bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lithium Acetate-Catalyzed Aldol Reaction between Aldehyde and Trimethylsilyl Enolate in Anhydrous or Water-Containing N,N-Dimethylformamide
Authors: Nakagawa Takashi , Fujisawa Hidehiko , Nagata Yuzo , Mukaiyama Teruaki 
Published: August 2004

Abstract
Lithium acetate (AcOLi)-catalyzed aldol reactions between trimethylsilyl enolates and aldehydes proceed smoothly in anhydrous DMF or pyridine to afford the corresponding aldols in good to high yields under weakly-basic conditions (Tables 1–5). This catalytic aldol reaction is performed smoothly also by using other metal carboxylates that are easily prepared in situ by treating carboxylic acids with lithium carbonate (Li2CO3) (Table 2, Scheme 5). In order to show the effect of mild and readily-available AcOLi catalyst, the aldol reaction in water-containing DMF was studied in detail. AcOLi and various metal carboxylates behaved as effective Lewis base catalysts in aldol reactions between trimethylsilyl enolate and aldehydes in DMF–H2O (50:1) (Tables 6, 7). One of the most characteristic points of the above reaction that took place in water-containing DMF is that the aldehydes having a free amide and a hydroxy or even a carboxyl group reacted smoothly and afforded the desired aldols 29–31 in moderate to high yields (Table 8, Entries 12–15). Trimethylsilyl enolates derived from carboxylic esters behaved similarly as excellent nucleophiles in the above reaction. This is the first example of Lewis base-catalyzed aldol reactions to afford the desired aldol adducts even when silyl enolates derived from carboxylic esters were used in a water-containing organic solvent.
Efficient Method for the Preparation of Inverted Alkyl Carboxylates and Phenyl Carboxylates via Oxidation–Reduction Condensation Using 2,6-Dimethyl-1,4-benzoquinone or Simple 1,4-Benzoquinone
Authors: Shintou Taichi , Fukumoto Kentaro , Mukaiyama Teruaki 
Published: August 2004

Abstract
Oxidation–reduction condensation using in situ formed alkoxydiphenylphosphines, 2,6-dimethy-1,4-benzoquinone, and carboxylic acids provides a useful method for the preparation of inverted tertiary alkyl carboxylates from the corresponding chiral tertiary alcohols under mild and neutral conditions. Similarly, it has afforded alkyl carboxylates successfully in good-to-high yields by the combined use of alkoxydiphenylphosphines having primary, secondary, or tertiary alkoxy groups, carboxylic acids, and simple 1,4-benzoquinone. When chiral secondary or tertiary alcohols are used, the corresponding inverted secondary or tertiary alkyl carboxylates are also obtained in good-to-high yields. In addition, a convenient method for the preparation of phenyl carboxylates in high yields has been established by utilizing oxidation–reduction condensation in toluene at 110 °C using phenoxydiphenylphosphines in situ-formed from phenols and chlorodiphenylphosphine, 2,6-dimethyl-1,4-benzoquinone, and carboxylic acids.
Transformation of Aldehydes into (E)-1-Alkenylsilanes and (E)-1-Alkenylboronic Esters with a Catalytic Amount of a Chromium Salt
Authors: Takai Kazuhiko , Kunisada Yuji , Tachibana Yukiko , Yamaji Nana , Nakatani Emi 
Published: August 2004

Abstract
(Diiodomethyl)trimethylsilane (Me3SiCHI2, 1) is produced by treatment of iodoform with manganese in the presence of Me3SiCl. Aldehydes are converted to (E)-1-trimethylsilyl-1-alkenes in a stereoselective manner with a geminal dichromium reagent generated from 1, manganese, Me3SiCl, and a catalytic amount of CrCl3[thf]3 in THF. Similarly, (E)-1-alkenylboronic esters are prepared stereoselectively in good to excellent yields by treatment of aldehydes with a geminal dichromium reagent derived from Cl2CHB(OR)2 [(OR)2 = OCMe2CMe2O] and LiI instead of 1.
Asymmetric Autocatalysis Initiated by Chiral Ephedrine Immobilized on Silica Gel in a Diisopropylzinc Addition to Pyrimidine-5-carbaldehyde
Authors: Sato Itaru , Shimizu Masako , Kawasaki Tsuneomi , Soai Kenso 
Published: August 2004

