bluuebunny/crossref_metadata_2025 huggingface dataset:
The Thermal Decomposition of N,O-Diacyl-N-t-butylhydroxylamines
Authors: Uchida Yuzuru , Hashimoto Yukinobu , Kozuka Seizi
Published: July 2006

Several N,O-diacyl-N-t-butylhydroxylamines and O-acyl-N-t-butylhydroxylamines were prepared, and their thermal decompositions were studied. The thermal decompositions of N,O-diacyl-N-t-butylhydroxylamines in tetralin gave substituted N-t-butylbenzamides, carboxylic acids, 1,1′-bitetralyl, and 1,2-dihydronaphthalene as the major products, together with small amounts of carbon dioxide, t-butylamine, and benzanilides. In the thermal decompositions of O-acyl-N-t-butylhydroxylamines, the products were t-butylamine, carboxylic acids, substituted N-t-butylbenzamides, 1,1′-bitetralyl, and 1,2-dihydronaphthalene.
Enolate Anions. III. Substituent Effects of Sodium Diethyl Alkylmalonates in DMSO
Authors: Kiyooka Syun-ichi , Kodani Tsukasa , Suzuki Kojiro
Published: July 2006

The conformations of sodium enolate anions, derived from diethyl malonate and diethyl alkylmalonates (alkyl=methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and s-butyl), have been determined to be Z,Z-type by the analysis of their 1H-NMR spectra in DMSO. In the case of diethyl t-butylmalonate, such a Z,Z type contributes to the lesser extent to the conformations of the sodium enolate anion because of repulsion between the t-butyl substituent and the two ethoxyl groups, which exist in three types (Z,Z, Z,E, E,E) of conformation, as is evident in the 1H-NMR spectra. The IR spectra of sodium diethyl malonate in DMSO showed two characteristic absorption bands at 1679 and 1556 cm−1. The IR isotope shifts upon the use of the enolates of diethyl malonate-2-13C and diethyl malonate-1,3-13C2 suggested that these two bands are attributable to the C··O and C··C··C bonds. All sodium diethyl alkylmalonates except for the t-butyl derivative have two characteristic IR bands in the region of 1500–1700 cm−1, the bands on the high-frequency side of which have nearly equal wave numbers, while those on the low-frequency side have a good correlation with the substituent constant, σ*.
Studies on Biologically Active Pteridines. IV. Synthesis of Several Biopterin Derivatives as an Antigen in Radioimmunoassay for Biopterin
Authors: Sugimoto Takashi , Matsuura Sadao , Nagatsu Toshiharu
Published: July 2006

The synthesis of biopterin, d(and l)-erythro-neopterins, and their derivatives having a substituent at the 2-amino group via the 2-methylthio analogues is described. The 2-(methylthio)pteridines were synthesized by condensation of 4,5-diamino-6-hydroxy-2-(methylthio)pyrimidine with 5-deoxy-l-arabinose and d(and l)-arabinose phenylhydrazones, followed by oxidation with K3[Fe(CN)6] and O2 in the presence of KI in an acidic solution, respectively. Aminolysis of these thioethers with ammonia and other amines in the presence of acetic acid gave the title compounds.
Stereochemical Studies on the Nucleophilic Substitution in the Reaction of Allylic Phosphates with Organoaluminum Reagents
Authors: Itoh Akira , Ozawa Shuji , Oshima Koichiro , Sasaki Shizuka , Yamamoto Hajime , Hiyama Tamejiro , Nozaki Hitosi
Published: July 2006

The reaction of cis- or trans-5-isopropenyl-2-methyl-2-cyclohexenyl diethyl phosphate (1) with Me2AlX (X=OPh, SPh, NHPh) in hexane results in substitution of the –O–PO(OEt)2 group with X under predominant inversion. In contrast, treatment of cis- or trans-1 with trialkylaluminum produces predominantly the allyl-nonallyl couplingproducts of the same (thermodynamically more stable) configuration. Similar alkylation of endo- and exo-2-acetoxynorcarane gave endo-2-methylnorcarane, exclusively.
Concentration and Spectrophotometric Determination of Molybdenum with Thiocyanate and Rhodamine 6G
Authors: Prasada Rao T , Ramakrishna T V
Published: July 2006

A method is described for the determination of molybdenum based on reaction with potassium thiocyanate and Rhodamine 6G in 0.55–0.8 mol dm−3 hydrochloric acid medium. The method is sensitive (ε=2.63×105 l mol−1 cm−1) and obeys Beer’s law over the range 0.04–0.24 ppm of molybdenum. Selectivity can be considerably improved by collecting molybdenum on iron (III) hydroxide. In conjunction with the collection procedure, the method is useful to determine as low as 5 ppb of molybdenum present in 100 cm3 of aqueous samples.
A Further Evidence of the Vibronic Coupling through b3g Vibrational Modes in the Fluorescence Spectrum of Anthracene
Authors: Terada Tomoyuki , Koyanagi Motohiko , Kanda Yoshiya
Published: July 2006

Angular dependence of the fluorescence polarization spectra of anthracene was investigated in polyethylene films using a sample rotation technique. An important role of a nontotally symmetric vibration, the b3g ring vibration at 1655 cm−1, was further confirmed by a combination of this technique and the modulation polarization technique developed previously.
Infrared Studies of the Oxidation of 2-Propanol on ZnO
Authors: Miyata Hisashi , Hata Kazuo , Nakajima Takashi , Kubokawa Yutaka
Published: July 2006

The oxidation of 2-propanol and acetone on ZnO has been studied by IR spectroscopy. Surface isopropoxide was oxidized to acetate and formate ions via enolate complex of acetone. Formation of α-diketone-like species was proposed for oxidation with dinitrogen oxide.
Naphthalene-sensitized Photolysis of Dibenzoyl Peroxide
Authors: Kitamura Akihide , Sakuragi Hirochika , Yoshida Masayuki , Tokumaru Katsumi
Published: July 2006

Naphthyl benzoates and phenylnaphthalenes were produced, on naphthalene-sensitized photolysis of dibenzoyl peroxide, in different distribution of their isomers from its thermolysis in the presence of naphthalene, suggesting that naphthalene as sensitizer interacts with dibenzoyl peroxide in a specific orientation in the sensitization process.
The Stoichiometry and Promoter Role of Chlorosulfuric and Fuming Sulfuric Acids for α-Halogenation of Aliphatic Acid
Authors: Ogata Yoshiro , Watanabe Shinya
Published: July 2006

