Fumio Ohseto - Academia.edu (original) (raw)
Papers by Fumio Ohseto
According to the regulation in Japan, the chlorine concentration is required to be above 0.1 ppm ... more According to the regulation in Japan, the chlorine concentration is required to be above 0.1 ppm in tap water. The authorized methods currently in use to measure the concentration involves o-tolidine and N,N’-diethylaminophenylenediamine (DPD) as a chromogenic indicator. o-tolidine, in particular, has been used most widely for this purpose, but the used is being limited because of a growing concern about its potential carcinogenicity. DPD, the analogous reagent but with less toxicity, is the only alternative dye currently in use to measure chlorine contents in tap water. We recently reported a new o-tolidine derivative, N,N'-bis(2-hydroxy-3-sulfopropyl)tolidine, disodium salt (SAT-3), as a sensitive chromogenic indicator dye for detecting hydrogen peroxide or peroxidase activity. We have demonstrated that SAT-3 also works well in determining chlorine concentration in water with a longer absorption wavelength, higher sensitivity and stability, less cytotoxicity than DPD and no mu...
![Research paper thumbnail of Combined NMR spectroscopy and molecular mechanics studies of OH-depleted calix[4]arenes: On the influence of OH groups on the relative stability of calix[4]arene conformers](https://attachments.academia-assets.com/73341419/thumbnails/1.jpg)
](Tetrahedron
Abetrack The effects of OH groups on the relative stabilities and tbe structures of four conforme... more Abetrack The effects of OH groups on the relative stabilities and tbe structures of four conformers of OH-depleted calix[4Jarenes are discussed on the basis of a compu~on~ method using molecular mechanics (MM3(92)) calculations. The results are compared with various NMR spectroscopic experiments. From these studies, it is found that tbe calix[4]arene framework with no OH group in the 'lower rim &.etra-OHsLrpleted calix[4]areaes: 4a and Sb) favors a cone confom~ation with C+ symmeQy and the changes in the relative stabilities in calix[4]areaes with OH-groups are due to the formarion of stable hydrogen bonds and/or the relaxation of the steric crowding around OH-substituents in a lower rim site. NMR studies suggest that mono-OH-depleted calix[4]amne lb forms intra-and intermolecular hydrogen bonds among pheaolic OH groups, white di-and ~~H~le~ calix[4]arenes (2b and 3b) scarcely form it. They also show that the ring inversion barriers of calix[4]arenes increase with the number of OH groups in 25.26.27 or 2&position.
Journal of Japan Oil Chemists' Society, 1997
Journal of Japan Oil Chemists' Society, 1994
Journal of the Chemical Society, Perkin Transactions 2, 1995
![Research paper thumbnail of Substitution of oh with nh2 calix[4]arenes: An approach to the synthesis of aminocalixarenes](https://attachments.academia-assets.com/73341416/thumbnails/1.jpg)
](Tetrahedron Letters, 1992
From p-t-butylcalixL4larene bis(diethylphosphate) ester(l), monodehydroxymonoamino_p_t_bccy2calix... more From p-t-butylcalixL4larene bis(diethylphosphate) ester(l), monodehydroxymonoamino_p_t_bccy2calix[4]a~ene{3~ and diamino-p-t-butylcalix[4]arene(B) were synthesized in liquid ammonia-co-solvent in the Dresence of KNH?.
Tetrahedron Letters, 1995
A calix[4]arene bearing two boronic acids on the upper rim and a crown loop on the lower rim was ... more A calix[4]arene bearing two boronic acids on the upper rim and a crown loop on the lower rim was synthesized. This compound formed 1:1 complexes with D-glucose, D-talose, and D-allose and showed negative allosterism upon addition of Mg2+, Ca2+, Li+, or Na+, but positive allosterism upon addition of K+, Rb+, or Cs+. This is a novel example of allosteric “communication”
Tetrahedron Letters, 1993
Journal of the American Chemical Society, 1994
... Microscopic Observation Kazutaka Murata, Masayosbi Aoki, T sayd Suzuki, Takaaki Harada, Hiros... more ... Microscopic Observation Kazutaka Murata, Masayosbi Aoki, T sayd Suzuki, Takaaki Harada, Hirosuke Kawabata, Takmhi Komri, Fumio olrseto, Keiko Ueda, and Seiji Shinkai' Contribution from the Chemirecognics Project, ERA TO, Research Development Corporation of ...
