bluuebunny/crossref_metadata_2025 huggingface dataset:
Triethylborane Induced Perfluoroalkylation of Silyl Enol Ethers and Ketene Silyl Acetals with Perfluoroalkyl Iodides
Authors: Miura Katsukiyo , Takeyama Yoshihiro , Oshima Koichiro , Utimoto Kiitiro
Published: July 2006

Reaction of perfluoroalkyl iodides with silyl enol ethers mediated by Et3B in the presence of base such as 2,6-dimethylpyridine provides mixtures of perfluoroalkylated trialkylsilyl enol ethers and α-perfluoroalkylated ketones. The yield and distribution of the products heavily depend on the nature of base employed. Treatment of a reaction mixture consisting of perfluoroalkylated silyl enol ether and α-perfluoroalkylated ketone with coned HCl in THF gives α-perfluoroalkylated ketone as a single product. Reaction of ketene silyl acetals with perfluoroalkyl iodides in the absence of base affords α-perfluoroalkylated esters in excellent yields.
Characteristics of the Membrane Permeability of Temperature-Sensitive Liposome
Authors: Ueno Masaharu , Yoshida Shoshin , Horikoshi Isamu
Published: July 2006

The relationship between the temperature-sensitivity of the release of an entrapped drug from liposome as well as the type of drug or liposome is discussed. The drug release from DPPC liposome (dipalmitoylphosphatidylcholine liposome) has been confirmed to increase abruptly near its phase-transition temperature for both low-molecular-weight compouds (such as calcein) and high-molecular-weight compounds (such as dextran). The amount of temperature-sensitive calcein released from the liposomes was dependent on the method of liposome preparation: that is, the release from REV (reverse phase evaporated vesicle) was the highest; next was that from LUV (large unilamellar vesicle prepered by detergent removal method), and lowest was from SUV (small unilamellar vesicle prepared by an ultrasonication method). In order to examine the size effect of liposomes on temperature-sensitive drug release, REV was fractionated into three groups according to their average sizes and calcein release for each group was investigated. The temperature at which calcein release showed a maximum was almost the same in each of three groups; while as the average liposome size of a group was larger, the initial rate of calcein release became higher and the temperature at which calcein release began became lower. The amount of release of a entrapped drug was primarily dependent on the molecular weight of the drug, in spite of the variety of drugs investigated.
Difference of the Final Products of the Photochemical Reactions of Azanaphthalenes and Naphthalene in Mixed Crystals of Durene
Authors: Hoshi Nagahiro , Yamauchi Seigo , Hirota Noboru
Published: July 2006

Final products of the photochemical reactions of quinazoline, quinoline, and naphthalene in 1,2,4,5-tetramethylbenzene (durene) mixed crystals are investigated on the basis of the phosphorescence and fluorescence spectra of the products. Quinazoline in durene is considered to transform into a benzene derivative, whereas naphthalene and quinoline tranform into anthracene derivatives. These products are different from a pyrazine derivative found in the case of quinoxaline, which is specific to the reaction in a durene mixed crystal. The cause of this difference is discussed in terms of the configurations of guests in the mixed crystals and the difference of the molecular structures.
Phase Separation Coupled with Gelation in Polyethylene Glycol–Gelatin–Aqueous Buffer System
Authors: Nezu Takashi , Maeda Hiroshi
Published: July 2006

Phase behavior of a pseudoternary system, gelatin–polyethylene glycol–acetate buffer, was examined. Phase diagram was constructed by determining the compositions of separated phases. One phase contained mostly gelatin but a trace amount of polyethylene glycol. When temperature was lower than the gelation temperature corresponding to the composition of the separated phase, diverse outlooks of the whole system were found. Observation of solutions under an optical microscope revealed microgels or network structure when gelatin was labeled with sirius red. Two different types of microgel formation were noted: nucleation-growth and spinodal decomposition. Size of the microgels formed by spinodal decomposition decreased with quench temperature.
Thermal and Electrooptical Properties of Ferroelectric Liquid Crystals Having OH Groups
Authors: Sugiyama Kazuo , Kato Koichi , Shiraishi Kohei
Published: July 2006

Four kinds of ferroelectric liquid crystals (FLCs) possessing OH groups, ((S)-2-methylbutyl 4-[4-(11-hydroxyundecyloxy)benzylideneamino]cinnamate 4a, (S)-2-methylbutyl 4-[4-(11-hydroxyundecyloxy)-2-hydroxybenzylideneamino]cinnamate 4b, (S)-2-hydroxypropyl 4-[4-(11-hydroxyundecyloxy)benzylideneamino]cinnamate 4c, and (S)-2-hydroxypropyl 4-[4-(11-hydroxyundecyloxy)-2-hydroxybenzylideneamino]cinnamate 4d) were prepared in order to understand how the introduction of OH groups in FLCs affect the phase behavior and electrooptical effects. α,ω-Diols 4c and 4d show a higher transition temperature of the smectic A (SA) phase than do ω-hydroxyl compounds 4a and 4b. Comparing 4b and 4d both of which have an OH group at the o-position of the benzylidene group with 4a and 4c, the former samples show a higher SA-isotropization (I) transition temperature than do the latter ones. It is suggested from IR spectroscopic results that inter- and intramolecular hydrogen bonding contribute to the stabilization of the SA phase. The order of the helical pitch in the chiral smectic C (Sc*) phase was found to be 4b>4a>4d>4c within 1.8–6.6 μm. From an electrooptical effect due to a deformation of the helical structure in the Sc phase, the rise time of the surface director (τsr) and the rise time of the bulk director (τbr) were measured to be as follows: τsr are 850, 1500, 30, and 70 μs, and τbr are 12, 100, 0.17, and 0.35 ms for 4a, 4b, 4c, and 4d, respectively. It was found that the intramolecular hydrogen bonding results in a slower optical response time, whereas intermolecular hydrogen bonding results in a faster one.
Determination of Rhodium by Third-Derivative Spectrophotometry with o-Hydroxyhydroquinonephthalein in the Presence of N-Hexadecylpyridinium Chloride
Authors: Mori Itsuo , Fujita Yoshikazu , Toyoda Minako , Maekubo Sachi
Published: July 2006