Abstract
5-Pyrimidyl alkanol with up to 97% ee was formed using chiral ephedrine immobilized on silica gel in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde in conjunction with asymmetric autocatalysis.
Syntheses of the Novel Acidic and Basic Ligands and Superlattice Formation from Gold Nanoparticles through Interparticle Acid–Base Interaction
Authors: Kanehara Masayuki , Oumi Yasunori , Sano Tsuneji , Teranishi Toshiharu 
Published: August 2004

Abstract
Novel acidic or basic aryl-alkyl disulfides having phenol, benzoic acid, benzenesulfonic acid, aniline, and benzylamine groups were synthesized as protective agents for gold (Au) nanoparticles. Monodisperse Au nanoparticles passivated by these ligands were prepared using a chemical reduction technique, and self-assembled into well-ordered hexagonal close-packed (hcp) 2D superlattices on the substrate. We also present, for the first time, the formation of an aggregated multilayer of Au nanoparticles at a water–organic solvent interface by mixing separately synthesized acidic and basic Au nanoparticles. This film was definitely different from those obtained by the LB method and the conventional self-assembly method through solvent evaporation.
Preparation of Aluminum-Containing Self-Standing Mesoporous Silica Films
Authors: Shimura Naoki , Ogawa Makoto 
Published: August 2004

Abstract
Siliceous and aluminum-containing self-standing mesoporous silica films with the thickness of ca. 50 μm were synthesized by the solvent evaporation method from tetramethoxysilane, aluminum chloride hexahydrate, and octadecyltrimethylammonium chloride. The films possessed highly ordered mesostructures and large surface areas (over ca. 700 m2 g−1). The mesostructures of the products were controlled by the chemical compositions (Si/surfactant); siliceous mesostructured materials with hexagonal (P6m) and cubic (Pm3n) phases were obtained when the molar Si/surfactant ratios were 9 and 8, respectively. The aluminum-containing films with the molar Si/Al ratios of 50, 20, and 10 were also synthesized.
The Induction of a Helical Conformation in Polysilanes with an Optically Active Terminal Group
Authors: Sanji Takanobu , Takase Katsuyuki , Sakurai Hideki 
Published: August 2004

Abstract
Polysilanes with an optically active terminal (+) or (−)-menthoxy group, prepared by the anionic polymerization of masked disilene, adopt a preferential helical-sense conformation in solution at low temperature and also in the solid state at room temperature. The dependence on the molecular weight of the helical induction is also discussed. In a good/poor mixed solvent system, the induction of a helical conformation in the polysilanes was observed when forming aggregates.
TICT Induced Fluorescence Color Change Actualized in an Organogel System
Authors: Iwashita Yuya , Sugiyasu Kazunori , Ikeda Masato , Fujita Norifumi , Shinkai Seiji 
Published: August 2004

Abstract
A dimethylaminobenzoate group (TICT probe) was conjugated with a cholesterol group to assess the microenvironmental effect of the gel fibrils by a fluorescence method. It was found that the solvent-dependent dual fluorescence mode characteristic of TICT molecules in the sol phase almost disappears in the gel phase and only the shorter-wavelength fluorescence arising from the coplanar conformation is observed.
Hydrothermal Synthesis of [Al]-SSZ-24 from [Al]-Beta Zeolite ([Al]-BEA) as Precursors
Authors: Maekawa Hiroyoshi , Kubota Yoshihiro , Sugi Yoshihiro 
Published: August 2004