Colloids and Surfaces B: Biointerfaces, 1996
ABSTRACT
Analytical Sciences, 1999
Colorimetric cell viability assays have been a technique of increasing use as an alternative meth... more Colorimetric cell viability assays have been a technique of increasing use as an alternative method to using radioisotopes or animals for measuring the number of viable cells. The assay is rapid and is normally performed using a chromogenic dye that responds to the activity of cellular enzymes, such as dehydrogenase or esterase. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) is among the most commonly used chromogenic dye with which dehydrogenase activity (probably of mitochondria) can be measured colorimetrically at 570 nm as an index for cell viability. 1 MTT, however, produces an extremely water-insoluble formazan dye upon cellular reduction, often forming deposits which can damage the cells, and therefore an extra step is required in its assay procedure to solubilize the formazan. To overcome this disadvantage, we reported a tetrazolium salt, 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H tetrazolium, monosodium salt (WST-1), which produced highly water soluble formazan and proved to be of value as a chromogenic indicator for cell viability. 2 Although WST-1 has found increasing applications 3,4 , it is useful only to measure the number of viable cells in the range between 1000 and 25000 cells per well (of microplates) for most cell lines. Because of the limited sensitivity for cell viability of these chromogenic tetrazolium saltbased techniques, we have been more interested in developing a fluorometric method which can detect other metabolic activities than that of mitochondria as 1025
Tetrahedron Letters, 1995
A calix[4]arene bearing two boronic acids on the upper rim and a crown loop on the lower rim was ... more A calix[4]arene bearing two boronic acids on the upper rim and a crown loop on the lower rim was synthesized. This compound formed 1:1 complexes with D-glucose, D-talose, and D-allose and showed negative allosterism upon addition of Mg2+, Ca2+, Li+, or Na+, but positive allosterism upon addition of K+, Rb+, or Cs+. This is a novel example of allosteric “communication”
Analytical Communications, 1999
ABSTRACT
According to the regulation in Japan, the chlorine concentration is required to be above 0.1 ppm ... more According to the regulation in Japan, the chlorine concentration is required to be above 0.1 ppm in tap water. The authorized methods currently in use to measure the concentration involves o-tolidine and N,N’-diethylaminophenylenediamine (DPD) as a chromogenic indicator. o-tolidine, in particular, has been used most widely for this purpose, but the used is being limited because of a growing concern about its potential carcinogenicity. DPD, the analogous reagent but with less toxicity, is the only alternative dye currently in use to measure chlorine contents in tap water. We recently reported a new o-tolidine derivative, N,N'-bis(2-hydroxy-3-sulfopropyl)tolidine, disodium salt (SAT-3), as a sensitive chromogenic indicator dye for detecting hydrogen peroxide or peroxidase activity. We have demonstrated that SAT-3 also works well in determining chlorine concentration in water with a longer absorption wavelength, higher sensitivity and stability, less cytotoxicity than DPD and no mu...
Tetrahedron
Abetrack The effects of OH groups on the relative stabilities and tbe structures of four conforme... more Abetrack The effects of OH groups on the relative stabilities and tbe structures of four conformers of OH-depleted calix[4Jarenes are discussed on the basis of a compu~on~ method using molecular mechanics (MM3(92)) calculations. The results are compared with various NMR spectroscopic experiments. From these studies, it is found that tbe calix[4]arene framework with no OH group in the 'lower rim &.etra-OHsLrpleted calix[4]areaes: 4a and Sb) favors a cone confom~ation with C+ symmeQy and the changes in the relative stabilities in calix[4]areaes with OH-groups are due to the formarion of stable hydrogen bonds and/or the relaxation of the steric crowding around OH-substituents in a lower rim site. NMR studies suggest that mono-OH-depleted calix[4]amne lb forms intra-and intermolecular hydrogen bonds among pheaolic OH groups, white di-and ~~H~le~ calix[4]arenes (2b and 3b) scarcely form it. They also show that the ring inversion barriers of calix[4]arenes increase with the number of OH groups in 25.26.27 or 2&position.
