研究者詳細 - 清田　洋正

論文 - 清田　洋正

分割表示 235 件中 161 - 180 件目／全件表示 >>

Syntheses and Odour Descriptions of Cyclopropanated Compounds 5. Analogs of Nor-leaf Alcohol and Monoterpene Dienols

Hiroyuki Sakauchi, Hiroki Asao, Tsutomu Hasaba, Shigefumi Kuwahara, Hiromasa Kiyota*

Chemistry and Biodiversity 3 ( 5 ) 544 - 552 2006年

Facile synthesis of (S)-gizzerosine - A potent inducer of gizzard erosion in chicks - Using successive zinc-mediated and palladium-catalyzed coupling reactions

Y Shimasaki, H Kiyota, M Sato, SN Kuwahara

SYNTHESIS-STUTTGART 2005 ( 19 ) 3191 - 3192 2005年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：GEORG THIEME VERLAG KG

Gizzerosine, a potent inducer of gizzard erosion in C chicks, was synthesized using successive zinc-mediated and palladium-catalyzed Coupling reactions as the key steps. The piperonyl inoiety was used as a novel N-protecting-1-group.

DOI： 10.1055/s-2005.918447

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Synthesis to determine the absolute configuration of (-)-pyricuol, a phytotoxin isolated from rice blast disease fungus Magnaporthe grisea

Y Nakamura, H Kiyota, R Ueda, S Kuwahara

TETRAHEDRON LETTERS 46 ( 42 ) 7107 - 7109 2005年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The absolute configuration of (-)-pyricuol, a phytotoxin isolated from rice blast disease fungus Magnaporthe grisea, was determined to be R by synthetic studies. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2005.08.099

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A novel 3,8-seco-taxane metabolite from the seeds of the Chinese yew, Taxus mairei

QW Shi, LG Li, ZP Li, CM Cao, H Kiyota

TETRAHEDRON LETTERS 46 ( 37 ) 6301 - 6303 2005年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The structure of a novel 3,8-seco-bicyclic taxanoid metabolite, isolated from the methanol extract of seeds of the Chinese yew, Taxus mairei, was established as (11 alpha H)-3,8-seco-taxa-3E,7E, 12(18)-triene-2 alpha,6 alpha,9 beta-triol (1) on the basis of spectral analysis including H-1 NMR, C-13 NMR, HMQC, HMBC, NOESY and HR-FABMS. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2005.07.040

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Intramolecular migration of long chain acyl group of Enacyloxin IIa methyl ester

Y Sugiyama, H Kiyota, T Watanabe, T Oritani

NATURAL PRODUCT RESEARCH 19 ( 6 ) 581 - 584 2005年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

Enacyloxin IIa methyl ester in non-protic solvent gave rearranged product in acidic conditions such as surface of TLC plate of silica gel or by treatment with a catalytic amount of p-toluenesulfonic acid. On the other hand, such a rearrangement did not occur in polar protic solvent. The structure of the rearranged product was elucidated as 4-acyl analog of the cyclohexane ring.

DOI： 10.1080/14786410412331271997

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Structure elucidation and complete NMR spectral assignments of a new taxane glycoside from the needles of Taxus cuspidata - Note

LG Li, CM Cao, CH Huo, ML Zhang, QW Shi, H Kiyota

MAGNETIC RESONANCE IN CHEMISTRY 43 ( 6 ) 475 - 478 2005年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY

Anew taxane glycoside was isolated from a methanol extract of the needles of Taxus cuspidata. The structure was established as 2 alpha,9 alpha,10 beta-triacetoxytaxa-4(20),11-dien-13-one-5 alpha-O-beta-D-glucopyranoside (1) on the basis of 1D and 2D NMR and high-resolution fast atom bombardment mass spectral analyses. Copyright (c) 2005 John Wiley & Sons, Ltd.

