bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of 3-Acetyltropolone and Its Methyl Ethers with Hydrazine
Authors: Yamane Akio , Nagayoshi Masatoshi , Imafuku Kimiaki , Matsumura Hisashi
Published: July 2006

3-Acetyltropolone (1) was synthesized from 3-isopropenyltropolone by treatment with sodium azide in concentrated sulfuric acid. Methylation of 1 by diazomethane gave two isomers, 3-acetyl-2-methoxytropone (2a) and 2-acetyl-7-methoxytropone (2b). 1, 2a, and 2b reacted with hydrazine to give some 1,8-dihydrocycloheptapyrazol-8-one derivatives.
Solvent Assisted Oxy-Cope Rearrangement of Diastereomeric 1,5-Hexaden-3-ols. A New Industrial Process for Polyprenyl Ketones
Authors: Fujita Yoshiji , Amiya Shigetoshi , Onishi Takashi , Nishida Takashi
Published: July 2006

Oxy-Cope rearrangement of diastereomeric l,5-hexadien-3-ols, new key intermediates for terpenoids pio-duction in industrial scale, were investigated in neat systems and solvent assisted systems. Various solvents affecting the selectivity of [3,3]-shift were classified by means of NMR studies on hydroxyl proton exchange time.
A Study of the Interactions between Free Radicals and Cobalt Complexes
Authors: Yoshino Kenji , Ohkatsu Yasukazu , Tsuruta Teiji
Published: July 2006

The interaction between free radicals and cobalt complexes (Co(II)TPP and Co(II)(sal)2(R-CHXDA)) has been studied using (S,S)-(−)-, (R,R)-(+)-, and meso-1,1′-diphenylazoethane as a radical source. The decomposition of meso-1,1′-diphenylazoethane by heat or UV-light in the presence of Co(II)(sal)2(R-CHXDA) having an asymmetric ligand produced an optically active (+)-2,3-diphenylbutane. The suggestion is that the α-methylbenzyl radical formed from the azo compound is stereoselectively stabilized by the Co(II)(sal)2(R-CHXDA).
Absorption Spectra of Heterocyclic Compounds. Some 6-Hydroxy[1,3,4]thiadiazolo[2,3-b]benzimidazoles and Their Quaternary Derivatives
Authors: Soni R P , Saxena J P
Published: July 2006

Some 2-alkyl-6-hydroxy[1,3,4]thiadiazolo[2,3-b]benzimidazoles have been synthesised. Their absorption spectra at different pH show bathochromic shift of the absorption band in the longer wavelengths, which is more pronounced in basic medium. This is ascribed to the dipolar nature of the compounds. Quaternary derivatives of the compounds show a further red shift in the absorption band in the visible region, which further corroborates their dipolar nature.
Determination of pH in Reversed Micelles
Authors: Fujii Hirotada , Kawai Tohru , Nishikawa Hiroyasu
Published: July 2006

A new method for the determination of pH in reversed micellar systems was proposed. The degree of dissociation (α) of Phenol Red in the systems was observed spectrophotometrically. The value of pH can be obtained by use of the Henderson-Hasselbach equation with the aid of pKa of Phenol Red measured by means of 31P-NMR in the systems containing phosphate buffer solutions. The method was applied to systems consisting of sodium octanoate, 1-hexanol, and water and some buffer solutions other than phosphate buffer solutions, and found to be effective within a wide pH range. Analysis of the fluorescence spectra of 8-anilino-1-naphthalene-sulfonic acid indicates that Phenol Red molecules are present at the interface between the water core and the 1-hexanol phase in reversed micelles. The hydrolytic reaction of p-nitrophenyl acetate was also studied kinetically and found to change slightly with pH.
Copper(I) Chloride Complex Containing p-Benzoquinone as a Ligand
Authors: Yamaguchi Hiroko , Kimura Hiroshi , Yasukouchi Kazuo
Published: July 2006

A new complex [(NH4)Cu3Cl4(C6H4O2)3⁄2·H2O] was synthesized from CuCl2, hydroquinone, and NH4Cl in an aqueous solution, and its structure was characterized on the bases of its UV, IR, and ESR spectra and TGA. On heating, this complex was stable up to 100 °C, but above 120 °C p-benzoquinone was released quantitatively. The complex was found to be a polynuclear copper(I) complex containing p-benzoquinone molecules and chlorides as ligands, and to be a charge-transfer complex in which π-electrons of the ring carbons of p-benzoquinone form coordinate bonds with Cu(I). The formation process of the complex was:

3CuCl2+3/2(C6H6O2)+H2O+NH4Cl=(NH4)Cu3Cl4(C6H4O2)3⁄2·H2O+3HCl
The Reaction between SO2 and MnO2 and the Role of the Sulfato Complex in the SO2-induced Isomerization of cis-2-Butene
Authors: Otsuka Kiyoshi , Tanaka Kimiaki , Morikawa Akira
Published: July 2006

The reaction between SO2 and MnO2 has been studied by measuring the consumption of SO2-gas and the infrared spectra of the wafer of MnO2. In the low-temperature range (<200 °C) the reaction is completed within one or two surface layers of MnO2, and the reaction products are the bidentate sulfato complex (C2V) and the sulfato complex in Td symmetry. In the high-temperature range, on the other hand, the reaction progresses deep into the bulk and can be described by this stoichiometric equation; MnO2+SO2→MnSO4. The catalysis of MnO2 for the SO2-induced isomerization of cis-2-butene is closely related to the formation of the sulfate ion. The initiation step proposed for the isomerization is a polarization of the charge-transfer complex of SO2 and butene under the influence of the strong electrostatic field caused by the generation of the surface sulfato complex.
Adsorption of the Chromate Ion on Cured Diphenyl Phosphonate-Aldehyde Resins
Authors: Mori Hidehiko , Fujimura Yoshikazu , Takegami Yoshinobu
Published: July 2006

