bluuebunny/crossref_metadata_2025 huggingface dataset:
1H NMR Study of the Regioisomers of Primary O-Di- and Trisubstituted α-Cyclodextrins
Authors: Matsui Yoshihisa , Fujie Masahiko , Sakate Hiroshi
Published: July 2006

The regioisomers of bis- and tris[C(6)-O-sulfonylated] α-cyclodextrins were converted in satisfactory yields to the corresponding C(6)-pyridinio derivatives, which afforded the characteristic splitting patterns of 1H NMR signals available for a regioisomer determination. Electrostatic repulsive interactions between the positively charged pyridinio groups play an important role in the remarkable splitting of the 1H NMR signals observed for some regioisomers.
The Preparation of Organo Colloidal Precious Metal Particles
Authors: Meguro Kenjiro , Torizuka Makoto , Esumi Kunio
Published: July 2006

Platinum particles were prepared by reducing the hydrogen hexachloroplatinate extracted in organic solvents from an aqueous solution by these extractants:dioctadecyldimethylammonium chloride(DDAC), trioctylmethylammonium chloride(TMAC), and trioctylphosphine oxide(TOPO). The extraction ratio of platinum(IV) increased in chloroform, isobutyl methyl ketone, and cyclohexane with an increase in the concentrations of the extractants, and then approached a constant state. The extracts were reduced by formaldehyde or benzaldehyde in the presence of water and a base (sodium hydroxide or triethylamine) for several hours at 65 °C. The platinum particles obtained in chloroform and isobutyl methyl ketone were very stable; their diameters were 15–25 Å.
The Zinc-Photosensitized Reaction of Propane
Authors: Yamamoto Shunzo , Kozasa Mitsuru , Sueishi Yoshimi , Nishimura Norio
Published: July 2006

The zinc-photosensitized reaction of propane has been studied at a wavelength of 307.6 nm, a temperature of 633 K and pressures from about 67 to 40000 Pa. The major products were hydrogen, methane, ethylene, and dimethylbutane, while minor products detected were propylene, isobutane, ethane, butane, and hexane. The yield of hydrogen fell off with time. The quantum yield calculated from the initial rates is about unity and almost independent of the propane pressure, while the quantum yield obtained at 20 min increased with increasing propane pressure and approached about unity at higher pressures. The methane/hydrogen ratio was always smaller than unity and was independent of the propane pressure. The yield of ethylene increased linearly with an increase in that of methane. It has been concluded that the decomposition of propane is initiated through a hydrogen atom abstraction by an excited zinc atom from both the primary and secondary hydrogen of propane. Possible mechanisms are discussed.
Molar Volumes and Electrostriction Behavior of Dicarboxylate, Disulfonate, Tartrate, and Bis(ethylenediamine)glycinatocobalt(III) Ions in Water
Authors: Yokoyama Haruhiko , Mochida Midori , Koyama Yuko
Published: July 2006

The ionic partial molar volumes at infinite dilution, V∞(ion), were determined for several dicarboxylate ions, disulfonate ions, tartrate ions, and [Co(gly)(en)2]2+ (gly=glycinate ion and en=ethylenediamine) from density measurements at 25°C. The values of V∞(ion) obtained for the divalent anions generally increased with their van der Waals volumes. Significant differences in V∞(ion) were observed between geometrical isomers with dicarboxylate and disulfonate ions and were attributed to those in both of electrostriction volume and the void space volume around the anions. The former volume was decreased and the latter was increased with increasing distance between two negatively charged groups in the anions. A relatively strong electrostriction behavior of the tartrate ions, compared to the dicarboxylate ions, suggested the presence of an extra electrostriction caused by hydroxyl groups. The electrostriction strength of [Co(gly)(en)2]2+ was significantly large compared to that of [Ni(en)3]2+, rather close to those of [Cr(en)3]3+ and [Co(en)3]3+, and was attributed to the dissymmetrically localized charge distribution in the [Co(gly)(en)2]2+ ion. The effective ionic radii and apparent van der Waals volumes were estimated by using Glueckauf’s equation from the ionic partial molar volume and were discussed in comparison with those calculated from the van der Waals increments of atoms.
The X-Ray Structure of Sodium trans-1,2-Cyclohexanediamine-N,N,N′,N′-tetraacetatochromate(III) 4.5-Hydrate, Na[Cr(cydta)]·4.5H2O
Authors: Kaizaki Sumio , Hayashi Mariko , Umakoshi Keisuke , Ooi Shun-ichiro
Published: July 2006

The crystal structure of the title compound has been determined from the X-ray diffraction data. This complex crystallizes in the monoclinic space group with unit-cell parameters of a=17.724(2), b=8.084(1), c=14.025(2) Å, β=95.06(1)°, and Z=4, and with a space group of P2⁄c. The structure converged to R=0.043 for 2898 reflections. In the complex anion, the chromium is coordinated by the sexadentate cydta ligand, producing a distorted octahedral CrN2O4 geometry. The glycinate chelates of the in-plane G(girdling) rings in the CrN2O2 plane are more distorted with respect to the Cr–O bond lengths and internal bond angles than are those of the out-of-plane R(relaxed) rings in the CrNO3 plane. This may be responsible for the lability to dissociation of the G-ring acetate chelates. A close proximity of non-bonded hydrogen atoms (ca. 1.90 Å) is found between the methylene groups in the R ring and the cyclohexane ring. There are two nonequivalent sodium ions in the unit cell, which link the cydta complex anions to form an anion layer along the c axis.
Heptafluoropropylation of Various Substituted Thiophenes with Bis(heptafluorobutyryl) Peroxide. Preparation of 3-Heptafluoropropylthiophene
Authors: Yoshida Masato , Yoshida Tatsuro , Kamigata Nobumasa , Kobayashi Michio
Published: July 2006

The heptafluoropropylations of several substituted thiophenes with bis(heptafluorobutyryl) peroxide were studied. The orientations of the heptafluoropropylation were examined and compared with those of usual electrophilic substitution. The method for the preparation of 3-heptafluoropropylthiophene was also explored.
Preparation and Complex Formation of Polymers Anchoring 2-Oxazolidinone
Authors: Ishikawa Tomomichi , Nishizuka Hidehiko , Kawai Tadashi
Published: July 2006

