bluuebunny/crossref_metadata_2025 huggingface dataset:
The Phosphorescence Spectra of 1,4-Naphthoquinone and Its Alkyl Derivatives in Solutions at 77 K
Authors: Kuboyama Akira
Published: July 2006

The phosphorescence spectra of 1,4-naphthoquinone (NQ), 2-methyl-, 2,6-dimethyl-, 2,6-diisopropyl-, and 2,6-di-t-butyl-NQ’s in various kinds of solutions at 77 K were studied. The phosphorescence bands of NQ and 2,6-di-t-butyl-NQ in all the solutions and those of the other NQ’s in saturated hydrocarbon solutions are assigned to the n,π* band. In the ethanol solution, 2-methyl-NQ shows a dual phosphorescence, the lifetimes of which are different and which depends on the excitation wavelength. In the Daifloil solutions, 2-methyl- and 2,6-dimethyl-NQ’s also show a dual phosphorescence. In the toluene solutions, these two NQ’s show remarkably broad phosphorescence bands. These facts are discussed on the basis of the electronic structures at the excited states of these NQ’s.
Studies on the Syntheses of Sesquiterpene Lactones. I. Chemical Transformation of α-Santonin into Vulgarin, C4-Epivulgarin, and Arglanine
Authors: Ando Masayoshi , Akahane Atsushi , Takase Kahei
Published: July 2006

Syntheses of vulgarin, C4-epivulgarin, and arglanine are reported. An efficient conversion of 3-oxo-5αH, 4β,6β,11βH-eudesm-1-en-6,13-olide into 1-oxo-5αH,4β,6β,11βH-eudesm-2-en-6,13-olide, a key intermediate of these syntheses, was achieved by the Meerwein-Ponndorf reaction and the allylic rearrangement of the resultant 3-hydroxyl derivative followed by the Collins oxidation. Acetalization of 1-oxo-5αH,4β,6β,11βH-eudesm-2-en-6,13-olide and successive isomerization of the double bond gave 1,1-ethylenedioxy-5αH,6β,11βH-eudesm-3-en-6,13-olide regioselectevity. Oxidation of this compound with OsO4 gave 3α,4α-dihydroxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesman-6,13-olide, 3α,4α-dihydroxy-1-oxo-5αH,6β,11β-eudesman-6,13-olide and 3β,4β-dihydroxy-1,1-ethylene-dioxy-5αH,6β,11βH-eudesman-6,13-olide. Oxidation of 1,1-ethylenedioxy-5αH,6β,11βH-eudesm-3-en-6,13-olide with m-chloroperoxybenzoic acid gave 3α,4α-epoxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesm-6,l3-olide stereoselectively in a quantitative yield. Treatment of 3α,4α-dihydroxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesman-6,13-olide,3α,4α-dihydroxy-1-oxo-5αH,6β,11βH-eudesman-6,13-olide, and 3α,4α-epoxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesm-6,13-olide with boiling 50% AcOH gave vulgarin. The same treatment of 3β,4β-dihydroxy-1,1-ethylene-dioxy-5αH,6β,11βH-eudesman-6,l3-olide gave C4-epivulgarin. Phenylselenenylation of 3α,4α-dihydroxy-1,1-ethylenedioxy-5αH,6β,11βH-eudesman-6,13-olide and successive syn-elimination of the resultant phenylseleno lactone gave 3α,4α-dihydroxy-1,1-ethylenedioxy-5αH,6βH-eudesm-11-en-6,13-olide, which was transformed into arglanine by treatment with boiling 50% AcOH.
Standard Redox Potentials of R−/R+ Reference Redox Couples and Solvent Activity Coefficients
Authors: Kakutani Tadaaki , Morihiro Yoshikazu , Senda Mitsugi , Takahashi Reiji , Matsumoto Koichi
Published: July 2006

The standard redox potentials of five R−/R+ redox couples that can be considered as candidates for the reference redox couple, i.e., the anion/cation couples of tris(2,2′-bipyridine)iron(II), tris(2,2′-bipyridine)ruthenium(II), cobaltocene, perylene, and 9,10-diphenylanthracene, have been determined in acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide and propylene carbonate by means of polarography and voltammetry. The results confirmed that the standard potentials of these redox couples are independent of the solvents studied so that they can be used as solvent-independent reference points for potential comparisons. The solvent activity coefficients of the silver ion have been estimated on the basis of these reference redox couples.
Reduction by a Model of NAD(P)H. XVI. Effect of Magnesium Ion for the Reduction of Thiopivalophenone
Authors: Ohno Atsuyoshi , Yasui Shinro , Nakamura Kaoru , Oka Shinzaburo
Published: July 2006

Magnesium ion retards the reduction of thiopivalophenone with 1-benzyl-1,4-dihydronicotinamide (BNAH) in acetonitrile. Kinetics and other investigation have revealed that the retardation is due to the formation of non-reactive complexes, thiopivalophenone·Mg2+ and BNAH·Mg2+.
An ESR Study of N-Benzoyl- and N-Pivaloyl-N-(arylthio)aminyls
Authors: Miura Yozo , Katsura Yosuke , Kinoshita Masayoshi
Published: July 2006

N-Benzoyl-N-(arylthio)aminyls, ArCO\dotNSAr′, and N-pivaloyl-N-(arylthio)aminyls, t-BuCO\dotNSAr, were generated in benzene by hydrogen-abstraction from N-benzoyl- and N-pivaloylbenzenesulfenamides. The hyperfine coupling constants (hfcc) for the radicals are in the range of 6.80–7.57 G for the nitrogen nucleus and 1.68–1.97 G for the S-phenyl ring protons. However, hfcc due to the benzoyl and pivaloyl protons were not detected. The g-values lie in the range of 2.0081–2.0084. On the basis of these ESR parameters, it is suggested that the acylaminyls exist in a π-electronic ground state and that the unpaired electron is located predominantly on the nitrogen atom (2pz orbital) and the phenylthio group. From the decay kinetic study of the radicals, it was found that N-benzoyl-N-(4-cnlorophenylthio)aminyl persisted for more than 3 h in benzene at 24 °C, and N-pivaloyl-N-(4-chlorophenylthio)aminyl decayed only a little, even after 20 h.
The Binding and Catalytic Properties of a Positively Charged Cyclodextrin
Authors: Matsui Yoshihisa , Okimoto Akihiko
Published: July 2006