A third-derivative spectrophotometric determination (d3A⁄dλ3) of rhodium with o-hydroxyhydroquinonephthalein (Qnph) in the presence of N-hexadecylyridinium chloride (HPC) was proposed by measuring the distance of d3A⁄dλ3 on the peak at 530 nm (λ3) and the troughs at 500 nm (λ2) and 560 nm (λ4). Beer’s law was valid for the range 0–10 μg rhodium 10−1 cm3; the apparent molar d3A⁄dλ3 was 7.37×105 dm3 mol−1 cm−1.
Reactions of 2-Hydrazino- and 8-Hydrazinocyclohepta[b]pyrroles with Dimethyl Acetylenedicarboxylate
Authors: Abe Noritaka , Yatabe Kumiko
Published: July 2006

2-Hydrazinocyclohepta[b]pyrrole reacted with dimethyl acetylenedicarboxylate (DMAD) to give the hydrazones (2a), the pyrimidinone-fused cyclohepta[b]pyrrole (3), 1,2,4-triazinone-fused cyclohepta[b]pyrroles, and the 1,2-dihydro-3H-pyrazol-3-one derivative. Thermolysis of 2a gave 3 and tetramethyl pyrrole-2,3,4,5-tetracarboxylate. The reaction of ethyl cyclohepta[b]pyrrole-3-carboxylate with DMAD at room temperature gave the hydrazone and the spiropyrazoline derivative.
Cycloadditions of 2,8,11-Triphenyl-7,9,10,11b-tetraazanaphth[1,2,3-cd]azulene and 2,8,10-Triphenyl-9-oxa-7,10b-diazaindeno[4,5,6-cd]azulene with Dimethyl Acetylenedicarboxylate
Authors: Abe Noritaka , Hirai Yoshimasa , Fukazawa Yoshimasa
Published: July 2006

Cycloadditions of the title compounds with dimethyl acetylenedicarboxylate gave 1:2-cycloadducts. The structural assignments of the products were deduced by spectral inspections; the structure for one compound was established by X-ray crystallography.
The Structure of Notoryne, a Halogenated C15 Nonterpenoid with a Novel Carbon Skeleton from the Red Alga Laurenda nipponica Yamada
Authors: Kikuchi Hajime , Suzuki Teruaki , Kurosawa Etsuro , Suzuki Minoru
Published: July 2006

A new halogenated C15 nonterpenoid with a novel carbon framework, named notoryne, has been isolated from the title alga and its structure was established on the basis of spectroscopic and chemical evidence. In addition, the structure of a rearranged product, whose structure has long remained unsettled, of laurefucin derivative was also determined by spectral and chemical methods. Furthermore, the biogenesis of the halogenated C15 nonterpenoids from L. nipponica collected at warm current region in Hokkaido is also discussed.
Some Unusual Properties of Tris(2,6-dimethoxyphenyl)phosphine Sulfide and the Related Compounds
Authors: Wada Masanori , Kanzaki Mitsuyuki , Fujiwara Masanobu , Kajihara Kazuhisa , Erabi Tatsuo
Published: July 2006

The title sulfide {2,6-(MeO)2C6H3}3P=S [abbr. (2,6)3P=S] reacted with acids to form a novel mercaptophosphonium salt [(2,6)3P–SH]X, solution thermolysis of which in the absence or presence of triphenylphosphine resulted in the unusual desulfurization to give the tertiary phosphonium salts [(2,6)3P–OH]X. (2,6)3P=S also reacted with alkyl iodides or bromides under mild conditions to give stable (alkylthio)phosphonium salts [(2,6)3P–SR]X (R=Me, Et, n-Bu), which reacted with thiols at room temperature in the presence of a catalytic amount of the tertiary phosphine (2,6)3P to give [(2,6)3P–H]X and unsymmetrical disulfides.
Photochemical Reactions of Aryl-Substituted Digermanes through a Pair of Organogermyl Radicals
Authors: Mochida Kunio , Wakasa Masanobu , Sakaguchi Yoshio , Hayashi Hisaharu
Published: July 2006

The photochemical reactions of aryl-substituted digermanes were investigated by trapping experiments and a laser flash photolysis technique. The photolysis of phenylated digermanes resulted in germanium–germanium bond homolysis to give a pair of two germyl radicals. The germyl radicals abstracted a chlorine atom from carbon tetrachloride to give chlorogermanes. The pair of germyl radicals also underwent ipso-substitution, which was a precursor of the germylenes. The mechanism for the photochemistry of phenylated digermanes is discussed.
Separation of Scandium Using Liquid–Liquid Extraction with Macrocyclic Polyether(s) from Picrate Media
Authors: Deorkar N V , Khopkar Shnpad M
Published: July 2006

Scandium was quantitatively extracted at pH 2.5–4.5 with 4.0×10−2 mol dm−3 18-crown-6 in dichloromethane from 4.0×10−2 mol dm−3 solution of picric acid. It was stripped with 0.1 mol dm−3 nitric acid and determined spectrophotometrically at 650 nm as its complex with Arsenazo-III. It was separated from yttrium, lanthanides, zirconium, hafnium, vanadium, niobium, and uranium in multicomponent mixtures. Scandium from rock sample was also analysed.
Spin-Trapping of Selenium-Containing Inorganic Radicals in Aqueous Solutions
Authors: Ozawa Toshihiko , Hanaki Akira
Published: July 2006

The selenite radical anion, SeO3\divdot, can be detected by ESR spectroscopy using water-soluble spin-traps, N-(4-pyridylmethylene)-t-butylamine N,N′-dioxide (POBN) and 3,5-dibromo-4-nitrosobenzenesulfonate (DBNBS), but selenate radical anion, SeO4\divdot, cannot be trapped by POBN or DBNBS.
Association of p-Halofluorobenzenes with α- and β-Cyclodextrins in Aqueous Medium
Authors: Takuma Tatsuyoshi , Deguchi Toshio , Sanemasa Isao
Published: July 2006

The complex formation of α- and β-cyclodextrins (CyDs) with p-(chloro, bromo, and iodo)fluorobenzenes has been studied in aqueous medium at 25°C. Formation constants are compared with those of CyD–monohalobenzene systems.
Synthesis of Azonia Derivatives of Benzoperylene and Benzocoronene by Photocyclization
Authors: Arai Sadao , Nakamura Norikazu , Yamaguchi Hiromichi , Okazaki Masa-aki , Hida Mitsuhiko
Published: July 2006

The 2-styrylbenzo[a]quinolizinium salt was photocyclized to afford 12a-azoniabenzo[ghi]perylene salt in 66% yield. The 2a-azoniabenzo[a]coronene salt was obtained by the photocyclization of 2-[2-(4-biphenylyl)vinyl]benzo[a]-quinolizinium salt and 2-styryl-10-phenylbenzo[a]quinolizinium salt in 80% and 75% yields, respectively.
Association Behavior of Protoporphyrin IX in Water and Aqueous Poly(N-vinylpyrrolidone) Solutions. Interaction between Protoporphyrin IX and Poly(N-vinylpyrrolidone)
Authors: Inamura Isamu , Uchida Kazutomo
Published: July 2006