The adsorption of the chromate ion on cured diphenyl phosphonate-aldehyde resins has been investigated. Phosphorus-containing novolak type resins, obtained from the reaction of diphenyl phosphonate with aldehydes have been cured with additional hexamethylenetetramine. The adsorption of the chromate ion on the cured resins decreased in the order: propionaldehyde≈acrylaldehyde>butyraldehyde>crotonaldehyde>acetaldehyde>furfuial> formaldehyde. The optimum pH for the adsorption of the chromate ion was in the range 3.0 to 4.0. In the case of the cured diphenyl phosphonate-propionaldehyde resin, the amount of the adsorption of the chromate ion was 20.5 mg Cr/g resin. Under the same conditions, the amounts of the adsorption of molybdate and tungstate ions were 40.5 mg Mo/g resin and 80.0 mg W/g resin, respectively. The adsorbed chromate ion was recovered at approximately 80 wt% as chromium by elution with 1.0 mol/1 aqueous HCl solution. The adsorbed molybdate and tungstate ions were desorbed with 2.0 and 3.0 mol/l aqueous H2SO4 solutions, respectively. The recovery rate for Mo and W was 100 wt%. The mechanism of adsorption of the chromate ion on the cured resins having phosphinylden groups, (Remark: Graphics omitted.)P(O)H, has been discussed.
ENDOR Spectrum of Some Dihydro-1,4-dithiin Cation Radical
Authors: Watanabe Kohji , Nagao Yoshimitsu , Fujita Eiichi , Ishizu Kazuhiko
Published: July 2006

The ENDOR spectrum of the 2,3-diphenyl-5,6-dihydro-1,4-dithiin cation radical, which was prepared with AlCl3 in dichloromethane solution, has been observed. The spin density distribution of the new radical was also discussed and compared with the MO calculation.
Substitution Reactions of (Acetonitrile)chlorobis(triphenylphosphine)rhodium(I) in Benzene
Authors: Ohtani Yoshimi , Yamagishi Akihiko , Fujimoto Masatoshi
Published: July 2006

The kinetics of the substitution reactions of RhCl(NCCH3)(PPh3)2 in benzene was studied at 20 °C by the stopped-flow method under anaerobic conditions. The following mechanism was proposed:

(Remark: Graphics omitted.)
Kinetics on the Formation and Decomposition of 2AlM2O3·B2O3 from Mixed Powders Prepared by the Alkoxy-method
Authors: Yamaguchi Osamu , Tada Minoru , Takeoka Kiyoshi , Shimizu Kiyoshi
Published: July 2006

The formation of the alkoxy-derived 2A12O3·B2O3 was observed in the temperature range 820–930 °C. Crystallization isotherms were best described by the contracting cube equation, the activation energy being determined as 368 kJ/mol. The kinetics on the decomposition of 2A12O3·B2O3 was also studied.
Determination of Alkyl Thioureas, Isothiocyanates and Amines with Iodine Monochloride
Authors: Verma Krishna K
Published: July 2006

Iodine monochloride oxidizes thioureas to respective urea and sulfate in hydrogencarbonate medium. The iodine formed in the reaction is titrated with iodine trichloride to an Andrews end-point. This method has been applied to determine isothiocyanates and amines by their conversion to thioureas.
The Reaction of 2,4,6-Heptanetrione with o-Phenylenediamine
Authors: Furuhashi Akiko , Aoki Koji , Sugimoto Morihito
Published: July 2006

2,4,6-Heptanetrione forms 2-acetyl-4-methyl-1,5-benzodiazepine with o-phenylenediamine in alkaline ethanol. In acidic ethanol, it would be expected that the 2-acetyl-4-methyl-1,5-benzodiazepinium cation would be formed. Contrary to expectations, however, the cation seems to be unstable. 2,4-Dimethyl-1,5-benzodiazepinium salt was obtained instead.
Asymmetric Reactions. IV. Asymmetric, Catalytic Activity of Poly(2-quinuclidinylmethyl acrylate)
Authors: Yamashita Tetsushi , Yasueda Hiroshi , Nakamura Nobuo
Published: July 2006

The asymmetric addition of methanol to phenylmethylketene has been conducted in the presence of poly(2-quinuclidinylmethyl acrylate) and 2-quinuclidinylmethyl propionate derived from (S)-2-quinuclidinylmethanol. The asymmetric functions of the above catalysts were similar to those of poly(O-acryloylquinine) and O-propionylquinine, which contain a quinoline ring and a vinyl group as additional groups to the quinuclidine ring.
Syntheses of 3,5-Dimethylspiro[5.5]undeca-2,4-diene-1,8-dione and 7,11-Dimethylspiro[5.5]undeca-7,10-diene-2,9-dione
Authors: Bhattagharya Kalyan Kumar , Sen Parimal Krishna
Published: July 2006

Syntheses of 1-diazo-5-(2-hydroxy-4,6-dimethylphenyl)-2-pentanone and 1-diazo-5-(4-hydroxy-2,6-dimethylphenyl)-2-pentanone and their acid catalysed spiroannulation to 3,5-dimethylspiro[5.5]undeca-2,4-diene-1,8-dione and 7,11-dimethylspiro[5.5]undeca-7,10-diene-2,9-dione respectively via Ar1-6 participation are described. Succinylation of 3,5-dimethylanisole is also discussed.
The Transport of Metal Ions against Their Concentration Gradients through a 1,2-Dichloroethane Membrane
Authors: Sugiura Masaaki , Shinbo Toshio
Published: July 2006

The uphill transport of metal ions such as copper, zinc, cobalt, and iron(II) ions through a bulk 1,2-dichloroethane membrane in the presence of various chelating agents has been studied. The membrane separated two aqueous phases, one containing the metal ion and potassium or lithium sulfate, and the other containing the metal ion and lithium nitrate or chloride. The chelating agents used were derivatives of 1,10-phenanthroline and acetylacetone. The accumulation of the metal ions in the aqueous phase containing the potassium or lithium sulfate was observed for only the following chelating agents: copper: 4,7-diphenyl-2,9-dimethyl- and 4,7-diphenyl-1,10-phenanthroline; zinc: 4,7-diphenyl-, 3,8-diphenyl-, 2,9-dimethyl-, and 4,7-diphenyl-2,9-dimethyl-1,10-phenanthroline; cobalt: 3,8-diphenyl- and 4,7-diphenyl-1,10-phenanthroline; and iron(II): 3,8-diphenyl-1,10-phenanthroline. In the system containing lithium sulfate in the aqueous phase, the rate of transport of the metal ions was slightly higher than that in the system containing potassium sulfate. The reduction of the nitrate ion in the aqueous phase brought about a lowering of the rate of transport of the metal ions. The transport of the metal ions was, however, unaffected by the electrostatic effect. The metal ion complexed by the chelating agent may be transferred in the 1,2-dichloroethane phase, thus forming an ion-pair with the nitrate or chloride ion.
Photo-oxidation Effect of Poly(N-vinylcarbazole) Film on Photoconductivity and Electronic Spectra
Authors: Itaya Akira , Okamoto Ken-ichi , Kusabayashi Shigekazu
Published: July 2006