Polymers anchoring 3-unsubstituted 2-oxazolidinone were prepared and their complex formation with phenol and mercury(II) acetate were investigated. Preformed poly(4-hydroxystyrene) was treated with tris(2,3-epoxypropyl) isocyanurate to give a polymer containing 2-oxazolidinone residues within the limits of 57.7 mol%. Polymers carrying 2-oxazolidinone were also prepared through the homopolymerization and copolymerization of 4-(2-oxo-5-oxazolidinylmethoxy)phenyl acrylate. The effective concentration of 2-oxazolidinone residue in the polymers, which is accessible to phenol, was determined on the assumption that the polymer-bound 2-oxazolidinone and phenol formed a 1 : 1 complex. 2-Oxazolidinone and a mercury atom formed a 2 : 1 complex; this relation on the molar ratio applies to all forms of complexes between the mercury atom and the 2-oxazolidinone residue in the polymers.
Aryliminodimagnesium Reagents. XIV. Reactions with Nitrobenzenes Having Electronegative ortho-Substituents. Effects of Reaction Conditions on Condensation, Replacement, and Substitution
Authors: Okubo Masao , Inatomi Yoshito , Taniguchi Naoki , Imamura Kaori
Published: July 2006

In reactions of ArN(MgBr)2 with o-MeO- and o-halo-substituted nitrobenzenes, types and yields of products were different from those in its reactions with m- and p-substituted substrates. Condensation (leading to unsymmetrical azoxy- and azobenzenes), o-substituent replacement, and nuclear substitution took place. Relative yields of products were greatly affected by substituents and reaction conditions. o-MeO and o-F favor replacement, while o-Cl, o-Br, and o-I favor substitution. Replacement and/or substitution predominate when small molar excess of reagent and low concentration are used, while condensation predominates when large molar excess of reagent and high concentration are used, which phenomenon is mechanistically discussed.
Efficient Electron Flux Conversion from Strongly Hydrophilic NADH Model in the Transmembrane Electron Transfer by Flavolipid
Authors: Hamachi Itaru , Kobuke Yoshiaki , Tabushi Iwao
Published: July 2006

By using a strongly hydrophilic NADH model, BzNAHCOOK in the external electron donor, a transmembrane electron transport to the internal acceptor, K3[Fe(CN)6] through the flavolipid (1) was observed. BzNAHCOOK was proved to be an appropriate NADH model in the transmembrane electron transport study because of (i) the very low permeability through the bilayer membrane (k=1.0×10−3 s−1) and (ii) the slow hydration rate (k=1.1×10−5 s−1). The artificial liposome modified with the flavolipid showed a 6–7 times more efficient electron flux conversion from BzNAHCOOK to K3[Fe(CN)6] than the liposome modified with the ubiquinone 10, a biologically important electron carrier. In association with the electron transport, electrochemical oxidation and reduction peaks of the flavolipid incorporated into the liposomal membrane were observed clearly by using Hg-electrode.
Peptide Synthesis in Alcohol Solvents by the Mixed Anhydride Method Using Dimethylphosphinothioyl Chloride
Authors: Ueki Masaaki , Saito Takashi , Sasaya Jun , Ikeda Shigeru , Oyamada Hidekazu
Published: July 2006

The formation and coupling of the dimethylphosphinothioic mixed anhydrides of protected amino acids can be performed in alcohol solvents. Sparingly soluble protected C-terminal segments of vasoactive intestinal peptide (VIP) up to the heptapeptide stage were synthesized by this technique and fully characterized.
State of Polarization of Light Scattered by Anisotropic Spherical Particles
Authors: Sano Yoh
Published: July 2006

Using the light-scattering theory of Rayleigh–Gans, theoretical expressions were derived for the state of the polarization of light scattered by anisotropic spherical particles in the case of linearly polarized incident light with its electric vector inclined by an angle ψ to the scattering plane. The azimuth angle of the ellipse of the light scattered is a function of only the scattering angles, θ and ψ; the ellipticity of the ellipse of the scattered light is always equal to zero, meaning that the scattered light is linearly polarized for linearly polarized incident light. The degree of polarization of the scattered light, P, defined as the ratio of the polarized component to the total intensity of the scattered light, depends on the intrinsic anisotropy, pm, the relative refractive index of the sphere to the solvent, m, and θ together with the angle ψ. Although P for isotropic spherical particles is always equal to 1 at any θ, P for anisotropic spherical particles is smaller than 1.0, but close to 1.0 if the incident light is unpolarized or linearly polarized with ψ=30°. If ψ is smaller than 30°, P varies from 1.0 to 0, depending strongly on the pm and m of the anisotropic sphere. It has been suggested that the determination of P as a function of ψ and θ would provide good information about the optical intrinsic anisotropy of anisotropic spherical particles.
Spectrophotometric Determination of Bismuth(III) and Indium(III) with 2,4,6-Tris(2-hydroxy-4-sulfo-1-naphthylazo)-1,3,5-triazine Trisodium Salt (THT)
Authors: Singh Ishwar , Kadyan Pratap Singh
Published: July 2006

Reaction behavior of bismuth(III) and indium(III) with 2,4,6-tris(2-hydroxy-4-sulfo-1-naphthylazo)-1,3,5-triazine trisodium salt (THT) is established under various conditions. Bismuth(III) forms a 2 : 3 dark red complex (absorption maximum at 530 nm) with the reagent at pH 4–6.5. Indium(III) reacts with THT to form a 1 : 2 dark red complex at pH 3–4.7 (λmax 530 nm) and a 1 : 3 purple blue complex at pH ca. 10.5 (λmax 620 nm). The molar absorptivities for the color reactions are 5.5×104 for bismuth(III), 8.4×104 for indium(III) at pH 3.5 and 7.9×104 L·mol−1·cm−1 for indium(III) at pH ca. 10.5 (in sodium carbonate medium). Other physicochemical characteristics of the complexes are established. A number of foreign ions are tested for their interference and the use of masking agents wherever necessary is tabulated.
Organophosphorus Analogues and Derivatives of the Natural l-Amino Carboxylic Acids and Peptides. II. Synthesis, Enzyme-Substrate Interactions of “Bialaphos” (SF-1293) and Its Cyclic and Phosphinic Amide Type Analogues
Authors: Natchev Ivan A
Published: July 2006