Abstract
The direct synthesis of [Al]-SSZ-24, a one-dimensional (1-D), high-silica, large-pore zeolite, using [Al]-BEA as precursors by hydrothermal route is successful.
Cluster Core Expansion through Incorporation of Transition-metal Fragments or an Alkyne Molecule into an Incomplete Cubane-type Fe2RuS4 Cluster
Authors: Okazaki Masaaki , Sakuma Atsushi , Tobita Hiromi , Ogino Hiroshi 
Published: August 2004

Abstract
Treatment of CpS22Fe2S4 (CpS2 = 1,3-C5H3(SiMe3)2) with [CpRu(MeCN)3]+ in acetonitrile at room temperature led to the formation of an incomplete cubane-type cluster [(CpS2Fe)2(CpRu)S4]+ (1). Further treatment of 1 with [Cp′Ru(MeCN)3]+ (Cp′ = Cp, Cp*) produced [(CpS2Fe)2(CpRu)(Cp′Ru)S4]2+. Cluster 1 reacted with DMAD to give the 1:1 adduct through formation of three sulfur–carbon bonds.
An Easy Route for the Synthesis of Ordered Three-Dimensional Large-Pore Mesoporous Organosilicas with Im-3m Symmetry
Authors: Zhang Zhendong , Tian Bozhi , Yan Xiaoxia , Shen Shaodian , Liu Xiaoying , Chen Dehong , Zhu Guangshan , Zhao Dongyuan , Qiu Shilun 
Published: August 2004

Abstract
Ordered three-dimensional (3-D) Im-3m-type mesoporous organosilicas with large-pore sizes ( &gt; 6 nm) have been prepared by an easy solvent evaporation method by using bridged silsesquioxane 1,2-bis(triethoxysilyl)ethane precursor and triblock copolymers as the structure-directing agents.
An Examination of the Gelation of Methacrylate Type Crosslinking Agents for the Preparation of Polymer Monolith with 3D Ordered Network Structures
Authors: Aoki Hiroshi , Kubo Takuya , Watabe Yoshiyuki , Tanaka Nobuo , Norisuye Tomohisa , Hosoya Ken , Shimbo Kuniaki 
Published: August 2004

Abstract
The gelation of dimethacrylate type crosslinking agents was studied from the perspective of formation of ordered three dimensional (3D) network structures. Dynamic light scattering (DLS) data showed that the gelation of hydrophilic crosslinking agents having OH groups such as glycerol dimethacrylate (GDMA) was enhanced through hydrogen bonding in a hydrophobic solvent system such as toluene, which afforded more ordered 3D structures.
Simple Metal Oxides as Efficient Heterogeneous Catalysts for Epoxidation of Alkenes by Molecular Oxygen
Authors: Liang Jun , Tang Qinghu , Meng Guanyu , Wu Hongli , Zhang Qinghong , Wang Ye 
Published: August 2004

Abstract
Magnetite iron oxide (Fe3O4) has been found to be an efficient heterogeneous catalyst for the epoxidation of alkenes by molecular oxygen in the absence of a sacrificial reductant among various transition metal oxides. The reaction probably proceeds via a radical mechanism.
Photooxygenation of Olefins, Phenol, and Sulfide Using Fullerodendrimer as Catalyst
Authors: Takaguchi Yutaka , Yanagimoto Yasushi , Fujima Shohoko , Tsuboi Sadao 
Published: August 2004

Abstract
Fullerodendrimer acts as a new catalyst that uses oxygen and light to generate singlet oxygen (1O2). The dendrimer facilitates various types of singlet oxygenation reactions including ene reaction, the Diels–Alder reaction, and oxidation of phenol and sulfide.
Rapid Separation of Palladium(II) from Platinum(IV) in Hydrochloric Acid Solution with Thiodiglycolamide
Authors: Narita Hirokazu , Tanaka Mikiya , Morisaku Kazuko , Abe Tsutomu 
Published: August 2004

