巻号一覧
58 巻, 2 号
選択された号の論文の9件中1～9を表示しています
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生合成および変異体解析に高津戸秀果した有機合成化学の役割渡辺剛高津戸 秀, 渡辺 剛2000 年 58 巻 2 号 p. 86-98
発行日: 2000/02/01
公開日: 2009/11/13
ジャーナル フリーOverview of the recent progress in the research of brassinosteroids, a new class of phytohormones, is described. This article covers 1) the chemical synthesis of natural C28 brassinosteroids and their deuterio-labeled compounds and precursor sterols, 2) related brassinosteroid analogs and their biological activity, 3) the role of synthetic organic chemistry in the clarification of brassinolide biosynthesis, and 4) its role in the analysis of brassinosteroid dwarf mutants.抄録全体を表示PDF形式でダウンロード (1978K) -
磯部 稔, 吉良 和信2000 年 58 巻 2 号 p. 99-107
発行日: 2000/02/01
公開日: 2010/01/22
ジャーナル フリーFollowing our previous review of this issue, chemistry of acetylene biscobalthexacarbonyl complex is discussed with special reference in the synthesis of natural and unnatural products. The first example is to do with protein phosphatase inhibitors; thus, okadaic acid and tautomycin are known as strong inhibitors to these enzymes with high specificity of the enzyme type. Hybrid molecules are discussed as unnatural product having enantiomeric spiro moieties. These syntheses have been achieved via enantio-switching method from the same D-glucose derivatives; namely, alkynylation of silylacetylene to sugars provides sugar acetylenes, which are convertible with or without epimerization into α or β heteroolefins leading to enantiomer to each other. Heteroconjugate addition on pyranose ring can provide either syn or anti adduct by switching the chelational anchor and metals of the nucleophile. Pauson-Khand reaction is demonstrated on the sugar acetylenes to provide tricyclic compounds with definite stereoisomer. A macrocyclic ring closure is a specific example of the cobalt complex with C-C bond formation in the critical step. Cobalt chemistry and sugar acetylene chemistry made it possible to provide both of the enantiomers of left end segments of ciguatoxin. This line also discussed to the potential methodology directed toward other portion of this marine natural toxin. These endo-cyclic complexes have reductively been decomplexed into the olefins or vinylsilanes.抄録全体を表示PDF形式でダウンロード (1391K) -
構造・反応性について松原 誠二郎2000 年 58 巻 2 号 p. 108-113
発行日: 2000/02/01
公開日: 2009/11/13
ジャーナル フリーReactions of gem-dimetallic reagents have attracted considerable attention as versatile reagents in organic synthesis. Consequently preparations of gem-dimetallic reagents have been extensively studied. Synthetic applications of the reagents have been focused on two reactions, regioselective olefination of carbonyl compounds and coupling with two different electrophilic building blocks.抄録全体を表示PDF形式でダウンロード (811K) -
小林 和裕2000 年 58 巻 2 号 p. 114-119
発行日: 2000/02/01
公開日: 2009/11/13
ジャーナル フリーMagnesium amides, generated from Grignard reagents and secondary amines, have been found to mediate Pummerer-type reactions. Sulfoxides bearing hydrogens at the α-position only (RSOCH2R1) react with the magnesium amides to produce dithioacetals (RSCHR1SR). The treatment of sulfoxides bearing hydrogens both at the α- and β-positions (RSOCHR1CHR2R3) with the magnesium amides affords vinyl sulfides (RSCR1=CR2R3). The reaction of sulfoxides bearing α-hydrogen (s) (RSOCHR1R2) with Grignard reagents (R3MgBr) in the presence of the magnesium amide results in the formation of sulfides (RSCR1R2R3). The reaction of sulfoxides (R1SOCHR2R3) with thiols (R4SH) in the presence of the magnesium amide gives unsymmetrical dithioacetals (R1SCR2R3SR4). Vinyl sulfoxides (PhSOCR1=CHR2) react with the magnesium amides to give β- (dialkylamino) dithioacetals [(PhS) 2CR1CHR2NR3R4]. The reaction of enamines with sulfoxides bearing α-hydrogens in the presence of the magnesium amide affords the corresponding α-sulfenylalkylated ketones and aldehydes.抄録全体を表示PDF形式でダウンロード (931K) -
