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655 results on '"Nagao, Yoshimitsu"'

1. Non-invasive Glucose Measurement Based on Ultrasonic Transducer and Near IR Spectrometer

Author

Gao, Yanan, Yamaoka, Yukino, Nagao, Yoshimitsu, Liu, Jiang, Shimamoto, Shigeru, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Ruediger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Liang, Qilian, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zhang, Junjie James, Series Editor, Kim, Kuinam J., editor, and Kim, Hyuncheol, editor

Published
2019
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8. New straightforward synthesis and characterization of a unique 1beta-methylcarbapenem antibiotic biapenem bearing a sigma-symmetric bicyclotriazoliumthio group as the pendant moiety

Author

Kumagai, Toshio, Tamai, Satoshi, Abe, Takao, Matsunaga, Hiroshi, Hayashi, Kazuhiko, Kishi, Ikuo, Shiro, Motoo, and Nagao, Yoshimitsu

Subjects
Antibiotics -- Structure-activity relationships, Organic compounds -- Synthesis, Heterocyclic compounds -- Research, Biological sciences, Chemistry
Abstract

An alternative expeditious synthesis of biapenem, a remarkable non-natural 1beta-methylcarbapenem antibiotic displaying a broad range of antibacterial activity, notable chemical stability and stability against human renal dehydropeptidase-I, is presented. An economically viable synthetic route to a new heterocyclic compound, mercaptobicyclotriazolium chloride, was developed, since it is useful for the pendant moiety of biapenem. X-ray crystallographic, 1H nuclear magnetic resonance and deuteration experiment analytic data are used to characterize the antibiotic.

Published
1998

9. Intramolecular nonbonded S***O interaction recognized in (acylimino)thiadiazoline derivatives as angiotensin II receptor antagonists and related compounds

Author

Nagao, Yoshimitsu, Hirata, Terukage, Goto, Satoru, Sano, Shigeki, Kakehi, Akikazu, Iizuka, Kinji, and Shiro, Motoo

Subjects
Angiotensin -- Receptors, Binding sites (Biochemistry) -- Research, Chemistry
Abstract

X-ray crystallographic analyses revealed intramolecular, nonbonded 1,5-type S***O interactions in (acylimino)thiadiazolines and the (acylamino)thiadiazole. These interactions are recognized in the crystalline structures of the (acylimino)thiadiazoline derivatives as angiotensin II receptor antagonists. A similar nonbonded 1,5-type O***O interaction in the (acylimino)oxadiazoline is also possible, based on X-ray crystallographic analysis. These results are encouraging for the development of new drugs using mimic-fused bicyclic heterocycles comprised of nonbonded S***O interaction.

Published
1998

10. Asymmetric total synthesis of new non-natural 1-beta-methylcarbapenems exhibiting strong antimicrobial activities and stability against human renal dehydropeptidase-I

Author

Nagao, Yoshimitsu, Nagase, Yunosuke, Kumagai, Toshio, Matsunaga, Hiroshi, Abe, Takao, Shimada, Osamu, Hayashi, Takaaki, and Inoue, Yoshinori

Subjects
Organic compounds -- Synthesis, Antineoplastic agents -- Research, Azo compounds -- Research, Organometallic compounds -- Usage, Biological sciences, Chemistry
Abstract

Two synthetic 1-beta-methylcarbapenems are made via the diastereoselective alkylation of the tin(II) enolates of 1,3-thiazolidine-2-thiones with chiral (4R, 4R)-3-(1R)-1-{(tert-butyl-dimethylsilyl)oxy}ethyl-4-acetoxyazetidin-2-one. The synthetic carbapenems are shown to be potent wide-spectrum antimicrobial agents resistant to human renal dehydropeptidase-I. The chiral synthon itself is obtained via a parallel diastereoselective aldol reaction between acetaldehyde and the tin(II) enolate of a 1,3-thiazolidine-2-thione.