Abstract
Solvent extraction of some platinum group metals (Pd(II), Pt(IV), Rh(III)) and base metals (Fe(III), Cu(II), Zn(II)) in hydrochloric acid solution with N,N′-dimethyl-N,N′-di-n-octylthiodiglycolamide (MOTDA) was investigated. The extraction percentage of Pd(II) with MOTDA was nearly 100%, while MOTDA hardly extracted any of the other metal ions. It is noteworthy that the extraction of Pd(II) was extremely fast compared with the conventional extraction reagent, di-n-hexyl sulfide.
A Mild, Efficient, and Inexpensive Protocol for the Selective Deprotection of TBDMS Ethers Using KHSO4
Authors: Arumugam Pandurangan , Karthikeyan Ganesan , Perumal Paramasivan T 
Published: August 2004

Abstract
Potassium hydrogensulfate in 30% aq. methanol deprotects a variety of tert-butyldimethylsilyl ethers at room temperature in excellent yields.
Pt-Catalyzed Regio- and Stereoselective Thienylthiolation of Alkynes
Authors: Hirai Takayoshi , Kuniyasu Hitoshi , Kambe Nobuaki 
Published: August 2004

Abstract
The Pt-catalyzed decarbonylative thienylthiolation of terminal alkynes by thienylthioesters took place regio- and stereoselectively under toluene reflux to give vinylsulfides with cis-thienyl group at β-carbon in moderate to good yields.
A Mild Reduction Route to PTFE Degradation at Low Temperature
Authors: Zou Guifu , Yu Dabin , Jiang Changlong , Xi Guangcheng , Qian Yitai , Zhang Houbo 
Published: August 2004

Abstract
Poly(tetrafluoroethylene) has been degradated by a benign method at low temperature. Metal K plays an important effect in this process. The mild and economical route may be applied to decompose other polymers with hard degradation.
Significant Effect of Molecular Structure on Surface Relief Grating Formation for Novel Azobenzene-Based Photochromic Amorphous Molecular Materials
Authors: Ueda Hiromichi , Tanino Takahiro , Ando Hiroyuki , Nakano Hideyuki , Shirota Yasuhiko 
Published: August 2004

Abstract
A significant effect of molecular structure on the formation of surface relief grating (SRG) was found for novel azobenzene-based photochromic amorphous molecular materials, N,N′-bis[4-(phenylazo)phenyl]-N,N′-diphenyl-p-phenylenediamine and N,N-bis[4-(phenylazo)phenyl]-N′,N′-diphenyl-p-phenylenediamine. The results provide helpful information about SRG formation.
Efficient Catalyst for Low Temperature Solid-Phase Imidization of Poly(amic acid)
Authors: Fukukawa Ken-ichi , Shibasaki Yuji , Ueda Mitsuru 
Published: August 2004

Abstract
Efficient base-catalysts for low temperature solid-phase imidization of poly(amic acid) (PAA) have been found. Thermal imidization of PAA proceeded smoothly in the presence of 1 wt % of strong bases such as 1,4-diazabicyclo[2.2.2]octane (DABCO) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) at 200 °C in a short time, and no residues of DBU remained in the polyimide film.
Bio-template Synthesis of Uniform CdSe Nanoparticles Using Cage-shaped Protein, Apoferritin
Authors: Yamashita Ichiro , Hayashi Junko , Hara Masahiko 
Published: August 2004

Abstract
CdSe nanoparticles were synthesized in the cavity of the cage-shaped protein, apoferritin, by designing the slow chemical reaction system of Cd2+ and Se2−. The cavity size of apoferritin molecules is around 7 nm and the diameter of synthesized CdSe nanoparticles is about 6 nm with small size dispersion. CdSe nanoparticles as prepared are multi-crystalline and can be made into a single crystal by the heat-treatment under nitrogen gas. This bio-template synthesis provides a new method to synthesize uniform CdSe nanoparticles.
Glucose Reduction Route Synthesis of Uniform Silver Nanowires in Large-scale
Authors: Wang Zhenghua , Chen Xiangying , Liu Jianwei , Zhang Meng , Qian Yitai 
Published: August 2004