In order to learn the significance of electrostatic interactions between charged groups in an enzymatic process, a positively charged cyclodextrin, mono-(6-trimethylammonio-6-deoxy)-β-cyclodextrin hydrogencarbonate (βCDtma), was prepared as a simple enzyme model, and its binding and catalytic properties were examined. The dissociation constant for an inclusion complex of βCDtma with an azo dye, sodium 4-(4-hydroxy-1-naphthylazo)-1-naphthalenesulfonate (1), was found to be 5.4×10−5 mol/dm3 in an alkaline solution (pH 10.5, Ic=0.0 mol/dm3) at 25 °C, the value being smaller than that for an inclusion complex of the parent β-cyclodextrin (βCD) with 1 by a factor of ca. 4. The catalytic effect of βCDtma on the alkaline hydrolyses of o-, m-, and p-acetoxybenzoic acids was significantly different from that of βCD. These observations were explained in terms of electrostatic and hydrophobic interactions between βCDtma and a guest molecule.
Macrocyclic Formals. IV. Macrocyclic Formals as Compiexing Agents
Authors: Kawakami Yuhsuke , Sugiura Tomiya , Yamashita Yuya
Published: July 2006

Eleven to twenty membered macrocyclic formals have been synthesized from the corresponding polyethylene glycols and paraformaldehyde. Their activating efficiency has been measured in nucleophilic substitution reactions with alkali metal ions as counter ions. These macrocyclic formals were not as good compiexing agents as crown ethers, but were much better than open chain polyethers which had the same number of oxygen atoms. In the reaction of butyl bromide with alkali metal acetate, 1,3,6,9,12,15-hexaoxacycloheptadecane was several times more effective than pentaethylene glycol dimethyl ether.
Pyrolytic Sulfurization Gas Chromatography. IV. Removal of Trace Amounts of Organic Compounds in Sulfur by Refluxing with Oxides
Authors: Hara Tadashi , Fujinaga Kaoru , Tsuji Katsuya , Okui Fujio
Published: July 2006

Oxides of aluminium, silicon, and titanium, instead of the magnesium oxide used in the Bacon-Fanelli method, were found to be effective for the elimination of trace amounts of organic compounds in sulfur. Prolonged refluxing in an inert gas atmosphere were especially favorable for the removal of organic compounds
Reaction of α-Keto Sulfoxides with Hydrogen Chloride and Trichloroacetic Acid
Authors: Wakui Toshimitsu , Nakamura Yoshio , Motoki Shinichi
Published: July 2006

α-Keto sulfoxides (1) reacted with hydrogen chloride to afford chloroformates, disulfides, and thiosulfonates. 1 also reacted with trichloroacetic acid to give methyl trichloroacetate, disulfide and thiosulfonate.
A Molecular Orbital Study of the Conformation and g-Factors of the HSSH− Radical Anion
Authors: Kikuchi Osamu
Published: July 2006

The electronic structure and g-factors of the HSSH− radical anion were calculated by means of a restricted open-shell SCF MO method with the MINDO/3 approximation, and the dependence of the g-factors upon the conformation was clarified. The most stable conformation predicted agreed well with the experimentally estimated –S–S– geometry of dialkyl disulfide anions, and its g-factors agreed well with the observed values.
Absolute Configurations of Asperlin, a Metabolite of Aspergillus nidulans, and Its Related Compounds
Authors: Fukuyama Keiichi , Katsube Yukiteru , Noda Akihiro , Hamasaki Takashi , Hatsuda Yuichi
Published: July 2006

The structures of asperlin (1) C10H12O5 and asperlinol (2) C10H14O6, isolated from Aspergillus nidulans, and a chloro derivative of asperlin (3) C10H13O5Cl have been studied by the X-ray diffraction method. The absolute configuration of 3 has been determined by the Bijvoet method by utilizing the anomalous scattering of chlorine atom for Cu Kα radiation. The present analysis has verified the configurations of the atoms in an αβ-unsaturated δ-lactone ring as suggested by spectroscopy. In each compound, the acetoxyl group occupies a quasi-axial and the three-carbon side chain a quasi-equatorial position on the lactone ring. All the crystals are orthorhombic, space group P212121with Z=4. The cell dimensions are a=26.536, b=5.955, c=6.973 Å for 1, a=25.496, b=7.097, c=6.329 Å for 2, and a=26.050, b=5.899, c=7.548 Å for 3. The structures of 1, 2, and 3 were refined by the block-diagonal least-squares method to R=0.068 for 1084 reflections, R=0.056 for 1127 reflections, and R=0.051 for 831 reflections, respectively.
Metachromasy. IV. The Simultaneous Determination of the Bound Dye Spectra and the Equilibrium Constants between Metachromatic Dyes and Various Polyelectrolytes by the Extended Principal Component Analysis Method
Authors: Yamaoka Kiwamu , Takatsuki Mineo
Published: July 2006

Fourteen sets of visible absorption spectra of two metachromatic dyes, Crystal Violet (CV) and Trypaflavine (TF), were measured in the presence of seven widely different polyelectrolytes—sodium polyphosphate, polyacrylate, and poly(ethylenesulfonate), sodium and potassium poly(p-styrenesulfonate)s, and native and denatured calf thymus DNA–in polymer residue-to-dye ratios between 0 : 1 and about 1 : 1. The optical titration curves of these dye-polyanion systems showed either of two changes, sigmoidal or monotonous. The method of principal component analysis was applied to the observed spectra of each dye-polyanion system in order to determine both the equilibrium constant of the binding reaction and the pure spectrum of the bound dye. An empirical parameter a was introduced into the expression for the equilibrium constant in such a way that K=[complex]/[free dye][unoccupied binding site]α, by which the sigmoidal titration curves could be reproduced only with α>1 and the monotonous ones, with α≤1. The spectra of bound CV and TF showed metachromasy bands, which depend on the functional group and the conformation of the polyanions, in wavelength regions both shorter and longer than the peak wavelength of the free dyes.
Resonance Raman Spectra of p-Benzosemiquinone Anion Dimer
Authors: Yamaguchi Satoshi , Yokoyama Kenji , Maeda Shiro
Published: July 2006