Published
1992

11. Highly diastereoselective alkylation of 4-acetoxyazetidin-2-one useful for 1-beta-methylcarbapenem synthesis

Author

Nagao, Yoshimitsu, Kumagai, Toshio, Nagase, Yunosuke, Tamai, Satoshi, Inoue, Yoshinori, and Shiro, Motoo

Subjects
Organic compounds -- Synthesis, Antibiotics -- Research, Dehydrogenases -- Research, Alkylation -- Methods, Esters -- Methods, Antineoplastic agents -- Research, Biological sciences, Chemistry
Abstract

The soft base formed by the tin(II) enolates of 3-acyl-(4S)-ethyl- and 3-acyl-(4S)-isopropyl-1, 3-thiazolidine-2-thione allows the diastereoselective alkylation of the acyl imine of 4-acetoxyazetidin-2-one at its C-4 soft-acid position. The alkylated azetidinones are converted to carboxylic acids and acetylated at the C-3 position to yield the (hydroxyethyl)azetidin-2-one intermediate for thienamycin and imipenem. The second (hydroxymethyl)azetidin-2-onecarboxylic acid is subjected to Masamune beta- keto esterification to yield the key intermediate for the synthesis of 1-beta-methylcarbapenems.

Published
1992

12. Diastereoselective alkylative discrimination of racemic 3-substituted 4-acetoxyazetidin-2-ones and its application to the synthesis of a chiral key intermediate for carbapenem syntheses

Author

Nagao, Yoshimitsu, Nagase, Yunosuke, Kumagai, Toshio, Kuramoto, Yasuhiro, Kobayashi, Shigeaki, Inoue, Yoshinori, Taga, Tooru, and Ikeda, Hirokazu

Subjects
Organic compounds -- Synthesis, Antineoplastic agents -- Research, Azo compounds -- Research, Alkylation -- Methods, Enantiomers -- Research, Carbamates -- Usage, Organometallic compounds -- Usage, Biological sciences, Chemistry
Abstract

The chiral tin enolate of 3-acetyl-(4S)-ethyl-1, 3-thiazolidine-2-thione effects a highly diastereoselective alkylation of 3-dimethylsilyloxy-4-acetoxyazetidin-2-one and its stereoisomer, giving 42:20:9 and 45:29:5 respective enantiomeric yields. The major enantiomer and its carboxylic acid derivative are transformed into a carboxylate, which can serve as a key intermediate in the synthesis of carbapenems. To evaluate the enantiomeric purity of chiral 4-acetoxyazetidin-2-one for research and industrial use, it is subjected to analytical resolution on an amylose (S)-methylbenzylcarbamate column. Other stereochemical data are presented.

Published
1992

17. Highly stereoselective asymmetric Pummerer reactions that incorporate intermolecular and intramolecular nonbonded S...O interactions

Author

Nagao, Yoshimitsu, Miyamoto, Satoshi, Miyamoto, Motoyuki, Takeshige, Hiroe, Hayashi, Kazuhiko, Sano, Shigeki, Shiro, Motoo, Yamaguchi, Kentaro, and Sei, Yoshihisa

Subjects
Sulfur compounds -- Chemical properties, Chemical synthesis -- Analysis, Chemistry
Abstract

New chiral sulfoxides ([R.sub.S],S)-3, ([S.sub.S],S)-3, ([R.sub.S],S)-4, and ([S.sub.S],S)-4 and known chiral sulfoxides ([R.sub.S])-5, ([R.sub.S])-6 and ([R.sub.S])-7 are synthesized based on the concept of intermolecular and intramolecular nonbonded S...O interactions. The mechanistic studies on the facile stereoselective Pummerer reactions have revealed the necessity for the amide/trimethylsilyl triflate complex to be an efficient activation reagent for [Ac.sub.2]O and a trapping reagent for the released acetate ion.