The association behavior of protoporphyrin IX was investigated at different pH by absorption spectroscopy and gel chromatography. Protoporphyrin IX existed as monomer in acidic water, as aggregate in neutral water, and as dimer in basic water. Poly(N-vinylpyrrolidone) tended to suppress dimerization and aggregation of protopophyrin IX.
Mesomorphic Properties of 4-[3,4-Bis(4-alkoxybenzoyloxy)benzylideneamino]azobenzenes and Related Compounds
Authors: Masuda Tatsuya , Matsunaga Yoshio
Published: July 2006

The mesomorphic properties of a homologous series of 4-[3,4-bis(4-alkoxybenzoyloxy)benzylideneamino]azobenzenes have been studied by differential scanning calorimetry and microscopy. While the nematic phases exhibited by the ethoxy and propoxy homologues are metastable, those exhibited by all of the butoxy-to-hexadecyloxy homologues exhibit the temperature range of stable existence. A metastable smectic A-phase is observed for the tetradecyloxy and hexadecyloxy homologues. Among the examined 4-[2,4-bis(4-alkoxybenzoyloxy)benzylideneamino]azobenzenes, only the dodecyloxy and tetradecyloxy members are nematogenic. Their clearing points are located at more than 30 °C below the melting points. 4-(Benzylideneamino)azobenzene and its 3-(4-dodecyloxybenzoyloxy) derivative are nonmesogenic; however, the phase diagrams of binary systems with 4-(4-nonyloxybenzylideneamino)azobenzene revealed that the addition of a 3-(4-dodecyloxybenzoyloxy) group to the former molecule depresses the virtual nematic behavior, but promotes the smectic A behavior. A further addition of the same group at the 4-position drastically raises the nematic-isotropic transition temperature.
Computational Studies of the Isomerization Pathways of Isocyanic Acid HNCO
Authors: Yokoyama Keiichi , Takane Shin-ya , Fueno Takayuki
Published: July 2006

Paths of isomerizations of isocyanic acid HNCO into various chain isomers via ring intermediates have been investigated by ab initio MO calculations with the MRD-CI procedure employing the 6-31G** basis sets. Geometry optimizations were accomplished at the RHF, UHF, or CASSCF level of theory. It is found that the isomerization from HNCO to cyanic acid HOCN is energetically the most favorable and that it should proceed via successive 1,2-hydrogen migrations rather than by a single 1,3-hydrogen migration. The overall barrier height is calculated to be 423 kJ mol−1, which is ca. 60 kJ mol−1 higher than the critical energy for the main decomposition channel, HNCO→NH(3Σ)+CO. Implications of the results to the kinetics of the thermal decompostion of HNCO at high temperatures are discussed.
Selenation of 1,5-Naphthoquinones: Novel Synthesis of Naphthopyridoselenazines
Authors: Sakakibara Makoto , Ishida Tetsuya , Watanabe Yoshihiko , Toru Takeshi , Ueno Yoshio
Published: July 2006

Selenation of 2-chloro- and 2,6-dichloro-1,5-naphthoquinones with benzeneselenolate ion, generated from diphenyl diselenide and tributylphosphine in an alkaline medium, afforded 2-phenylseleno- and 2,6-bis(phenylseleno)-1,5-naphthoquinones in excellent yields. Reaction of halo-1,4-naphthoquinones with 3-amino-2-pyridineselenolate ion generated from bis(3-amino-2-pyridyl) diselenide gave naphtho[2,1-b]pyrido[3,2-e][1,4]selenazines and pyrido[2,3-b]pyrido[3″,2″:5′,6′][1,4]selenazino[2′,3′:3,4]naphtho[1,2-e][1,4]selenazines in high yields.
On the Role of Gallium for the Aromatization of Lower Paraffins with Ga-Promoted ZSM-5 Catalysts
Authors: Fujimoto Kaoru , Nakamura Ikusei , Yokota Kohshiroh , Aimoto Kohjiroh
Published: July 2006

H–ZSM-5 showed a high selectivity of propane and low selectivity of aromatic hydrocarbons in butane conversion at 450°C, whereas Ga-supportd ZSM-5 (Ga–ZSM-5) showed higher selectivities of aromatic hydrocarbons and hydrogen. A small amount of oxygen in the feed promoted butane conversion to aromatic hydrocarbons on H–ZSM-5. Hybrid catalysts composed of the physical mixture of Ga/Al2O3 and H–ZSM-5 showed comparable activities and aromatic selectivities to those of the Ga-supported ZSM-5 zeolite (Ga–ZSM-5). Hydrogen was adsorbed quickly on the Ga–ZSM-5 and on the hybrid catalyst at 400°C and the adsorbed hydrogen was desorbed at around 450°C during the temperature programmed desorption experiment from both catalysts. However, little hydrogen was adsorbed on H–ZSM-5 and was desorbed from it. It was pointed out that the supported Ga promoted the zeolite-catalyzed aromatization of lower paraffins by promoting hydrogen desorption via the “reverse spillover” effecct.
Effect of Water Vapor on the Formation of Lithium cyclo-Hexaphosphate
Authors: Nariai Hiroyuki , Motooka Itaru , Tsuhako Mitsutomo
Published: July 2006

The effect of water vapor on the formation of lithium cyclo-hexaphosphate Li6P6O18(P6m) from trilithium hydrogenpyrophosphate monohydrate Li3HP2O7·H2O was investigated by means of DTA-TG, X-ray diffraction analysis, isothermal heating with electric furnace, and HPLC. Li3HP2O7·H2O lost the water of crystallization at about 180°C to give anhydrous Li3HP2O7. At 300°C the disproportionation of Li3HP2O7 anhydride to Li4P2O7 and Li4P4O12 (P4m) proceeded faster under humid conditions than under dry air, and subsequently P4m increased with a decrease in P2 and soluble polyphosphates (Ppoly). At 400°C, P4m changed largely to P6m under humid conditions. In these reaction processes, water plays an important role as catalyst in the cyclization by dehydration of the end group and in ring opening by attacking the P–O–P bond. At 450°C, the amounts of P2 and P6m were almost equal under both humid and dry conditions, because all of P4m thermally changed to P6m.
Kinetics and Mechanism of Reduction of Metmyoglobins by Dithionite. Role of the Heme Propionates
Authors: Tsukahara Keiichi , Ishida Kazuyo
Published: July 2006