The photo-oxidation effect on poly(N-vinylcarbazole) (PVCz) and amorphous 1,3-di(N-carbazolyl)propane films was studied by means of ultraviolet absorption, infrared absorption, and fluorescence spectra. The photoconductivity of the photo-oxidized PVCz films was also measured as a function of photoirradiation time. A photo-oxidation product which formed near the surface of films had a carbonyl substituent group, acted as a singlet exciton trap in competition with the excimer-forming sites, and formed an exciplex with an excited carbazolyl chromophore. The very slight amount of the photo-oxidation product enhanced the photoconductivity of PVCz films by a factor of ca.15, suggesting that the product acted as an electron-accepting impurity in the photo-carriergeneration mechanism in the lowest π-π* absorption region of PVCz films.
Solubility Isotherm of Reciprocal Salt-Pairs Containing Bis(ethylene-diamine)oxalatocobalt(III) (1R,3S,4S,7R)-3-Bromocamphor-9-sulfonate
Authors: Fuyuhiro Akira , Yamanari Kazuaki , Shimura Yoichi
Published: July 2006

Four-component solubility isotherm of reciprocal salt-pairs consisting of (Λ-[Co(ox)(en)2]+, Δ-[Co(ox)(en)2]+)–(Cl−, d-C10H14OBrSO3−)–H2O has been determined experimentally at 25 °C. It was found that a pseudoracemate, Λ-[Co(ox)(en)2]·Δ-[Co(ox)(en)2](d-C10H14OBrSO3)2·2H2O, is present as the only double salt, optical resolution of the bis(ethylenediamine)oxalatocobalt(III) ion in this system at 25 °C being impossible as in the case of the ternary system, Λ-[Co(ox)(en)2](d-C10H14OBrSO3)–Δ-[Co(ox)(en)2](d-C10H14OBrSO3)–H2O, at 25 °C.
The Thermochemical Behavior of Pentaamminedinitrogenruthenium(II) Complexes and the Kinetics of the Liberation of Ammonia from the Complex in the Solid State
Authors: Kohata Susumu , Itoh Noriko , Kawaguchi Hitoshi , Ohyoshi Akira
Published: July 2006

The thermochemical reactions of [Ru(NH3)5N2]X2 (X=Cl, Br, I) were investigated in the solid state. The ammonia ligand was liberated at a lower temperature (165–213 °C) than the nitrogen ligand (243–270 °C). The isothermal measurement reveals that the first step of the degradation of the complex can be expressed as: [Ru(NH3)5N2]X2(s)→[RuX(NH3)4N2]X(s)+NH3(g) (X=Cl, Br, or I). The rate of the reaction is first-order to [Ru(NH3)5N2]X2, and the first-order rate constant increased in the order of: chloride<bromide<lodide. The activation energies and the activation entropies (E/kJ mol−1 and ΔS\eweq/J K−1 mol−1 respectively) for the reaction were as follows: chloride (181±1,62±1), bromide (99±1, −95±2), and iodide (89±1, −102±3). The values of ΔS\eweq suggest that the salt with Cl− degrades through an SNl-like mechanism, while those with Br− and I− degrade through an SN2-type mechanism. The thermochemistry of [Ru(NH3)5N2]X2 has been discussed on the basis of the strong π-backbonding ability of the nitrogen ligand and the electronegativity of the outer-sphere ions.
Equilibria of Imidazole Derivatives with (Protoporphyrin IX dimethyl ester)iron(III) Chloride
Authors: Yoshimura Tetsuhiko , Ozaki Tomio
Published: July 2006

The equilibria of sterically hindered and unhindered imidazoles (B) with (protoporphyrin IX dimethyl ester)iron(III) chloride (Fe(PPDME)Cl) have been spectrophotometrically investigated in chloroform and 1,2-dichloroethane. The addition reaction of hindered imidazole with Fe(PPDME)Cl proceeds in two steps to give Fe(PPDME)B2Cl, with a formation constant, K1, greater than K2. The mono-adduct of hindered imidazoles exhibits an absorption band at around 590 nm, which shifts to longer wavelengths as the formation constant K1 decreases in this order; 2,4-dimethyl->2-methyl->2-ethyl->2-phenyl->1,2-dimethylimidazole. The addition reaction of an unhindered imidazole with Fe(PPDME)Cl proceeds in an apparent one step to give Fe(PPDME)B2Cl, with an overall formation constant of β2. The logβ2 linearly increases with the basicity, pKa(BH+), of unhindered imidazoles. The logβ2 for the system with NH-containing imidazoles is greater than that for the system with N-substituted imidazoles by about 3.1 log units, on the average, based on the stabilization of the positive charge on iron(III) through NH…Cl hydrogen bonding. The solvent effect on the formation constants is also discussed.
Curve Fitting Methods Applied to the Elucidation of Asymmetric Gas-Liquid Chromatographic Peaks
Authors: Takeuchi Koji , Kambara Tomihito
Published: July 2006

It was shown that the shape of gas-liquid chromatographic peak is expressed by the Gaussian distribution multiplied by a higher order algebraic equation of time. Application of the curve fitting methods, i.e., the Newton’s divided-difference formula and the orthogonal polynomials method, could well clear up the experimentally observed gas-liquid chromatograms of trailing and leading types, respectively. The asymmetric shapes of gas-liquid chromatographic peaks are attributed to the slowness of vaporization or dissolution in the partition process.
Thermodynamics of 1:1 Adduct-formation of Bis(trifluoroacetyl-acetonato)copper(II) with Lewis Bases
Authors: Sasaki Yoshihiro , Sakurada Matsujiro , Matsui Masakazu , Shigematsu Tsunenobu
Published: July 2006

Formation constants and thermodynamic parameters for the 1: 1 adduct-formation reactions of bis(trifluoroacetylacetonato)copper(II), Cu(tfac)2, with alkylamines, α-picoline, 2,6-lutidine, and THF have been determined spectrophotometrically. The ΔH°–ΔS° plots for primary and secondary alkylamines gave a linear relationship for the thermodynamic parameters of the Cu(tfac)2-heterocyclic base systems. The plots for the 2,6-lutidine, THF and tertiary alkylamine systems have been found consistent with a correlation between ΔH° and ΔS° values for bis(acetylacetonato)copper(II)–heterocyclic base systems. It has been subsequently deduced that the 1: 1 adducts of Cu(tfac)2 with Lewis bases possess a square-pyramidal structure on the basis of the ESR data for the 63Cu(tfac)2–Lewis base systems.
A Possible Method for Obtaining Precise Isotope Ratio of the Element Having Only Two Isotopes
Authors: Kanno Hitoshi
Published: July 2006