Published
2006

20. Principle and clinical usefulness of the infrared fluorescence endoscopy

Author

Ito, Susumu, Muguruma, Naoki, Kimura, Tetsuo, Yano, Hiromi, Imoto, Yoshitaka, Okamoto, Koichi, Kaji, Masako, Sano, Shigeki, Nagao, Yoshimitsu, Ito, Susumu, Muguruma, Naoki, Kimura, Tetsuo, Yano, Hiromi, Imoto, Yoshitaka, Okamoto, Koichi, Kaji, Masako, Sano, Shigeki, and Nagao, Yoshimitsu

Abstract

Since there is no infrared fluorescence materials in the living body, infrared fluorescence labeling materials are very useful for making a diagnosis of a micro cancer. We have developed an infrared fluorescence endoscope (IRFE) and indocyanin green (ICG)-derivative as infrared fluorescence labeling materials to evaluate gastrointestinal neoplastic lesions. The study aims were to apply an IRFE and to demonstrate its usefulness in detecting cancerous tissue using an antibody coupled with ICG-derivative. IRFE consisted of an infrared endoscope equipped with excitation (710-790nm) and barrier (810-920nm) filters and an intensified CCD camera. We have developed ICG N-hydroxy sulfo succinimide ester (ICG-sulfo-OSu) and 3-ICG-acyl-1, 3-thiazolidine-2-thione (ICG-ATT) as an infrared fluorescent-labeling reagent. ICG-derivative-labeled mouse anti-human carcinoembryonic antigen (CEA)antibodyandMUC1 antibody were employed in this study. Moreover, we examined the ability of a reinforcement agent, octylglucoside, to intensity fluorescence from the labeled antibody. Biopsy specimens of gastric cancer were stained with anti-CEA antibody by the avidin-biotinylated peroxidase complex method. Among the positive specimens, freshly resected stomach from three cases were used for the infrared (IR) imaging analysis. The incubation of freshly resected stomach specimens with ICG-anti-CEA antibody-complex resulted in positive staining of the tumor sites by IRFE, and the IR fluorescent images correlated well with the tumor sites. The immunohistochemical studies suggested that the intensity of IR fluorescence of ICG-ATT-MUC1was stronger than that of ICG-sulfo-OSu. In tumor sections, the reinforcement agent intensified fluorescence, ever at low antibody concentrations. Therefore, we conclude that an anti-CEA (and/orMUC1) antibody with affinity for cancerous lesions and labeled with ICG-derivative can be imaged with this IRFE. Specific antibodies tagged with ICG-derivative with the reinforceme

Published
2006

21. Optimal labeling condition of antibodies available for immunofluorescence endoscopy

Author

Tadatsu, Yoko, Muguruma, Naoki, Ito, Susumu, Tadatsu, Masaya, Kusaka, Yoshihiro, Okamoto, Koichi, Imoto, Yoshitaka, Taue, Hiromi, Sano, Shigeki, Nagao, Yoshimitsu, Tadatsu, Yoko, Muguruma, Naoki, Ito, Susumu, Tadatsu, Masaya, Kusaka, Yoshihiro, Okamoto, Koichi, Imoto, Yoshitaka, Taue, Hiromi, Sano, Shigeki, and Nagao, Yoshimitsu

Abstract

Purpose: In recent years, labeled antibodies have been used for diagnostic imaging in many studies. In this study, we investigated the mode of binding in antibodies labeled with ICG derivatives newly developed for the diagnosis of microcarcinomas, and evaluated the optimal binding molar ratio between the labeling compounds and antibody. Methods: MUC1 antibody and ICG derivatives (ICG-ATT and ICG-sulfo-OSu) were used. ICG derivatives noncovalently bound to the antibody were removed with ethyl acetate, and the ratio of ICG derivatives covalently bound to the labeled antibody was confirmed. During purification of the labeled antibody, the amount of each labeling compound reacting with 1molecule of the antibody varied as follows: 4, 8, 16, and 32molar equivalents. Subsequently, the intensity of fluorescence was evaluated by spectroscopy and infrared fluoroscopy. Results : The ratio of residual ICG derivative labeling the antibody was 67.4% for ICG-ATT and 65.0% for ICG-sulfo-OSu. When fluorescent antibody labeled with ICG-ATT at anF/Pratio of 2.94or 4.18wasused, specific and clear fluorescent images of the antigen were obtained. When ICG-ATT-labeled antibody at an F/P ratio of 6.50 or 6.75 was used, the fluorescence intensity decreased and the fluorescent images of antigen became unclear. Conclusions: It was found that the ICG-ATT-labeled antibody was a more specific and sensitive marker than ICG-sulfo-OSu-labeled antibody, and that lower binding molar ratios of ICG-ATT were more useful for labeling the antibody.

Published
2006

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