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Volume 46, Issue 8
Displaying 1-10 of 10 articles from this issue
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Hiromichi OHTA1988 Volume 46 Issue 8 Pages 726-741
Published: August 01, 1988
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESSMicrobial and enzymatic transformation of synthetic substrates is attracting much attention as a useful method in synthetic organic chemistry. In this article, recent developements in this field are reviewed, dividing into three major sections which include oxidation, reduction and hydrolysis reactions. Methods for increasing the selectivity of some reactions are also described. Emphasis has been placed to the formation of optically active compounds, because enzymes are able to catalyze asymmetric reactions under mild conditions.View full abstractDownload PDF (1999K) -
Fumikazu MUKAWA1988 Volume 46 Issue 8 Pages 742-752
Published: August 01, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSAromatase is a cytochrome P-450 exzyme complex which catalyzes the biosynthetic transformation of androgens to estrogens. Estrogen biosynthesis occurs not only in the female reproductive tissues, but also in such diverse sites as testes, adipose tissues and muscles.
We review here evidences and advances in characterizing aromatase and its inhibitors. Topics of aromatase inhibitors are outlined by categorizing them in two classes ; competitive inhibitors and irreversible suicide inhibitors.
Possible usefulness of selective and powerful aromatase inhibitors in the therapy of estrogen-dependent breast cancer promoted the research in this area.View full abstractDownload PDF (975K) -
Yoshihiro HAYAKAWA1988 Volume 46 Issue 8 Pages 753-766
Published: August 01, 1988
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESSA 2'-5', 3'-5'-linked oligoribonucleotide (branched RNA) was discovered by Wallace and Edmonds as important compound being an intrinsic part of eukaryotic RNA splicing. Further progress toward understanding the mechanism of splicing revealed that certain kinds of branched RNAs play significant role as enzymatic catalysts in some biological reactions. On the other hand, immunochemical studies on 2-5 A implied that the analogs having adenylyl (2'-5') adenosine structure are chemotherapeutically attractive compounds which are expected to show new biological activities. Such importance has stimulated the development of effective chemical synthesis to supply large amounts of branched RNAs. This article surveys the methods developed for the synthesis of branched RNAs.View full abstractDownload PDF (1025K) -
Masaki HASEGAWA1988 Volume 46 Issue 8 Pages 767-775
Published: August 01, 1988
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESS[2 + 2] Topochemical photoreaction is reviewed focussing on the photopolymerization of diolefin crystals.
In α-type crystal of olefin compounds, double bonds make contact at a distance of approximately 4 Å across a center of symmetry and, on photoirradiation it gives a centrosymmetric cyclobutane dimer (1-dimer). A β-type crystal is characterized by a lattice with one axial length of 4Å between translationally related molecules, and gives a dimer of mirror symmetry (m-dimer). In a typical topochemical photoreaction of these olefin compounds, the reaction proceeds stereospecifically with the retention of space group of the starting crystal.
In the polymerization of α-type diolefin crystals, highly crystalline linear high polymers are obtained in extremely high yields. On the other hand, from the β-type diolefin crystals, crystalline or amorphous oligomers having a zigzag main chain, or cyclophanes are obtained. Topochemical studies of unsymmetric diolefin crystals have revealed a great variety of reaction behaviors and of photoproduct configurations which are influenced strictly by a slight modification of chemical structures. The polymers having new types of alternating chain structures are prepared from unsymmetric diolefin crystals. These polymers are expected to be promising functional materials. The optically active oligomeric substances are prepared from the prochiral unsymmetric diolefin compounds through the topochemical photoreaction of chiral crystal. Lattice energy calculation has been recently applied to explain the structure-reactivity correlation including the exceptional behavior of [2+2] topochemical photoreations.View full abstractDownload PDF (1025K) -
Mitsuru HASHIDA1988 Volume 46 Issue 8 Pages 776-788
Published: August 01, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSSynthesis and physicochemical, biopharmaceutical, and chemotherapeutical characteristics of cationic and anionic conjugates of mitomycin C with dextrans having different molecular weights are reviewed. Anionic conjugate with a molecular weight of 70, 000 was retained in the blood circulation for a considerable long period and accumulated in the tumor site after intravenous injection, and concluded to be suitable for systemic targeting. On the other hand, cationic conjugates showed strong adsorption on the tumor cell surface and remarkable antitumor activities in the case of local injection. Clinical trials of catinic conjugates with 50 patients gave promising results without any serious side effects.View full abstractDownload PDF (1701K) -
Yoshihisa WATANABE, Take-aki MITSUDO, Yasushi TSUJI1988 Volume 46 Issue 8 Pages 789-800
Published: August 01, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe following novel organic syntheses catalyzed by ruthenium (1-7) and platinum complexes (8-9) which have been disclosed by the authors are reviewed. 1) Activation of alcohols which provides novel synthetic methods for alkylamines and N-heterocycles such as piperidines, pyrrolidines, quinolines and indoles. 2) Hydroamidation of olefins. 3) Addition of carboxylic amides to olefins. 4) Addition of aldehydes to olefins to give unsymmetric ketones. The reactions 3) and 4) involve the activation of carbon-hydrogen bond of formyl groups. 5) [2 + 2] Cross cycloaddition of norbornenes with acetylene which provides the synthetic tool for linear polycyclo compounds. 6) Linear codimerization of acetylenes with 1, 3-dienes. 7) Addition of carboxylic acids to acetylenes to give enol esters. 8) Reductive carbonylation of nitroarenes to amides, urethanes and ureas. 9) Thermal and photo-chemical carbonylation of alkyl iodides to esters or aldehydes. Even alkyl halides with β-hydrogens are efficiently carbonylated. The mechanisms of these novel reactions are suggested.View full abstractDownload PDF (1306K) -
Tohru FUKUYAMA1988 Volume 46 Issue 8 Pages 801-810
Published: August 01, 1988
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESSTotal syntheses of the nitrogen-containing quinone antitumor antibiotics saframycin B (2), cyanocycline A (3), and mitomycin C (6) are described. Brief retrosynthetic analyses of these challenging molecules are provided to show our basic synthetic strategy.View full abstractDownload PDF (1073K) -
Hisao NISHI, Kiyoshi KITAHARA1988 Volume 46 Issue 8 Pages 811-820
Published: August 01, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSQuinoneimines having a linear five ring system such as triphenodioxazines (TPDO) and triphenodithiazines (TPDT) were not only useful for dye and pigment, but also expected to show new functions because of their peculiar electron structures.
This article describes syntheses and functions of TPDO, TPDT, triphenodiselenazines and their related compounds as high performance pigmentsView full abstractDownload PDF (1020K) -
Minoru ARAMAKI1988 Volume 46 Issue 8 Pages 821-823
Published: August 01, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESS -
[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...1988 Volume 46 Issue 8 Pages 824
Published: August 01, 1988
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (149K)
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