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Volume 63, Issue 11
Displaying 1-10 of 10 articles from this issue
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From Aqueous Reaction to Enantioselective ReactionsTakahiko Akiyama, Kohei Fuchibe, Junji Itoh2005 Volume 63 Issue 11 Pages 1062-1068
Published: November 01, 2005
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESSBrønsted acid-catalyzed nucleophilic addition and cycloaddition reaction with imines are described. In the first part, HBF4-catalyzed Mannich-type reaction of silyl enolate with aldimine in aqueous media is described. When SDS was used as a surfactant, an organic solvent was not necessary and the carbon-carbon bond forming reactions proceeded smoothly in water alone as a solvent. Aza Diels-Alder reaction also took place in aqueous media by Brønsted acid catalysis. In the latter part, chiral Brønsted acidcatalyzed enantioselective reactions are presented. We prepared a cyclic phosphoric acid diester starting from (R) -BINOL. It was found that the acid exhibited excellent catalytic activity as a chiral Brønsted acid in the Mannich-type reaction, hydrophosphonylation, and aza Diels-Alder reaction.View full abstractDownload PDF (1229K) -
Tadashi Eguchi2005 Volume 63 Issue 11 Pages 1069-1079
Published: November 01, 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSA new practical approach to the preparation of highly and multiply deuterated isoprenoids, archaeal membrane lipid, diterpene antibiotic terpentecin, and carotenoids as examples, and its potential for analyzing the biosynthetic mechanism of isoprenoids are described by using fully deuterated mevalonolactone (MVL-d9). Racemic MVL-d9 was successfully synthesized starting from deuterated dimethoxyphenyl-acetone and trimethyl phosphonoacetate in gram scale. Enantiomerically pure (R) -MVL-d9 was also synthesized using Sharpless asymmetric epoxidation. The methodology for biosynthetic studies using MVL-d9 is meritorious for mechanistic enzymology, particularly, the key transformation involving proton attack and/or proton quench as observed in isoprenoids biosynthesis.View full abstractDownload PDF (1875K) -
Hajime Iwamoto, Yoshimasa Fukazawa2005 Volume 63 Issue 11 Pages 1080-1089
Published: November 01, 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSConformational analyses of flexible compounds with a chemical shift simulation method are described. It is known that NMR chemical shifts reflect the molecular structure, and hence, our method of analysis utilizes chemical shifts. Our newly developed chemical shift simulation method together with molecular dynamic calculation succeeded in the conformational analysis of the flexible compounds; cyclophanes, dicarboxylate complexes of Sn (IV) porphyrins and supramolecular complexes.View full abstractDownload PDF (1833K) -
Toshiaki Sunazuka, Tomoyasu Hirose, Satoshi Omura2005 Volume 63 Issue 11 Pages 1090-1101
Published: November 01, 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe first total synthesis of madindolines A and B, potent selective inhibitors of interleukin 6 (IL-6), has been achieved by stereoselective aldol reaction, ring-closing metathesis, reductive amination, followed by an asymmetric oxidative ring closure of indole, and resulted in determination of their absolute stereochemistries. We have further developed a more efficient second-generation synthesis, which is suitable for gram-scale preparation of these compounds, by stereoselective acylation of ester 34, followed by an intramolecular acylation of ester 32 with allylsilane (19% yield over 9 steps). Synthetic [3H] -madindoline A bound to gp-130, selectively. Furthermore, synthetic madindoline A markedly inhibited osteoclastogenesis in vitro and bone resorption in ovariectomized mice in vivo.View full abstractDownload PDF (1886K) -
Takenori Kusumi, Tetsuya Yabuuchi, Haruko Takahashi, Takashi Ooi2005 Volume 63 Issue 11 Pages 1102-1114
Published: November 01, 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSBased on the modified Mosher's method, we have developed several chiral anisotropic reagents. Together with a unique application of the modified Mosher's method to an enantiomeric mixture, utility of methoxy- (1- and 2-naphthyl) acetic acids (1NMA, 2NMA and other analogues) and phenylglycine methyl ester (PGME) in elucidation of the absolute configuration of secondary alcohols, amines, and carboxylic is summarized.View full abstractDownload PDF (2169K) -
Shigehiro Yamaguchi, Caihong Xu2005 Volume 63 Issue 11 Pages 1115-1123
Published: November 01, 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe intramolecular reductive cyclization of bis (ο-silylphenyl) acetylenes with lithium naphthalenide produces bis-silicon-bridged stilbenes. Based on this new cyclization, a series of silicon-bridged ladder π-conjugated systems consisting of the p-phenylenevinylene framework have been synthesized, including the partially or fully silicon-bridged bis (styryl) benzenes, extended ladder oligo (p-phenylenevinylene) s, and bis-silicon-bridged stilbene-based π-conjugated polymers. All the ladder π-electron systems show intense fluorescence in the visible region. The detailed elucidation of their photophysical properties revealed the significant effect of the silicon moieties on the fluorescence properties.View full abstractDownload PDF (1633K) -
Zhaomin Hou2005 Volume 63 Issue 11 Pages 1124-1136
Published: November 01, 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThis article describes the synthesis and polymerization catalysis of rare earth metal bis (alkyl) complexes bearing mono (cyclopentadienyl) ligands. Polymerization and copolymerization of ethylene, 1-hexene, styrene, norbornene, dicyclopentadiene, 1, 3-hexadiene, cyclohexene oxide, and carbon dioxide are reported. Many of these reactions show unprecedented regio-and stereoselectivity, and afford a series of new polymers that were difficult to be prepared previously by other catalysts.View full abstractDownload PDF (1980K) -
Development, Applications and Future WorksTeck-Peng Loh, Guan-Leong Chua2005 Volume 63 Issue 11 Pages 1137-1146
Published: November 01, 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (1613K) -
Nobuyoshi Yasuda, Lushi Tan, Naoki Yoshikawa, Frederick W. Hartner2005 Volume 63 Issue 11 Pages 1147-1156
Published: November 01, 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSA few different approaches for the preparation of highly substituted bicyclo [3.1.0] hexane mGluR2/3 agonists are reviewed. Addition and elimination, carbene insertion, SN2 type cyclization, and application of Trost's asymmetric allylic alkylation (AAA) are methods of choice for the construction of the ring system. Functionalization of the bicyclo [3.1.0] hexane core structure and synthesis of one of the most potent and selective mGluR2/3 agonists, MGS0028, are also reviewed.View full abstractDownload PDF (1940K) -
Kei Gotot, Takayuki Kawashima2005 Volume 63 Issue 11 Pages 1157-1170
Published: November 01, 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSSeveral kinds of bowl-type molecules were designed for regulation of the reactivities of the functional groups in their cavities, especially for kinetic stabilization of highly reactive species which have been difficult of access by conventional methods. The “peripheral steric protection” by these molecular cavities effectively prevents the bimolecular decomposition of the reactive species such as dimerization or self-condensation, and enabled the isolation of various species including a sulfenic acid, a selenenic acid, an S-nitrosothiol, and a Se-nitrososelenol, which have been known as important but elusive intermediates in biological reactions. Utilization of the molecular bowls as the ligands for transition metal complexes is also described.View full abstractDownload PDF (2657K)
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