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Biomedical subjects

Toshio Fuchigami

Publications and source records attributed to Toshio Fuchigami.

At least 19 recordsLinked to original sources
PubMed2006

Development of a novel environmentally friendly electropolymerization of water-insoluble monomers in aqueous electrolytes using acoustic emulsification.

Electropolymerization of water-insoluble monomers, such as 3,4-ethylenedioxythiophene (EDOT), 3,4-dimethylthiophene (3,4-DiMeTh), 3-methylthiophene (3-MeTh), and 3-ethylthiophene (3-EtTh), proceeded successfully in aqueous electrolytes using acoustic emulsification. Ultrasonication to the water-insoluble monomer/aqueous electrolyte mixtures allowed the formation of very stable emulsions having the characteristic of giving narrow monomer droplet size distributions in the submicrometer range in aqueous electrolytes without added surfactants, and the smooth electropolymerization in the emulsions took place via direct electron transfer between the electrode and the water-insoluble monomer droplets. In this kind of electron-transfer system, the supporting electrolyte should be dissolved not only in the aqueous phase but also in the monomer droplets and contribute to the formation of an electric bilayer inside the droplets. The properties of a polymer EDOT film obtained by the present method were also investigated.

Journal Article↗
PubMed2006

Electrolytic partial fluorination of organic compounds. 83. Anodic fluorination of N-substituted pyrroles and its synthetic applications to gem-difluorinated heterocyclic compounds.

Anodic fluorination of N-substituted pyrroles was carried out in MeCN containing supporting fluoride salts such as Et3N-nHF (n = 2-5) and Et4NF-4HF with use of platinum electrodes under constant current conditions. Anodic fluorination of N-methyl- and N-p-tosylpyrroles having an electron-withdrawing cyano group proceeded smoothly to provide the corresponding fluorinated products in moderate to excellent yields, while anodic fluorination of N-methylpyrrole devoid of an electron-withdrawing cyano group did not take place and a polymeric product was formed at the anode surface. In sharp contrast to the cases of N-methylpyrroles, even N-p-tosylpyrrole devoid of an electron-withdrawing cyano group underwent anodic fluorination efficiently. Diels-Alder reaction of 5,5-difluoro-1-methyl-3-pyrrolin-2-one (2e) derived from anodic fluorination of 2-cyano-1-methylpyrrole (2a) with various dienes was carried out to provide the cycloaddition products in excellent yields. Furthermore, Michael reaction of 2e with various nucleophiles was also successfully carried out to provide the Michael addition products in good to excellent yields.

Acetonitriles↗
PubMed2006

Ultrasonic effects on electroorganic processes. Part 27. Electroreduction of acrylonitrile at suspended lead particle-electrode.

Ultrasonic effect on the electroreduction of acrylonitrile at suspended lead particle-electrode was examined. The product selectivity for adiponitrile, which was formed as the corresponding hydrodimeric product along with propionitrile as the hydromonomeric one in the cathodic reduction of acrylonitrile, was increased by addition of lead particles as a particle-electrode, and moreover the selectivity was further increased under ultrasonication. This ultrasonic effect is rationalized as due to not only mass transport of lead particles to the feeder cathode but also an increase in the effective surface area of particle-electrode by ultrasonic dispersion. A mechanism for the ultrasonic effect is discussed in detail on the basis of the reaction system.

Acrylonitrile↗
PubMed2005

Electrochemical partial fluorination of organic compounds. 80. Synthesis of cyclic alpha-arylthio-alpha-monofluorophosphonate esters.

[Reaction: see text]. Seven-membered cyclic alpha-monofluorophosphonate esters such as 2-allyloxy-3-fluoro-3-phenylthio-4,7-dihydro-[1, 2]-oxaphosphinine-2-oxide were successfully synthesized in moderate total yield as 41% from open-chain allyl phosphonates having an alpha-arylthio group as an electroauxiliary using an alternative sequence of anodic fluorination and ring-closing olefin metathesis (RCM). On the other hand, in an attempt to synthesize an eight-membered analogue, a different type of seven-membered fluorinated cyclic product was formed predominantly by the RCM reaction between the allyloxy groups.