The stoichiometry for the chlorosulfuric acid promoted α-halogenation and the role of fuming sulfuric acid instead of chlorosulfuric acid have been studied. In the α-bromination with molecular bromine, 1 mol of halogen afforded 2 mol of aliphatic α-bromo acid just as the α-iodination, but it is different from α-chlorination which affords only 1 mol of α-chloro acid. Fuming sulfuric acid instead of chlorosulfuric acid was found to be effective for α-bromination, but the yield was lower, while no α-iodination was observed with fuming sulfuric acid.
Photoinduced Decomposition of Peracetic Acid in Isopropylbenzene
Authors: Ogata Yoshiro , Tomizawa Kohtaro
Published: July 2006

Irradiation of peracetic acid in isopropylbenzene with 254 nm and over 290 nm lights gave as aromatic products mainly t-butylbenzene, 2-phenyl-2-propanol, and 2,3-dimethyl-2,3-diphenylbutane. The yield of t-butylbenzene was higher in 254 nm photolysis than that with >290 nm, while the yield of hydroxylated aromatics, i. e., 2-phenyl-2-propanol, was much higher with >290 nm than that with 254 nm. The distribution of products was little affected by the intensity of light. These results are discussed by a mechanism involving radicals of different reactivity derived from peracetic acid decomposition.
12,13-Epoxy-C-nor-D-homosteroids. VI. Reaction of 17-Oxygenated 12,13-Epoxyetiojervanes with Boron Trifluoride Etherate
Authors: Murai Akio , Iwasa Noriaki , Takeda Masami , Masamune Tadashi
Published: July 2006

17-Oxygenated 12,13-epoxyetiojerv-5-en-3-one 3,3-ethylene acetals (1A–10A) were treated with boron trifluoride etherate in benzene at room temperature. The epoxy ring cleavage reactions proceeded slowly with increase of electronegativity of the 17-substituents without and/or with deacetalization to give a variety of compounds including rearranged products (23A and 23B). The results summarized in Table 1 indicated that the reactions produced compounds formed by initial cleavage at less electronegative C-12 rather than at C-13 except several compounds (11A, 20A, 20B, and 34A). Formation of the latter compounds was attributed by hydride shift or neighboring participation of the 17-acetoxyl groups.
Studies of the Anodic Oxidation of the Cyanide Ion in the Presence of the Copper Ion. III. Identification of the Reaction Intermediate by Means of ESR Spectroscopy
Authors: Yoshimura Seiji , Katagiri Akira , Deguchi Yasuo , Yoshizawa Shiro
Published: July 2006

The formation of the tetracyanocuprate(II) ion (Cu(CN)42−), which was expected as a reaction intermediate in the anodic oxidation of the cyanide ion in the presence of the copper ion, has been investigated by means of ESR measurement. When a potassium cyanide solution containing a small amount of copper(I) cyanide was electrolyzed, an intermediate copper(II) species was found at the anode in the dissolved state. The ESR spectrum of the intermediate in the solidified state was obtained by freezing the solution in the resonant cavity. The intermediate was identified as Cu(CN)42− by a comparison of its spectrum to that of Cu(CN)42− already reported by other authors. When the ratio of the total copper(I) concentration to the total cyanide concentration in the solution was not too small, solid copper(II) cyanide was deposited on the anode during electrolysis.
Studies of the Anodic Oxidation of the Cyanide Ion in the Presence of the Copper Ion. IV. The Kinetics and Mechanism of the Decomposition of the Intermediate Tetracyanocuprate(II) Ion
Authors: Yoshimura Seiji , Katagiri Akira , Deguchi Yasuo , Yoshizawa Shiro
Published: July 2006

The kinetics and mechanism of the decomposition of the tetracyanocuprate(II) ion (CuII(CN)42−) have been investigated by ESR measurements. Aqueous solutions of potassium cyanide with a small amount of copper(I) cyanide were electrolyzed in a cell the platinum anode of which was set in the resonant cavity of an ESR spectrometer. Since CuII(CN)42−, which is formed as an intermediate, gives a definite ESR spectrum, its concentration in the anode compartment is estimated from the intensity of the first-derivative spectrum at a fixed magnetic field. From the decay curves of the ESR intensity after the steady-state electrolysis currents have been switched off, a rate equation for the decomposition of CuII(CN)42− is derived; v=k0[CuII(CN)42−]2⁄[CN−]2, where k0 is calculated to be 74 mol·dm−3·s−1 at 25 °C. This rate equation is also confirmed by ESR measurements during steady-state electrolysis, where the value of k0=60 mol·dm−3·s−1 is obtained. On the basis of the kinetics, two possible mechanisms are proposed: the formation of CuII(CN)3−, followed by the rate-determining bimo-lecular reaction of CuII(CN)3− to give 2CuI(CN)2−+(CN)2 (Mechanism A), and the formation of a binuclear complex, CuII2(CN)62−, followed by the rate-determining decomposition of CuII2(CN)62− to give 2CuI(CN)2−+ (CN)2 (Mechanism B). The kinetics and the mechanism are compared with those of the chemical reaction between the copper(II) ion and the cyanide ion.
The Flotation of Cd2+ Ions in the Presence and Absence of Zn2+ Ions
Authors: Kobayashi Koichi , Shimizu Yoshiko , Sasaki Tsunetaka
Published: July 2006

The flotation of Cd2+ ions was investigated in the presence and absence of Zn2+ ions. It was found that the flotation efficiency of Cd2+ ions in the Cd2+–anionic surfactant system is markedly small in the presence of Zn2+ ions, but the flotation efficiency of Cd2+ ions in the Cd2+–bentonite–cationic surfactant system (adsorbing particle flotation) decreased only slightly in the presence of Zn2+ ions. The flotation efficiency in the latter case was further increased by the addition of 3 ppm of polyacrylamide. The doubling of the flotation reagents and time did not effectively increased the flotation efficiency of Cd2+ ions in the presence of Zn2+ ions, but the two-stage flotation did. It was confirmed that the adsorbing particle flotation of Cd2+ ions would be an excellent method in the presence of Zn2+ ions.
Direct Measurement of the Interaction Energy between Solids and Gases. VI. Calorimetric Studies on Acidic Properties of Solid Super Acids Prepared from Silica–Alumina
Authors: Taniguchi Hitofumi , Masuda Tatsuo , Tsutsumi Kazuo , Takahashi Hiroshi
Published: July 2006