Resonance Raman specta have been observed for the dimer of p-benzosemiquinone anion. When the exciting-light frequency was exactly resonant with the absorption band characteristic of this dimer, a new polarized Raman line appeared at 177 cm−1 with a striking resonance enhancement. The resonant behavior and the frequency value both indicate that it can reasonably be assigned to the interradical stretching vibration of the parallel D2h dimer molecule, much as in the case of the previous Würster’s cation dimers.
Structural Study of Optical Resolution. VI. The Crystal Structure of (+)589-cis-Chloroamminebis(ethylenediamine)cobalt(III) d-3-Bromocamphor-9-sulfonate Monohydrate
Authors: Kuramoto Masahiro , Kushi Yoshihiko , Yoneda Hayami
Published: July 2006

The crystal structure of cis-chloroamminebis(ethylenediamine)cobalt(III) d-3-bromocamphor-9-sulfonate monohydrate, (+)589-[CoClNH3(en)2](d-BCS)2·H2O, has been determined by three-dimensional X-ray analysis. The deep red crystals are orthorhombic, space group P212121, with four formula units in the unit cell of dimensions a=34.97(2), b=14.25(1), and c=7.08(1) Å. The calculated density of 1.64 g·cm−3 compares well with the observed density 1.65 g·cm−3. The structure has been refined by the block -diagonal least-squares method to an R-factor of 0.096 for 2662 reflection data points. In the complex cation, one of the two ethylenediamine chelate rings has a “50% ob, 50% lel” type disordered character in its conformation and the other ring is in a “lel” type. The absolute configuration of the complex cation is denoted as Λ[(50%λ, 50%δ)δ], which was determined by comparison with that of the d-BCS anion. There are notable differences between the two crystallographically independent d-BCS anions with respect to their local packing modes.
Solution Equilibria of Ternary α-Amino Acid-Copper(II) Complexes with Electrostatic Ligand-Ligand Interactions
Authors: Sakurai Takeshi , Yamauchi Osamu , Nakahara Akitsugu
Published: July 2006

The stability constants for the parent and mixed copper (II) complexes involving an acidic α-amino acid (aspartic acid or glutamic acid, abbreviated as A) and/or a basic α-amino acid (arginine, lysine, or ornithine, abbreviated as B) have been determined by potentiometric titration at 25 °C in 0.1 and 0.03 M KNO3 (M=mol dm−3). The protonated ternary species Cu(l-A)(l-B)(H) and Cu(d-A)(l-B)(H) (species 1111) have essentially the same stability constants, the log β1111 values being in the range 25.0–27.5. The species distribution curves for the systems Cu(II)-l- or d-glutamic acid-l-lysine at the ionic strength I=0.1 and 0.03 reveal that species 1111 is more predominant at I=0.03 than at I=0.1, suggesting that electrostatic ligand-ligand interactions between the carboxylate group in the side chain of A and the ammonium or the guanidinium group in the side chain of B are reinforced in solution at lower ionic strength to favor the ternary complex formation. The constants for deprotonation from species 1111 to form 1110, e.g. Cu(l-A)(l-B), are given by the difference log β1111−log β1110, which is higher for the Cu(II)–A–B systems than for the systems containing alanine in place of A. The results indicate that intramolecular electrostatic interactions are present in the ternary species 1111, stabilizing them under favorable conditions.
Photochemical Reactions of Aromatic Compounds. XXIX. Photochemical and Thermal Cycloreversions of 1,2,2a,8b-Tetrahydrocyclobuta[a]naphthalenes
Authors: Pac Chyongjin , Mizuno Kazuhiko , Sakurai Hiroshi
Published: July 2006

Photochemical and thermal cycloreversions of 1,2,2a,8b-tetrahydrocyclobuta[a]naphthalenes were investigated. The cycloreversion in the excited singlet state was completely stereospecific; a concerted mechanism was assigned. The benzophenone-sensitized and thermal decomposition gave a mixture of cis- and trans-olefins, but favored stereoretention. The mechanisms are discussed in terms of singlet and triplet 1,4-biradicals.
Reactive Troponoids and o-Aminophenol. II. The Formation of Cyclohepta[b][1,4]benzoxazine and 11H-Cyclohepta[b][1,4]benzoxazin-10-one Derivatives from Isomeric Isopropyl-2-chlorotropones
Authors: Nozoe Tetsuo , Someya Taichi
Published: July 2006

The reactions of three isomeric isopropyl-2-chlorotropones with o-aminophenol were investigated. 8-Isopropylcyclohepta[b][1,4]benzoxazine was obtained from 5-isopropyl-2-chlorotropone, while 4- and 6-isopropylderivatives gave the same mixture of 7- and 9-isopropylcyclohepta[b][1,4]benzoxazine. These facts showed that the amino group of o-aminophenol attacked both the C-1 and C-2 positions of 2-chlorotropones. Also 6-, 7-, and 8-isopropyl-11H-cyclohepta[b][1,4]benzoxazin-10-ones were obtained as the minor products of these reactions.
The Acetoxylation of p-Substituted Acetophenones and β-Diketones with (Diacetoxyiodo)benzene
Authors: Mizukami Fujio , Ando Moriyasu , Tanaka Tatsuo , Imamura Juichi
Published: July 2006

The methyl groups of p-substituted acetophenones and the methylene groups of β-diketones were acetoxylated with (diacetoxyiodo)benzene. When the substrates were p-chloroacetophenone, p-nitroacetophenone and 4,4,4-trifluoro-1-phenyl-1,3-butanedione, the corresponding acetoxylated compounds were obtained in high yields.
Dehydroannulenes. X. Synthesis and Properties of 3,9,12,18-Tetra-substituted-1,10-bisdehydro[18]annulenes
Authors: Iyoda Masahiko , Akiyama Shuzo , Nakagawa Masazumi
Published: July 2006

The cyclic dimerization of 1,7-disubstituted-1-oxo-2,4,6-nonatrien-8-ynes on treatment with a suspension of potassium hydroxide in liquid ammonia to give tetrasubstituted 18-membered cyclic glycols has been achieved. The cyclic glycols could be converted into 3,9,12,18-tetrasubstituted 1,10-bisdehydro[18]annulenes which were found to be conformationally stable and strongly diatropic.
Dehydroannulenes. XI. Synthesis and Properties of 3,11,14,22-Tetra-t-butyl-1,12-bisdehydro[22]annulene
Authors: Iyoda Masahiko , Nakagawa Masazumi
Published: July 2006