As an extension of the atomic/molecular vaporization model, a new method is presented for correcting the isotopic fractionation effects in the multiple filament thermal ionization source (MFTIS). It is applicable to the isotope ratio measurements of the element having only two observable isotopes.
Spectrophotometric Determination of Cobalt(II) with Eriochrome Black T after Extraction as Methyltrioctylammonium Tetrathiocyanatocobaltate(II)
Authors: Rokugawa Yuh’ichi , Sugawara Masao , Kambara Tomihito
Published: July 2006

A sensitive extraction-spectrophotometrie method for determination of cobalt(II) with Eriochrome Black T is described, which involves the preliminary separation of cobalt from aqueous solution by the benzene extraction of methyltrioctylammonium tetrathiocyanatocobaltate(II). The quantitative formation of ion pair between cobalt–Eriochrome Black T complex anion and the quaternary ammonium cation is attained by shaking the resulting extract with aqueous Eriochrome Black T solution of pH 5.5–8.2. Beer’s law holds for 0.57–4.0 μg cobalt in 5 ml of the extract with the molar absorption coefficient of ε587=6.62×104 cm−1 mol−1l (Sandell sensitivity 8.90×10−4 μg cm−2). The composition of the extracted ion pair is estimated to be cobalt: Eriochrome Black T:methlytrioctylammonium ion=1:2:3.
The Electrochemical Oxidation of Aminopurines and Their Hydroxy Derivatives at the Glassy Carbon Electrode
Authors: Yao Toshio , Musha Soichiro
Published: July 2006

The electrochemical oxidation of aminopurines and their hydroxy derivatives, which gave a single voltammetric peak at the glassy carbon electrode, was investigated by means of linear-sweep voltammetry, cyclic voltammetry, coulometry, and macroscale control!ed-potential electrolysis. In general, the ease of oxidation of these compounds increased in proportion to the number of hydroxyl or amino groups on the molecule. The coulometric n-values for monosubstituted purines were 5.86–6.08, for disubstituted purines they were 3.90–4.20, and for trisubstituted purines they were 2.07–2.33. The electrochemical oxidation of the different aminopurines appeared to follow initially the same path as the enzymatic oxidation; i.e., the primary attack for the electrochemical oxidation occurred first at the C-8 position, and then the C-2 position. Thus, aminopurines were oxidized in two sequential two-electron processes to give first 8-hydroxy and then 2,8-dihydroxy(or 6,8-dihydroxy) intermediates. Then, this latter intermediate was further oxidized in a two-electron process to produce a diimine intermediate, which was unstable and which then broke down to the ultimate products, such as parabanic acid, oxaluric acid, urea, ammonia, allantoin, and guanidine.
Crystal and Molecular Structure of Mitomycin C, an Anticancer Antibiotic
Authors: Ogawa Keizo , Nomura Akiko , Fujiwara Takaji , Tomita Ken-ichi
Published: July 2006

The crystal structure of mitomycin C was determined by means of X-ray diffraction. Mitomycin C was crystallized in the orthorhombic space group P212121, with a=12.887, b=13.851, c=9.718 Å, and Z=4, and its structure solved by the trial and error method using the rigid-body approximation. The absolute configuration was determined by referring to that of N-(p-bromobenzoyl) mitomycin C. The carbamoyloxymethyl side chain participates in hydrogen bonds as in the case of other mitomycins in the crystalline state.
Relative Spin-trapping Ability of N-Benzylidene-t-butylamine Oxide, N-Benzylideneaniline Oxide, and 2,3,5,6-Tetramethylnitrosobenzene towards Phenyl and Phenylcyclohexadienyl Radicals
Authors: Kamimori Mariko , Sakuragi Hirochika , Sawatari Katsuhiko , Suehiro Tadashi , Tokumaru Katsumi , Yoshida Masayuki
Published: July 2006

N-Benzylidene-t-butylamine oxide (PBN), N-benzylideneaniline oxide (DPN), and 2,3,5,6-tetraraethylnitrosobenzene (ND) trap phenyl radicals in a relative rate of 1 : 0.72 : 2.6, whereas they trap phenylcyclohexadienyl radicals in a relative rate of 1 : 2.3 : 130. The origin of such different spin-trapping abilities of these spin traps towards phenylcyclohexadienyl radicals is discussed.
Effect of Hydration on the Thermal Stability of Protein as Measured by Differential Scanning Calorimetry. Lysozyme–D2O System
Authors: Fujita Yukihisa , Noda Yukinao
Published: July 2006

The thermal denaturation of the deuterated lysozyme has been investigated by differential scanning calorimetry in the range of deuterium oxide (D2O) content from 0.03 to 1.6 g of D2O per g of protein. At D2O contents above 0.55 g/g, the temperature, Td, and enthalpy change, ΔHd, of denaturation were almost independent of the degree of hydration. At lower D2O contents, however, both Td and ΔHd showed marked dependence on the degree of hydration. The values of Td increased with a decrease in the D2O content. Whereas the values of ΔHd decreased with a decrease in the D2O content in the same region. The degree of hydration dependency of ΔHd exhibited a break at approximately 170 mol/mol, which indicates that at least two types of hydration contributes to the thermal stability of the protein. The conformational enthalpy change of the protein and the enthalpy change of the hydration layer have also been estimated from the degree of hydration dependency of ΔHd. The results have been compared with those of the Iysozyme–H2O system.
Solvolysis in Carboxamides. VI. Kinetic, Product, and Deuterium Tracer Studies on the N,N-Dimethylacetamide Solvolysis of threo-2-(p-Methoxyphenyl)-1-methylpropyl Brosylate. Nature of the kΔ Pathway
Authors: Saito Seiki , Doihara Kenji , Moriwake Toshro , Okamoto Kunio
Published: July 2006

Solvolysis of threo-2-(p-methoxyphenyl)-1-methylpropyl brosylate (1) and its deuterium derivative (1-2-d) has been carried out in N,N-dimethylacetamide (DMA) as solvent at 50.0 and 75.0 °C. Product examination revealed that in the presence of water (0.17 mol/dm3) the main product is threo-2-(p-methoxyphenyl)-1-methylpropyl acetate (73% at 50 °C), but in the absence of water (Z)-2-(p-methoxyphenyl)-2-butene (5) (ca. 70% at 50 °C). Both of these products are derived from a threo-imidatonium ion [threo-R-Amide]+ which is produced by DMA capture of the tight ion-pair [R+OBs−] (2) from the front-side. A part (ca. 14% yield) of the (Z)-olefin 5 is directly led from the tight ion-pair 2. The formation of the olefin 5 can not be explained by intervention of the phenyl-bridged ion. Although the rate of the brosylate 1 exhibits the kΔ portion deviating upwards from the Hammett plot for a series of threo-2-aryl-1-methylpropyl brosylates, the Schleyer’s kΔ-ks treatment for the rate-(retained)product correlation was unsatisfactory. The classical simple SN1 mechanism can preferably elucidate the product distribution, including the isotope distribution, without intervention of the phenyl-bridged ion intermediate.
The Transformations of Terpene Eetones by Oxygen. II. The Base-catalyzed Autoxidation of Pulegone and Fukinone and Their Dihydro Compounds
Authors: Horinaka Akio , Yo Eiyu , Mori Otoji , Naya Keizo
Published: July 2006