Solid super acids were prepared by the reaction of gaseous antimony pentafluoride with silica–alumina and heats of adsorption of ammonia on their surfaces were measured. Solid super acids gave about 170 kJ/mol of an initial differential heat of adsorption and their adsorption energies were mainly distributed in the vicinity of 137 kJ/mol, while the initial differential heat of adsorption on original silica–alumina was about 150 kJ/mol and its adsorption energy was chiefly distributed in the vicinity of 117 kJ/mol. Therefore, it was shown that solid super acid had stronger, more homogeneous and much more acid sites than original silica–alumina.
Effect of Pressure on Mesomorphic Transitions in Cholesterol Esters of Unsaturated C18 Aliphatic Acids
Authors: Nakahara Masaru , Maeda Katsumi , Osugi Jiro
Published: July 2006

The smectic to cholesteric, cholesteric to isotropic liquid, and solid to isotropic liquid transitions in the following cholesterol esters are determined by an optical method as a function of pressure up to 1 kbar; cholesteryl oleate, cholesteryl linoleate, and cholesteryl linolenate. The pressure dependence of the transition temperatures (dT⁄dP) is in the range of 21 to 36 K kbar−1, and the volume changes (ΔV) computed by means of Clapeyron’s equation are between 0.42 and 1.3 cm3 mol−1 at 1 bar. The volume change for the smectic to cholesteric transition increases with the number of the double bonds in the acids, while that for the cholesteric to isotropic liquid is little affected by the double bonds.
Studies of the Ion Flotation by Poly(ethyleneimine) Resin
Authors: Sasaki Tsunetaka , Kurosawa Hisayo , Miyasaka Keiichi , Mizushima Minoru
Published: July 2006

Flotation of Crystal violet (CV+), neucoccin (NO−), CrO42−, PO43−, Fe3+, and Cu2+ ions was studied with use of poly(ethyleneimine) resin (PEI) as an adsorbent, Na-polyacrylate or polyacrylamide as a coagulant and sodium dodecyl sulfate or hexadecyltrimethylammonium chloride as a frother. In line with the results of adsorption studies, NC−, PO43−, and CrO42− ions were effectively floated from their dilute solutions but CV+ was not floated so much. The most effective flotation was attained for CrO42− ions, a rapid initial decrease in concentration due to the flotation within 30 s being followed by a gradual decrease and nearly 100% flotation achieved within 10 min for a dilute solution. The rate of flotation follows a bimolecular reaction. The activation energy of flotation, 28.03 kJ mol−1, is equal to that of CrO42− ion adsorption by PEI. Flotation of Fe3+ and Cu2+ ions was effectively carried out through chelate formation of these ions with PEI.
12,13-Epoxy-C-nor-D-homosteroids. VII. Reaction of 11-Oxygenated 17α-Acetyl-12β,13β-epoxy-13-epietiojervanes with Boron Trifluoride Etherate and Potassium Hydroxide
Authors: Murai Akio , Sasamori Hiroshi , Masamune Tadashi
Published: July 2006

The title compounds were treated with boron trifluoride etherate in benzene at room temperature. 11β-Hydroxy- and 11-oxo-12β,13β-epoxides (1 and 14) underwent cleavage of the epoxy group at C-13 by the acid treatment to give the corresponding fluorohydrins (2 and 5) as the respective major products, while the former (1) also afforded a 13β-pregnane derivative (3) with a normal steroid skeleton. On the other hand, several 11-oxygenated 12α, 13α- and 12β,13β-epoxides (17, 17a, 19, 21, 1, and 23) were treated with potassium hydroxide in aqueous methanol at room temperature. All epoxides gave the corresponding Δ13(17)-20-ketones, and only 11-hydroxy- and 11-acetoxy-12α,13α-epoxides (17, 19, and 17a) were further transformed into a 13α-pregnane derivative (12).
Syntheses and Characterization of Some New (3-Oxo-1-cyclohexenyl) palladium(II) Complexes
Authors: Onishi Masayoshi , Yamamoto Hideharu , Hiraki Katsuma
Published: July 2006

trans-Chloro(3-oxo-1-cyclohexenyl)bis(triphenylphosphine)palladium(II) (1) reacted with 1,2-bis(diphenylphosphino)ethane (dppe), 1,10-phenanthroline (phen), sodium diethyldithiocarbamate–water (1/3), and sodium tetra(1-pyrazolyl)borate {Na[BPZ4]} (Pz=1-pyrazolyl) to give the corresponding new (3-oxo-1-cyclohexenyl)palladium(II) complexes, [Pd(oxch)Cl(dppe)] (oxch=3-oxo-1-cyclohexenyl) (2), [Pd(oxch)Cl(phen)], [Pd(oxch)(S2CNEt2)(PPh3)], and [Pd(oxch)(BPZ4)(PPh3)], respectively. Complex 2 was treated with carbanions derived from methyl and ethyl cyanoacetates and malononitrile, and new diorganopalladium(II) complexes were obtained. These complexes were characterized by means of elemental analyses and IR and 1H-NMR spectroscopy. The stereochemical nonrigidity of the BPZ4 complex was discussed.
Use of the Copper(II) Ion-selective Electrode for the Determination of the Stability Constant of Binuclear Copper(II) Complex with 3,6-Dioxaoctane-1,8-diamine-N,N,N′,N′-tetraacetric Acid
Authors: Ohzeki Kunio , Saruhashi Masakuni , Kambara Tomihito
Published: July 2006

The stability constant of binuclear copper(II) complex with 3,6-Dioxaoctane-1,8-diamine-N,N,N′,N′-tetraacetric acetic acid (ethylene glycol bis[2-[bis(carboxymethyl)amino] ethyl] ether, customarily abbreviated to EGTA of Y) was determined on the basis of potentiometric titration by means of a copper(II) ion-selective electrode. In acetate buffer solution of pH 5.8 titration curves of copper(II) with EGTA show two distinct end points corresponding to Cu2Y and CuY complexes. The formation constant of the binuclear copper(II) complex was determined from the potential response in the titration fraction between first and second end points. The logarithmic value was found to be log KCu2Y=6.40 at ionic strength of 0.2 M (KNO3–acetate buffer solution) at 25±0.5 °C.
Studies of Unusual Amino Acids and Their Peptides. XII. The Chemistry of N-(Carboxymethyl)amino Acids. I. The Preparation, Properties, and Characterization of N-(Carboxymethyl)amino Acids and Their Esters
Authors: Miyazawa Toshifumi
Published: July 2006