The kinetics of the reduction by dithionite ions of metmyoglobins reconstituted with porphinatoiron(III) complexes containing the protoporphyrin IX dimethyl ester, the deuteroporphyrin IX dimethyl ester, and octaethylporphyrin were studied at 25°C and pH 6.3–9.2 in aqueous solution. Esterification of the heme propionate groups accelerated the reduction rate by SO2\divdot as well as the case of octaethylporphyrin (which does not contain the propionate groups); it also affected the redox potential of metmyoglobin, but much less so the rate of the self-exchange reaction. The reaction mechanisms are discussed.
A Novel Catalyst System, Trimethylsilyl Chloride and Indium(III) Chloride, as an Efficient Catalyst in the Sulfide Synthesis
Authors: Mukaiyama Teruaki , Ohno Takashi , Nishimura Takashi , Han Jeong Sik , Kobayashi Sh\={u}
Published: July 2006

O-Trimethylsilyl monothioacetals, which are generally difficult to activate under acidic conditions due to their rapid disproportionation, smoothly react with triethylsilane in the presence of a novel catalyst system, trimethylsilyl chloride and indium(III) chloride, to afford the corresponding sulfides in good to high yields. One pot synthesis of sulfides from aldehydes is also attained in high yields by successive treatments of aldehydes with trimethylsilyl alkyl (aryl) sulfides and triethylsilane in the presence of the above catalyst system under extremely mild conditions.
Inclusion Compounds of α-Truxillic Acid. X-Ray Crystal Structures of the Coordinatoclathrates with Methanol (1 : 2) and Dimethylacetamide (1 : 2)
Authors: Csöregh Ingeborg , Czugler Mátyás , Kálmán Alajos , Weber Edwin , Hecker Manfred
Published: July 2006

The crystal structures of the inclusion compounds of the 2c,4t-diphenylcyclobutane-1r,3t-dicarboxylic acid (α-truxillic acid) host (1) with methanol [MeOH] (1 : 2) and with dimethylacetamide [DMA] (1 : 2) have been determined by single crystal X-ray diffraction. The substantial difference between the effects of the protic (MeOH) and aprotic (DMA) guests on the molecular packing is discussed. Crystal data: 1 · 2MeOH: monoclinic (P21⁄n), a=12.528(4), b=5.589(1), c=13.715(4) Å, β=101.16(4)°, Z=2, R=0.064 for 1300 reflections; 1 · 2DMA: monoclinic (P21⁄c), a=6.151(1), b=26.586(2), c=7.938(1) Å, β=105.32(6)°, Z=2, R=0.056 for 1488 observations. In both clathrates, half of the rigid α-truxillic acid molecule occupies the asymmetric unit together with one guest molecule. The hydrogen bonds between the trans-positioned functional groups of the host acid and the guest molecules in 1 · 2MeOH give rise to infinite layers parallel with the crystallographic ac diagonal. In contrast, the only one-way hydrogen bond from host to guest in 1 · 2DMA leads to discrete 1 : 2 host–guest aggregates. In this latter case, the hosts and guests are stacked separately, along the c axis direction.
Synthesis and Properties of Gramicidin S Analogs Consisting of Eight Amino Acid Residues
Authors: Tamaki Makoto , Akabori Sadatoshi
Published: July 2006

Three cyclic octapeptides (des-Val1,1′-gramicidin S, des-Leu3,3′-gramicidin S and des-Val1, Leu3′-gramicidin S), showed no antibiotic activity. Although their CD spectra resembled each other, they differed from that of gramicidin S. These results indicate that the removal of two of the Val and/ or Leu residues at positions 1, 1′, 3, and 3′ of gramicidin S greately affects both the antibiotic activity and conformation.
Synthesis of N-Methylaniline and N,N-Dimethylaniline with Methanol over Alumina Catalyst
Authors: Matsuhashi Hiromi , Arata Kazushi
Published: July 2006

Alumina catalysts prepared by different methods were used for the synthesis of N-methylaniline and N,N-dimethylaniline from aniline and methanol. Al2O3 catalysts prepared from isopropoxide and nitrate showed high activity and JRC-ALO-1 and JRC-ALO-3 supplied by the Catalysis Society of Japan showed low activity. The highest selectivity for N,N-dimethylaniline was 82.8% with 90.1% aniline conversion. The catalytic activity of Al2O3 was not poisoned by pyridine and CO2.
Stereoselectivity in Diastereomeric Tetrahedral Metal(II) Complexes of Chiral Salicylideneamines: Crystal Structure and Molecular Mechanics Calculation of Bis[N-(l-menthyl)salicylideneaminato]cobalt(II)
Authors: Sakiyama Hiroshi , Okawa Hisashi , Matsumoto Naohide , Kida Sigeo
Published: July 2006

Stereoselectivity of bis[N-(l-menthyl)salicylideneaminato]cobalt(II) [Co(sal-ment)2] has been studied by single crystal X-ray analysis and molecular mechanics calculations. The X-ray analysis has revealed a nearly tetrahedral surrounding (dihedral angle of 82.5°) and Δ configuration about the metal ion. Molecular mechanics calculations were made based on MM2 program, assuming a tetrahedral surrounding about the metal ion and fixing the four donor atoms and six atoms adjacent to the donor atoms at the positions as determined by the single crystal X-ray analysis. The most stable structure obtained from the MM2 calculation coincides well with that from the crystal structure analysis. Together with the X-ray structural results for [Cu(sal-ment)2] and bis[N-[(R)-1-phenylethyl]salicylideneaminato]cobalt(II) [Co(sal-Rmb)2] studied in this study and for related [Zn(sal-Rmb)2] and [Cu(sal-Rmb)2] studied previously, the factors responsible for the stereoselectivities of those bis(salicylideneaminato)metal(II) complexes have been discussed.
Benzo[b]cyclohepta[e][1,4]thiazines and Their Diazine Analogues. III. π-Electronic Structures of 5H,11H+-Cyclohepta[b]quinoxalinium Ions and Their O- and S-Analogues
Authors: Kurihara Teruo , Shindo Kimio , Ishikawa Sumio , Nozoe Tetsuo
Published: July 2006