DOI： 10.1002/mrc.1579

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First synthesis of (+)-pteroenone: A defensive metabolite of the abducted antarctic pteropod Clione antarctica 査読

Yoko Nakamura, Hiromasa Kiyota, Bill J. Baker, Shigefumi Kuwahara

Synlett ( 4 ) 635 - 636 2005年3月

Synthesis of southern (C1 '-C11 ') fragment of pamamycin-635A

A Miura, H Kiyota, S Kuwahara

TETRAHEDRON 61 ( 5 ) 1061 - 1067 2005年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The synthesis of the southern (C1'-C11') fragment of pamamycin-635A, isolated from Streptomyces alboniger, was achieved via an Evans aldol reaction, a cis-selective iodoetherification and a stereospecific deiodination as the key steps. (C) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2004.11.067

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New natural taxane diterpenoids from Taxus species since 1999

Qing-Wen Shi, Hiromasa Kiyota*

Chemistry and Biodiversity 2 ( 12 ) 1597 - 1623 2005年

First example of 11,12-epoxytaxane-glucoside from the needles of taxus cuspidata

CL Wang, ML Zhang, CM Cao, QW Shi, H Kiyota

HETEROCYCLIC COMMUNICATIONS 11 ( 3-4 ) 211 - 214 2005年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：FREUND PUBLISHING HOUSE LTD

A new taxane-glucoside was isolated from the needles of Taxus cuspidata. The structure was established as 2 alpha,9 alpha,10 beta-triacetoxy-11,12-epoxytax-4(20)-en-13-one-5 alpha-O-beta-D-glucopyranoside (1) on the basis of 1D- and 2D spectral analyses.

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Enzymatic Resolution and Odor Descriptions of Both Enantiomers of Lavandulol, a Fragrance of Lavender Oil

Hiroyuki Sakauchi, Hiromasa Kiyota,* Shin-ya Takigawa, Takayuki Oritani, Shigefumi Kuwahara

Chemistry and Biodiversity 2 ( 9 ) 1183 - 1186 2005年

Facile synthesis of (-)-tabtoxinine-beta-lactam and its (3 ' R)-isomer

H Kiyota, T Takai, M Saitoh, O Nakayama, T Oritani, S Kuwahara

TETRAHEDRON LETTERS 45 ( 44 ) 8191 - 8194 2004年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

A concise and high yielding synthesis of (-)-tabtoxinine-beta-lactam 1, the cause of tobacco wildfire disease, was achieved from L-serine using a zinc-mediated coupling reaction, Sharpless asymmetric dihydroxylation and lactamization of N-OBn amide as the key steps. (C) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2004.09.033

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Induction of differentiation of human myeloid leukemia cells by jasmonates, plant hormones

Y Ishii, H Kiyota, S Sakai, Y Honma

LEUKEMIA 18 ( 8 ) 1413 - 1419 2004年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

Some regulators of plant growth and differentiation have been shown to induce the differentiation of several human myeloid leukemia cells, and might be effective as differentiation inducers to control acute myelogenous leukemia cells. In this study, the growth-inhibiting and differentiation-inducing effects of jasmonates on human myeloid leukemia cells were examined. Several myeloid leukemia cells were cultured with methyl jasmonate (MJ) and its derivatives. Cell differentiation was determined by nitroblue tetrazolium-reducing activity, morphological changes, alpha-naphthyl acetate esterase activity and expression of differentiation-associated surface antigens. MJ induced both monocytic and granulocytic differentiation of HL-60 cells. MJ activated mitogen-activated protein kinase (MAPK) in the cells before causing myelomonocytic differentiation. MAPK activation was necessary for MJ-induced differentiation, since PD98059, an inhibitor of MAPK kinase, suppressed the differentiation induced by MJ. MJ also induced the differentiation of other human leukemia cell lines. Introduction of a double bond at the 4,5-position greatly enhanced the differentiation-inducing activity of MJ. MJ and its derivatives potently induce the differentiation of some myelomonocytic leukemia cells. One novel derivative is a particularly promising therapeutic agent for the treatment of leukemia.