N-Carboxymethyl(Cm-)amino acids and their mono- and diesters were prepared by several routes, and their physical and chiroptical properties were compared with those of the parent amino acids and their esters. The isolation procedure was improved for the preparation of the free Cm-amino acids obtained from the corresponding amino acids and bromoacetic acid; the aimed-at compounds were also obtained by the catalytic hydrogenolysis of the dibenzyl esters. The isomeric pairs of monoalkyl esters of Cm-amino acids were similarly accessible via the benzyl alkyl esters. The diesters proved to be suitable for the GLC and MS analyses of Cm-amino acids. All the free Cm-l-amino acids and the dicyclohexylammonium salts of their N-ethylthiocarbonothioyl derivatives show positive Cotton effects at 200–225 nm and at 335–350 nm respectively in CD measurements; therefore, these correlations can be used for the configurational assignments of Cm-amino acids.
Reactions of Substituted Epoxides with Alkyl Chloroacetate
Authors: Takeda Tokuji , Yasuhara Satoshi , Watanabe Shoji
Published: July 2006

The reactions of substituted epoxides with alkyl chloroacetate in the presence of lithium salts, quarternary salts and zinc chloride were studied. The reaction of 1-chloro-2,3-epoxypropane (1a) with butyl chloroacetate (BCA) in the presence of any of these catalysts yielded exclusively butyl [2-chloro-1-(chloromethyl)ethoxy]acetate (2a) via the normal cleavage of 1a followed by the reaction with the chloroacetate. On the other hand, the reaction of 1,2-epoxypropane(1b) with BCA yielded a mixture of isomeric products resulting from the normal and abnormal cleavages of 1b, and the ratio of the normal and abnormal products is dependent on the type of the catalyst. Moreover, it was found that lithium salt alone catalyzed the insertion reaction in a polar aprotic solvent, whereas the reaction in aromatic solvent needed a suitable co-catalyst such as hexamethylphosphoric triamide and triphenylphosphine oxide.
A New Synthesis of Glutathione via the Thiazoline Peptide
Authors: Ozawa Yoichi , Tsuji Toshiaki , Ariyoshi Yasuo
Published: July 2006

A convenient synthesis of glutathione (GSH) by the use of minimal protecting groups was investigated. N-Formyl-l-2-amino-4-cyanobutyric acid ethyl ester was condensed with ethyl l-cysteinylglycinate to give (4R)-2-[(3S)-3-ethoxycarbonyl-3-(formylamino)propyl]-4-(ethoxycarbonylmethylcarbamoyl)-2-thiazoline. This compound was saponified in aqueous acetone at −15–−20 °C and subsequently treated with dilute H2SO4 (pH 4) to yield formylglutathione, whose formyl group was then hydrolyzed with 0.5 M (1 M=1 mol dm−3) H2SO4 to give free GSH. For purification, this was changed to a copper thiolate, which was then decomposed with H2S to afford pure GSH.
Electron Transfer Sensitization. III. A Kinetic Study of Oxidative Dye Formation from Leuco Crystal Violet
Authors: Kitamura Noboru , Tazuke Shigeo
Published: July 2006

The action of electron transfer sensitization was quantitatively discussed by measuring photooxidative dye formation of leuco Crystal Violet (LCV) in the perylene (Pe)-1,4-dicyanobenzene(DCB)–LCV combination in polar media. Under the conditions of exclusive photoexcitation of perylene (λex at 435 nm), the kinetic study revealed that the turn over number of perylene as a sensitizer was immeasurably large in the ternary system in vacuo. This is an indication that perylene is indeed recycled via two successive electron transfer processes. The turn over number decreased to 58 in air, probably due to instability of intermediate ion radicals. The quantum yield was larger for the ternary system than for the binary system(Pe–LCV) irradiated at 435 nm. Although the absolute quantum yield of photooxidation was in the order of 10−3 or less in both systems, the ternary electron transfer system was apparently advantageous since the efficiency of back electron transfer would be reduced when multiple electron transfer processes are linked. Furthermore, the concept of electron transfer sensitization enables spectral sensitization and utilization of low energy photons in singlet state photoredox reactions. Such systems would be considered as a model for the primary action of photosynthesis.
Spherical Particles and Their Surface Properties. I. Interaction of Water with the Surface of Spherical Silica
Authors: Morimoto Tetsuo , Kadota Toshie , Yanazawa Hiroshi , Kittaka Shigeharu
Published: July 2006

Spherical particles of silica were prepared by passing fine silica material through the O2–H2 flame. Spherical particles obtained were amorphous, creviceless, and very large in size compared to those of the starting material which indicates that spheres are made by complete comelting of a large number of fine particles. Water adsorption measurements showed that the rate of rehydration of the dehydroxylated silica surface is very slow, especially at low water pressures, and that the spherical silica has a heterogeneous surface, this heterogeneity being enhanced when the sample is heated at elevated temperatures. The ratio of the number of water molecules adsorbed in the first physisorption layer to that of the underlying surface hydroxyls was found to be 1:1.
Studies of Polyphenyls and Polyphenylenes. II. The Synthesis and Physical Properties of Polyphenyls Containing Para Linkage
Authors: Ozasa Shigeru , Hatada Noriko , Fujioka Yasuhiro , Ibuki Eiichi
Published: July 2006

Twelve linear polyphenyls, including quinque- to octiphenyl, were synthesized by the Ullmann cross-coupling reaction of iodobiphenyl with diiodobenzene or iodoterphenyl. Ultraviolet spectral studies of the polyphenyls indicated that the positions of the K-bands above ca. 260 nm, regardless of the presence of o- or m-phenylene unit(s), may be considered to be an indication of the approximate number of consecutive p-phenylene units. Infrared studies also showed that the locations of strong or medium bands in the 815–850 cm−1 region may give the same information. The HMO calculations of the longest wavelength absorption bands of twenty-four polyphenyls were carried out. A comparison between the calculated and observed wavelengths gave rather good agreement, except in the cases of two compounds. The signals of the proton magnetic resonance spectra of eighteen polyphenyls were assigned tentatively. The correlations between the arrangement of the benzene rings and the spectral patterns are discussed.
Synthesis of 2,5-Dehydrohomoadamantane (Tetracyclo[5.3.1.02,5.03,9]undecane) from 2,4-Dehydrohomoadamantane (Tetracyclo[5,3.1.03,5.04,9]undecane)
Authors: Katsushima Takeo , Yoshikawa Masato , Yamagughi Ryohei , Kawanisi Mituyosi
Published: July 2006