Cyclization↗
PubMed2005

Development of a novel environmentally friendly electrolytic system by using recyclable solid-supported bases for in situ generation of a supporting electrolyte from methanol as a solvent: application for anodic methoxylation of organic compounds.

We have successfully developed a novel environmentally friendly electrolytic system using recyclable solid-supported bases for in situ generation of a supporting electrolyte from methanol as a solvent. It was found that solid-supported bases are electrochemically inactive at an electrode surface. It was also found that solid-supported bases dissociate methanol into methoxide anions and protons. Therefore, in the presence of solid-supported bases, it was clarified that methanol serves as both a solvent and a supporting electrolyte generated in situ. Anodic methoxylation of various compounds with solid-supported bases was carried out to provide the corresponding methoxylated products in good to excellent yields with a few exceptions. The methoxylated products and the solid-supported bases were easily separated by only filtration, and the desired pure methoxylated products were readily isolated simply by concentration of the filtrates. The separated and recovered solid-supported bases were recyclable for several times.

Journal Article↗
PubMed2005

Electropolymerization of an immiscible monomer in aqueous electrolytes using acoustic emulsification.

This paper reports on the novel electropolymerization of an immiscible monomer, such as 3,4-ethylenedioxythiophene (EDOT), in aqueous electrolytes using acoustic emulsification. This new methodology has many practical advantages and characteristics: (a) the formation of stable monomer droplets in aqueous electrolytes without added surfactants using ultrasonic treatment; (b) very smooth electropolymerization in aqueous electrolytes via the direct electron transfer between the electrode and the immiscible monomer droplets; (c) good conductivity after doping of the polymer film formed.

Bridged Bicyclo Compounds, Heterocyclic↗
PubMed2005

Electrolytic partial fluorination of organic compounds. 79. Anodic fluorination of spiropyrazoline-5,3'-chroman-4-ones and thiochromanone analogues. A route to aroyl fluoride derivatives.

[reaction: see text] Anodic fluorination of spiropyrazole-5,3'-chroman-4-ones and their thiochromanone analogues in dimethoxyethane containing Et4NF x 4HF resulted in ring opening of spiroheterocycles, which led to the formation of (5-pyrazolyl)methyl o-carbomethoxyphenyl ethers and their thioether analogues via benzoyl fluoride derivatives.

Chromans↗
PubMed2005

Synthesis of multiple shapes of gold nanoparticles with controlled sizes in aqueous solution using ultrasound.

Effects of concentration of stabilizer (sodium dodecylsulfate: SDS) and ultrasonic irradiation power on the formation of gold nanoparticles (Au-NPs) were investigated. Au-NPs with multiple shapes and size were synthesized by controlling the concentration of stabilizer and ultrasonic irradiation power. The shapes and size of Au-NPs were controlled by changing either the ratio of Au(III) ion/SDS or the power of ultrasonic irradiation. The multiple shapes and size distribution of Au-NPs are dependent on not only the ratio of Au(III) ion/SDS but also ultrasonic irradiation power. The sonochemically synthesized Au-NPs were characterized by TEM and UV-vis spectroscopy.

Journal Article↗
PubMed2005

Development of an electrolytic system using solid-supported bases for in situ generation of a supporting electrolyte from methanol as a solvent.

We have successfully developed a novel electrolytic system using solid-supported bases for in situ generation of a supporting electrolyte from methanol as a solvent. Anodic methoxylation of phenyl 2,2,2-trifluoroethyl sulfide using solid-supported bases was carried out to provide the alpha-methoxylated product in good to excellent yields. The alpha-methoxylated product and solid-supported bases were easily separated by only filtration, and the separated solid-supported bases were recyclable. Anodic methoxylation of phenyl 2,2,2-trifluoroethyl sulfide was successfully carried out 10 times by the recycling of silica gel-supported piperidine in good yields.

Journal Article↗
PubMed2005

Ultrasonic effects on electroorganic processes. Part 25. Stereoselectivity control in cathodic debromination of stilbenedibromides.