The natural tripeptide antibiotic “Bialaphos” (5) has been synthesized by condensation of the protected l-phosphinothricin (1) with the dipeptide alanylalanine ethyl ester. The dicyclohexylcarbodiimide method has been used, followed by enzyme-catalyzed hydrolysis. Analogously, a cyclic analogue and the phosphac-peptide (phosphinic amide type) analogue (14) of the antibiotic (5) have been found to possess antitumour activity.
Mechanistic Study of the Oxidation of Substituted Benzylamines by N-Bromoacetamide
Authors: Banerji Kalyan K
Published: July 2006

The oxidation of ortho-, meta-, and para-substituted benzylamines by N-bromoacetamide (NBA), to the corresponding benzaldehydes, is first order with respect to NBA and the amine. The pH dependence of the reaction rate suggests that the unprotonated benzylamine is the reductant. There is no effect of added acetamide. NBA itself has been postulated as the reactive oxidizing species. The oxidation of benzylamine-α,α-d2 exhibited a substantial primary kinetic isotope effect (kH⁄kD=5.81). The rates of the oxidation of the meta- and para-substituted benzylamines were separately correlated in Taft’s and Swain’s dual substituent parameter equations. For the para-substituted compounds, the best correlation is obtained with σI and σR+ values, while meta-substituted compounds correlated best with σI and σR° values. The reaction constants have negative values. The oxidation rates of the ortho-substituted compounds yield excellent correlation in a triparametric equation involving Taft’s σI and σR+ values and Charton’s steric parameter, V. A mechanism involving transfer of a hydride ion from the amine to NBA, in the rate-determining step has been proposed.
An 27Al NMR Study on the Complexes Present in the Solutions of Potassium Hexathiocyanatoaluminate(III)
Authors: Komatsu Noriyuki , Yokoi Masatoki , Kubota Eiji
Published: July 2006

The species present in the solutions of potassium hexathiocyanatoaluminate(III) in various solvents were identified by 27Al NMR spectra of the solutions. In dimethyl sulfoxide solution containing excess KSCN, the spectrum consists of 7 resonances due to [Al(NCS)n(DMSO)6−n](3−n)+ (n=0–6), whereas a single resonance arising from [Al(NCS)6]3− was observed in propylene carbonate or acetone.
Free Radical Addition of Thiophenol to 3-Substituted 1-Alkyne with or without Migration of the Substituents
Authors: Miyake Hideyoshi , Yamamura Kimiaki
Published: July 2006

Thiophenol reacts with 3-phenylthio- and 3-bromo-1-alkyne in the presence of radical initiator to give 1,2-bis(phenylthio)-1-alkene and 2-bromo-1-phenylthio-1-alkene.
A Convenient Synthesis of 1,3-Pyrenedicarbaldehyde
Authors: Goltz Michael , Murata Ichiro
Published: July 2006

A convenient and preparatively useful access to the unknown 1,3-pyrenedicarbaldehyde is presented. When treated with an excess amount of N,N-dimethylformamide and phosphoryl chloride, 3,4-dihydro-2aH-cyclopenta[cd]phenalene was smoothly converted into dialdehyde in 57% yield. A plausible mechanism for this transformation was suggested from a labeling experiment using N,N-dimethylformamide-d7.
Study on Electroreduction Mechanism of Aromatic Dicarboxylic Acids. Electrosynthesis of 1,4-Benzenedimethanol
Authors: Oi Ryu , San-Nohe Kunio , Takenaka Shinji
Published: July 2006

The electroreduction mechanisms of terephthalic acid and isophthalic acid in acidic solution were studied by molecular orbital (MO) calculations. Further, a practical stepwise route to 1,4-benzenedimethanol has been developed by the electroreduction of p-(hydroxymethyl) benzoic acid.
Surface Activity of Complexes Formed with N-Dodecyl-β-alanine and Copper(II) Ion in Aqueous Solution
Authors: Nakamura Akio , Tajima Kazuo
Published: July 2006

The surface activity of the equimolar mixed solutions of N-dodecyl-β-alanine (NDA) and inorganic salts was studied at 30 °C. The surface tension of the NDA–CuCl2 solution decreased more than that of the single NDA solution, whereas the surface tensions of the NDA–NaCl, NDA–CaCl2, and NDA–MgCl2 solutions were almost the same as that of the single NDA solution in the concentration region studied. The experiments with the bulk solution have shown that the 1 : 1-complex ion formed with NDA and the copper(II) ion is soluble and more surface-active than NDA alone, but the 1 : 2-complex is not effective in the surface activity because of its extremely low solubility. The formation constant of the 1 : 1-complex ion was determined, by potentiometry with both copper(II) and hydrogen ion-selective electrodes, to be 5.5×10−5, while the standard free energy of the complex formation was found to be 24.7 kJ mol−1. The composition and structure of the 1 : 2-complex were studied by means of X-ray diffractometry, IR spectroscopy, and elemental analyses for the precipitate. The total amounts of NDA adsorbed at the air/aqueous solution interface were determined by radiometry using tritiumlabeled NDA, and the amount of the 1 : 1-complex adsorbed was calculated by the Gibbs adsorption isotherm. Thus, the compositions were determined in both the adsorbed and bulk phases. It was seen that the relative adsorbability of the 1 : 1-complex was larger than that of NDA by a factor of about 1.5×102 and, further, was larger than that of a 1 : 1-complex formed with NDA and sodium dodecylsulfate by a factor of about 3.7.
Catalytic Activity of Nb–Si Mixed Oxides Induced by Reduction with Hydrogen
Authors: Wada Yuji , Inaida Masakatsu , Murakami Yasushi , Morikawa Akira
Published: July 2006

Mixed oxides of niobium and silicon became catalytically active for butene isomerization by a reduction with hydrogen, and their catalytic activities depended on the duration of the reduction. The activity was irreversibly poisoned by oxygen. The formation of Nb4+ by the hydrogen reduction was revealed by ESR technique. Nb4+ was oxidized to Nb5+ by the admission of oxygen gas, and at the same time O2− was formed. It was concluded that the catalytically active site on the mixed oxide surface was Nb4+ ion formed by the reduction. The importance of isolation of Nb4+ ion in silica network was suggested for the retention of the catalytic activity.
Crystal Structures of Chiral Smectogenic 4-Pentyloxyphenyl and 4-Heptyloxyphenyl 4′-[(S)-2-Methylbutyl]biphenyl-4-carboxylates
Authors: Hori Kayako , Ohashi Yuji
Published: July 2006