高橋 秀依, 橘高 寿枝, 池上 四郎2000 年 58 巻 2 号 p. 120-128
発行日: 2000/02/01
公開日: 2010/01/22
ジャーナル フリーHighly ftinctionalized cyclohexanes are useful intermediates for the synthesis of natural products and their derivatives having 6-membered ring systems. Among the preparation of chiral substituted cyclohexanes, Hg (II) salts mediated conversion of aldohexoses into cyclohexanones [Ferrier (II) carbocyclization] has become one of the most efficient and intriguing process. This article summarizes our recent works concerning the development of the catalytic Ferrier (II) carbocyclization mediated by Pd (II) salts and the application of this reaction to the total syntheses : i) β-glucosidase inhibitor, cyclophellitol, ii) all diastereoisomers of inositol and D-myo-inositol phosphates. It should be emphasized that PdCl2-mediated transformation enabled us to prepare such expensive inositol derivatives efficiently.抄録全体を表示PDF形式でダウンロード (1486K) -
西山 豊, 坂口 聡, 石井 康敬2000 年 58 巻 2 号 p. 129-137
発行日: 2000/02/01
公開日: 2010/01/22
ジャーナル フリーThe utilization of lanthanide metal salts and organolanthanide compounds in organic synthesis has been attracted considerable attention, however, there have been a limited number of studies on the synthetic reactions using divalent samarium compounds such as SmI2 and Cp*2Sm (thf) 2 as catalysts or catalyst precursors. We report here several synthetic reactions by the use of samarium complexes (II), namely SmI2 and Cp*2Sm (thf) 2, as catalysts : (i) coupling reaction of vinyl esters with aldehydes, (ii) acylation of alcohols and amines with vinyl esters, (iii) acylation of tertiary alcohols with vinyl esters in the presence of a catalytic amount of oxime ester, (iv) synthesis of 1, 3-diol monoesters by the trimerization of aldehydes, (v) aldol type condensation of imines, and (vi) one-pot synthesis of pyrroles by the reaction of amines, aldehydes, and nitroalkanes.抄録全体を表示PDF形式でダウンロード (1192K) -
梶原 康宏2000 年 58 巻 2 号 p. 138-146
発行日: 2000/02/01
公開日: 2010/01/22
ジャーナル フリーThis article presents a new synthetic method for the preparation of cytidine-5′-monophospho-neuraminic acid analogues (CMP-NeuAc analogues) and the application of this reaction in combination with sialyltransferases. Several CMP-NeuAc analogues have been synthesized in moderate yields. The sialyltransferase reaction has further been applied to glycoprotein immobilization, in which a CMP-NeuAc was attached to a solid support at the 9″ position and the ability of this imbobilized molecule to effect a transfer reaction was confirmed by an assay using an asialoglycoprotein as the acceptor. Another aspect is a chemoenzymatic synthesis of modified sialyloligosaccharide. 9-Deoxy-9-fluoro- [3-13C] -NeuAc-α-2, 6- [U-13C] -Gal-β-1, 4-GlcNAc sequence was synthesized at the nonreducing end of an intact glycoprotein (ovalbumin) and its conformational properties were analyzed by NMR spectroscopy. The conformational properties of sialylgalactoside on this protein turned out to be similar to those of NeuAc-α-2, 6-Gal-β-1, 4-GlcNAc-β-1- O (CH2) 8COOMe.抄録全体を表示PDF形式でダウンロード (1450K) -
鈴木 正暢, 酒井 健一2000 年 58 巻 2 号 p. 147-148
発行日: 2000/02/01
公開日: 2009/11/13
ジャーナル フリーN-ベンジル-1-フェニルエチルアミン (BPA) は, N-ベンジル-α-メチルベンジルアミンとも呼ばれ, R体が右旋性, S体が左旋性を示す。抄録全体を表示PDF形式でダウンロード (278K) -
磯部 稔, 松原 誠二郎, 西山 豊, 梶原 康宏2000 年 58 巻 2 号 p. 149
発行日: 2000/02/01
公開日: 2009/11/13
ジャーナル フリーPDF形式でダウンロード (187K)
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