7-t-Butyl-9-trimethylsilyl-2,4,6-nonatrien-8-ynal prepared from 5-t-butyl-7-trimethylsilyl-2,4-heptadien-6-ynal diethyl acetal was converted into 8-t-butyl-1,3,5,7-decatetraen-7-ynyl t-butyl ketone. Treatment of the tetraenyne ketone with potassium hydroxide in liquid ammonia gave 22-membered cyclic glycol in a high yield. Reductive dehydroxylation of the cyclic glycol by tin(II) chloride and hydrogen chloride yielded tetra-t-butylbisdehydro[22]annulene in good yield. The [22]annulene was found to be strongly diatropic and conformationally stable.
Ionic Motion and Phase Transition in Potassium Hydrogendifluoride KHF2 Studied by Pulsed NMR
Authors: Furukawa Yoshihiro , Kiriyama Hideko
Published: July 2006

Nuclear spin-lattice relaxation times, T1 and T1ρ, have been measured above room temperature for 1H and 19F nuclei in powdered KHF2 and its deuterated analogue. Below 400 K and in the high-temperature β-phase (Tt=469.8 K), the magnetization recovery for both nuclei in KHF2 is strongly non-exponential owing to the heteronuclear H–F interaction. In the low-temperature α-phase the T1  vs. 1/T curves show broad minima ascribable to the 180°-flip motion of linear [FHF]− anions. The activation energy Ea of this motion was determined to be 50.5±2 kJ/mol. The phase transition, which is defined by discontinuous changes in both T1 and T1ρ, is associated with diffusional disorder superimposed on rapid isotropic reorientation of the HF2− ion. The relaxational process in the β-phase is governed by self-diffusion of the anions with an Ea of 80±6 kJ/mol deduced from the T1ρ data. In contrast to the earlier suggestion from electrical measurements, the NMR results indicate that the dominantly mobile species in the conducting high-temperature β-phase are not single F− ions but complex [FHF]− anions.
Photoelectron Angular Distribution Measurements for Some Pyridines
Authors: Utsunomiya Chikatoshi , Kobayashi Tsunetoshi , Nagakura Saburo
Published: July 2006

The angular distributions for the He I photoelectron spectra of pyridine, pentafluoropyridine, and 2,6-lutidine have been measured in order to solve the ambiguities on the band assignment of pyridine. It has been concluded that the first band of pyridine is assigned to the a1n orbital and the fifth band to the lowest occupied b1π orbital.
Synthesis of 6-Hydroxy-12-methyl-7,12-dihydrobenzo[6,7]cyclohept[1,2-b]indol-7-one
Authors: Fujimori Kunihide , Yamane Kameji
Published: July 2006

5,6,7,12-Tetrahydrobenzo[6,7]cyclohept[1,2-b]indol-7-ones were obtained by the oxidation of 5,6,7,12-tetrahydrobenzo[6,7]cyclohept[1,2-b]indoles with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in wet dioxane. The α,α-dibromo compound, obtained by bromination of 12-methyl-5,6,7,12-tetrahydrobenzo[6,7]cyclohept[1,2-b]indol-7-one with phenyltrimethylammonium tribromide (PTAB), was hydrolyzed to give the diketone (5). By treatment with alkali, compound 5 was converted to 6-hydroxy-12-methyl-7,12-dihydrobenzo[6,7]cyclohept[1,2-b]indol-7-one.
5,9-Dihydroxy-4,8,11,11-tetramethyltricyclo[6.3.0.02,4]undecane. Acidcatalyzed Cyclization Product of 6,7-Epoxyhumula-2,9-diene
Authors: Namikawa Misuzu , Murae Tatsushi , Takahashi Takeyoshi
Published: July 2006

6,7-Epoxyhumula-2,9-diene (2) was treated with 1.8 M sulfuric acid–acetone (1 : 1) to yield a new tricyclic diol, 5,9-dihydroxy-4,8,11,11-tetramethyltricyclo[6.3.0.02,4]undecane (9; diol B), together with tricyclohumuladiol (3; diol A), humulenol-II (4), a diol C (5b), a diol D (5a), and an acetonide (8a). The same reaction at 0° gave only 3. Tricyclohumuladiol (3) was shown to be a key intermediate in the reaction of 2 to form 4, 5a, 5b, 8a, and 9.
Intramolecular Dimer and Excimer Phosphorescence of Poly(2-vinylnaphthalene) and Copolymers of 2-Vinylnaphthalene and Phenyl Vinyl Ketone
Authors: Aikawa Masayuki , Takemura Takeshi , Baba Hiroaki , Irie Masahiro , Hayashi Koichiro
Published: July 2006

Phosphorescence spectra and lifetimes of poly(2-vinylnaphthalene) and copolymers of 2-vinylnaphthalene and phenyl vinyl ketone have been measured as a function of the composition ratio between the constituent benzoyl and naphthyl groups in both rigid and fluid solutions.
Preparation and Electrical Conductivity of Some Simple and Complex Salts Formed between N,N-Dialkyl-1,3-dichalcogena-cycloalkan-2-iminium and TCNQ\ewdot
Authors: Araki Shingo , Ishida Hiromi , Tanaka Toshio
Published: July 2006

Four simple salts and six complex salts of TCNQ\ewdot radical anion with N,N-dialky1-1,3-dichalcogenacycloalkan-2-iminium cations, (Remark: Graphics omitted.) and (Remark: Graphics omitted.) (n=2 or 3, Y=S or Se, R=Me or Et) were prepared. The electrical resistivity of (Remark: Graphics omitted.) (1.1×104 ohm cm) was more than 10 times lower than other three simple salts ((6.1–8.7)×105 ohm cm). Electronic absorption spectra and magnetic susceptibilities suggest that the latter three involve dimeric (TCNQ)22−, while in the former the interaction between two TCNQ\ewdot radical anions is weak in the solid state. All the complex salts with compaction samples exhibited the resistivity of 2.4–4.0 ohm cm with very low activation energies (0.018–0.087 eV). Electronic spectra and magnetic susceptibilities show that the interaction between two TCNQ\ewdot radical anions decreases owing to the implication of neutral TCNQ.
The Use of Solvent ET-values in High Pressure Kinetics
Authors: Jouanne Jörn von , Palmer Donald A , Kelm Hartwig
Published: July 2006

The solvatochromic shift and its pressure dependence of the charge transfer band of 2,4,6-triphenyl-pyridinium-N-(3,5-diphenyl-)phenol betaine (ET-values) have been measured together with partial molar volumes of the betaine in a number of solvents.
The Preparation and Some Properties of 3-Substituted 2,4-Pentanedionato Metal(II, III) Complexes
Authors: Kasuga Kuninobu , Anami Masao , Yamamoto Yasuo
Published: July 2006