Abstract
Silver nanowires with average diameters of ≈100 nm and lengths up to 800 μm were hydrothermally prepared in large scale by reducing silver nitrate with glucose in the presence of poly(vinyl alcohol) (PVA) at 160 °C. The reaction temperature, the initial concentrations of the reagents, and the kind of polymer have effects on the formation of silver nanowires. The possible formation mechanism of silver nanowires was proposed.
Selective Synthesis of Wurtzite CdSe Nanorods and Zinc Blend CdSe Nanoparticals through Solvothermal Routes
Authors: Liu Yong , Xu Yao , Li Jun-Ping , Zhang Bin , Wu Dong , Sun Yu-Han 
Published: August 2004

Abstract
By simply changing the reactants’ composition, highly crystallized wurtzite CdSe nanorods and zinc blend CdSe nanoparticles were separately fabricated through a convenient solvothermal route with the reaction of cadmium nitrate (Cd(NO3)2·4H2O), hydrazine hydrate (N2H4·H2O), and Se in ethylenediamine at 140 °C.
Structural Reinvestigation of the Core Oligosaccharide of a Mutant Form of Aeromonas Salmonicida Lipopolysaccharide Containing an

O

-4 Phosphorylated and

O

-5 Substituted Kdo Reducing end Group Using Electrospray Quadrupole Time of Flight Tandem Mass Spectrometry
Authors: Banoub Joseph , Cohen Alejandro , Aneed Anas El , LeQuart Vincent , Martin Patrick 
Published: August 2004

The molecular structure of the mutant form of the lipopolysaccharide (LPS) of Aeromonas salmonicida was determined to contain an O-4 phosphorylated and O-5 substituted Kdo reducing group, and is proposed as the following: It was established that during the cleavage of this LPS with 1% acetic acid, to release the core oligosaccharide from the Lipid A portion, we obtained a degraded core oligosaccharide which eliminated its phosphate group with extreme ease. The precise molecular structure of this dephosphorylated core was deduced by electrospray mass spectrometry and is proposed as the following: Low-energy collision electrospray ionization quadrupole quadrupole time-of-flight tandem mass spectrometry (ESI-QqToF-MS/MS) analysis of the dephosphorylated core oligosaccharide confirmed the presence of the O-5 glycosylated 4,8- and 4,7-anhydro derivatives of the enolizable α-keto-acids. The collision-induced dissociation (CID) tandem mass spectrometric analysis of the heterogeneous mixture of the permethylated core oligosaccharide established the unreported methylation reaction on the diastereomeric 4,8- and 4,7-anhydro α-keto-acids and the complete permethylation and addition reaction of the O-5 glycosylated open chain reducing end terminal D- arabino-3-en-2-ulonic acid. The stereo-specific fragmentation routes obtained during the tandem mass spectrometric analysis permitted the precise sequencing of this dephosphorylated rough core oligosaccharide of the mutant LPS of A. salmonicida.
Quality of life of well-differentiated thyroid carcinoma patients
Authors: Dagan Tal , Bedrin Lev , Horowitz Zeev , Chaushu Gavriel , Wolf Michael , Kronenberg Jona , Talmi Yoav P. 
Published: August 2004

The thyroid gland is the second most common site for malignancy in the head and neck region. Quality of life (QOL) of thyroid cancer patients has not been studied directly. The QOL of long-term thyroid carcinoma patients was investigated. A standardized set of questions based on the University of Washington QOL questionnaire for head and neck cancer with specific domains associated with thyroid disease was created. This questionnaire was mailed to patients who underwent total thyroidectomy for well-differentiated cancer in the department of Otolaryngology-Head and Neck surgery at the Chaim Sheba Medical Centre in Israel between the years 1994–2000.Seventy-eight patients undergoing total thyroidectomy were identified. Forty-eight patients were excluded and 20 out of the 30 remaining patients responded to the questionnaires. Six were male and 14 female, 12 were under the age of 45 (these 12 patients were staged as stage 1). Eleven patients underwent neck dissection. General health and QOL were significantly better for the younger age group and so was the calcium balance score. General health and QOL were significantly better for patients undergoing neck dissection. The overall QOL score was 3.8 conforming with ‘good’ in the questionnaire. Surgery and initial radioiodine treatment scored 6.75 and 6.9 respectively in the distressing scale (0–10 range: 10 = most distressing). The highest distress was encountered during withdrawal from thyroid hormone. Women rated the importance of proper replacement therapy significantly higher than men. Global low scores were found for employment and for effective L-thyroxine replacement therapy.Overall, QOL in these patients was good although lower than expected when compared with other forms of cancer. Age and gender-related differences were noted. Better QOL in neck dissection patients is probably associated with age under 45 years. High distress scores for hormone withdrawal during periodical imaging correspond with former reports and supports use of Thyrogen®. Better hormone balance is warranted for this group.
Prostaglandins, leukotrienes and perennial rhinitis
Authors: Shahab Riad , Phillips David E. , Jones Andrew S. 
Published: August 2004