A reaction of 2,4-dehydrohomoadamantane with NBS in AcOH followed by LiAlH4 reduction and subsequent CrO3–pyridine complex oxidation gave endo-2-bromohomoadamantan-4-one (9) in good yield. A treatment of 9 with t-BuOK in t-BuOH followed by Wolff-Kishner reduction furnished 2,5-dehydrohomoadamantane.
Photo- and Thermally-induced Radical Rearrangements of Hypoiodites of 3α- and 3β-Methyl-5-cholesten-3-ols in the Presence of Mercury(II) Oxide and Iodine or Silver(II) Oxide and Iodine
Authors: Suginome Hiroshi , Maeda Norio
Published: July 2006

Hypoiodites of 3α- and 3β-methyl-5-cholesten-3-ols in benzene containing mercury(II) oxide and iodine gave 3α,5-epoxy-6β-iodo-3β-methyl-A-homo-4-oxa-5α-cholestane in 50–66% yield on irradiation or heating in the dark. Some minor products including the 6α-epimer were also found. The corresponding reaction with silver oxide and iodine reagent gave the same epoxide in 52% yield, together with a low yield of 3,4-seco-3-methyl-3-oxo-5-cholesten-4-al. Hydrogenolysis of the 6β-iodide with Pd–C as a catalyst gave 3α,5-epoxy-3β-methyl-A-homo-4-oxa-5α-cholestane (52% yield), together with the 6α-epimer arising from isomerization. The former, on treatment with boron trifluoride etherate and acetic anhydride in benzene, was transformed into 2-acetyl-3-methyl-5-acetoxymethyl-4-oxa-5β-cholestan-2-one. This was converted into 2β-acetyl-3α,5-epoxy-3β-methyl-4-oxa-A-homo-5α-cholestane by the treatment with aqueous methanolic potassium hydroxide.
The Catalytic Reactions on Hafnium Dioxide
Authors: Onishi Yoshito , Iizuka Yasuo , Hamamura Takuya
Published: July 2006

The mechanisms of the catalytic oxidations of carbon monoxide and hydrogen on hafnium dioxide are similar to those on titanium dioxide (anatase and rutile) and zirconium dioxide, and the activation energies of these reactions have been correlated with the oxygen bond energies of these four oxides.
The Reaction of 3-Hydroxyflavones with Metal Salts
Authors: Hamado Mutsumi , Kurosawa Kazu
Published: July 2006

The reaction of 3-hydroxyflavones (1a–d) with lead(IV) acetate gave 1,2-diphenylethanediones (2a–d), 1,2-diphenyl-2-hydroxyethanones, 2-hydroxybenzoic acids (7 and 9), and benzoic acids (8 and 10), and the reaction with manganese(III) acetate yielded 2, 7, 8, 9, and 10. In addition to 2, 7, and 10, 6-methoxy-2-(4-methoxybenzoyloxy)-3(2H)-benzofuranone and 2-hydroxy-4-methoxybenzaldehyde were obtained in the reaction of 1c with manganese(III) acetate. It has been established by the studies of 14C-labelled compounds that the C(3) in the 3-hydroxyflavone was lost during the reaction.
Reduction by a Model of NAD(P)H. 27. Role of Bivalent Metal Ion in the Reduction of 2-Acylpyridines and 1-Acylisoquinolines
Authors: Ohno Atsuyoshi , Yasui Shinro , Oka Shinzaburo
Published: July 2006

Reductions of 1-acetylisoquinoline (AQ), 1-benzoylisoquinoline (BQ), and isoquinoline-1-carbaldehyde have been studied kinetically and the results are compared with those of 2-acetylpyridine (AP), 2-benzoylpyridine (BP), and pyridine-2-carbaldehyde. Equilibrium constants for complexes between these substrates and zinc ion have also been studied. Kinetic deuterium isotope effects for AQ and BQ are smaller than the corresponding product isotope effects, respectively, whereas those for AP and BP are identical. The results are discussed in terms of stability and reactivity of intermediate radical-ion pair, and it is concluded that strong coordination of a metal ion onto the reaction site of a substrate facilitates the complexation but interferes the reduction.
The Synthesis and Decomposition of Calcium Tetraphosphate
Authors: Watanabe Makoto , Suzumori Hiroyasu , Maeda Mioko , Yamada Tamotsu
Published: July 2006

Calcium tetraphosphate was made by hydrolyzing cyclotetraphosphate in a 5-mol dm−3-solution of sodium hydroxide, neutralizing the phosphate solution with 1 mol dm−3 hydrochloric acid, and then adding calcium chloride to the solution. The P/Ca molar ratio of the product was 1.4–1.5. The tetraphosphate was an amorphous substance containing 20–30% of water and was decomposed to phosphates with a shorter chain length with bound water at room temperature or at a higher temperature. Upon decomposition at 300 °C, the main product at the early stage was pyrophosphate. The hydrolysis of the tetraphosphate obeyed the first-order kinetics with respect to the concentration of the phosphate, and the activation energy of the hydrolysis was 105 kJ mol−1 at pH 3.5.
Studies on Diazo Type Process. VII. Electronic Spectra of 2-(Substituted phenylazo)-1-naphthol-4-sulfonic Acid
Authors: Suzuki Shin , Das Rebati C , Harada Kieko , Stoyanov Stefan
Published: July 2006

The absorption of 2-(substituted phenylazo)-1-naphthol-4-sulfonic acid has been studied in neutral, acidic, and alkaline aqueous solutions as well as in solid state. Assignment of band positions to azo and hydrazone tautomers has been made by calculations using the SCF-CI-MO method. Introduction of electron-donating (or electron-withdrawing) substituent in the diazo part showed bathochromic (or hypsochromic) shift of the absorption band, which was elucidated by the charge migration and the character of the substituents taking into account azo-hydrazone tautomerism. In case of compounds containing electron-donating substituents, aggregation seems to take place in the solid state.
On the Nature of the 5,10-Dimethyl-5,10-dihydrophenazine–Tetracyanoquinodimethane
Authors: Fujita Isao , Matsunaga Yoshio
Published: July 2006

The 5,10-dimethyl-5,10-dihydrophenazine–tetracyanoquinodimethane appears to be largely ionic at room temperature. The results of various physical measurements of this compound can be explained without the reversible nonionic-to-ionic transition proposed by Soos et al.
MINDO/3 Prediction of the Π and Σ Electronic States of the Succinimido Radical
Authors: Kikuchi Osamu , Sato Yumiko , Suzuki Keizo
Published: July 2006