In the substitution reactions of phenol, benzenethiol, and their sodium salts on the chelate ring of 3-bromo-2,4-pentanedionato metal complexes (metal=iron(III), aluminium(III), and beryllium(II)), benzenethiol was found to be substituted for bromine, while phenol was not substituted under the same conditions. In the case of sodium salts, both sodium phenoxide and benzenethiolate gave substituted products. The UV and PMR data of tris(3-substituted 2,4-pentanedionato)aluminium(III) complexes gave some information on the substituted groups.
The Crystal Structure of Guanidinium Hexamolybdobis(phenylarsonate) Tetrahydrate, (CN3H6)4[(C6H5As)2Mo6O25H2]·4H2O
Authors: Matsumoto Kazuko Y
Published: July 2006

Two heteropoly anions, [C6H5AsMo6O21(H2O)6]2− and [(C6H5As)2Mo6O25H2]4−, have been synthesized by the reaction of phenylarsonic acid with molybden um trioxide in an aqueous solution of pH ca. 2. The latter anion has been subjected to crystal-structure analysis as a guanidinium salt, (CN3H6)4[(C6H5As)2Mo6O25H2]·4H2O, and a heteropoly anion with a new type of structure has been established. The crystal is monoclinic with the space group of P21 and cell dimensions of a=13.754(5), b=15.752(7), c=11.900(5) Å, β=115.59(2)°, V=2325.3 Å3, Dm=2.25, Dx=2.28 g cm−3, and Z=2. The formula of the anion has been proved to be [(C6H5As)2Mo6O25H2]4−, which is different from the expected formula, [(C6H5As)2Mo6O24]4−, though the latter had previously been proposed on the basis of a 17O NMR study and an independent X-ray investigation of the methyl derivative had confirmed the existence of the [(CH3As)2Mo6O24]4− anion. The present anion, [(C6H5As)2Mo6O25H2]4−, consists of six MoO6 octahedra, which form a ring with one face-, two corner- and three edge-sharings, the two C6H5AsO3 tetrahedra are attached to the ring from above and below, with their three oxygens shared with molybdenums. The two phenyl groups are oriented upwards and downwards from the ring respectively.
Structural Assignment by NMR Analyses of N-(Diacylamino)imide Derivatives. Diels-Alder Adducts of 2,3-Dimethylnaphthalene and 6,6-Diphenylfulvene with Maleic Anhydride
Authors: Verma Shiva Mohan , Singh Ashok Kumar
Published: July 2006

The configurations of the Diels-Alder adducts of maleic anhydride with 2,3-dimethylnaphthalene and 6,6-diphenylfulvene have been investigated by NMR spectroscopy. Restricted rotation and non-planar conformations about the N–N bond in the corresponding N-aminoimide derivatives of the adducts have been employed in solving the structural problem. While the N′,N′-diacetyl system has been shown to be a suitable probe for configurational assignment, N′-acetyl-N′-aroyl-N′-aminoirnide derivatives have been found to be a more diagnostic probe even to simple adducts.
Low Temperature Photolysis of o-Benzoquinones. Spectroscopic Detection of Cyclopentadienones and Bis-Ketenes
Authors: Tomioka Hideo , Fukao Hiroshi , Izawa Yasuji
Published: July 2006

The photodecarbonylation of o-benzoquinone to cyclopentadienone at low temperature was monitored by infrared and ultraviolet spectra which showed that the reaction is highly sensitive to substituents. 3,5-Di-t-butyl-o-benzoquinone undergoes clean decarbonylation to give cyclopentadienone under irradiation at −170 °C. Similar irradiation of 4-t-butyl-, 4-methyl-, 3-methyl-, and unsubstituted o-benzoquinones also leads to decarbonylation to cyclopentadienones. However, competitive α-cleavage to bis-ketene becomes important in these systems. Direct spectroscopic observation of the elusive cyclopentadienone was unsuccessful because of the overlapping absorption of the by-product. The infrared spectrum of bis-ketene from 4-t-butyl-o-benzoquinone shows that it exists as a mixture of rotamers, not undergoing thermal interconversion even at −170 °C.
Chemical Modification of Neamine. 5. Preparation of Amino-deoxyneamines
Authors: Nishiyama Shigeru , Ishikawa Yasuhide , Yamazaki Masahiko , Suami Tetsuo
Published: July 2006

An aminocyclitol antibiotic neamine has been modified in its 2-deoxystreptamine moiety by converting the hydroxyl group into an amino group to give three antibiotic amino-deoxyneamines. Their antimicrobial activities were determined against several microorganisms.
Some Aspects on the Mechanism of Palladium-complex-catalyzed Decomposition of and Cyclopropanation with Ethyl Diazoacetate
Authors: Nakamura Akira , Koyama Teruhisa , Otsuka Sei
Published: July 2006

Carbenoid decomposition of ethyl diazoacetate in the presence of various palladium complexes as catalysts was found to kinetically depend on the identity of halide ligands. The use of several chiral ligands did not induce appreciable enantioselective catalytic cyclopropanation between ethyl diazoacetate and styrene. The active catalyst species is not under the influence of the chiral ligands but under control of halides which are bound more strongly to the metal.
The Hydrocracking of Polynuclear Aromatic Hydrocarbons over Molten Salt Catalysts
Authors: Nakatsuji Yohji , Kubo Toshio , Nomura Masakatsu , Kikkawa Sh\={o}ichi
Published: July 2006

The hydrocracking of phenanthrene, anthracene, pyrene, chrysene, and fluoranthene over molten salt catalysts at 400 °C in the batch autoclave systems was examined. The products were mainly identified by means of GC-MS, but the representative products were isolated by preparative GLC and characterized by using NMR, IR, UV, and mass spectrometry. Most of the isolated products are compounds not previously confirmed in detail, although their formation has been expected in the hydrocracking of the corresponding aromatic compounds. Probable reaction routes are offered based on the product distributions. The binary mixture of zinc chloride and copper(I) chloride is considered to act as a molten dual-functional catalyst.
A Simple Method for the Calculation of the Polycrystalline ESR Lineshape
Authors: Shimokoshi Kazuo
Published: July 2006