π-Electronic structures of 5H,11H+-cyclohepta[b]quinoxalinium ions and their O- and S-analogues were elucidated by means of 1H and 13C NMR spectra, electronic spectra, and theoretical calculations. Consequently, it was shown that these compounds had very stable aromatic characters with positive resonance energies and that the 6π-tropylium-6π-benzonoid form plays an important role for the π-conjugation structure.
Molecular Orbital Approach to Antioxidant Mechanisms of Phenols by an Ab Initio Study
Authors: Tanaka Kazunori , Sakai Shogo , Tomiyama Shogo , Nishiyama Tomihiro , Yamada Fukiko
Published: July 2006

An ab initio molecular orbital theory has been applied to a study of the hydrogen abstractions of phenolic antioxidants in the chain process of autoxidation. The optimum structures of phenols, of peroxides, and of those compounds in the transition states were obtained with a Hartree–Fock/STO-3G basis set. From the values of enthalpy (ΔH) and activation energy (Ea) obtained, it was found that the rates of the reaction of peroxyl radical with phenolic antioxidant were faster than those with organic substrate in the propagation, and that the effect of the aromatic ring of the antioxidants not only stabilized a product state but also decreased an energy level in the transition state. The para-substituent effect that an electron-releasing substituent increased the antioxidant activity, whereas an electron-withdrawing one decreased it, was recognized. The relationship between ΔH and Ea values followed the Evans–Polanyi rule. The transition states in the hydrogen abstractions with lower Ea values prefer reactant-like structures, whereas those with higher Ea values prefer product-like ones.
Hydration of Propene over Proton- and Metal Ion-Exchanged Zeolite Catalysts at Atmospheric Pressure
Authors: Mori Hiroshi , Mizuno Noritaka , ShiRouzu Toshihiro , Kagawa Shuichi , Iwamoto Masakazu
Published: July 2006

The gas-phase hydration of propene over proton-exchanged or metal ion-exchanged zeolites with various Si/Al ratios and structures (such as ZSM-5, mordenite, ferrierite, and Y-type) has been studied. It was found that the catalytic activity of proton-exchanged zeolites for the conversion of propene to 2-propanol did not depend on their framework structure, but showed a volcano-shaped dependence on the Al content, as was observed in the hydration of ethene. On the basis of temperature-programmed desorption experiments of NH3 adsorbed on the zeolites, it was confirmed that the activity is controlled by the acidity of the catalysts. The catalytic activity of metal ion-exchanged Y zeolites increased with an increase in the electronegativity of the metal ion.
Enantioselective Extraction of Di-O-benzoyltartrate Anion by Ion-Pair Extractant Having Binaphthyl-Unit
Authors: Ohki Akira , Miyashita Ryo , Naka Kensuke , Maeda Shigeru
Published: July 2006

A lipophilic diphosphonium salt 1 having binaphtyl-type axial chirality was developed as a novel ion-pair extractant. By use of (R)-1, (−)-di-O-benzoyltartrate ((−)-DBT) was extracted more effectively than (+)-DBT. The enantioselectivity (α=D(−)⁄D(+); D: distribution ratio) was 1.3–1.4. When monophosphonium-type extractants (2 and 3) having structures similar to that of 1 were used, the enantioselectivity was heavily lowered. Equilibrium studies revealed that the extraction occurs via formation of a 1 : 1 ion-pair complex between 1 and DBT at pH 7.5–8.0. The effects of pH, ionic strength, and temperature on the extractability and the enantioselectivity were investigated. The enantioselectivity decreased with lowering pH, and was higher at lower temperatures. The optical purity of DBT in the aqueous phase was gradually enhanced by multistage extraction. From an NMR analysis of the 1·DBT complex, the resonances of methylene-protons adjacent to phosphonium in the more extractable complexes ((R)-1·-(−)-DBT and (S)-1·(+)-DBT) shifted to a higher field compared to those of the less extractable complexes ((R)-1·(+)-DBT and (S)-1·(−)-DBT).
Formation and Properties of Ferroelectric Liquid Crystalline Compound Containing –C(O)–S–O– Linkage
Authors: Takatoh Kohki , Sakamoto Masanori
Published: July 2006

During our investigations of the synthesis of ferroelectric liquid crystal compounds containing a fluorenone nucleus, the formation of a novel compound having a –C(O)–S-O– linkage was discovered as a by-product when a derivative of fluorenone carboxylic acid was treated with thionyl chloride and a phenol. This compound also exhibited ferroelectric liquid crystal properties. Compounds with a –C(O)–S–O– linkage have been little reported; this is the first report concerning a liquid crystalline compound with this type linkage. The thermal stability of the mesophase is reduced upon changing from the –C(O)–O– linkage to the –C(O)–S–O– linkage. The synthesis and properties of this compound are discussed in detail.
Asymmetric Michael Addition of the N-Alkylidene Derivative of an α-Amino Ester to Methyl (E)-3-[(3R,7aS)-2-Phenylperhydropyrrolo[1,2-c]imidazol-3-yl]propenoate
Authors: Yamamoto Hidetoshi , Kanemasa Shuji , Wada Eiji
Published: July 2006

The exclusively diastereoselective asymmetric Michael addition of the lithiated methyl N-(2,2-dimethylpropylidene)glycinate to methyl (E)-3-[(3R,7aS)-2-phenylperhydropyrrolo[1,2-c]imidazol-3-yl]propenoate is described. The synperiplanar conformer of the acceptor propenoate participated in the reaction where the re-face of the acceptor molecule was attacked by the re(β)-face of the lithiated intermediate.
Thermal Decomposition of Barium Amidotriphosphate
Authors: Takenaka Atsushi , Yamasaki Hiromu , Motooka Itaru , Nariai Hiroyuki
Published: July 2006

Barium amidotriphosphate (Ba3P3O9NH2·3.5H2O) was heated at 5 K min−1 in streams of dried air, humid air, and dried hydrogen chloride. cyclo-Triphosphates were not observed in any products, unlike in the pyrolysis of (NH4)4P3O9NH2·H2O. Water vapor or hydrogen chloride hydrolyzed phosphorus–nitrogen and phosphorus–oxygen bonds of the products.
A Convenient Preparation of Ketones by the Oxidation of Secondary Alcohols with Chromium(VI) Trioxide in Aprotic Solvent in the Presence of “Wet”-Aluminum Oxide
Authors: Hirano Masao , Nagasawa Sonoko , Morimoto Takashi
Published: July 2006

The oxidation of aliphatic and alicyclic secondary alcohols with chromium(VI) trioxide in the presence of “wet”-aluminum oxide in hexane gave the corresponding ketones in excellent yields under mild conditions.
An Efficient Preparation of 3,3′-Methylenebisazulenes
Authors: Matsubara Yoshiharu , Morita Masanori , Takekuma Shin-ichi , Zhao Zhendong , Yamamoto Hiroshi , Nozoe Tetsuo
Published: July 2006