Restricted open-shell SCF MINDO/3 calculation gives the Σ state for the electronic ground state of the succinimido radical.
Thermal Rearrangements of 1,5-Dimethyl- and 1,3,5-Trimethyl-8-vinyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-ol and Their Alkoxides
Authors: Nitta Makoto , Komatsu Nobuo , Kasahara Ichiro
Published: July 2006

The reactions of 1,5-dimethyl- and 1,3,5-trimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one with vinylmagnesium bromide at 0 °C afforded 1,5-dimethyl- and 1,3,5-trimethyl-8-vinyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-ol, respectively. The thermal rearrangements of IIa,b and their alkoxybromomagnesium afforded 1,5-dimethyl or 1,3,5-trimethylbenzocyclohepten-6-one. It is suggested that the pathways involve an oxy-Cope rearrangement and the subsequent hydrogen migrations.
ESR Studies of a New Stable π-Conjugated 4,4′-(Biphenyl-3,3′-diyl)bis(aryloxyl) Biradical
Authors: Mukai Kazuo , Inagaki Noriko
Published: July 2006

ENDOR observations were carried out for 2,6-di-t-butyl-4-phenylphenoxyl and some of its derivatives. Based on the proton hyperfine splittings, the structure of the aryloxyl monoradicals was investigated in terms of the McLachlan MO calculation. A new stable π-conjugated bis(aryloxyl) biradical, 4,4′-(biphenyl-3,3′-diyl)bis(2,6-di-t-butylphenoxyl), was prepared, and the g- and D-tensor values of the biradical in toluene have been determined from its asymmetric frozen ESR spectrum. The D-tensor values were calculated for the twisted “cis” and “trans” conformers of the biradical molecule, using the McLachlan spin densities of 2,6-di-t-butyl-4-phenylphenoxyl, which is a monoradical half of the biradical.
Electron Spin Resonance Spectra of Square Planar Cobalt(II) Complexes with Various N4-Macrocyclic Ligands
Authors: Nishida Yuzo , Hayashida Kazuki , Sumita Akira , Kida Sigeo
Published: July 2006

ESR spectra of square planar cobalt(II) complexes with various N4-macrocyclic ligands were measured, the results being discussed in relation to the π-basicity and π-conjugation of the macrocyclic ligands.
Selective cis-Isomerization of 1-Pentene Catalyzed by Ni(I)-Triphenylphosphine Complexes
Authors: Kanai Hiroyoshi , Kushi Kenji , Sakanoue Kei , Kishimoto Nobuji
Published: July 2006

Selective cis-isomerization of 1-pentene was carried out by NiX(PPh3)3 (X=halogen and pseudohalogen). First-order plots were obtained except for the iodo-complex. The addition of tin(II) chloride increased both activities and ratios of cis-2-pentene to the trans-isomer. Protic solvents accelerated the isomerization. Isotopic exchange between C2D4 and C2H4 or 1-pentene reveals that a metal hydride addition-elimination mechanism is operative.
Calorimetric Study on Orientationally Disordered Crystals. Cyclohexene Oxide and Cyclohexanone
Authors: Nakamura Nobuo , Suga Hiroshi , Seki Syûzô
Published: July 2006

Low-temperature calorimetric quantities were determined for cyclohexene oxide and cyclohexanone in the temperature range between 13 and 300 K. Molar heat capacity at saturation pressure of the condensed phases, transition and melting temperatures, and enthalpies of transition and melting were measured by an on-line automated adiabatic calorimeter with intermittent heating mode. Purities of both calorimetric specimens were determined from their melting behavior. The following thermodynamic quantities, CS°, SS°, [HS°(T)−HS°(0)]/T, and −[GS°(T)−HS°(0)]/T were tabulated at selected temperatures. The entropies of melting of both compounds were compared with those of cyclohexanol and cyclohexane. A factor affecting the entropy of melting was discussed from the viewpoint of non-globularity of the constituting molecules. The discussion was extended to the thermal stability of a number of orientationally disordered crystals so far studied.
Electrical and Optical Properties of the 5,6:11,12-Bis(epidithio)naphthacene-Bromine System (TTT–Brn). Formation of Organic Mixed-valence Compounds (TTT)(TTT+)Br− and (TTT+)(TTT2+)(Br−)3
Authors: Matsunaga Yoshio , Takayanagi Kazuhiro
Published: July 2006

The electrical resistivity of the 5,6: 11,12-bis(epidithio)naphthacene-bromine system (TTT–Brn) was examined over the composition range from n=0.3 to 2.0 using polycrystalline compactions. The room-temperature resistivity shows a minimum of about 7 Ω cm near n=0.5, suggesting the formation of a mixed-valence compound, (TTT)(TTT+)Br−. The resistivity increases monotonously with n. No anomaly was found at the composition of (TTT+)Br−. The formation of another mixed-valence compound, the ideal composition of which may be expressed by the formula (TTT+)(TTT2+)(Br−)3, is indicated by an abrupt change of the resistivity from 100 to 4000 Ω cm around n=1.5. This change is accompanied by an increase of the activation energy for semiconduction by a factor of almost two and also by the change of sign in the variation of the Seebeck coefficient with the temperature from positive to negative. A further increase of the resistivity by a factor of ten was observed between n=1.5 and 2.0. The electronic and vibrational spectra support the coexistence of the TTT molecule and the TTT+ ion near n=0.5 and that of the TTT+ and TTP2+ ions near n=1.5.
Nuclear Magnetic Resonance in Hemihydrate Gypsum
Authors: Shimomura Kenji , Nagashima Toshikazu , Sanjoh Akira , Yoshida Makoto , Negita Hisao
Published: July 2006

The proton spin-lattice relaxation times T1 and T1D along the static and dipolar magnetic fields have been measured at 18 MHz for the water molecule in powdered hemihydrate gypsum CaSO4·(1/2)H2O. The minima of T1 and T1D were observed at 103⁄T=4.3(233 K) and 7.0(143 K) respectively. These are ascribed to the 180° flip motion of water molecules, with an activation energy of 15.1 kJ/mol. At higher temperatures, the translational diffusion of water molecules becomes dominant; this is not observed in gypsum CaSO4·2H2O. The activation energy of this motion is estimated to be 32.2 kJ/mol. In hemihydrate gypsum, though the diffusion is supposed to be anisotropic, the jumping distance of the water molecule is tentatively examined by Torrey’s lattice diffusion theory.
Studies on 2-Aziridinecarboxylic Acid. III. Reaction of 1-Acyl-2-aziridinecarboxylic Acid Peptide with Amines
Authors: Nakajima Kiichiro , Tanaka Takumi , Morita Kaoru , Okawa Kenji
Published: July 2006