A simple interpolation method is developed for calculating the magnetic resonance lineshapes of the polycrystalline samples. The method uses the spline function with the optional number of calculated points, at which the spin Hamiltonian is solved most accurately. The calculation procedure and some examples will be given.
NMR Spectroscopic Studies of the Tautomerism in Tetramic Acid Analogs and Their Anilides. III. Polar Solvent Effects on the Tautomeric Populations
Authors: Saito Kimitoshi , Yamaguchi Tatsuaki
Published: July 2006

NMR spectroscopic studies of 3-acetyltetramic acid (3-acetyl2,4-azolidinedione), 3-acetyltetronic acid (3-acetyl-2,4-oxolanedione), 3-acetylthiotetronic acid (3-acetyl-2,4-thiolanedione) and their anilides (3-(2-phenyliminoethyl) derivatives) showed variations in the tautomeric equilibria with certain polar solvents. For example, the strong solvation effect of DMSO-d6 causes a predominance of the lactim forms of 3-acetyltetramic acid over the lactam forms and up-field shifts of the enolic protons.
The Microenvironmental Effect of Cyclodextrin on the Acid Dissociation of Some Azo Dyes in Aqueous Solutions
Authors: Matsui Yoshihisa , Moghida Kazuo
Published: July 2006

The effects of α- and β-cyclodextrins (CD) on the acid dissociations and tautomeric equilibria of sodium 4-(4′-hydroxy-1′-naphthylazo)-1-naphthalenesulfonate (1) and of the conjugate acid (2) of Methyl Orange were spectrophotometrically examined and were compared with the effect of a nonpolar solvent (THF). The apparent pKa values for the dyes decreased with increasing CD concentration. The effect of CD is mainly explained in terms of the hydrophobic interactions between the azo dyes and CD, resulting in a shift in the tautomeric equilibria from less acidic azonium or hydrazone forms to more acidic azo forms of 1 and 2 in an aqueous solution.
Mixed Monolayers of Long Normal Chain Fatty Acids with Long Normal Chain Fatty Alcohols
Authors: Matuo Hirosi , Hiromoto Kimio , Motomura Kinsi , Matuura Ryohei
Published: July 2006

The mixed monolayers of long normal chain fatty acids with long normal chain fatty alcohols were studied at various compositions and temperatures. The π-A curves of these systems were measured and the two-dimensional phase diagrams were obtained. The partial molar enthalpy change from the expanded to the condensed state was calculated. It was observed that the phase diagram and enthalpy change of these systems are similar to those previously obtained from the mixed monolayers of long normal chain fatty acids. The miscibility of these systems changes with the increase in the difference of the chain length, as in the systems of fatty acids. It was concluded that the monolayer behavior of the mixed system of an acid and an alcohol is analogous to that of the mixed system of the acid and an acid which contains one more carbon atom in a molecule than the corresponding alcohol.
The Spatial Distribution of Secondary Electrons Produced in the γ-Radiolysis of Water
Authors: Kowari Ken-ichi , Sato Shin
Published: July 2006

The spatial distribution of secondary electrons produced in the γ-radiolysis of water in the liquid phase has been theoretically calculated. The method consists of the combination of the procedure previously developed for the calculation of the G-value of electrons with the theory proposed by Fr\ddotohlich and Platzman for the slowing down of electrons in polar liquids. The G-value of the ion-pairs initially produced was calculated to be 6.8 on the assumption that the binding energies of electrons in water are equal to those in solid water at 77K. 27% of the ion-pairs were generated in isolated spurs. Another 27% of the ion-pairs were generated in condensed spurs, each of which contains more than one hundred ion-pairs. The other ion-pairs formed less condensed spurs, each of which contains from 2 to 100 ion-pairs. A new definition was given for the classification of spurs: isolated spurs, blobs, and short tracks; the original proposal was by Mozumder and Magee. The diameter of the isolated spur was estimated to be about 100 Å. The distribution of the distance between the parent positive ion and the thermalized electron in the isolated spur was well expressed by the function proposed by Abell and Funabashi, except at very short distances.
X-Ray Fluorescence Spectroscopy of Metal Sulfides
Authors: Maekawa Takashi , Kikuchi Niro , Fukuda Noriyuki , Yokokawa Toshio
Published: July 2006

The S Kα spectra of the sulfur compounds were measured. The S Kα energies of metal sulfides were less than that of the pure sulfur in accordance with the theoretical prediction. The S Kα shift for CaS (−0.239 eV) is the largest among those of metal sulfides examined in this study. In the sulfur+selenium binary mixtures, the S Kα energy goes more negative than that of sulfur with increasing the selenium content. These results can be interpreted in terms of the electronegativity of the counter atoms.
Studies of the Hydrous Titanium Oxide Ion Exchanger. IV. The Effect of Radiation and Heat Treatment
Authors: Inoue Yasushi , Tsuji Masamichi
Published: July 2006

The effects of 60Co γ-ray irradiation and of heat treatment in air have been studied on the properties of the hydrous titanium oxide ion exchanger. The ion-exchange capacity of the sodium form did not change at all, while that of the hydrogen form decreased a little, by the exposure of 5.2×108 R. The color of the exchanger, initially white, turned yellow upon irradiation. This exchanger was stable against heat treatment up to around 80 °C; thereafter the exchange capacity gradually decreased with the temperature until 324 °C, where it was abruptly reduced to about a quarter of the initial value. The examination of the titration curves showed that the most acidic exchange site was weaker than less acidic sites against heat treatment. The structural formula of this hydrous titanium oxide ion exchanger has been suggested on the basis of the ion-exchange capacity, the thermal decomposition curves, and such auxiliary data as the X-ray diffraction and the infrared spectra.
The Template-directed Synthesis of Oligonucleotide. II. The Interactive Properties of Nucleic Acid Base-binding Poly(4-vinylpyridine) and Its Related Compound with Nucleotides
Authors: Shimidzu Takeo , Murakami Akira , Konishi Yoshiyuki , Minami Manabu
Published: July 2006

The interactive properties of positively charged polynucleotide analogs, such as nucleic acid base-binding poly(4-vinylpyridine)s and their derivatives, with nucleotides have been investigated. The interactions of the positively charged polynucleotide analogs such as N-alkylated poly(4-vinylpyridine)s with 9-(ω-chloroalkyl)adenine and of N-alkylated poly(4-vinylpyridine) with 1-(2-bromoethyl)thymine with nucleotides were attributed predominantly to a base-base stacking under reinforcement by the coulombic attractive force. The purinepurine base interaction was found to be stronger than the purine-pyrimidine and the pyrimidine-pyrimidine interactions. The interaction was reduced by an increase in the ionic strength. The higher the charge density of the nucleotide was, the stronger was the interaction observed. On the other hand, a cross-linked positively charged polynucleotide analog such as N-alkylated cross-linked poly(4-vinylpyridine) with 9-(2-chloroethyl)adenine showed considerable selective interaction with the complementary nucleotide, uridine-5′-phosphate (pU), in both aqueous and pyridine solutions.
Isomorphism in the High-temperature Forms of the Pyrene Complexes with Five Polynitro Aromatic Compounds
Authors: Inoue Nobuaki , Matsunaga Yoshio
Published: July 2006