Journal of Japan Oil Chemists' Society, 1997
Journal of Japan Oil Chemists' Society, 1994
Journal of the Chemical Society, Perkin Transactions 2, 1995
Tetrahedron Letters, 1992
From p-t-butylcalixL4larene bis(diethylphosphate) ester(l), monodehydroxymonoamino_p_t_bccy2calix... more From p-t-butylcalixL4larene bis(diethylphosphate) ester(l), monodehydroxymonoamino_p_t_bccy2calix[4]a~ene{3~ and diamino-p-t-butylcalix[4]arene(B) were synthesized in liquid ammonia-co-solvent in the Dresence of KNH?.
Tetrahedron Letters, 1995
A calix[4]arene bearing two boronic acids on the upper rim and a crown loop on the lower rim was ... more A calix[4]arene bearing two boronic acids on the upper rim and a crown loop on the lower rim was synthesized. This compound formed 1:1 complexes with D-glucose, D-talose, and D-allose and showed negative allosterism upon addition of Mg2+, Ca2+, Li+, or Na+, but positive allosterism upon addition of K+, Rb+, or Cs+. This is a novel example of allosteric “communication”
Tetrahedron Letters, 1993
Journal of the American Chemical Society, 1994
... Microscopic Observation Kazutaka Murata, Masayosbi Aoki, T sayd Suzuki, Takaaki Harada, Hiros... more ... Microscopic Observation Kazutaka Murata, Masayosbi Aoki, T sayd Suzuki, Takaaki Harada, Hirosuke Kawabata, Takmhi Komri, Fumio olrseto, Keiko Ueda, and Seiji Shinkai' Contribution from the Chemirecognics Project, ERA TO, Research Development Corporation of ...
Colloids and Surfaces B: Biointerfaces, 1996
ABSTRACT
Analytical Sciences, 1999
Colorimetric cell viability assays have been a technique of increasing use as an alternative meth... more Colorimetric cell viability assays have been a technique of increasing use as an alternative method to using radioisotopes or animals for measuring the number of viable cells. The assay is rapid and is normally performed using a chromogenic dye that responds to the activity of cellular enzymes, such as dehydrogenase or esterase. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) is among the most commonly used chromogenic dye with which dehydrogenase activity (probably of mitochondria) can be measured colorimetrically at 570 nm as an index for cell viability. 1 MTT, however, produces an extremely water-insoluble formazan dye upon cellular reduction, often forming deposits which can damage the cells, and therefore an extra step is required in its assay procedure to solubilize the formazan. To overcome this disadvantage, we reported a tetrazolium salt, 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H tetrazolium, monosodium salt (WST-1), which produced highly water soluble formazan and proved to be of value as a chromogenic indicator for cell viability. 2 Although WST-1 has found increasing applications 3,4 , it is useful only to measure the number of viable cells in the range between 1000 and 25000 cells per well (of microplates) for most cell lines. Because of the limited sensitivity for cell viability of these chromogenic tetrazolium saltbased techniques, we have been more interested in developing a fluorometric method which can detect other metabolic activities than that of mitochondria as 1025
Tetrahedron Letters, 1995
A calix[4]arene bearing two boronic acids on the upper rim and a crown loop on the lower rim was ... more A calix[4]arene bearing two boronic acids on the upper rim and a crown loop on the lower rim was synthesized. This compound formed 1:1 complexes with D-glucose, D-talose, and D-allose and showed negative allosterism upon addition of Mg2+, Ca2+, Li+, or Na+, but positive allosterism upon addition of K+, Rb+, or Cs+. This is a novel example of allosteric “communication”
Analytical Communications, 1999
ABSTRACT