Crystal structures of the title compounds, which have a Sm* C phase adjacent to a cholesteric, have been determined by single crystal X-ray analysis. 4-Pentyloxyphenyl 4′-[(S)-2-methylbutyl]biphenyl-4-carboxylate: monoclinic, P21, a=25.085(2), b=5.7522(3), c=18.668(1) Å, β=110.275(9)°, Z=4. 4-Heptyloxyphenyl 4′-[(S)-2-methylbutyl]biphenyl-4-carboxylate: triclinic, P1, a=14.607(1), b=17.212(2), c=5.7322(8) Å, α=94.84(1), β=84.03(1), γ=108.607(9)°, Z=2. Final R-values were 0.113 and 0.083, respectively. Both crystals have layer structures similar to those of Sm* C phase. Two crystallographically independent molecules in each crystal are related by a pseudo-inversion. Paraffin chains with extended conformations have close contacts between layers.
Equilibrium Study on the Characteristic Color-Changing Reaction of Lanthanum Complex of 3-[[Bis(carboxymethyl)amino]methyl]-1,2-dihydroxyanthraquinone (Alizarin Complexon) with Fluoride Ion
Authors: Yuchi Akio , Mori Hiroki , Hotta Hitoshi , Wada Hiroko , Nakagawa Genkichi
Published: July 2006

Complexation equilibria between lanthanum (M), 3-[[bis(carboxymethyl)amino]methyl]-1,2-dihydroxyanthraquinone (Alizarin Complexon, H4L) and fluoride were studied by potentiometry with fluoride ion selective electrodes and by spectrophotometry. M2HL2 and a further protonated species react with fluoride to form M2HL2F and M2H2L2F, whereas M2L2 does not. The unexpectedly large stability constant of 104.12 for the reaction, M2HL2+F−\ightleftharpoonsM2HL2F, may be ascribed to the incorporation of fluoride ion in a specially organized core of M2HL2.
Syntheses and Characterization of Dinuclear High-Spin Iron(II,III) and (III,III) Complexes with 2,6-Bis[bis(2-benzimidazolylmethyl)aminomethyl]-4-methylphenolate(1—)
Authors: Suzuki Masatatsu , Oshio Hiroki , Uehara Akira , Endo Kazutoyo , Yanaga Makoto , Kida Sigeo , Saito Kazuo
Published: July 2006

Two types of dinuclear high-spin mixed valence iron(II,III) complexes, [Fe2(L-Bzim)(RCOO)2](BF4)2·nH2O (RCOO=CH3COO (1) or C6H5COO (2)), and [Fe2(L-Bzim)(C6H5COO)2(OH)]BF4·H2O (3), and dinuclear high-spin iron(III,III) complexes, [Fe2(L-Bzim)(CH3COO)2](ClO4)3·3.5H2O (4) and [Fe2(L-py)(C6H5COO)2](ClO4)3·CH3CN·H2O (5) were prepared, where L-Bzim is 2,6-bis[bis(2-benzimidazolylmethyl)aminomethyl]-4-methylphenolate(1—) and L-py is 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenolate(1—). Mössbauer spectra of the mixed valence complexes revealed that they involve high-spin iron(II) and (III) ions in equimolar amount. Their ESR spectra exhibited a signal at gav=1.7 near liquid helium temperature characteristic of an antiferromagnetically spin coupled high-spin iron(II,III) dimer. Magnetic susceptibility measurements over the temperature range 80–300 K revealed that weak antiferromagnetic spin-exchange interactions are present between iron(II) and iron(III) ions (J≈−5 cm−1). The complexes showed an intervalence absorption band in the near infrared region, indicating that they belong to class II mixed valence type on the classification of Robin and Day. Cyclic voltammogram of 3 in acetonitrile showed two sets of reversible redox couples at 0.00 and 0.66 V vs. SCE, which are assigned to the redox reactions of Fe(II,III)/Fe(II,II) and Fe(III,III)/Fe(II,III), respectively. The complexes 4 and 5 exhibited weak antiferromagnetic interaction (J=−9–−12 cm−1). ESR spectra of 4 and 5 showed a significant temperature dependence.
Se-Aryl Alkane- or Arenecarboselenothioates: Synthesis and Some Reactions
Authors: Kato Shinzi , Yasui Eiji , Terashima Kiyomitsu , Ishihara Hideharu , Murai Toshiaki
Published: July 2006

A series of Se-aryl carboselenothioates 3 (RCSSeAr, R=alkyl, aryl) were synthesized and characterized from the reaction of bis(thioacyl) sulfides 1 with sodium areneselenolates. The thionselenolesters 3 are stable (liquid or crystals) both thermally and to moisture. Reactions of 3 with aliphatic primary and secondary amines gave the corresponding ammonium carbodithioates 8 together with diphenyl diselenide 7. In contrast, treatment with aromatic amines or sodium alcoholates afforded the corresponding thioamides or O-alkyl or O-aryl thionesters in good yields. The oxidation of 3 with m-chloroperbenzoic acid gave the corresponding sulfides 12 [RCS(O)SeAr] and acyl arylseleno sulfides 13 [RCOSSeAr] which are formed by a rearrangement of the ArSe group to the thiocarbonyl sulfur atom.
Reaction of 1,4,2-Dithiazolium Salts with Amino Compounds
Authors: Yonemoto Katsumi , Shibuya Isao
Published: July 2006

Systematic studies on the behavior of 1,4,2-dithiazolium cations (1) toward various amino compounds (ammonia, aliphatic and aromatic amines, hydrazine, semicarbazide, thiosemicarbazide derivatives, etc.) were performed. The reaction pathway could be classified into three types depending on possible three fission modes of the initially-formed adduct. The main products were 5-imino-1,4,2-dithiazole, thiourea, and 1,3,4-thiadiazole derivatives, through the three different pathways, respectively. In order to clarify the factors controlling the reaction courses, the reactions of 1 with p-substituted aniline derivatives were carried out under systematically varying conditions. The strength of bases and the polarity of solvents had clear influence on the reactivity. The reaction mechanism is also discussed.
Highly Regio- and Stereoselective Ring-Opening Reaction of γ-Alkenyl-γ-butyrolactones with Allylsilanes in the Presence of Trimethyloxonium Salt Leading to Methyl 4,8-Alkadienoates
Authors: Kawashima Masatoshi , Fujisawa Tamotsu
Published: July 2006