Various 3,3′-methylenebis azulenes were prepared in high yields upon treatment of 1-substituted azulenes with a solution of 0.1–0.2 wt% paraformaldehyde in glacial acetic acid at 25°C for 1 h. Thus, 1-methyl-, 1-isopropyl-, 1,5-diisopropylazulene, guaiazulene, and methyl 2-hydroxy-1-azulenecarboxylate readily provided the corresponding 3,3′-methylenebisazulenes, respectively. Acetic acid which had been refluxed with 5 wt% KMnO4 for 2 h and then distilled according to a purification method was found to contain 0.1–0.2 wt% formaldehyde and exert the same 3,3′-methylenebisazulene formation. 3,3′-Dideuteriomethyl-enebis(guaiazulene) was obtained by employing the similar distillate from acetic acid-d4.
Time-Resolved Resonance Raman Investigation of Cytochrome Oxidase Catalysis: Observation of a New Oxygen-Isotope Sensitive Raman Band
Authors: Ogura Takashi , Takahashi Satoshi , Shinzawa-Itoh Kyoko , Yoshikawa Shinya , Kitagawa Teizo
Published: July 2006

The reduction of dioxygen by cytochrome oxidase has been investigated, in the time interval between 0.1 and 5.4 ms after initiation of the reaction, by using time-resolved resonance Raman spectroscopy combined with the Artificial Cardiovascular System [Ogura et al., Biochemistry, 28, 8022 (1989)]. At 0.5 ms we observed a new oxygen-isotope sensitive Raman band at 356 cm−1 for 16O2, which shifted down to 341 cm−1 for 18O2. The temporal behavior of this band was found to be very close to that of another oxygen-isotope sensitive band at 788 cm−1 which had been assigned previously to the Fe(IV)=O stretching mode of the ferryloxo intermediate [Ogura et al., J. Biol. Chem., 265, 14721(1990)]. However, the fact that the 788 cm−1 band shifts to a higher frequency (802 cm−1) in 2H2O, taken together with the present detection of two oxygen-isotope sensitive bands, prompts us to suggest an alternative assignment; namely, that these bands arise from the O−–O− (788 cm−1) and Fe(III)–O− (356 cm−1) stretching modes of the Fe(III)–O−–O−–H intermediate. This conclusion forces a reconsideration of the currently accepted view of cytochrome oxidase catalysis.
Effect of Unpaired Terminal Nucleotides of Substrate RNAs on the RNA Ligation with T4 RNA Ligase
Authors: Sugimoto Naoki , Matsumura Akiko , Hasegawa Keiko , Sasaki Muneo
Published: July 2006

The effect of double-helix formations and unpaired terminal nucleotides of RNA oligomer substrates on a RNA ligation with T4 RNA ligase has been investigated by using high-performance liquid chromatography (HPLC), UV absorbance, and circular dichroism (CD) measurements, and the energy calculation for the double-helix stability of RNAs. In the 1-hour reaction of single-stranded RNA acceptors, the yield of the product increased in the order of pyrimidine donors pCp>pUp and purine donors pAp>pGp. In the reaction of a double-stranded RNA acceptor, UGCGCA, the yield also increased in the same order of the donors. On the other hand, in the reaction of double-stranded RNA acceptors containing unpaired terminal nucleotides (dangling ends), pUp and pGp donors gave the largest yields of the products in the reactions of AUGCGCA and CAUGCAU acceptors, respectively. Furthermore, the yield of the product is the largest for CAUGCAU acceptor within the acceptors having A, C, G, and U dangling ends in the reaction of pGp donor. These results sugggest that the formation of the terminal base pairs of the donors and the dangling ends may affect the RNA ligation with T4 RNA ligase.
Synthesis of 14,14-Difluoro-4-demethoxydaunorubicin
Authors: Matsuda Fuyuhiko , Matsumoto Teruyo , Ohsaki Masako , Terashima Shiro
Published: July 2006

The title compound, (+)-14,14-difluoro-4-demethoxydaunorubicin hydrochloride (9), was prepared starting from the readily available (−)-hydroxy ester (10). This synthesis featured the efficient synthetic route to (−)-14,14-difluoro-4-demethoxy-7-deoxydaunomycinone (20) employing the Reformatsky reaction of ethyl bromodifluoroacetate with the (−)-siloxy aldehyde (14) and previously developed glycosylation method in which trimethylsilyl trifluoromethanesulfonate was used as an activator. In P388 in vitro test, 9 was found to be fifty times more active than adriamycin (1). Prominent antitumor activity was also observed for 9 in P388 in vivo test.
Coated Wire Electrodes Sensitive to Local Anesthetic Cations and Their Application to Potentiometric Determination
Authors: Satake Hiromu , Miyata Takahiro , Kaneshina Shoji
Published: July 2006

Coated wire electrodes sensitive to procaine(PC), tetracaine(TC), lidocaine(LC), dibucaine(DC), mepivacaine(MC), and bupivacaine(BC), based on ion-pair formation between tetraphenylborate ions and the corresponding local anesthetic cations in a plasticized poly(vinyl chloride) membrane were prepared. The electrodes showed linear responses with Nernstian slopes (55–58 mV/decade) over concentration ranges of 4×10−5–10−2, 4×10−5–10−2, 10−4–10−−2, 4×10−5–10−2, 5×10−5–10−2, and 2×10−4–10−2 mol dm−3 for PC, TC, LC, DC, MC, and BC, respectively. The change in pH did not affect the electrode performance within ranges of 3.2–7.4, 3.2–7.4, 2.1–7.7, 2.5–7.4, 3.5–7.0, and 2.4–5.6 for PC, TC, LC, DC, MC, and BC, respectively. The reproducibility, stability, response time, and selectivity were also investigated. The electrodes were applied satisfactorily to the determination of local anesthetics by potentiometry.
Spectrophotometric Determination of Palladium Using 2-(2-Hydroxyimino-1-oxoethyl)thiophene
Authors: Chhakkar Anoop Kumar , Kakkar Lajpat Rai
Published: July 2006