DOI： 10.1038/sj.leu.2403421

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New 2(3->20)Abeotaxane and 3,11-Cyclotaxane from Needles of Taxus cuspidata

Qing-Wen Shi, Zuo-Ping Li, Ding Zhao Ji-Shun Gu, Takayuki Oritani, Hiromasa Kiyota*

Bioscience, Biotechnology, and Biochemistry 68 ( 7 ) 1584 - 1587 2004年7月

Syntheses and Odour Descriptions of Cyclopropanated Compounds 5. Analogues of Methyl Jasmonate to Fix the Relative Stereochemistry of the Two Side Chains.

Hiromasa Kiyota,* Shin-ya Takigawa, Shigefumi Kuwahara

Helvetica Chimica Acta 87 ( 7 ) 1854 - 1859 2004年

88(P-12) タバコ野火病原因菌由来の非選択的植物毒素tabtoxinine-β-lactamの合成研究(ポスター発表の部)

清田洋正, 高井隆文, 齋藤正年, 中山修, 折谷隆之, 桑原重文

天然有機化合物討論会講演要旨集 ( 45 ) 521 - 526 2003年9月

記述言語：日本語出版者・発行元：天然有機化合物討論会

Tobacco wildfire disease, caused by infection of tobacco wildfire disease fungus Pseudomonas tabaci, has been the most serious pest for tobacco, and tabtoxin (1) was isolated from the fungus as a phytopathogenic toxin. 1 is converted by host plant peptidases to tabtoxinine-β-lactam (2), which inactivates glutamine synthetase irreversibly. 1 can be a selective pesticide when crops resistant to 1 are developed. We began the synthetic studies of 2 to supply samples to its biological tests and to develop an efficient synthetic route. Zinc mediated coupling of iodide 4b with ester 6 and silyl ether 9 gave 10b and 13b, respectively. Sharpless asymmetric dihydroxylation of the double bonds of each compound afforded 19b (20-30%de) and 21b (81-91%de), respectively. The primary hydroxy group of the diol 19b was converted to amino group, and magnesium mediated β-lactam formation and deprotection gave 2. However, the diastereomeric selectivity of the dihydroxylation of 19b had not improved. So, we tried the conversion of 21b. Oxidation of the primary hydroxy group of 21b gave acid 32b. The corresponding benzyloxy amide 33b was converted to mesylate 35b. The key β-lactam formation using NaH afforded 36b. The last deprotection steps are now in progress.

DOI： 10.24496/tennenyuki.45.0_521

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Biosynthesis and metabolism of abscisic acid and related compounds

Takayuki Oritani, Hiromasa Kiyota

Natural Product Reports 20 ( 4 ) 414 - 425 2003年8月

Synthesis and Biological Evaluation of 1-Deoxy-4,7-dideacetoxy Azetidine Paclitaxel Analogs

Qian Cheng, Hiromasa Kiyota,* Marina Yamaguchi, Tohru Horiguchi, Takayuki Oritani

Bioorganic and Medicinal Chemistry Letters 13 ( 6 ) 1075 - 1077 2003年3月

Syntheses and odour descriptions of cyclopropanated compounds: 4. Modification of aliphatic dienols

H Kiyota, T Takai, S Kuwahara

FLAVOUR AND FRAGRANCE JOURNAL 18 ( 2 ) 100 - 105 2003年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JOHN WILEY & SONS LTD

Several long-chain aliphatic dienols used as commercial odourants were modified with cyclopropane rings, and their characteristics were examined. We used commercially available (2E, 4E)-2, 4-decadien-l-ol, (3Z, 6Z)-3, 6-nonadien-1-ol, and (2E, 6Z)-2, 6-nonadien-1-ol as parent compounds. Monocyclopropanation of the two double bonds in each compound resulted in a significant increase of odour quality. However, dicyclopropanated analogues lost their original odour quality and intensity. Copyright (C) 2003 John Wiley Sons, Ltd.

DOI： 10.1002/ffj.1171

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First Synthesis of (±)-Pyricuol, a Plant Pathogen Isolated from Rice Blast Disease Fungus Magnaporthe grisea

Hiromasa Kiyota, Rumi Ueda, Takayuki Oritani, Shigefumi Kuwahara

Synlett 2003 ( 2 ) 219 - 220 2003年2月

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