The reaction of γ-alkenyl-γ-butyrolactones with allylic trimethylsilanes in the presence of trimethyloxonium tetrafluoroborate proceeded regio- and stereoselectively with an allylic rearrangement of the substrate to afford methyl (E)-4,8-alkadienoates in high yields. On the other hand, the ring opening of 4-hexen-6-olide afforded exclusively methyl (Z)-4,8-alkadienoates in high yields. The synthetic utility of the reaction was demonstrated by the short step synthesis of β-sinensal and β-farnesene.
Transesterification Reaction of Tetraethoxysilane and Butyl Alcohols
Authors: Hasegawa Isao , Sakka Sumio
Published: July 2006

Tetraethoxysilane was treated with Amberlyst 15 cation-exchange resin in the presence of butyl alcohols. On treating the mixture of tetraethoxysilane and 1-butanol, the transesterification took place in which butoxyl groups were substituted for ethoxyl groups in tetraethoxysilane. The degree of the transesterification depended on the molar ratio of tetraethoxysilane to 1-butanol of the mixture. The distribution of alkoxysilane species present in the tetraethoxysilane–1-butanol solution was compared with the tetrabutoxysilane–ethanol solution, and it was found that the degree of the transesterification depended on the ratio of numbers of alkyl groups in tetraalkoxysilane and alcohol used. The time required for equilibrium in the distribution of alkoxysilane species in the solution was different with the variety of butyl alcohols used, suggesting the presence of steric effect of butyl alcohols on this reaction.
Structural Study of Na2O–TeO2 Glasses by Mössbauer Spectroscopy and Differential Thermal Analysis
Authors: Nishida Tetsuaki , Saruwatari Setsuko , Takashima Yoshimasa
Published: July 2006

A Mössbauer spectrum of xNa2O·(95−x)TeO2·5Fe2O3 glasses (0≤x≤35) consists of a paramagnetic quadrupole doublet peak with an isomer shift of 0.39±0.01 mm s−1 with respect to metallic iron. Quadrupole splitting of the doublet peak changes gradually from 0.76 to 0.60 mm s−1 when Na2O content is changed from 0 to 35 mol% at 5 mol% intervals. These results suggest that Fe3+ ions are present at substitutional sites of Te4+ ions constituting distorted TeO4 trigonal bipyramids. Each of the distorted TeO4 trigonal bipyramids has an oxygen vacancy and a lone electron pair at one of the equatorial sites. Decreased quadrupole splitting is ascribed to an increased symmetry of FeO4 (and also TeO4) trigonal bipyramids, due to a formation of nonbridging oxygen atoms followed by a gradual change of the glass matrix from a two-(β-TeO2) or three-(α-TeO2) dimensional network structure to a lower dimensional network structure. These structural changes are also deduced from a composition dependency of glass transition temperatures (Tg), which decrease continuously from 318 to 232 °C with increasing Na2O content.
Extraction–Spectrophotometric Determination of Pd(II) with 4-(3,5-Dichloro-2-pyridylazo)-1,3-diaminobenzene and Trichloroacetate. II
Authors: Fontán C A , Marone C B , Olsina R
Published: July 2006

The influence of different variables affecting the extraction of Pd(II) with 4-(3,5-dichloro-2-pyridylazo)-1,3-diaminobenzene (3,5-C12PADAB) and trichloroacetate are described. The complexation reaction between palladium(II) and 3,5-C12PADAB, in 1 M trichloroacetic acid aqueous solutions containing ethanol (10% v/v) and an acidity range from pH near 1 to 2 M H2SO4 is completed 10 min after having mixed the reagents. Under these experimental conditions, Pd(II) is extracted into benzene as an colored ion-association compound with trichloroacetate. At 600 nm, Beer’s law is fulfilled up to a Pd(II) concentration of 2.16 ppm, being the most appropriate concentrations for the metal spectrometry those ranging from 0.24 to 2.12 ppm. The apparent molar absorptivity is 8.60×104 dm3 mol−1 cm−1, and the method’s sensitivity (Sandell) of 0.00123 μg Pd(II)·cm−2. The assayed procedures for suppressing the most serious interferences produced by Au(III) and Hg(II) are specified, and the procedure for increasing the tolerance as to Ag(I), Cu(II), Co(II), Cr(III)–(IV), Ir(III)–(IV), Os(VIII), and Ru(III)–(VIII) are described.
Asymmetric Induction during the Aminolysis of 5(4H)-Oxazolones from N-Benzoyl Amino Acids; Almost Specific Formation of One Epimer in the Reaction of the Oxazolone from N-Benzoyl-Dl-t-leucine with Methyl l-Prolinate
Authors: Miyazawa Toshifumi , Otomatsu Toshihiko , Higashi Katsutoshi , Yamada Takashi , Kuwata Shigeru
Published: July 2006

Asymmetric induction during the aminolysis of 5(4H)-oxazolones from N-benzoyl amino acids was investigated using a series of amino acid esters as amine nucleophiles. The reaction of the oxazolone from N-benzoyl-Dl-t-Meucine with methyl l-prolinate was found to produce the diastereomeric Dl isomer, almost specifically, under appropriate conditions.
Intercalation of a Triethylenetetraminated Cyclodextrin by Na-, Ca-, Zn-, and Cu-Montmorillonites
Authors: Kijima Tsuyoshi , Nakazawa Hiromoto , Kobayashi Michiko
Published: July 2006

The uptake of mono[6-[(8-amino-3,6-diazaoctyl)amino]-6-deoxy]-β-cyclodextrin (CDtrien) by Na-, Ca-, Zn-, and Cu-montmorillonites has been examined at 25 °C. All of the minerals form only one intercalated phase in which the CDtrien molecules are arranged as a bilayer with their cavity axes perpendicular to the silicate layers. The modes of intercalation for Na- and Ca-montmorillonites are explained differently by an ion exchange of the interlayer Na+ ions with the divalent cationic forms of CDtrien and by the formation of CDtrien(H2O)2–Ca complexes, respectively. The intercalation by Zn- and Cu-montmorillonites proceeds by complexation at low uptakes and by the combined modes of ion exchange and complexation at higher loadings.
Resonance Raman Spectroscopic Studies of Electrogenerated Cation Radicals by Column-Electrolytic Continuous-Flow Method
Authors: Oyama Munetaka , Nozaki Koichi , Hatano Hiroyuki , Okazaki Satoshi
Published: July 2006