Upon autoxidation in alkaline media, pulegone and fukinone (2) gave pairs of hydroxy ketones respectively as the major products; also, hydroxyeremophilone was isolated as its acetate from 2. On the other hand, their dihydro compounds afforded hydroxy ketones, diosphenols, and acids.
Preparation of Chlorophyll-a and Chlorophyll-b by Column Chromatography with Sephasorb HP Ultrafine
Authors: Yoshiura Masahiko , Iriyama Keiji , Shiraki Masaru , Okada Akira
Published: July 2006

A method for the preparation of chlorophyll-a (Chl-a) and chlorophyll-b (Chl-b) by column chromatography with Sephasorb HP Ultrafine has been developed. The partially purified chlorophyll preparation containing Chl-a, Chl-b and nonsorbed carotenes was applied to a Sephasorb HP Ultrafine column and good separation of Chl-a and Chl-b achieved with a solvent program of (I), a diethyl ether/hexane mixture (1:9, volume ratio) followed by 0.2 and 0.5 vol % isopropyl alcohol in (I). 13.1 mg of Chl-a and 7.6 mg of Chl-b were obtained from 24.7 mg of the partially purified chlorophyll using the above method.
A Simple Synthesis of α-Ylidene γ-Lactones from γ-Trimethylsiloxy Nitriles
Authors: Matsuda Isamu , Murata Shizuaki , Izumi Yusuke
Published: July 2006

α-Cyano carbanions which are generated from γ-trimethylsiloxy nitriles have been found to react with aldehydes to give α-(1-hydroxyalkyl)-γ-trimethylsiloxy nitriles (6). α-Ylidene γ-lactones (5) are derived from 6 in two steps; hydrolytic lactonization to α-(1-hydroxyalkyl) γ-lactones and dehydration. The stereochemistry of the lactones 5 with one exception have been found to be of the E form on the basis of the NMR spectra.
The Difference in Solvolytic Reactivity between Diastereomers in α-(trans-2-Arylcyclopropyl)arylmethyl 3,5-Dinitrobenzoates
Authors: Takata Toshimasa , Matsusaki Hajime , Ohkata Katsuo , Hanafusa Terukiyo
Published: July 2006

Each diastereoisomeric pair of α-(trans-2-p-tolylcyclopropyl) benzyl and α-(trans-2-phenylcyclopropyl)-p-tolylmethyl 3,5-dinitrobenzoates (I-4a, b, II-4a, b) has been synthesized. The relative solvolytic rates of I-4b to I-4a and of II-4b to II-4a in 80% aqueous acetone have been found to be 3.59 and 1.86 respectively at 25 °C. In the presence of 2,6-lutidine, the major products in the solvolysis were homoallylic alcohols.
The Nucleophilic Reaction of Electron-deficient Pyridone Derivatives. I. The Ring Transformation of 1-Substituted 3,5-Dinitro-2-pyridones with Sodio β-Keto Esters
Authors: Matsumura Eizo , Ariga Masahiro , Tohda Yasuo
Published: July 2006

A novel ring transformation is found in a series of reactions of 1-substituted 3,5-dinitro-2-pyridones, electron-deficient substrates, with monosodium salts of β-keto esters. A variety of 1-substituted 3,5-dinitro-2-pyridones are treated with diethyl sodio-3-oxopentanedioate and ethyl sodioacetoacetate to give, in addition to N-substituted nitroacetamides (3), 2,6-bis(ethoxycarbonyl)-4-nitrophenol (2), and 2-ethoxycarbonyl-4-nitrophenol (4) respectively. The bicyclic intermediates, 2-azabicyclo[3.3.1]nona-3,7-dienes, can be isolated on the reaction of 3,5-dinitro-1-methyl-2-pyridone at room temperature. The phenol derivatives (2 and 4) may consist of the reagent and a C4–C5–C6 moiety of the parent pyridone, while N-substituted nitroacetamides, 3, may result from the other fragment, N–C2–C3, of the pyridone. A probable course of the reaction, involving the step-by-step nucleophilic attack of the ambident nucleophiles, sodio β-keto esters, at the ambident electrophilic centers of 2-pyridones to form bicyclic intermediate, is proposed.
Sesquiterpenoids. LIV. Absolute Configuration of Eudesma-4(14),7(11)-dien-8-one
Authors: Endo Katsuya , Hikino Hiroshi
Published: July 2006

(+)-Eudesma-4(14),7(11)-dien-8-one (1)isolated from Atractylodes rhizomes has been degraded with basic alumina to the trisnor ketone (3). From the CD spectra of 1 and 3, the absolute configuration of 1 has been established to be 5S, 10R, which has so far been allocated to the (−)-enantiomer.
Oxidation-Reduction Equilibrium between Cation Radicals. An Approach to Determine Ionization Potentials of Electron Donor Molecules
Authors: Iida Yôichi , Yamagishi Akihiko
Published: July 2006

For several electron donor molecules, the adiabatic ionization potential and the oxidation-reduction potential in the formation of cation radical from its parent molecule were estimated by using the equilibrium constant of a preferred electron transfer reaction from neutral donor molecule to another cation radical molecule in solution.
Structural Interconversions of Dichlorobis(triphenylphosphine)nickel(II) in Various Solvents
Authors: Katô Hajime , Yorita Kazuko , Kato Yoshifumi
Published: July 2006