Crystalline pyrene complexes with 2,4-dinitrofluorobenzene, 2,4-dinitrochlorobenzene, 2,4-dinitrotoluene, 2,4-dinitrophenol, and picryl chloride exhibit polymorphic transitions. Their temperatures and associated enthalpies are presented. The high-temperature forms show essentially identical X-ray diffraction patterns, losing the special natures of the substituents on the acceptor molecules. Isomorphism is supported by the formation of complete solid solutions demonstrated for combinations of these forms. The enthalpy and entropy of melting of the present complexes are characterized by rather small values, 4–6 kcal mol−1 and 12–14 cal deg−1 mol−1respectively, indicative of anomalously high thermal motion or disorder in the high-temperature forms. Marked changes in the spectral and electrical properties by the transitions are noted in some cases.
The Formation of Alkyl Acetate in the Reaction of Trialkylborane with Lead(IV) Acetate or Phenyliodoso Acetate
Authors: Masuda Yuzuru , Arase Akira
Published: July 2006

In the reaction of trialkylborane with lead(IV) acetate or phenyliodoso acetate in benzene, about two thirds of the alkyl groups of trialkylborane were converted to the corresponding alkyl acetate without any isomerization of the alkyl group. Lead(IV) acetate reacted preferentially with the secondary alkyl group, while phenyliodoso acetate reacted only with the primary alkyl group. In either reaction, one mole of oxidizing agent was consumed for the formation of one mole of alkyl acetate.
An ESR Study of N-Sulfonylaminyls
Authors: Miura Yozo , Nakamura Yuji , Kinoshita Masayoshi
Published: July 2006

N-(3,5-Di-t-butylphenyl)-N-sulfonylaminyls, 3,5-t-Bu2C6H3–N–SO2-R, were investigated by means of ESR spectroscopy. The aN values are 7.8 G, and the aH values due to the N-phenyl ring protons are 5.6 (o-H) and 7.6 G (p-H). However, no couplings due to the protons in R have been detected. From these results, it is concluded that the unpaired electron is located on the nitrogen atom and the N-phenyl ring, negligibly delocalized onto the sulfonyl group.
Application of Infrared ATR Spectroscopy to Liquid Crystals. II. Surface-induced Orientation of Nematic MBBA and Reorientation in Electric Fields
Authors: Hatta Aritada , Nohara Hideaki , Suëtaka Wataru
Published: July 2006

A polarized infrared ATR technique was used to demonstrate the orientation of a nematic liquid crystal, N-(p-methoxybenzylidene)-p-butylaniline (MBBA), due to the walls of the electrode and an externally applied DC electric field. Polarized ATR spectra were obtained as a function of the field strength on liquid films 15 (μm thick between a silicon ATR prism and a brass plate serving as electrodes. The observed infrared dichroism revealed the average orientation of molecules in boundary layers about 1 μm thick on the Si electrode surface. The ordering or packing of molecules before application of the field affects the response of molecules to the electric field in a striking manner. Molecular orientations on the Si electrode are discussed in some detail.
Pyrolysis of Tetrasulfur Tetraimide
Authors: Hamada Shuichi , Kudo Yoshiyuki
Published: July 2006

Tetrasulfur tetraimide was pyrolyzed into sulfur, tetrasulfur tetranitride, tetrasulfur dinitride, ammonia, and nitrogen even below its apparent melting point, 143 °C, under atmospheric pressure; a small amount of hepta-sulfur imide was also observable. The tetrasulfur dinitride and nitrogen were formed from subsequent reactions between products. The overall pyrolysis consisted of the primary decomposition and the following subsequent ones, as judged from the stoichiometric relationships among the pyrolytic products: 3S4(NH)4=4S+2S4N4+4NH3, S4N4=S4N2+N2 (in the presence of sulfur), and S4N2=4S+N2. Partial pressures of ammonia at the primary pyrolysis were estimated to be 8.5×10−2, 2.1×10−1, 5.2×10−1, and 1.4 Pa at 60, 70, 80, and 90 °C respectively.
The Synthesis and Crystal Structure of Bis(cyclo-l-histidyl-l-histidyl)copper(II) Perchlorate Tetrahydrate
Authors: Hori Fumio , Kojima Yoshitane , Matsumoto Keiji , Ooi Shun’ichiro , Kuroya Hisao
Published: July 2006

The title compound was prepared, and its structure then determined by X-ray structure analysis. The crystal is trigonal with the space group P3221, a=8.450(3), c=42.00(6)Å, and Z=3. The crystal structure has been determined from the diffractometer data and refined by a least-squares method to an R value of 0.103 for 1349 independent reflections with I>3σ(I). The cyclo-l-histidyl-l-histidyl is coordinated to the Cu atom via the N atoms of the respective imidazolyl groups. The coordination of Cu is not planar but distorted toward the tetrahedral configuration, the interplanar angle betweent (Remark: Graphics omitted.) planes being 29°. The complex has virtually D2 symmetry: there are two pseudo two-fold axes and one crystallographically imposed two-fold axis which relates two chelate rings. The chelate rings assume the δ conformation, and the ligating cyclo-l-histidyl-l-histidyl is of a folded form with a bowsprit-boat 2,5-piperazinedione ring. The electronic and circular dichroism spectra in the visible region are presented.
The Formation of the Cd-bearing Ferrite by the Air Oxidation of an Aqueous Suspension
Authors: Kaneko Ken , Takei Katsumori , Tamaura Yutaka , Kanzaki Tadao , Katsura Takashi
Published: July 2006

