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Volume 63, Issue 10
Displaying 1-7 of 7 articles from this issue
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Keiichi Katoh, Tomoyuki Akutagawa, Takayoshi Nakamura2005 Volume 63 Issue 10 Pages 960-969
Published: 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSWe have synthesized series of amphiphilic bis-TTF annulated macrocycles 1-6 by using complementary routes involving deprotection-alkylation methods of monothiolate. These amphiphilic bis-TTF annulated macrocycles were designed from the viewpoints of (i) electrically active TTF units for realizing electrically conducting one-dimensional π-π stacks, (ii) ion recognition at the macrocyclic moiety, and (iii) two-hydrophobic alkyl chains to fabricate nanoscale thin films. Nanostructures such as molecular nanowires, nanodots of the charge transfer (CT) complexes of amphiphilic bis- (TTF) -annulated macrocycle 1 and 2, 3, 5, 6-tetrafluoro-7, 7, 8, 8-tetracyano-P-quinodimethane (F4-TCNQ) were constructed. The nanowires are oriented to specific directions, by recognizing the potassium array on mica surface. The open-shell electronic structure of nanostructures was determined by electronic spectra. Other nanostructures such as nanodomains and nanodots in addition to molecular thin films were fabricated from CT complexes of 1-6 and organic or inorganic acceptor molecules.View full abstractDownload PDF (2632K) -
Hideyuki Higashimura2005 Volume 63 Issue 10 Pages 970-981
Published: 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSA new methodology of polymer synthesis, radical-controlled oxidative polymerization of phenols unsubstituted at ortho position (s) with high regioselectivity catalyzed by a tyrosinase model complex, is described. This catalyst forms only basic μ-η2:η2-peroxo dicopper (II) complex 1 as the active oxygen complex, and 1 reacts with phenols to give phenoxo-copper (II) complexes 2, equivalent to phenoxy radical-copper (I) complexes 3. These species 2 and/or 3 are not free radicals but controlled radicals, and hence all the couplings of the controlled radicals are regulated by the present catalyst. On the other hand, the oxidative polymerization by conventional catalysts includes free radical formation process, in which the coupling selectivity cannot be controlled by the catalysts. By the radical-controlled method, oxidative polymerization of 4-phenoxyphenol produces crystalline poly (1, 4-phenylene oxide) for the first time. From 2, 5-dimethylphenol, novel crystalline poly (2, 5-dimethyl-1, 4-phenylene oxide) with a melting point above 300°C has been developed. It is also discussed how C-O/C-C coupling selectivity for 2, 6-dimethylphenol is controlled by use of conventional catalyst, which must generate its free radical.View full abstractDownload PDF (1641K) -
Akiko Saito, Noriyuki Nakajima2005 Volume 63 Issue 10 Pages 982-994
Published: 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe proanthocyanidins are known as condensed tannins and/or oligomeric flavonoids, and their many biological activities, powerful antioxidant activity, free-radical-scavenging activity and an anti-tumor-promoting effect, have been reported. Proanthocyanidins have been obtained from many kinds of plants, but because they are usually obtained as a complex mixture of structurally related compounds, it is very difficult to isolate them in a pure form. Consequently, we planned to develop efficient synthetic methods leading to procyanidins with a high level of purity and stereoselectivity for biological assay. We developed stereoselective condensation method under TMSOTf-catalyzed intermolecular and intramolecular conditions for procyanidin synthesis. The relationships between the structure of proanthocyanidins and their bioactivities (SAR) against the Maillard reaction inhibitory activity, antioxidant activity, DPPH radical scavenging activity, DNA polymerase inhibitory activity and DNA metabolic enzymes inhibitory activity using synthesized procyanidin oligomers including 3-substituted oligomers, were investigated.View full abstractDownload PDF (2031K) -
Kazunori Toma, Katsuji Haneda2005 Volume 63 Issue 10 Pages 995-1003
Published: 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSMore than 40 glycosylated calcitonin derivatives were synthesized using chemo-enzymatic procedure. The derivatives vary in the glycosylation site on calcitonin and/or the carbohydrate structure. For N-glycosylation with natural large oligosaccharide structures, transglycosylation reactions of endoglycosidases were employed. The yield of the transglycosylation reaction was improved and it became possible to prepare glycopeptides with two different natural carbohydrate structures on a single peptide. Using these derivatives, the effects of glycosylation on the peptide backbone conformation and the biological activity of calcitonin were studied. Some of the glycosylated calcitonin changed their backbone conformation depending mainly on the glycosylation site. The change in the hypocalcemic activity, the main biological activity of calcitonin, changed depending not only on the glycosylation site but also on the carbohydrate structure. The main cause of the carbohydrate structure-dependent change in the hypocalcemic activity was shown to be the altered biodistribution which was regulated by the carbohydrate structure.View full abstractDownload PDF (1494K) -
Design, Synthesis and Biological Activity of Non-hydroxamate Histone Deacetylase InhibitorsTakayoshi Suzuki, Hidehiko Nakagawa, Naoki Miyata2005 Volume 63 Issue 10 Pages 1004-1015
Published: 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSAs part of our studies towards molecularly targeted cancer therapy, we developed novel nonhydroxamate histone deacetylase (HDAC) inhibitors. A series of compounds modeled after suberoylanilide hydroxamic acid (SAHA) was designed as follows : (i) structure-based drug design., (ii) design applying the thiophilicity of zinc ion; (iii) design based on the structure of the transition state; (iv) design based on the enzyme catalysis mechanism; and (v) irreversible inhibition-oriented design. In this series, compound 7, in which the hydroxamic acid of SAHA is replaced by a thiol, was found to be as potent as SAHA, and optimization of this series led to HDAC inhibitors 43, 47, 52 and 53, which were more potent than SAHA. In cancer cell growth inhibition assay, S-acyl derivative 68, a prodrug of thiol 48, showed strong activity, and its potency was comparable to that of SAHA. Kinetical enzyme assay and molecular modeling study suggested that the thiol interacts with the zinc ion in the active site of HDACs.View full abstractDownload PDF (1567K) -
Toshikazu Bando, Hiroshi Sugiyama2005 Volume 63 Issue 10 Pages 1016-1027
Published: 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSFifty years after the discovery of the double helical structure of DNA, the complete sequence of the human genome has been determined. All genetic information, which is necessary for life, is written in 30 billion base pairs of DNA. Many diseases, including cancer, hereditary and viral diseases, can be understood at the DNA sequence level. Local DNA conformations are thought to play an important role in biological processes such as gene expression. Therefore, DNA sequences and local DNA conformation are targets of novel drugs that would precisely switch certain genes on or off. Modified bases that perform various functions can also be incorporated into defined DNA sequences. Since DNA can be amplified by PCR and in other organisms, DNA becomes a promising unit for nanotechnology applications. In this review, we focus on the sequence and conformation-specific chemical reactions that occur in DNA, and the prospective uses of the chemical biology of DNA will be discussed.View full abstractDownload PDF (2539K) -
[in Japanese], [in Japanese], [in Japanese]2005 Volume 63 Issue 10 Pages 1028
Published: 2005
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (203K)
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