Structural interconversions, ligand exchange, the temperature- and concentration-dependent equilibrium of configurational isomers, and the solvolysis of NiCl2(Ph3P)2 in various solvents have been studied. The MCD and absorption spectra were employed, together with the calculation based on ligand-field theory and the NMR spectra. Paramagnetic tetrahedral NiCl2(Ph3P)2 and the solvated paramagnetic octahedral NiCl2(Ph3P)2(dmso)2are in equilibrium in the coordinating solvent DMSO. The ratio of the former to the latter increases with the rise of concentration and temperature. Configurational isomers of NiCl2(Ph3P)2, a paramagnetic tetrahedral one and a diamagnetic square-planar one, are found in a non-coordinating solvent CHCl3. The former species decreases gradually and a yellow precipitate is formed. The same two species, and two other solvated paramagnetic tetrahedral and octahedral species, NiCl2(CH3CN)2 and NiCl2(CH3CN)4, are found to be in equilibrium in CH3CN.
An Ultrasonic Absorption Study of the DMF–Water System
Authors: Kawaizumi Fumio , Nomura Hiroyasu , Ohno Makoto , Miyahara Yutaka
Published: July 2006

Using the pulse method, the ultrasonic absorption was measured for binary mixtures of water and N,N-dimethylformamide (DMF) at 5.5 and 57 MHz in the temperature range of 5–45 °C. At lower temperatures α⁄f2 as a function of the concentration produces a plateau up to x (x is the mole percent of DMF in solution)=1.5, a minimum point at x=6, and a maximum point at x=25. An increase in the temperature causes these characteristic features of α⁄f2 to disappear. At 45 °C the values of α⁄f2 increase monotonically. No relaxation process is observed in the frequency range of this work. The general features of the concentration dependence of α⁄f2 resemble those of the urea–water system in a water-rich region and those of the dioxane–water system in a DMF-rich region. The mechanism of the plateau can be explained by the cooperative nature of the formation and breaking of water clusters. The maximum of α⁄f2 is ascribed to the complex formation between DMF and water molecules, while the minimum of α⁄f2 arises from the competition between the breaking-down of the water structure and the complex formation in solution. The maximum behavior in the ultrasonic absorption can be interpreted in terms of a kinetic model, DMF+mH2O\ightleftharpoonsDMF·(H2O)m. m is determined to be 3, and the following values have been obtained for the model mentioned above: ΔVm\simeq1 cm3/mol, Km=10±2.
Effect of Diffusion Layers on Bi-ionic Potentials across Liquid Ion-exchange Membranes
Authors: Yoshida Nobuo
Published: July 2006

In a bi-ionic system in which a liquid membrane is interposed between aqueous solutions containing different counterions, the solution composition is often not maintained uniform right up to the membrane–solution interface owing to the presence of diffusion layers adjacent to the interface. Taking the effect of the diffusion layers into account, an expression is derived for the bi-ionic potential across a membrane having completely dissociated ion-exchange sites and counterions. The expression contains as an empirical parameter the ratio between the thicknesses of the diffusion layers at the solution and membrane sides of the interface. The expression is found to agree with experimental data, with the parameter given a single value.
Film Dichroism. II. Linearly-polarized Absorption Spectra of Acridine Dyes in the Stretched Poly(vinyl alcohol) Films
Authors: Matsuoka Yukio , Yamaoka Kiwamu
Published: July 2006

The linear dichroic absorption spectra of the protonated and quaternized acridine dyes were measured in the UV and visible regions by the stretched film technique. The dyes examined were acridine, 10-methylacridine, Proflavine, Trypaflavine, Acridine Yellow, 10-Methylacridine Yellow, Acridine Orange, and 10-Methylacridine Orange, all of which belong to the C2v point symmetry group. Poly (vinyl alcohol) was used as a film matrix. The absorption spectrum of each dye was resolved into the long-axis and short-axis polarized components. Two orthogonally-polarized electronic transitions (the 1La and 1Lb bands) of 3,6-disubstituted acridine dyes were reduced to overlap in the visible region of the spectra. The orientation factors Ky and Kz of each dye were evaluated at a constant degree of stretching and were related to the geometry of the dye molecule.
The Determination of the Formation Constant of Triiodide Ion in Micellar Solution of Dodecyltrimethylammonium Chloride
Authors: Hayakawa Katumitu , Kanda Mitsuo , Satake Iwao
Published: July 2006

Spectrophotometric measurements were undertaken at 360 nm in order to estimate the formation constant of triiodide ion in micellar solution of dodecyltrimethylammonium chloride. The absorption spectra of the solutions suggested that both iodine molecule and triiodide ion are solubilized in a hydrophilic surface region of the surfactant micelle. The apparent formation constant of triiodide ion, Ka, was found to be much larger in micellar solution than in water. It was also shown that the value of Ka decreases regularly with increasing surfactant concentration. A tentative estimation based on a lamellar micelle model led to the intrinsic formation constant of triiodide ion of 650 mol−1 dm3 or less at 30 °C, which is comparable with that in water. The thermodynamic consideration revealed that the formation reaction of triiodide ion from iodine and iodide ion in micellar solution is accompanied by an anomalous entropy decrease.
Metathesis of 1,5-Cyclooctadiene over Supported Rhenium Oxide Catalysts
Authors: Saito Kaizaburo , Yamaguchi Tsutomu , Tanabe Kozo , Ogura Toshimasa , Yagi Misao
Published: July 2006

The metathesis of 1,5-cyclooctadiene (COD) was investigated over supported rhenium oxide catalysts in terms of carrier effects, acid properties of the catalysts, product distributions, and the reversibility of the reaction. Only alumina plays an effective role as a support. The reaction of COD over rhenium oxide–alumina catalyst yields oligomers, C8n, sesqui-oligomers, C8n+4, and polymers. The important results are as follows: 1) The product distribution in terms of the carbon number of the products shows a decay curve with maxima around C12, C16, and C20. 2) The reaction of oligomers gives COD and some products similar to those of COD. 3) The reactivity of 1,5,9-cyclododecatriene (CDT) was low compared with COD, 1,5,9,13-cyclohexadecatetraene (CHT), and 1,5,9,13,17-cycloeicosapentaene (CEP). 4) A reaction of a mixture of macrocyclic polyenes and polymers gave appreciable amounts of CDT, CHT, and CEP, whereas no COD was obtained. On the basis of the results, we conclude that the products, oligomers, sesqui-oligomers, and polymers, are formed independently from the active intermediary polymers which are formed from COD.
A Thermodynamic Study on the Hydrolysis of Beryllium Ion in Dioxane–Water Mixed Solvents
Authors: Ishiguro Shin-ichi , Ohtaki Hitoshi
Published: July 2006