The reaction of Z–Gly–Azy–Gly–OBzl with amines was studied. With primary amines, the 1-acyl group (Z–Gly) of the aziridine peptide mainly migrated to the reactant amine with cleaving of the amide bond between glycine and aziridine, whereas aniline and diethylamine gave diaminopropionic acid derivatives via the ring opening reaction.
Reaction between Various Copper(II) Complexes and Ascorbic Acid or 3,5-Di-t-butylcatechol
Authors: Oishi Naoyasu , Nishida Yuzo , Ida Kazuhiko , Kida Sigeo
Published: July 2006

The electron transfer reactions between various copper(II) complexes and two-electron donors, such as ascorbic acid and 3,5-di-t-butylcatechol, were investigated. Mononuclear copper(II) complexes with a distorted tetrahedral and a trigonal bipyramidal structure, and some binuclear complexes were readily reduced to copper(I) complexes by the two-electron donors, but not mononuclear planar copper(II) complexes. The catalytic activities of these copper(II) complexes for the oxidation of 3,5-di-t-butylcatechol by O2 were studied in relation to the above reactions.
Electrochemical Reduction of Elemental Sulfur in Acetonitrile
Authors: Fujinaga Taitiro , Kuwamoto Tooru , Okazaki Satoshi , Hojo Masashi
Published: July 2006

Electrochemical reduction of elemental sulfur (S8) has been carried out in acetonitrile using a platinum electrode. The products were identified by means of spectrophotometry and ESR. Sulfur is reduced voltammetrically in two steps:

S_8+2e→S_8^2-, S_8^2-+2e→2S_4^2-

These products turns into more stable species by the succeeding chemical reactions in a bulk solution as follows:

2&S_8^2\oversetK\ightleftarrowsS_6^2-+1/4S_8& &(K=1.6×10^-2)

&S_6^2-\oversetK_d\ightleftarrows2S_3^\ewdot& &(K_d=1.2×10^-3)

The S42− species was enough active to react with S8 into S82−, which was regarded as the cause of a current maximum on the current-time curve in a controlled potential coulometry of S8 at a potential of the second reduction step.
Cyclization Reactions of 2,3-Bis(2-cyanophenyl)propionitriles. III. Substituent Effect on the Carbanion Reactivies of the Propionitriles and Tautomerism of 5-Acetamido-11-cyanoindeno[1,2-c]isoquinolines
Authors: Ando Kazuo , Tokoroyama Takashi , Kubota Takashi
Published: July 2006

The substituent effect in the base-catalyzed cyclization reaction of 2,3-bis(2-cyanophenyl)propionitriles (1) to 5-amino-11-cyano-11H-indeno[1,2-c]isoquinolines has been studied and the result is discussed in terms of the dichotomic carbanion reactivities of 1. Preparation of 1 and the tautomerism of 5-acetamido-11-cyanoindeno[1,2-c]isoquinolines between 5H and 11H structures are described.
Nucleophilic Reaction of Electron-deficient Pyridone Derivatives. II. Ring Transformation of 1-Substituted 3,5-Dinitro-4-pyridones with Sodio β-Keto Esters
Authors: Matsumura Eizo , Ariga Masahiro , Tohda Yasuo
Published: July 2006

The reactions of 1-substituted 3,5-dinitro-4-pyridones [1-substituents: methyl (1a), 2-pyridyl (1b), 6-methyl-2-pyridyl (1c), and 4-pyridyl (1d)] with diethyl sodio-3-oxopentanedioate give 1-substituted 3,5-bis(ethoxycarbonyl)-4-pyridones and sodio-1,3-dinitro-2-propane. On the other hand, the reactions of the 4-pyridones (1b, 1c, and 1d) with ethyl sodioacetoacetate give ethyl 4-hydroxy-3,5-dinitrobenzoate together with aminopyridine homologues, and that of la gives furo [3,2-b] pyridine derivative. On the basis of the concept of soft and hard acids and bases, a stepwise nucleophilic attack of the anion of β-keto esters at the electrophilic center of the 2 and 6-positions or 2 and 3-positions of the 4-pyridones is proposed to interpret the variations of the reaction courses.
Synthesis of Lipophilic Muramyl Dipeptide Derivatives via O-Aminoacyl Intermediates
Authors: Kobayashi Shigeru , Fukuda Tsunehiko , Yukimasa Hidefumi , Imada Isuke , Fujino Masahiko , Azuma Ichiro , Yamamura Yuichi
Published: July 2006

Incorporation of an amino acid into the 6 position of the muramic acid moiety of muramyl dipeptide has been achieved, providing an effective means for the synthesis of various new derivatives. Six new muramyl dipeptide derivatives with an N-acylated amino acid were synthesized using these intermediates and their immunological activity was examined. All the derivatives exhibited adjuvant activity on the induction of delayed-type hypersensitivity to N-acetyl-3-(4-arsonophenylazo)-l-tyrosine.
Aromatic Nucleophilic Substitution. XIII. Confirmation of the Anionic σ Complexes in the Reactions of 2,4-Dinitro- and 2,4,5-Trinitro-1-(1-piperidyl)naphthalenes with Piperidine in Dimethyl Sulfoxide
Authors: Sekiguchi Shizen , Hikage Reiko , Obana Kenmi , Matsui Kohji , Ando Yumiko , Tomoto Noboru
Published: July 2006

In the reactions of 2,4-dinitro- and 2,4,5-trinitro-1-(1-piperidyl)naphthalenes with piperidine in dimethyl sulfoxide, the 1,1-disubstituted anionic σ complex was confirmed to exist with visible absorption and NMR spectra. Especially in the latter case the 1,3-disubstituted anionic σ complex was formed, the cause of formation of which was ascribed to the deactivating effect of 1-piperidyl group on C1-position of a napthtalene ring and the steric effect of 1-piperidyl group on the nucleophilic attack of piperidine on C1-position. These factors make the 1,1-disubstituted anionic a complex unstable.
Synthetic Identification of Bitter Heptapeptide in Tryptic Hydrolysate of Casein
Authors: Hashimoto Akio , Aoyagi Haruhiko , Izumiya Nobuo
Published: July 2006