A highly sensitive and selective method for the determination of palladium in trace amounts is developed by complexation of Pd(II) with 2-(2-hydroxyimino-1-oxoethyl)thiophene (INAT) at pH 2.8–6.5, adjusted with diluted acetic acid. The colored species is quantitatively extracted into chloroform, whose absorbance is measured at 425 nm. The method is free from the interference of a large number of elements of great analytical importance. The usefulness of the method is further tested by analyzing different samples and the results obtained are quite satisfactory.
Transport Studies across the Pericardial Membrane: Evaluation of Fixed Charge Density
Authors: Ahmad Mohammad , Arif Hasan , Khan Haroon Rashid , Shoaib Mohammad , Hasan Mohadi
Published: July 2006

The fixed charge density, the permselectivity, and the transport number in several electrolytic solutions of varying concentration were determined across the pericardial membrane of freshly slaughtered buffalo (Bof. Bubalis). The irreversible thermodynamic equations originally meant for understanding the behavior of artificial membranes have been found to be equally applicable to those of the biological membranes.
Fluorescence Quenching of Few Aromatic Amines by Chlorinated Methanes
Authors: Goswami Debabrata , Sarpal Ranjit S , Dogra Sneh K
Published: July 2006

Fluorescence quenching of few aromatic amines; aniline (AB), 1-naphthylamine (1-AN), 2-naphthylamine (2-AN), 2,3-naphthalenediamine (2,3-DAN), 9-phenanthrenamine (9-AP), 1-pyrenamine (1-APy), 2-chrysenamine (2-AC), 6-chrysenamine (6-AC), and 3-fluoranthenamine (3-AF) by dichloromethane, chloroform, and carbon tetrachloride has been studied in cyclohexane and acetonitrile. The quenching rate constants (kq) have been determined in both the solvents and these values are nearly independent of the solvent polarity. The values of kq are nearly equal to diffusion-controlled limits (kdiff) for CHCl3 and CCl4 in both the solvents, whereas for CH2Cl2 it is three to four order of magnitude less than kdiff. For a given amine, kq increases with the increase in electron affinity of the quencher, whereas for a given quencher (dichloromethane) kq increases with the increase in singlet state energy of fluorophore. The results obtained are explained in terms of a quenching mechanism involving an intermediate donor–acceptor (DA)* complex formed between the excited aromatic amine and quencher.
Synthesis and Reaction of Triaminosulfoxonium Salts
Authors: Okuma Kentaro , Takeuchi Hiroshi , Ohta Hiroshi , Matsuyama Haruo , Kamigata Nobumasa , Kobayashi Michio
Published: July 2006

Triaminosulfoxonium salts were synthesized by the oxidation of triaminosulfonium salts with sodium perbenzoate. The reaction of these salts with nucleophiles was carried out.
Thienylpyridines as a New Fluorescent Reagent. II. Determination of Carboxylic Acid with 5-(4-Pyridyl)-2-thiophenemethanol Using HPLC
Authors: Nakajima Riichiro , Shimada Kazuhiko , Fujii Yasuhiro , Yamamoto Akifumi , Hara Tadashi
Published: July 2006

The title compound has been prepared and used as a new derivatization reagent. The reagent reacts with the carboxylic acids in chloroform in the presence of 1-isopropyl-3-(3-dimethylaminopropyl)carbodiimide to produce the corresponding fluorescent esters, which can be separated on an octadecyl-silica column. Each 5 fmol of hexadecanoic or octadecanoic acids and about 50 fmol of benzoic and p-anisic acids (1 μl injection) (S/N=2) were detected.
Redox Photochromism of Waterproof Viologen-Matrix Polymer System
Authors: Kamogawa Hiroyoshi , Yamada Hiroshi
Published: July 2006

A waterproof viologen-matrix polymer system exhibiting redox photochromism in thin films was devised using water-insoluble viologens embedded in N-vinyl-2-pyrrolidone(VP)–methyl acrylate (MA) copolymers also insoluble in water. Both the photosensitivity and the stability of the colors developed decreased with decrease in the VP-content.
Redox Photochromism of Arylviologen Crystals
Authors: Kamogawa Hiroyoshi , Sato Shigeki
Published: July 2006

Reversible color development induced by near UV light (photochromism) was observed for some crystalline powder of 1,1′-diaryl-4,4′-bipyridinium bis(p-toluenesulfonate). Redox mechanism by the electron transfer from the sulfonate anion to viologen dication is claimed.
Conformational Change of Benzoquinone Crown Ether Radical Anions Induced by Complexation with Alkali Metal Cation: An ESR Study
Authors: Hashimoto Kiichi , Togo Hideo , Morihashi Kenji , Yokoyama Yukihiro , Kikuchi Osamu
Published: July 2006

The crowned p-benzoquinone anion radicals, O5−–O8−, were generated either electrochemically or by using a reducing metal, and their ESR spectra were examined in both the absence and presence of the Na+ or K+ cation. The hyperfine coupling (hfc) constants of the methylene protons bonded to the quinone ring depend largely on the size of the crown ring; the orientation of the benzoquinone skeleton with respect to the crown ring was analyzed. The metal-free O5− has a fixed conformation in which the benzoquinone ring is nearly perpendicular to the crown ring, while O8− interconverts freely between two equivalent conformations. The critical case is O6−; the line-width alternation observed in its ESR spectra was well-analyzed using the two-jump model. Temperature-dependent ESR spectra and MNDO calculations have suggested that O6− undergoes a restricted interconversion between two conformations in which the benzoquinone ring has an orientation similar to that of O5−. An activation energy of 10.0 kcal mol−1 was determined for this motion. The ESR spectra of the ion-paired O5−–O8− anion radicals have suggested that the conformational motion of the anion radicals is fixed by complexation with the Na+ or K+cation. The hfc constants of the methyl protons in the benzoquinone ring increased upon complexation, indirectly confirming the interaction between the carbonyl oxygen of benzoquinone at the crown-ring side and the metal cation.
Equations of State for the Lennard–Jones Mixtures at High Temperatures
Authors: Wakayama Shin-ichi , Koshi Mitsuo , Matsui Hiroyuki
Published: July 2006

The virial coefficients for binary mixtures at high temperatures were directly calculated up to the fifth term by use of a Monte-Carlo integration technique and the various empirical mixing rules that have been proposed for estimating mixture virial coefficients were tested. It was found that these empirical mixing rules tend to fail as the molecular size differences increased. Accurate compressibility of the Lennard–Jones binary mixtures were also calculated by adopting Metropolis Monte-Carlo simulations in order to examine validity of the fifth order virial equation of state. At high temperature (T*=20), the compressibility factors calculated by the fifth order virial equation of state were in good agreement with the results of the simulations in the range of V⁄b≥0.4 (b=2πσ3Na/3). It was also found that the van der Waals one fluid theory could provide accurate compressibility factors even for mixtures of molecules with large size differences at high temperatures.
Photochemical Lumiketone-Type Rearrangement of 3-Methoxyphenol Promoted by AlBr3
Authors: Kakiuchi Kiyomi , Ue Masaki , Yamaguchi Bunji , Nishimoto Atsushi , Tobe Yoshito
Published: July 2006