For the measurement of resonance Raman (RR) spectra of electrogenerated cation radicals in solution, a column-electrolytic continuous-flow method has been developed. This method has the advantage that the concentration of cation radicals can be easily varied by controlling the applied current. The RR spectra of the thianthrene cation radical (TH+·) have been successfully observed. The structure of TH+· is discussed, based on the assignment of the RR band. The RR spectra of the oxidized solutions of three aromatic amines have also been measured. These spectra were assigned not due to those of cation radicals but to those of dimer cation radicals produced in the consecutive reactions.
Kinetic Study on the Reaction of p-Nitrophenyl Acetate with 6-Substituted 2,4-Diamino-1,3,5-triazines
Authors: Konakahara Takeo , Kishimoto Koji , Sato Hiroyuki , Takagi Yasushi , Sato Kenji
Published: July 2006

The reactions of p-nitrophenyl acetate (1) with six 6-substituted 2,4-diamino-1,3,5-triazines, (2a–2f), were kinetically investigated in aqueous DMSO or in water at 30 °C. It was found that the reaction rate R could be expressed according to the equation R=(k0+kN[2])[1], and that Brönsted-type plots for the kN-reaction give a straight line with a slope (β) of 1.05. The solvent deuterium isotope effect was not observed in this reaction [kN(H)⁄kN(D)=1.0–1.15]. Furthermore, the isolated reaction product was 2-acetylamino-4-amino-6-methyl-1,3,5-triazine (4c), which was formed by a nucleophilic attack of 2c to 1. From these results, the mechanism for this nucleophilic reaction is discussed.
Reactions of Wittig Reagents with Episulfides or Elemental Sulfur
Authors: Okuma Kentaro , Tachibana Yuji , Sakata Jun-ichi , Komiya Takashi , Kaneko Isao , Komiya Yasuo , Yamasaki Yusuke , Yamamoto Shin-ichi , Ohta Hiroshi
Published: July 2006

The reactions of Wittig reagents with episulfides gave symmetrical olefins and triphenylphosphine sulfide in moderate yields. The same olefins were obtained by reactions of Wittig reagents with elemental sulfur. These reactions might proceed through thiocarbonyl intermediates, the existence of which was confirmed by Diels–Alder reactions with dienes.
Cyclopropenone Oximes: Preparation and Reaction with Isocyanates
Authors: Yoshida Hiroshi , Ohtsuka Hideki , Yoshida Keisuke , Totani Yoshiyuki , Ogata Tsuyoshi , Matsumoto Kiyoshi
Published: July 2006

2,3-Diphenyl-, 2-methyl-3-phenyl-, and 2-methyl-3-(4-methylphenyl)cyclopropenone oxime hydrochlorides (3) were prepared in good yields from the corresponding cyclopropenones and hydroxylamine hydrochloride in methanol. The salts 3 reacted with alkyl and aryl isocyanates in the presence of triethylamine to afford 1:2 addition products 4,6-diazaspiro[2.3]hexenones in moderate yields. In contrast, acetone, acetophenone, and cyclohexanone oximes reacted with twice excess of methyl isocyanates to give linear 1:2 addition products and benzophenone oxime yielded only 1:1 addition product.
The Use of Silica Gel-Supported Ionenes as Reagents and Catalysts for Several Substitution Reactions in Toluene
Authors: Ohtani Noritaka , Chida Kosaku , Serita Hajime , Matsunaga Toshiaki , Kimura Chikai
Published: July 2006

Several ionene bromides were used as reagents for the displacement of decyl methanesulfonate into 1-bromodecane. They were very reactive when adsorbed by silica gel. The enhanced activities of the ionenes were hardly dependent on their structures and molecular weights but decreased gradually with increasing the amount of ionene adsorbed by silica gel. Ionene chlorides exhibited a similar enhancement of reactivity when adsorbed by silica gel. However, unlike the ionenes, a large increase in activity due to adsorption was not observed with pendant-type polycations such as poly(4-vinylpyridinium bromide) and poly[(4-vinylbenzyl)tributylammonium chloride]. The silica gel-supported ionenes also exhibited excellent catalytic activities for solid–liquid–solid triphase substitution reactions, particularly for the reactions between 1-bromodecane and such inorganic salts as consisted of relatively hard-basic nucleophilic anions.
Synthesis of γ-Butyrolactones, Quinoxalines, and Azauracils from 4-Aryl-2-oxobutanoic Acid Derivatives
Authors: Labib G H , Abdel Rahman M , El-Kilany Y , El-Massry A I , El-Ashry E S H
Published: July 2006

4-Aralkyl-5-aryl-3-hydroxy-2(5H)-furanones (2) have been prepared from the corresponding 4-aryl-2-oxobutanoic acids (1). The anticipated products from the reaction of the furanones (2) with o-phenylenediamine (3) have not been isolated, but products resulting from the condensation followed by retro-aldol type of reaction are obtained and determined as 3-(2-arylethyl)-2(1H)-quinoxalinones (4). Compounds 4 could be readily obtained by the condensation of 3 with 1. 4-Aryl-2-oxobutanoic acid thiosemicarbazones (5) have been cyclized to 5-(2-arylethyl)-6-azauracils (6).
The Synthesis of 5-(p-Bromophenacylthio)- and 5-(Carbamoylthio)isothiazoles
Authors: Fukada Naoaki , Mori Toshihisa , Muraoka Motomu , Yamamoto Tatsuo , Takeshima Tatsuo
Published: July 2006

The reaction of the ammonium salts of 5(2H)-isothiazolethiones with p-bromophenacyl bromide, and methyl and phenyl isocyanates afforded 5-(p-bromophenacylthio)-, and 5-(carbamoylthio)isothiazoles. From phenyl isothiocyanate and hydrazine, 2,4-pyrimidinedithione, and 3H-pyrazole-3-thione derivatives were obtained, respectively.
Phospholipid Inverted Micellar Aggregate as an Ionophore in Liquid Membrane System
Authors: Kaibara Kozue , Ito Keiko , Miyakawa Kenji
Published: July 2006

Electrochemical, thermochemical, and light scattering investigations were performed on the 1-octanol liquid membrane systems containing dipalmitoyl-Dl-phosphatidylcholine (DPPC) as an ionophore. It was suggested that DPPC molecules form inverted micellar aggregate in water saturated 1-octanol and that the membrane processes can be regulated by an endothermic phase transition of the DPPC multimolecular cation carrier.
Ferrocene-Mediated Enzyme Electrode for Glucose with the Use of Conducting Polymer Support
Authors: Mizutani Fumio , Asai Michihiko
Published: July 2006