A heptapeptide, H–Cly–Pro–Phe–Pro–Ile–Ile–Val–OH (1), was synthesized and found to be indistinguishable from the natural peptide (2), isolated from a tryptic hydrolysate of Hammersten casein by means of chromatography, amino acid analyses, and mass spectrometric measurements. Both peptides (1 and 2) have a strong bitter taste.
Highly Strained Ring Systems. Hydrolysis of endo-Tetracyclo[5.2.0.02,4.03,5]non-8-en-6-yl p-Nitrobenzoate. Importance of Anchimeric Assistance by Bicyclobutane Ring. II
Authors: Isobe Masayoshi , Yano Kazuyuki
Published: July 2006

Solvolytic reactivity of endo-tetracyclo[5.2.0.02,4.03,5]non-8-en-6-yl p-nitrobenzoate(1-OPNB), endo-bicyclo-[4.1.0]hept-2-yl p-nitrobenzoate(2-OPNB), and endo-bicyclo[4.2.0]oct-7-en-2-yl p-nitrobenzoate(4-OPNB) was investigated in 50% aqueous acetone. 1-OPNB was less reactive than 2-OPNB that has no cyclobutene ring and more reactive than 4-OPNB that has no bicyclobutane ring. Product study in solvolysis of 1-OPNB was undertaken leading to the rearranged tricyclic alcohol as a major product. The importance of conformational factor for anchimeric assistance by bicyclobutane ring is discussed.
Oxidative Cleavage of Tin–Tin Bonds in Hexaalkyldistannane with Several 1,4-Benzoquinones, Detection of the Semiquinone Radicals and 4-(Trialkylstannoxy)phenoxyl Radicals by ESR spectroscopy.
Authors: Kozima Sinpei , Fujita Hideo , Hitomi Torazô , Kobayashi Kazuhiko , Kobayashi Kazuko , Kawanisi Mituyoshi
Published: July 2006

The mechanism of the oxidative cleavage of tin–tin bonds in hexamethyldistannane (Me3SnSnMe3) and hexabutyldistannane (Bu3SnSnBu3) with several 1,4-benzoquinones was investigated. Chlorine-substituted 1,4-benzoquinones exerted higher reactivity, implying that the electron-acceptability of quinone is a factor governing the reaction. Stoichiometric treatments of chloranil with the distannanes ruled out the alleged isolation of the free radical, 4-(trimethylstannoxy)phenoxyl radical, reported by Gornwell et al. The final products were not the free radical entity but normal compounds, 1,4-bis(trimethylstannoxy)benzenes. Measurements of ESR spectra revealed the formation of the semiquinone radical anions and the subsequent formation of 4-(tributylstannoxy)phenoxyl radicals as reactive intermediates in the reaction pathway.
New Routes to the Pyrrolo[2,1,a]isoquinoline System
Authors: Iwao Masatomo , Kuraishi Tsukasa
Published: July 2006

Some derivatives of the title ring system were prepared from methyl α-(1-isoquinolyl)-β-aminocrotonate and ethyl α-(1-isoquinolyl)-β-amino-β-ethoxyacrylate in moderate to good yields via their quaternary salts.
Restricted Rotation Involving the Tetrahedral Carbon. XXXIII. Restricted Rotation about a Csp3–Csp2 Bond in 10,10-Disubstituted 9-(2,6-Xylyl)-9,10-dihydroanthracene Derivatives
Authors: Nakamura Mikio , Oki Michinori
Published: July 2006

A series of 10,10-disubstituted 9-(2,6-xylyl)-9,10-dihydroanthracene derivatives have been prepared and their conformations and barriers to internal rotation about the Cxylyl–C9 bond have been examined. These compounds exist predominantly as a pseudo-equatorial form in the ground state for rotation. A large effect is inserted by the substituents in 10 position on barriers to rotation and is interpreted in terms of a rotation-inversion mechanism rather than a simple rotation mechanism for the methyl-exchange process which is observed by 1H NMR spectra. The highest barrier to rotation has been found in the compound having two peri-chloro groups and a hydroxyl group in 9-position. The high barrier is ascribed to destabilization of the transition state, where 9-aryl group takes axial conformation, due to the three electronegative groups which are forced to be arranged parallelly in quite a near region. The change of 9-OH to 9-H thus decreases the barrier to rotation when peri-chlorines are present, while the increase in barrier is observed as in the case of 9-arylfluorenes and 9-arylxanthenes when they are absent.
Differential Refractometric Studies on Some Strong and Weak Molecular Complexes
Authors: Sahai Ram , Singh Vinod , Verma Rekha
Published: July 2006

A more adequate model has been developed to determine the equilibrium constant (K1) and stoichiometry of molecular complexes. This model involves the assumption:

&Δφ_a/C_D°={K_1C_A°/α(1+K_1C_A°)}-{K_1Δφ_a/(1+K_1C_A°)^2}

&Δφ_d/C_D°={K_1C_A°/α(1+K_1C_A°))}-{K_1Δφ_d/(1+K_1C_A°)^2}

where Δφa difference in the refraction per cm3 of solution and acceptor; Δφd is the difference in the refraction per cm3 of solution and donor; α is the extent of electronic polarization. CA° and CD° are the initial concentrations of acceptor and donor respectively. This model has been verified on some strong and weak complexes and was found better than that of earlier methods. Δφa, Δφd, and ΔΩCDA (refraction per cm3 due to chargetransfer complex) have also been used to Yoshida and \barOsawa’s method. The K1 obtained from the plot of Δφa or Δφd  versus molar ratio of solutes were found more reliable for weak complexes than K1 calculated from Yoshida and \barOsawa’s plot. From these plots the percentage of contribution of donor or acceptor in total 30% solute aggregation as proposed by Yoshida and \barOsawa has been calculated. It is also noted that Yoshida and \barOsawa’s method may give the reliable value for strong complexes but for weak complexes only differential refractometric method can provide the best values.
Synthesis and Studies of Some Novel Analogues of Phthalein Dyes
Authors: Chamoli R P , Rai S J , Gupta P C
Published: July 2006

Some novel analogues of phthalein dyes have been synthesized by condensing a γ-keto acid, 2-(2-thenoyl) benzoic acid with various phenols. The dyes so obtained are unsymmetrically substituted phthalides where the central carbon atom is attached with two different rings and these dyes have been named as phthal-as-eins;-‘as’ representing unsymmetry, and-‘ein’ class of the compound (phthal-ein). The structures of these products have been established on the basis of their elemental analysis and chemical reactions. Absorption maxima of these new dyes have been determined and compared with those of true phthaleins.