Irradiation of 3-methoxyphenol in the presence of 2 equiv of AlBr3 in CH2Cl2 gave 4-methoxybicyclo[3.1.0]hex-3-en-2-one in a 38% yield. 3-Methoxy-2-methylphenol also yielded the lumiketone rearrangement product. On the other hand, 3-methoxy-4-methyl-, 3-methoxy-5-methyl-, and 5-methoxy-2-methylphenol underwent transposition of the methyl group to give equilibrium mixtures of the three methoxycresols.
Synthesis of Antiprismatic [5.5]Ferrocenophane ([5](1,1′)[5](3,4′)Ferrocenophane)
Authors: Hisatome Masao , Yoshida Shuichi , Yamakawa Koji
Published: July 2006

The title compound 2, which is the first example of a C2 symmetric dibridged ferrocenophane, has been synthesized via a base-catalyzed condensation of 3,4′-diacyl[5]ferrocenophane. The spectroscopic properties of 2 are briefly discussed by comparing them with the corresponding prismatic [5,5]ferrocenophane having C2v symmetry.
Preparation, Stereochemistry, and Antibacterial Activity of Gramicidin S Analogs Containing N-Methyl Groups
Authors: Kawai Masao , Ohya Masashi , Fukuta Norihito , Butsugan Yasuo , Saito Kazuki
Published: July 2006

The N-methylated analogs of gramicidin S, namely [Orn(Me3+)2,2′]-, [MeOrn2,2′, d-MePhe4,4′]-, [MeOrn(Me)2,2′, d-MePhe4,4′]-, and [MeOrn(Me3+)2,2′, d-MePhe4,4′]gramicidin S, were prepared by the use of quaternization reaction of free amino groups with CH3I–KHCO3 in methanol and/or selective amide-methylation with CH3I–Ag2O in DMF. The conformations of these synthetic analogs were shown to be of β-sheet type similar to that of parent gramicidin S by 1H NMR analysis and CD spectral comparison. The N-methyl group-containing analogs exhibited essentially the same antibacterial activity against Gram-positive bacteria as gramicidin S itself.
Reaction of Tetraiodomercurate Anion with HSO3Cl: Synthesis of and Physico-Chemical Studies on M2[Hg(SO3Cl)4] (M=Cu(I), K), (Et4N)2[Hg(SO3Cl)2I2], and K2[Hg(SO3Cl)nI4n] (n=1, 2, and 3)
Authors: Yamin Siddiqi Mohammad , Siddiqi Zafar Ahmad , Shakir Mohammad
Published: July 2006

Reactions of [M2HgI4] with excess of HSO3Cl afford M2[Hg(SO3Cl)4] (M=Cu(I), K). However, the reactions of K2HgI4 with stoichiometric amounts of HSO3Cl, i.e., in 1 : 3, 1 : 2, and 1 : 1 molar ratios, yield K2[Hg(SO3Cl)nI4−n](n=3,2,1). In these reactions HSO3Cl acts as both chlorosulfating agent as well as medium of the reaction. Et4NI reacts with CuI2[Hg(SO3Cl)4] suspended in CH2Cl2 affording (Et4N)2[Hg(SO3Cl)2I2] and [CuSO3Cl]x. All these compounds have been characterized by elemental analysis, electrical conductivity measurements, IR and electronic spectral studies.
Reaction of α-Oxo Ketene Dithioacetals with Glycine
Authors: Fukada Naoaki , Yuzawa Masato
Published: July 2006

3-Carboxymethylamino-3-methylthio-1 -phenyl-2-propen-1-ones were synthesized by the reaction of 3,3-bis(methylthio)-1-phenyl-2-propen-1-ones with glycine in the presence of sodium hydroxide.
Preparation of N-(Substituted formyl) dialkylamino(thioxo)methanesulfenamides
Authors: Yonemoto Katsumi , Shibuya Isao , Yasumoto Masahiko , Taguchi Yoichi , Tsuchiya Tohru
Published: July 2006

N-(Substituted formyl)dialkylamino(thioxo)methanesulfenamides (R2NCSSNHCOR′, 2), anti-foggants for silver halide photographic materials as well as potential precursors for 1,4,2-dithiazolium salts, were prepared in good yields in two “one-pot” procedures. Various amide-type compounds (R′CONH2, 1) were treated successively with NaH and I2 and then condensed with dialkyldithiocarbamates (Method A); or 1 were reacted with tetraalkylthiuram disulfides after treatment with NaH (Method B). These methods allowed a wide variation of substituents R′ in 2: R′=H, dialkylamino, alkoxy, aryl, alkyl, and heterocyclic substituent.
Asymmetric Hydrocyanation of Benzaldehydes Catalyzed by (5R)-5-(4-Imidazolylmethyl)-2,4-imidazolidinedione
Authors: Danda Hidenori
Published: July 2006

The catalytic activity of (5R)-5-(4-imidazolylmethyl)-2,4-imidazolidinedione (3) was examined in the asymmetric hydrocyanation of 3-phenoxybenzaldehyde (1a) to (S)-2-hydroxy-2-(3-phenoxyphenyl)acetonitrile ((S)-2a), an important alcohol moiety of optically active pyrethroid insecticides. Among the catalysts, 3-benzyl derivative (3d) exhibited moderate enantioselectivities for 1a and other benzaldehydes.
On the Reaction of N-(Diphenylphosphinyl)-1-phenylethanimine with Aromatic Aldehydes Giving 4-Aryl-2,6-diphenylpyridine Derivatives
Authors: Kobayashi Tomoshige , Kakiuchi Hidetaka , Kato Hiroshi
Published: July 2006

N-(Diphenylphosphinyl)-2-phenyl-1-azaallyl anion (1), generated from N-(diphenylphosphinyl)-1-phenylethanimine, reacted with aromatic aldehydes in a 2 : 1 molar ratio to give 4-aryl-2,6-diphenylpyridines in moderate yields. The intervention of N-phosphinyl-1-azadiene intermediates is proposed on the basis of the independent synthesis of an N-phosphinyl-1-azadiene and its conversion into a pyridine by the reaction with 1.