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Volume 66, Issue 8
Displaying 1-9 of 9 articles from this issue
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Shin-ichi Hirashima, Akichika Itoh2008 Volume 66 Issue 8 Pages 748-756
Published: August 01, 2008
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSMolecular oxygen has recently received much attention, since it is photosynthesized by plants and is an effective oxidant of larger atom efficiency than that of other oxidants. In the course of our study of photo-oxidation, we have found that alcohols and methyl group at aromatic nucleus were oxidized directly to the corresponding carboxylic acids in the presence of catalytic bromine sources, such as lithium bromide, bromine, and hydrobromic acid, in an oxygen atmosphere under irradiation of UV or VIS. This new oxidation reaction is interesting in keeping with the notion of Green Chemistry due to non-use of heavy metals, waste reduction, use of molecular oxygen, and inexpensive acquisition of reagents. Herein, we report our study on the generality of this aerobic photo-oxidation in detail.View full abstractDownload PDF (3922K) -
Fumio Sanda, Toshio Masuda2008 Volume 66 Issue 8 Pages 757-764
Published: August 01, 2008
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThis article reviews the secondary structures, properties, and functions of helical polyacetylenes substituted with optically active groups, including cis-stereoregular poly (1-methylpropargyl ester) s, poly (N-alkynylamide) s, and poly (alkynamide) s synthesized by the polymerization using rhodium catalysts. The polymers take tightly twisted cis-cisoidal and loosely twised cis-transoidal helices according to the substituents and media, some of which undergo reversible transformation of helical sense with external stimuli such as temperature and pH. The helical polymers are applicable to chiral recognition materials and catalyts for asymmetric synthesis.View full abstractDownload PDF (8869K) -
Toshiyuki Kan, Tohru Fukuyama2008 Volume 66 Issue 8 Pages 765-773
Published: August 01, 2008
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIt is widely believed that the production and deposition of amyloid β-peptides (Aβ) play a key role in the pathogenesis of Alzheimer's disease (AD). These Aβ are generated through a sequence of proteolytic cleavages of the amyloid precursor protein (APP) by membrane-bound aspartic proteases, .β-secretase and γ-secretase. It is believed that the direct inhibition of β-and γ-secretases would reduce the production of Aβ and served as an important therapy for AD. Furthermore, in the view of the direct implication of γ-secretase in the generation of Aβ42 peptide, which has been shown to aggregate senile plaques, the γ-secretase was considered as a more important therapeutic target for the pathogenesis of AD. Thus, we started to screen potent inhibitors of γ-secretase by modification of DAPT (13) derivatives and develop a functional analysis of these inhibitors. During the course of our investigation of potential inhibitors for γ-secretases, we found that the our original synthetic methodologies (Ns-strategy and efficient immobilization of our resin 7) would enable efficient syntheses of inhibitors and photoaffinity probe molecule (28). Furthermore, our synthetic probe (28) clarified that the major direct target molecules for the DAPT (13) are PS 1 CTFs, which were discovered from the genetically investigation of familial AD. In this report, we described our synthetic methodology and its medicinal chemistry as well as chemical biology applied to for the pathogenesis of AD.View full abstractDownload PDF (4668K) -
Susumu Saito, None Momiyama, Hisashi Yamamoto2008 Volume 66 Issue 8 Pages 774-784
Published: August 01, 2008
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSProper design of amine-Bronsted acid catalysis has been shown to be effective for achieving high reactivity and selectivity in the asymmetric direct aldol reaction. During the course of this study, two principal approaches have been implemented to create a new type of catalysis: One is derived from Bronsted acid and diamine; the other is pyrrolidine with tetrazole functionality. The developed amine-Br?Onsted acid catalysts have been found to effectively catalyze the direct aldol reaction of aldehyde, chloral and nitrosobenzene.View full abstractDownload PDF (4296K) -
Teruyuki Kondo2008 Volume 66 Issue 8 Pages 785-794
Published: August 01, 2008
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSNovel catalytic reactions via ruthena- or rhodacyclic intermediates developed by our research group are reviewed. We initiate our study from (1) ruthenium-catalyzed [2 + 2] cycloaddition of alkynes with alkenes, followed by developing (2) intramolecular Pauson-Khand-type reaction of 1, 6-enynes, (3) hydroquinone synthesis, (4) codimerization of styrenes with ethylene . Another approach to construct novel functional monomers, such as cyclopentenones, pyranopyrandiones, and phenols, involves cleavage of carbon-carbon bonds in cyclobutenediones, cyclopropenones, and cyclobutenones. All reactions proceed with high atom-efficiency via ruthena- or rhodacyclicintermediates. In addition, rhodium-catalyzed [2 + 2 + 2] cocyclization of alkynes with isocyanates as well as novel ruthenium-catalyzed [2 + 2 + 1] cocyclization of alkynes, isocyanates, and carbon monoxide have been disclosed.View full abstractDownload PDF (3191K) -
Yoshihiko Yamamoto2008 Volume 66 Issue 8 Pages 795-805
Published: August 01, 2008
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSIn the presence of catalytic amounts of an organoruthenium complex, Cp* RuCl (cod), the partiallyintramolecular cyclotrimerizations of various C-alkynylglycosides proceeded at ambient temperatureto afford C-arylglycosides. The [2+2+2] cycloaddition of α, ω-diynes with C-alkynylglycosides successfully afforded C-arylglycosides in good yields. This method was further extended to the cycloaddition of C-diynylglycosides to obtain C-aryldisaccharides. Spirocyclic C-arylglycosides were also synthesized in good yields via the [2+2+2] cycloadditionof sugar diynes derived from appropriately protected ?A-gluconolactones. This strategy was also extended to the synthesis of spirocyclic C-arylribosides from the known γ-ribonolactone derivative. Moreover, silver-catalyzed iodination of the sugar diynes followed by ruthenium-catalyzed [2+2+2] cycloaddition with acetylene delivered spirocyclic C-iodophenylglycosides and ribosides, which were then subjected to palladium-catalyzed C-C bond formations such as Sonogashira, Mizoroki-Heck, and Suzuki-Miyaura couplings, or copper-catalyzed Ullmann coupling with nitrogen heterocycles, resulting in the production of various interesting spirocyclic C-arylglycosides.View full abstractDownload PDF (3116K) -
Sota Sato2008 Volume 66 Issue 8 Pages 806-807
Published: August 01, 2008
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDue to its clean combustion and high heating value, hydrogen fuel has attracted much interest from 1990s. It is crucial to develop safe and efficient hydrogen storage material for practical applications. In recent years, porousmetal-organic frameworks (MOFs) have been identified as promising adsorbents for H2 storage. They provide unique systems with large surface areas and precise molecular structures. This review will focus on the development of highly efficient MOFs for H2 storage.View full abstractDownload PDF (1932K) -
Minoru Tamiya2008 Volume 66 Issue 8 Pages 808-809
Published: August 01, 2008
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (4132K) -
2008 Volume 66 Issue 8 Pages 811
Published: August 01, 2008
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (198K)
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