When the Cd2+/Fetotal ratio in the initial solution is below 0.1, almost all cadmium ions are incorporated into the ferrite with the spinel-type structure by the air oxidation of an aqueous suspension at a pH 9.0 and at 65 °C. The Cd-bearing ferrite thus obtained is a ferromagnet and is oxidized to form a completely oxidized Cd-bearing ferrite at 150 °C in the air; this ferrite is still a ferromagnet and belongs to the Fe2O3–CdFe2O4 binary system, with the same spinel type structure. When the Cd2+/Fetotal ratio in the initial solution increases to 0.5, the crystalline phases formed is complicatedly changed; the products are also significantly affected by the pH value of the suspension. The most favorable pH value at 65 °C to form the Cd-bearing ferrite is proposed to be 10.0.
Photochemical Reactions of N-Acyl-2,3-dihydrobenzoxazol-2-ones
Authors: Ishida Sadahiro , Hashida Yoji , Shizuka Haruo , Matsui Kohji
Published: July 2006

Photo-Fries rearrangements of N-acyl-2,3-dihydrobenzoxazol-2-ones are described. Irradiation of N-acyl-2-3-dihydrobenzoxazol-2-ones in acetonitrile afforded a mixture of 2-acyl-2,3-dihydrobenzoxazol-2-one and 6-acyl-2,3-dihydrobenzoxazol-2-one together with other minor products. However, 2,3-dihydrobenzoxazol-2-one and N-methyl-2,3-dihydrobenzoxazol-2-one were very photostable. The reaction scheme involving Norrish type I dissociation has been discussed.
Interactions between Sulfur Ylides and Electrophilic Monosulfides
Authors: Matsuyama Haruo , Matsumoto Masae , Kobayashi Michio , Minato Hiroshi
Published: July 2006

The catalytic activities of electrophilic monosulfides, Ar–S–R* (R*=CN, CF3, OMe), for the transylidation reactions of sulfur ylide, Ph(Me)\overset⊕S–\overset\ominusC(CO2Me)2, with alkyl sulfides and pyridines were investigated. Among these monosulfides, methyl arenesulfenates reacted with dimethylsulfonium phenacylide (or dimethylsulfonium ethoxycarbonylmethylide) to give α-(arylthio)phenacylides (or α-(arylthio)ethoxycarbonylmethylides) and methanol. The 13C-NMR spectra of several sulfur ylides and aryl thiocyanates were investigated in CDCl3, and the presence of S-ylide-thiocyanate adduct intermediates was established.
Furanoeremophilan-14β,6α-olide. A New Furanosesquiterpene Lactone of an Eremophilane-type from Ligularia Hodgsoni Hook, f.
Authors: Ishizaki Yoshiaki , Tanahashi Yoshiaki , Tsuyuki Takahiko , Takahashi Takeyoshi , Tori Kazuo
Published: July 2006

A new sesquiterpene lactone of an eremophilane-type was isolated from Ligularia Hodgsoni Hook, f., and the structure including the absolute stereochemistry was shown to be furanoeremophilan-14β,6α-olide.
Reaction of Coordinated Phosphines. V. Aryl and Alkyl Transfer from Tertiary Phosphine to Transition Metal
Authors: Kikukawa Kiyoshi , Yamane Toru , Ohbe Yoshihiro , Takagi Makoto , Matsuda Tsutomu
Published: July 2006

A carbon-phosphorus bond cleavage was observed in the reaction of MCl2(PR3)2 (M=Ni, Co, or Pd, R=Ph, n-C8H17) with p-tolyllithium, p-tolylmagnesium halide, lithium aluminum hydride, or magnesium amalgam, and the reactivity was most pronounced with Ni followed by Co and Pd. Reaction of NiCl2(PPh3)2 with p-tolyllithium gave biphenyl and 4-methylbiphenyl, along with 4,4′-dimethylbiphenyl. Phenyllithium was formed in the reaction mixture, and the recovered tertiary phosphine contained tri-p-tolylphosphine, di-p-tolylphenylphosphine, and p-tolyldiphenylphosphine as well as triphenylphosphine. 1-Octene was formed in the reaction of NiCl2{P(n-C8H17)3}2 with p-tolyllithium. Thermal decomposition of Ni(mesityl)X(PEt3)2 (X=mesityl or Br) and Co(mesityl)2(PPhEt2)2 at 30 °C gave vinyl mesitylene.
Studies on Nucleosides and Nucleotides, VII. Preparation of Pyrimidine Nucleoside 5′-Phosphates and N3,5′-Purine Cyclonucleosides by Selective Activation of the 5′-Hydroxyl Group
Authors: Kimura Junji , Fujisawa Yoshiyuki , Yoshizawa Toyokichi , Fukuda Kazuhiro , Mitsunobu Oyo
Published: July 2006

The reaction of thymidine or uridine with 1.5 molar equivalents each of dibenzyl hydrogenphosphate, diethyl azodicarboxylate, and triphenylphosphine in HMPT at room temperature for 1 day, followed by debenzylation, afforded dpT and pU in 73 and 78% yields, respectively. Neither nucleoside 3′-phosphate nor 3′,5′-diphosphate was formed. 5′-O-Benzoyl thymidine 3′-(2-cyanoethyl)phosphate also reacted smoothly with thymidine at room temperature giving d-bzT3′p(CNEt)5′T in a 54% yield. Adenosine and Guanosine gave the corresponding N3,5′-cyclonucleosides as main products, less than 1% pA and pG being formed.
An Approach to the Interpretation of the Mass Spectra of Aliphatic Acids
Authors: Nakashima Hiroshi , Okamoto Katsunobu
Published: July 2006

A method of comparing the sum of the total energies of fragment molecules has been applied to the interpretation of simple cleavage and rearrangement reactions in electron-impact mass spectrometry for the straight chain aliphatic acids.
The Cross-Aldol Reaction of 3-Alkoxy-2-cyclohexen-1-ones with α,β-Enals. A Synthesis of 4-(trans-2-Butenylidene)-3,5,5-trimethyl-2-cyclohexen-1-ones
Authors: Torii Sigeru , Inokuchi Tsutomu , Ogawa Hidenori
Published: July 2006

The cross-aldol reaction of 3-alkoxy-2-cyclohexen-1-ones with α,β-enals afforded the corresponding 3-alkoxy-6-(1 -hydroxy-2-alkenyl(or aryl)-2-cyclohexen-1-ones in 78–98 % yields. The condensation of a kinetic enolate anion of 3-ethoxy-5,5-dimethyl-2-cyclohexen-1-one with trans-2-butenal, and subsequent dehydration together with methylation, afforded 4-(trans-2-butenylidene)-3,5,5-trimethyl-2-cyclohexen-1-ones, one of the most important constituents of tobacco flavour, in a 74% yield.