An amperometric glucose-sensing electrode has been constructed by immobilizing glucose oxidase and fine particles of ferrocene in a photo-crosslinked poly(vinyl alcohol) layer. The magnitude of the response of the ferrocene-mediated electrode to glucose (0.5–50 mmol dm−3) increases when polypyrrole, an electrically conducting polymer, is incorporated into the poly(vinyl alcohol) support.
Crystal Structure of 1:2 Charge Transfer Complex of 2,7-Bis(methylthio)-1,6-dithiapyrene (MTDTPY) and Tetrahydrobarrelenotetracyanoquinodimethane (THBTCNQ)
Authors: Nakasuji Kazuhiro , Sasaki Mitsuru , Murata Ichiro , Kawamoto Atsushi , Tanaka Jiro
Published: July 2006

The crystal structure of a 1:2 complex of bis(methylthio)dithiapyrene and tetrahydrobarreleno–TCNQ contained face-to-face packings of acceptor–donor–acceptor units which are isolated from each other. The IR spectrum, geometry, and absorption spectrum showed the neutral nature of this complex.
Preparation of Pyrroles Having Long Alkyl Chains from Nitroalkenes
Authors: Ono Noboru , Maruyama Kazuhiro
Published: July 2006

Pyrroles having long alkyl chains at the 3-and/or 4-positions are readily prepared by the reaction of ethyl isocyanoacetate with nitroalkenes having long alkyl chains.
Organophosphorus Analogues and Derivatives of the Natural l-Amino Carboxylic Acids and Peptides. VI. A PhosphaC-Peptide Analogue of Plumbemycin A
Authors: Natchev Ivan A
Published: July 2006

A phosphaC-peptide of Plumbemycin A has been studied. Condensation of N-trifluoroacetyl-3,4-didehydro-5-(ethoxyhydroxyphosphinyl)norvaline (1) and 1-analyl-l-aspartic acid diethyl ester (2) is carried out by the DCC method to give the entirely protected phosphaC-tripeptide (3). Conditions for the enzyme-catalyzed hydrolysis of the ester groups with alkaline mesintericopeptidase, phosphodiesterase I, and α-chymotrypsin and the removal of the trifluoroacetyl group with an aqueous ammonia solution has been achieved.
2-(Trifluoromethylsulfonyloxy)pyridine as a Reagent for the Ketone Synthesis from Carboxylic Acids and Aromatic Hydrocarbons
Authors: Keumi Takashi , Yoshimura Kiichiro , Shimada Masakazu , Kitajima Hidehiko
Published: July 2006

A new reagent 2-(trifluoromethylsulfonyloxy)pyridine (TFOP) was prepared by the reaction of sodium salt of 2-pyridinol with trifluoromethylsulfonyl chloride in dioxane. The compound TFOP in trifluoroacetic acid has been found to intermolecularly dehydrate from benzoic acid and aromatic hydrocarbons to give the corresponding benzophenones in high yield. It was further elucidated, in the reaction of fluorene, that a variety of carboxylic acids can be used as the acyl precursor for the aromatic ketone synthesis in conjunction with the TFOP/TFA system. This acylation procedure has been applied to the synthesis of 2-acylthiophenes, which are hard to prepare in a satisfactory yield by the classical Friedel–Crafts reaction using aluminum chloride as the catalyst.
NAD(P)+–NAD(P)H Models. 65. Photochemical Reductive Desulfonylation of β-Keto Sulfones with Hantzsch Ester
Authors: Fujii Masayuki , Nakamura Kaoru , Mekata Hideyuki , Oka Shinzaburo , Ohno Atsuyoshi
Published: July 2006

A new procedure for the reductive desulfonylation of β-keto sulfones is described. The reaction proceeds under a photochemical conditions with the Hantzsch ester in pyridine in the presence of ruthenium(II). Various functional groups are unaffected under the reaction conditions. Application of the procedure to the syntheses of certain natural products is also described.
Thermal Cycloaddition Reaction of Tropone to 1,1-Diethoxyethene. Structure Revision of Cantrell’s Diels–Alder Adduct
Authors: Takeshita Hitoshi , Nakashima Hisataka , Sugiyama Shigeru , Mori Akira
Published: July 2006

A reinvestigation of Cantrell’s thermal cycloaddition of tropone to 1,1-diethoxyethene has led to the isolation of three products: [4+2], [6+2], and [8+2] cycloadducts. The structure of the [4+2] cycloadduct was revised on the basis of an NMR analysis of the hydrolyzed diketone, and newly identified was a superficial anti-Woodward–Hoffmann [6+2] cycloadduct. These adducts did not cause mutual isomerization by heating under formation conditions.
Halogenation Using Quaternary Ammonium Polyhalides. VI. Bromination of Aromatic Amines by Use of Benzyltrimethylammonium Tribromide
Authors: Kajigaeshi Shoji , Kakinami Takaaki , Inoue Kazuhisa , Kondo Manabu , Nakamura Hiroko , Fujikawa Masahiro , Okamoto Tsuyoshi
Published: July 2006

The reaction of aromatic amines with benzyltrimethylammonium tribromide in dichloromethane–methanol containing calcium carbonate powder for 0.5 h at room temperature gave bromo-substituted aromatic amines in good yields.
Metal Complexes with Tetrapyrrole Ligands. 47. Yttrium(III) Bis(octaalkylporphyrinate)s: Synthesis and Electron Spin Resonance Spectra of Earth Metal Porphyrin Sandwich Compounds
Authors: Buchler Johann Walter , Hüttermann Jürgen , Löffler Jürgen
Published: July 2006

