methylsulfonyl-1-(1H-1,2,4-triazol-1-yl)-2-butanol (SM-8668) is described. The key step is the selective synthesis of intermediate threo-2(2,4-difluorophenyl)-2-(1-substituted ethyl)oxirane. threo-2-(2,4-Difluorophenyl)-2-(1-methylthioethyl)oxirane was synthesized threo-selectively by the reaction of 1-(2,4-difluorophenyl)-2-methylthio-1-propanone with dimethyloxosulfonium methylide in a heterogeneous media consisting of a hydrophobic solvent and aqueous alkaline solution.
A New Approach to β-Fluoropyrroles Based on the Michael Addition of Isocyanomethylide Anions to α-Fluoroalkenyl Sulfones and Sulfoxides
Authors: Uno Hidemitsu , Sakamoto Katsuji , Tominaga Takashi , Ono Noboru
Published: July 2006

The reactions of 2-aryl-1-fluorovinyl phenyl sulfones with carbanions derived from isocyanoacetates gave mixtures of 3-aryl-4-fluoro-2-pyrrolecarboxylates and 3-aryl-4-fluoro-4-phenylsulfonyl-2-isocyanobutanoates, simple Michael addition products, in variable ratios depending upon the conditions employed. On the other hand, the reaction of 1-fluoro-1-propenyl phenyl sulfone afforded mainly the simple Michael addition products in moderate yields as well as a small amount of 4-phenylsulfonyl-3-methyl-2-pyrrolecarboxylates and a trace amount of 4-fluoro-3-methyl-2-pyrrolecarboxylates. 1-Fluoropropenyl phenyl sulfoxide underwent mainly the simple Michael addition to give butenoates and a small amount of 4-fluoro-2-pyrrolecarboxylates.
11B NMR Spectroscopic Observation of a Borate Ion–Diol Complex with a Seven-Membered Ring and Comparison of Stability among Complexes with Different Ring Sizes
Authors: Takeda Takuya , Oi Takao
Published: July 2006

A 11B NMR signal, which corresponded to a 1 : 1 complex of the borate ion and 1,4-butanediol (considered to have a seven-membered ring structure), was observed in aqueous solutions. The stability of the complex was lower than those of complexes with five- or six-membered rings between borate ions and structurally similar diols.
Improved Synthesis of 5,11,17,23,29-Penta-t-butylcalix[5]arene-31,32,33,34,35-pentol and Immobilization of the Conformation by O-Alkylation
Authors: Iwamoto Koji , Araki Koji , Shinkai Seiji
Published: July 2006

The synthetic method of the title compound was improved to 16.1% yield. The 1H NMR studies established that the oxygen-through-the-annulus rotation is not inhibited by the butyl group but inhibited by the bulkier octyl group.
Ion Transport Phenomena across the Parallel Composite Membrane
Authors: Matsubara Akira , Komada Fumiko , Kimizuka Hideo
Published: July 2006

The equations of ionic currents in the parallel composite membrane-NaCl system were derived from the phenomenological equations presented by Kedem and Katchalsky.

The elements of the conductance matrix for the composite membrane system, gαβ, as well as those for the single membrane systems with cation-exchange or anion-exchange membranes, or , respectively, were determined by the measurements of membrane potential, membrane conductance, and salt flux. It was found that gαβc or gαβa for the constituent elements of the composite membrane system was different from or for the single membrane systems, respectively. These differences may be attributed to the situation that gαβc and gαβa represent the intra- and intermembrane transport phenomena, while and represent the former phenomena only. The composite membrane system is characterized by the large cross coefficient which is comparable in the magnitude to the straight coefficients, i.e., gNa·Cl ≈ gNa·Na ≈ gCl·Cl. Kedem and Katchalsky have predicted that the strong circulation of current is produced by the partial currents through the element membranes even when the total membrane current is absent. However, because of the large cross coefficient, the partial current through each element membrane due to the conjugate force is nearly canceled by that due to the nonconjugate force.
Structural Effect on Chelation Selectivity of Alkaline Earth Metal Ions with Aminopolycarboxylate-Type Chelators
Authors: Kimura Takahide , Maruyama Tetsushi , Okamura Mutsuo , Sugiyama Takashi , Ando Takashi , Ohno Atsuyoshi
Published: July 2006

Two derivatives of 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (H4bapta), in which the distance between the chelating functions is changed, have been synthesized. The structure–interaction relationships of their complexation behavior with alkaline earth metal ions are discussed from the viewpoint of their acidity constants and stability constants of their chelate-complexes.
Syntheses of Optically Active 2,3,6-Tri-O-benzyl-d-myo-inositol, Laminitol, and Mytilitol from d-Glucose
Authors: Sato Ken-ichi , Bokura Masayuki , Taniguchi Makoto
Published: July 2006

2,3,6-Tri-O-benzyl-d-myo-inositol, which is a key intermediate of d-inositol 1,4,5-triphosphate, was synthesized from d-glucose without performing any optical resolution by utilizing C2 symmetry. Laminitol and mytilitol were also synthesized from d-glucose via the same key intermediate, 1d-(1,3/2,4)-tetra-O-benzyl-2-C-methyl-5-cyclohexene-1,2,3,4-tetrol.
Substituent Effects on Mesomorphic Properties of Some Liquid Crystals with 4-Nitrobenzene at the Terminal Position
Authors: Takenaka Shunsuke , Teshima Koichi
Published: July 2006

This paper describes the thermal properties of 4-nitrophenyl 4-(4-alkoxybenzoyloxy)benzoates and 4-N-[(4-alkoxybenzoyloxy)benzylidene]-4-nitroanilines that have an additional methyl, normal alkoxyl, or hydroxyl substituent on the nitrophenyl group. Methyl and methoxyl groups adjacent to the nitro group reduced the liquid crystalline properties, and derivatives with a long alkoxyl group at the 2 position are nonmesogenic. On the other hand, a hydroxyl group at the 2 position rather enhances the nematic and smectic properties, although a hydroxyl group has a similar volume to the methyl one. The results are discussed in terms of the steric effects of the substituent and electrostatic circumstances around the nitro group.