Ultrasonic effects on the cathodic debromination of stilbenedibromides on a platinum cathode was examined. Current efficiency and stereoselectivity for trans-stilbene, which was formed along with cis-stilbene in the cathodic debromination of stilbenedibromides, were significantly increased under ultrasonication with an intensity over the ultrasonic cavitation threshold. This ultrasonic effect is rationalized as due to mass transport promotion in the electrode-electrolytic solution interface. A mechanism for the ultrasonic effect is discussed in detail on the basis of the reaction pathway of the debromination of stilbenedibromides.

Bromides↗
PubMed2004

Electrochemical partial fluorination of organic compounds. 74. Efficient anodic synthesis of 2-fluoro- and 2,3-difluoro-2,3-dihydrobenzofuran derivatives.

Anodic fluorination of 3-substituted benzofuran derivatives in a variety of fluoride salts resulted in the formation of three fluorinated products; two stereoisomers of 2,3-difluoro-2,3-dihydrobenzofuran (cis and trans) and cis-2-fluoro-3-hydroxy-2,3-dihydrobenzofuran derivatives. Dehydrofluorination of the main products, cis-difluoro derivatives, furnished the nonaromatic 2-fluoro-3-benzofuranyledene derivatives instead of the aromatic 2-fluorobenzofuran derivatives.

Journal Article↗
PubMed2004

Electroorganic synthesis using a fluoride ion mediator under ultrasonic irradiation: synthesis of oxindole and 3-oxotetrahydroisoquinoline derivatives.

[reaction: see text] Anodic intramolecular cyclization of alpha-(phenylthio)acetamides using a fluoride ion mediator was realized. Under ultrasonic irradiation, cyclization was accelerated markedly to give desired cyclized products in moderate to good yields. The local heating effect of ultrasonic irradiation seems to be more advantageous than usual heating.

Journal Article↗
PubMed2004

Electrolytic partial fluorination of organic compounds.71. Highly diastereoselective anodic fluorination of sulfides having oxygen-containing heterocyclic groups.

Diastereoselective anodic fluorination of sulfides having various oxygen-containing heterocyclic substituents such as 2-furanyl, 1,3-dioxolanyl, 2,2-dimethyl-1,3-dioxolanyl, 2-spirocyclohexyl-1,3-dioxolanyl, 2-spiroadamantyl-1,3-dixolanyl, and 1,3-dioxolanonyl groups at the beta-position was comparatively studied. Among the oxygen-containing heterocyclic substituents, the 2-spirocyclohexyl-1,3-dioxolanyl group gave the best diastereoselectivity (80% de). The diastereoselectivity was also affected by supporting fluoride salts and solvents. Chemical fluorination using selectfluor resulted in much lower diastereoselectivity and extremely poor yield. The fluorinated products were readily converted into the corresponding fluorinated diol in good yields by acidic hydrolysis.

Journal Article↗
PubMed2003

Preparation of conducting polyaniline colloids under ultrasonication.

The effects of ultrasonication on the chemical polymerization of aniline leading to the formation of conducting polyaniline colloids were examined. The formation rate of the colloids was significantly increased under ultrasonication. Furthermore, it was also observed that the morphological structure of the colloids thus prepared was greatly affected by the sonication. The polyaniline colloids were further characterized by a range of techniques including electric resistance meter, gel permeation chromatography, FT-IR and cyclic voltammetry. It is noteworthy that the application of ultrasound to the polymerization resulted in a marked increase in the doping level, which reflected to the high electroconductivity of polyaniline colloids.

Journal Article↗
PubMed2002

Electrolytic partial fluorination of organic compounds. 64.(1) Anodic mono- and difluorination of thiazolyl sulfides.

The anodic fluorination of 2-thiazolyl methyl sulfide, 2-thiazolyl propargyl sulfide, and 2-thiazolyl acetonyl sulfide was successfully carried out to provide the corresponding 5-fluorothiazole and 2,5,5-trifluorothiazoline derivatives. The latter products were readily hydrolyzed to give isolable 5,5-difluoro-2-hydroxythiazoline derivatives. On the other hand, anodic fluorination of 2-thiazolyl cyanomethyl sulfide afforded 5-fluorothiazole and alpha-fluorinated thiazole derivatives. Thus, the product selectivity was found to be greatly changed by the electron-withdrawing ability of substituents at the side chain of the thiazole ring. This is the first report of a successful anodic fluorination of a thiazole ring.

Journal Article↗