Reaction of tris(2,4-pentanedionato)yttrium(III) with octaethylporhyrin, H2oep in refluxing 1,2,4-trichlorobenzene (TCB) produces a trace (2%) of the double-decker, Y(oep)2 (3A) besides major amounts (72%) of the yttrium(III) monoporphyrinate, Y(oep)(acac) which are separated by chromatography. Appreciable yields of Y(oep)2 (3A) (25%) are obtained from dilithium octaethylporphyrinate, Li2(oep), formed in situ and Y(oep)(acac) in refluxing TCB. The constitution of the double-decker 3A is proved by UV/VIS, IR, 1H NMR, ESR, ENDOR, and mass spectra. The well-defined composition Y(oep)2 requires that one of the porphyrin rings is electron-deficient, i.e. the charge of the YIII ion is compensated by the normal porphyrinate dianion and a porphyrinate monoanion radical. The magnetic moment in the solid state, μeff=1.5 B.M. (5–100 K), demonstrates the radical nature of 3A as well. Under the time resolution of the methods used, the unpaired electron is delocalized between the two porphyrin rings. The wavenumber of the internal charge transfer absorption band in the near infrared (λCTI 1175 nm) agrees well with the value expected for the ionic radius of YIII according the linear relationship of the energy of the CTI band and the ionic radius which has been established for the series of lanthanoid octaethylporphyrinates, Ln(oep)2 (Ln=La···Lu). 3A can be reduced to the diamagnetic sandwich anion, [Y(oep)2]−. YIII double-decker radicals Y(omp)2 (3B; λCTI 1100 nm) or Y(hbp)2 (3C, λCTI 1100 nm) containing octamethylporphyrin or hexadecahydrotetrabenzoporphyrin have also been prepared.
Structure and Properties of Chloro(N,N-diethylglycinato)copper(II)
Authors: Yukawa Yasuhiko , Nakagome Shin , Yamaguchi Hiromitsu , Inomata Yoshie , Takeuchi Toshio
Published: July 2006

An X-ray diffraction study of the title complex has been carried out, along with spectroscopic measurements and thermal analyses. The crystal is orthorhombic, space group P212121, Z=4, a=9.978(2), b=12.624(3), c=7.129(1) Å, U=898.0(3) Å3. Block-diagonal least-squares refinements have led to the final R value of 0.032. The structure consists of a one-dimensional polymer chain bridged by a carboxylato group of an N,N-diethylglycinato ligand. One oxygen atom in the carboxylato group is coordinated to two copper atoms, and the other is coordinated to one of these two copper atoms. This is the same bridging form as in aquachloro(4-hydroxy-l-prolinato)copper(II). The copper atom reveals a distorted five-coordination: the copper atom is surrounded by three carboxylato oxygen atoms, one nitrogen atom, and one chlorine atom. The infrared spectra of the title complex and of aquachloro(4-hydroxy-l-prolinato)copper(II) both show the characteristic pattern at the peaks assigned to the vibrations of the carboxylato group. The peaks can be an indicator of the bridging form.
The Photoinduced Removal of Nitro Groups from Steroidal 6-Membered α,α′-Dinitro Cyclic Ketones
Authors: Suginome Hiroshi , Kurokawa Yoshitaka
Published: July 2006

2,4-Dinitro-5α- and 5β-cholestan-3-ones were prepared by dinitration of the parent 3-ones by a modified standard method. Spectroscopy indicated that in ethanol these α,α′-dinitro ketones exist in their enol forms. Photolysis of these dinitro ketones in ethanol gave diosphenols arising from the removal of their two nitro groups. On the basis of the results of the irradiation of hypothesized intermediate obtained by synthesis, we suggest the path likely to lead to the removal of the nitro groups.
Synthesis of Salvilenone, a Diterpenoid Phenalenone of Salvia miltiorrhiza
Authors: Zheng Guo-Chi , Kakisawa Hiroshi
Published: July 2006

Salvilenone 1, a phenalenone diterpene isolated from the roots of Salvia miltiorrhiza Bunge, was synthesized in thirteen steps from resorcinol dimethyl ether. Dihydrophenalenol derivative 19, a key intermediate, was treated with aqueous hydrobromic acid to give salvilenone accompanied by the formation of a hydroxy diketone 20.
Dehydrooligopeptides. XI. Facile Syntheses of Various Kinds of Dehydrodi- and tripeptides, and Dehydroenkephalins Containing ΔTyr Residue by Using N-Carboxydehydrotyrosine Anhydride
Authors: Shin Chung-gi , Obara Takumi , Taniguchi Shuji , Yonezawa Yasuchika
Published: July 2006

Several kinds of N-free and protected N-carboxydehydrotyrosine anhydride (ΔTyr·NCA) derivatives, derived by both the cyclization of the corresponding N-benzyloxycarbonyldehydrotyrosine derivatives and the protection of the resulting ΔNCA, were employed for a one-pot dehydrooligopeptide (DHP) synthesis. As a result, various kinds of DHPs with a wide variety of combinations of sequences could be synthesized in fairly good yields. In addition, by utilizing the obtained information, two kinds of leucine-dehydroenkephalins containing a ΔTyr1 and both ΔTyr1 and ΔPhe4 residues were also synthesized.
Superjacent and Subjacent Orbitals Participations for Kinetically-Controlled Cycloaddition Reactions of 2H-Cyclohepta[b]furan-2-ones and 8,8-Dicyanoheptafulvene to 2,3-Bis(methoxycarbonyl)-7-oxabicyclo[2.2.1]heptadiene
Authors: Tian Guan Rong , Sugiyama Shigeru , Mori Akira , Takeshita Hitoshi , Higashi Miwako , Yamaguchi Hiroyuki
Published: July 2006

Thermal cycloaddition reactions of 2,3-bis(methoxycarbonyl)-7-oxabicyclo[2.2.1]heptadiene with 2H-cyclohepta[b]furan-2-ones and 8,8-dicyanoheptafulvene gave [4+2]adducts exclusively. This mode is different from the reported [8+2]adduct formations for 2H-cyclohepta[b]furan-2-ones with enamines and alkoxyethenes. A consideration of the superjacent and subjacent orbitals effects of the MO calculations gave a better result in favor of [4+2]adduct formation. Thermolysis of cycloadducts gave the methylene derivatives of homobarrelenes.
Studies on Ferrocene Derivatives. V. Oxidation Reaction of (o-Substituted phenyl)ferrocenes
Authors: Okada Yutaka , Yamamoto Noriyuki , Hayashi Takatoshi
Published: July 2006

The oxidation reactivity of (o-substituted phenyl)ferrocenes with air was measured in acidic solution. The reactivity of o-acetyl, o-methoxycarbonyl, and o-methoxy derivatives was higher than that of the corresponding p-isomers. On the other hand, for o-hydroxy and omethyl derivatives, the reactivity was lower than that of p-isomers. It was considered that the reactivity of o-isomers is influenced by the coordination ability of proton to iron atom. The coordination ability is governed by both the I-effect and steric effect of substituent.