The hydrolytic reactions of beryllium(II) ions were calorimetrically studied at 25 °C in aqueous solution and dioxane–water mixtures, both containing 3.0 mol dm−3 (Li)ClO4 as a constant ionic medium. On the basis of the formation constants previously determined, the enthalpy and entropy changes for the reaction, qBe2++pH2O=Beq(OH)p(2q−p)++pH+, were estimated for the Be2OH3+ and Be3(OH)33+ complexes in aqueous solution and 0.1 mole fraction dioxane–water mixture and for Be2OH3+, Be3(OH)33+, and Be2(OH)22+ complexes in 0.2 mole fraction dioxane–water mixture. The enthalpy and entropy changes of formation of the Beq(OH)p(2q−p)+ complex obtained in solutions of various mole fractions of dioxane were as follows: 2Be2++H2O=Be2OH3++H+; ΔH12 (mole fraction: 0.0)=18.6±0.2 kJ mol−1, TΔS12(mole fraction: 0.0)=1.3±0.2 kJ mol−1, ΔH12(0.1)=15.2±0.2 kJ mol−1, TΔS12(0.1)=−3.4±0.2 kJ mol−1, ΔH12(0.2)=8.4±0.4 kJ mol−1, TΔS12(0.2)=−12.4±0.4 kJ mol−1, 3Be2++3H2O=Be3(OH)33++3H+; ΔH33(0.0)=61.7±0.2 kJ mol−1, TΔS33(0.0)=12.2±0.2 kJ mol−1, ΔH33(0.1)=59.4±0.2 kJ mol−1, TΔS33(0.1)=10.0±0.2 kJ mol−1, ΔH33(0.2)=59.0±0.4 kJ mol−1, TΔS33-(0.2)=9.1±0.4 kJ mol−1, 2Be2++2H2O=Be2(OH)22++2H+; ΔH22(0.2)=42.3±0.4 kJ mol−1, TΔS22(0.2)=1.3±0.4 kJ mol−1. The enthalpy and entropy changes of the reaction, H2O=H++OH−, in the solutions of the same compositions were also determined as ΔHw(0.0)=56.6±0.1 kJ mol−1, TΔSw(0.0)=−22.6±0.1 kJ mol−1, ΔHw(0.1)=58.1±0.1 kJ mol−1, TΔSw(0.1)=−25.3±0.1 kJ mol−1, ΔHw(0.2)=61.2±0.1 kJ mol−1, TΔSw(0.2)=−26.6±0.1 kJ mol−1. These results were discussed in connection with interactions between the hydroxo complexes and the solvent molecules and with those between solvent molecules in the mixed solvents.
An Interpretation of the “Molecular Space” on the Basis of Quantum Chemical Calculations of Hydrated Ions
Authors: Fujiwara Shizuo , Rode Bernd M
Published: July 2006

Quantum chemical calculation has been made for the sizes of the hydration shells of the metal ions as well as for the binding energies of water molecules in the hydration shells. The results of the both calculations give the basis of the size of the molecular space. Although the experimental value of the molecular space, (20±5A)3, does not exactly agree with the calculated value, we assume that the quantum chemically obtained hydration sphere refers to the molecular space.
Photoelectron Spectra of Hydrogen-bonded Complexes
Authors: Utsunomiya Chikatoshi , Kobayashi Tsunetoshi , Nagakura Saburo
Published: July 2006

The photoelectron spectra of typical hydrogen-bonded complexes, CF3COOH–(C2H5)2NCH3, CF3COOH–(n-C3H7)3N, CF3CF2COOH–(C2H5)2NCH3, and CF3CF2COOH–(n-C3H7)3N were observed in the gas phase. It was found that the nonbonding orbital of the proton acceptor is stabilized significantly by hydrogen-bond formation while the three higher occupied orbitals of the proton donor are destabilized. The large orbital energy changes due to hydrogen-bond formation strongly support the charge-transfer model for the hydrogen bond.
Vibrational Distribution of CS(X1Σ+) Fragments Formed in the UV Flash Photolysis of CS2
Authors: Ebata Takayuki , Kawasaki Masahiro , Obi Kin-ichi , Tanaka Ikuzo
Published: July 2006

The vibrational distribution of the CS(X) fragment has been studied by the UV flash photolysis and kinetic spectroscopic technique. The CS fragment was generated by the flash photolysis of CS2 at ≈200 nm. The vibrational distribution is well represented by a sum of two modified Poisson distributions with different mean values. This distribution is explained by assuming the following two photodissociation processes of CS2; one is a predissociation through a triplet state and the other is a direct photodissociation.

(Remark: Graphics omitted.)
Pressure Effects on the Base Hydrolysis Reaction Rates of α-, β-[Co(edda)(NH3)2]+ and α-[Co(edda)(NO2)2]− in a Carbonate Buffer
Authors: Kitamura Yoichi
Published: July 2006

The pressure effects on the base hydrolysis reaction rates of α-, β-[Co(edda)(NH3)2]+ and α-[Co(edda)(NO2)2]− in a carbonate buffer were measured up to 1500 kg/cm2 (1 kg/cm2=98.0665 kPa). The activation volumes at normal pressure were found to be 16.6, 22.3, and 11.9cm3/mol respectively. These values are consistent with those expected from the SN1 CB mechanism, where the conjugate bases dissociate via the Id mechanism.
The Thermal Decomposition of Vanadium(III) Chloride Oxide and Its Reaction with Oxygen
Authors: Yajima Akimasa , Matsuzaki Ryoko , Saeki Yuzo
Published: July 2006

The thermogravimetry and differential thermal analysis of VClO in an argon stream were carried out. The products obtained by heating VClO in an argon stream at various temperatures were examined by chemical analysis and X-ray analysis. Also, the reaction between VClO and oxygen was examined in the same manner. When VClO is heated in an argon stream, it decomposes above about 400 °C to form V2O3 and VCl3, 3VClO(s)→V2O3(s)+VCl3(s). Subsequently, the resulting VCl3 disproportionates to form VCl2 and VCl4, 2VCl3(s)→VCl2(s)+VCl4(g). VClO reacts with oxygen above about 120 °C to form V2O5 and VCl3O, 6VClO(s)+3O2(g)→2V2O5(s)+2VCl3O(g); this reaction is accompanied by the 4VClO(s)+3O2(g)→2V2O5(s)+2Cl2(g) reaction.
A Proton Conductive Coordination Polymer. I. [N,N′-Bis(2-hydroxyethyl)dithiooxamido]copper(II)
Authors: Kanda Seiichi , Yamashita Kenichi , Ohkawa Kuwako
Published: July 2006