Prostaglandins and leukotrienes are implicated in conditions of both the upper and lower airways. In the former they are deranged in nasal polyposis, intrinsic rhinitis and allergic rhinitis while in the latter they are involved in the pathogenesis of asthma. The aim of the present study was to measure mucosal eicosanoid levels in the three types of rhinitis and compare with controls. In addition, the effect of topical steroids on eicosanoid levels in rhinitis was examined.The levels of prostaglandins E2 (PGE2) and D2 (PGD2) and of leukotrienes E4 (LTE4) and B4 (LTB4) were measured in nasal biopsies from the inferior turbinates of patients suffering from perennial rhinitis and a control group. Rhinitis patients were classified into three categories: perennial allergic rhinitis (PAR), non-allergic rhinitis with eosinophilia (NARES) and noneosinophilic non-allergic rhinitis (NENAR) on the basis of symptoms, secretion eosinophilia, nasal resistance and allergy testing. Patients with rhinitis were randomized into two groups. One received fluticasone propionate nasal spray (FPANS) and the other a placebo (PNS) over a period of six weeks prior to the biopsies.One hundred and one patients with PAR, NARES or NENAR were recruited sequentially and the control group consisted of 21 patients with no evidence of rhinitis but with nasal obstruction due to septal deviation.Untreated rhinitics had significantly lower levels of PGE2, PGD2 and LTE4 than non-rhinitic controls. Six-weeks’ treatment with FPANS significantly increased the levels of those eicosanoids in patients with PAR and NARES but they were still significantly below normal. Levels of LTB4 in all three rhinitis groups were not significantly different from controls and treatment with topical steroids had no effect. Their findings are contrary to current thinking that increased levels of eicosanoids, in particular cysteinyl-leukotrienes, play an important role in the pathogenesis of chronic, non-infective upper airway inflammation.
Adduction arytenopexy for vocal fold paralysis: indications and technique
Authors: Zeitels Steven M. , Mauri Marcelo , Dailey Seth H. 
Published: August 2004

Adduction arytenopexy was designed as an innovation to arytenoid adduction, however the pragmatic issues regarding patient selection for these procedures has not been comprehensively assessed.A prospective examination was performed on 100 consecutive patients who had undergone laryngoplastic phonosurgical reconstruction for paralytic dysphonia. Seventy-seven of 100 (77 per cent) were judged pre-operatively to gain potentially significant phonatory enhancement from an arytenoid procedure. Fifty-six of 77 (73 per cent) underwent adduction arytenopexy; 17 of 77 (22 per cent) were judged pre-operatively to have inadequate respiratory abduction of the contralateral arytenoid and two out of 77 (three per cent) had athletic aerodynamic requirements. In another two out of 77 (three per cent), there was a chance of favourable reinnervation and thus it was not the preferred method.The majority of patients were judged pre-operatively to gain potentially substantial phonatory enhancement from an arytenoid procedure. However, in this series, approximately 25 per cent of the patients were considered to be unsuitable candidates for an arytenoid medializing procedure, primarily because it was deemed that the operation could result in an inadequate airway.