In a family of catena-μ-N,N′-disubstituted dithiooxamidocopper(II) complexes which have been assumed as two-dimensional coordination polymers, one complex with HOC2H4- substituents is an electronic conductor as well as others, and also a protonic conductor uniquely. The latter property was proved both by spectroscopic detection of the hydrogen molecules evolved from d.c. electrolysis of pressed pellets of the powder specimen and by observation of the anomalous increase (three orders of magnitude) of the electric conductivity as an effect of 103 Pa of H2O or D2O vapor on the dehydrated specimen in an evacuated conductivity cell. A novel conduction mechanism was suggested for such a solid system with both conjugated double bonds and extended hydrogen bonds.
Studies of Unusual Amino Acids and Their Peptides. XI. The Resolution of β-(2-Furyl)-β-alanine and β-(2-Thienyl)-β-alanine and Their Absolute Configurations
Authors: Kuwata Shigeru , Yamada Takashi , Shinogi Tatsuya , Yamagami Naoki , Kitabashi Fumio , Miyazawa Toshifumi , Watanabe Hiroshi
Published: July 2006

(+)-β-(2-Furyl)-β-alanine and (+)-β-(2-thienyl)-β-alanine were obtained by resolving the N-benzyloxycarbonyl-Dl-amino acids with quinine and by removing the protecting group from them. It was concluded, from the changes in their ORD curves depending on the pH, and also from the sign of the Cotton effects of their DCHA salts of the N-ethylthiocarbonothioyl derivatives, that both the compounds belong to the l-series. This conclusion was supported by the fact that the aspartic acid obtained by the oxidation of these amino acids belongs to the d-series.
Acyl Cyanide. VI. The Synthesis of 1-Cyano-1-alkenyl Esters by the Reaction of Acyl Cyanides with Acid Chlorides. Synthesis and Mechanism
Authors: Oku Akira , Arita Shingo
Published: July 2006

The reactions of enolizable acyl cyanides (acetyl, propionyl, isobutyryl, and diphenylacetyl cyanide) with acid chlorides (acetyl, propionyl, benzoyl, p-nitrobenzoyl, diphenylcarbamoyl, and dimethylcarbamoyl chloride) in the presence of tertiary amines gave the corresponding 1-cyano-l-alkenyl carboxylates or carbamates in good yields. Among several solvents and amines examined in the reaction of acetyl cyanide with propionyl chloride, benzene and pyridine seem to be most appropriate. The maximum yield (98%) of the ester was attained in benzene when both the chloride and pyridine were used in excess amounts (1.2–1.4 times the amount of the cyanide). The rate of reaction depended little on the concentration of the chloride but on both the cyanide and the amine being of first order in each reactant; it was also influenced by the basicity of tertiary amines and, in the case of weak bases, additionally by their nucleophilic power.
Halogenated and Non-halogenated Aromatic Sesquiterpenes from the Red Algae Laurencia okamurai Yamada
Authors: Suzuki Minoru , Kurosawa Etsuro
Published: July 2006

The taxonomic reexamination of the red alga ‘L. intermedia Yamada,’ previously collected at Oshoro Bay, Hokkaido, showed that this alga consistd of a mixture of L. intermedia Yamada, L. capituliformis Yamada, and L. okamurai Yamada. Within the Japanese species of genus Laurencia, laurinterol and debromolaurinterol were found to be characteristic metabolites of L. okamurai, not of L. intermedia. In the course of this examination, dibromophenol and debromoaplysinol were newly isolated.
A Synthesis of 7α-Methoxycephalosporins through Selenenamides
Authors: Kobayashi Takeo , Hiraoka Tetsuo
Published: July 2006

The o-nitrobenzeneselenenamides were oxidized with active manganese dioxide to give the irnines, which were converted to the 7α-methoxycephalosporins 3 by the reaction with lithium methoxide. The selenenamides 3 were acylated with phenoxyacetyl chloride to afford the desired cephamycin derivatives 4  via tertiary amide 5, which was not isolable. This methoxylation reaction was also carried out in penicillin series to give the desired 6α-methoxypenicillin 8 although the ring opening compound 9 was a major product. The difference between sulfenamides and selenenamides in their acylation reactions was discussed.
Reactions of 1-Halo-1-nitroso- and 1-Halo-1-nitrocycloalkanes with Triphenylphosphine. A New Synthesis of Lactam
Authors: Sakai Ikuo , Kawabe Norio , Ohno Masaji
Published: July 2006

Reactions of 1-halo-1-nitroso- and 1-halo-1-nitrocycloalkanes with triphenylphosphine have been carried out. The Perkov reaction and Beckmann rearrangement occurred successively with the formation of lactams in high yields. The reaction of cycloalkanone oxime with halogen in the presence of triphenylphosphine also gave lactams in one step.
1,3-Dipolar Cycloadditions to 2-Phenyl-1-azaspiro[2.2]pent-1-ene
Authors: Tsuge Otohiko , Watanabe Hiroyuki , Kiryu Y\={o}ko
Published: July 2006

Benzonitrilium-p-nitrobenzylide undergoes 1,3-dipolar cycloaddition to highly strained 2-phenyl-1-azaspiro[2.2]pent-1-ene, yielding the cycloadduct which is thermally converted to the dihydrobenzo[f]quinazoline and pyrimidine. In the reaction with α,N-diarylnitrone, the spiroazapentene gives 1-(benzylideneamino)-1-(N-phenylbenzamido)cyclopropane arising from the initial cycloadduct.
Stereochemistry of Diels-Alder Reactions at High Pressure. II. Influence of High Pressure on Asymmetric Induction in Condensation of (−)-Di-(R)-menthyl Fumarate with Butadiene and Isoprene
Authors: Jurczak Janusz
Published: July 2006

The high-pressure Diels-Alder condensation of (−)-di-(R)-menthyl fumarate with butadiene and isoprene, followed by reduction of the adducts with lithium aluminium hydride, produced (1S,2S)-(+)-4-cyclohexene-1,2-dimethanol and (1S,2S)-(+)-4-methyl-4-cyclohexene-1,2-dimethanol in 6.2–12.8% optical yield, depending on the pressure applied. Results of asymmetric synthesis were discussed in light of the concept of parallel transition states. An interpretation of the thermal and Lewis-acid-catalyzed asymmetric Diels-Alder condensations using (−)-di-(R)-menthyl fumarate was proposed.
SO2-Produced Acidic Hydroxyl Groups and the Catalytic Activities of Alkaline Earth X Zeolites
Authors: Otsuka Kiyoshi , Wada Yuji , Tanaka Kimiaki , Morikawa Akira
Published: July 2006

The generation of Brönsted acid sites by SO2-adsorption on alkaline earth X zeolites has been examined by infrared spectroscopy. The SO2-induced catalytic activities of the zeolites in the double-bond isomerization of butenes can be ascribed to both the increase in the number of acidic hydroxyl groups and the enhancement in the catalytic activities of the groups after the SO2 adsorption.