2000 Fiscal Year Final Research Report Summary
Biological and Organic Chemical Investigation on Blepharismins and Their Related Natural Products
| Project/Area Number |
10480151
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bioorganic chemistry
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| Research Institution | Kochi University |
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Principal Investigator |
KOTSUKI Hiyoshizo Kochi University, Faculty of Science, Department of Materials Science, Professor, 理学部, 教授 (80093954)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUOKA Tatsuomi Kochi University, Faculty of Science, Department of Natural Science, Professor, 理学部, 教授 (90209510)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Blepharismins / Aromatic Alkylation / Anthraquinone Structures / Oxidative Coupling / Photosignaling / Stentorins / Hypericin / Photosensory Transduction |
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| Research Abstract |
(a) Structural Study of Blepharismins and Their Related Natural Pigments : Computer-aided analysis of blepharismins, stentorins, and hypericin has been performed and their three-dimensional structures having the "propeller" butterfly-like conformation have been clarified.
(b) Synthetic Study of Blepharismins and Their Related Natural Pigments :
-1. New Method for Aromatic Alkylation : To introduce an alkyl side chain on an aromatic ring, we developed the following two methods : (a) Friedel-Crfats-type alkylation using secondary alcohol methanesulfonates as an electrophile in the presence of a catalytic amount of Sc(OTf)_3 or TfOH ; (b) Regioselective nucleophilic aromatic substitution using Grignard reagents upon o- or p-methoxy-substituted aromatic carboxylates.
-2. Synthesis of Anthraquinone Key Skeletons : The anthraquinone key component of blepharismin-3 and stentorin-C was prepared by treatment of benzoic acid derivatives with (CF_3CO)_2O via intramolecular Friedel-Crafts acylation f
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ollowed by oxidation in the air.
-3. High-Pressure Promoted Construction of Biphenol Key Skeleton : High-pressure promoted condensation between phenols and aromatic aldehydes was efficiently proceeded in the presence of a catalytic amount of TfOH to produce the desired biphenol key skeleton of blepharismins.
-4. Synthesis of Perylene Quinone Structure : Intramolecular oxidative coupling of biphenol derivatives has been achieved by using the Koga' reagent (CuCl(OH)・
TMEDA complex) in giving the perilene quinone structure of blepharismins.
(c) Structure of Photosensory Complex : Spectroscopic analysis of free pigment
(blepharismin) and pigment (blepharismin)/protein complex, analysis of pigment contents bound to the protein or observation of photosensory organelle suggested that a large number of free pigment molecules are regularly arranged in vivo. This crystal -like structure may function as light-harvesting antenna for activating reaction center blepharismin/200 kD protein
complex.
(d) Photosensory Transduction : Analyses of molecular structure of light-irradiated blepharismin suggested that light-induced dissociation of phenol group (side chain) is not
involved in activation of photosensory transduction chain. Spectroscopic analysis of photoreceptor complex indicated that active oxygen produced by photosensitization of light-activated blepharismin or energy or electron transfer from first excited singlet of pigment would be involved in activation of photosensory transduction chain.
(e) Singaling Mechanism between Photoreceptor Organelle and Cell Membrane : We revealed that photosignal is finally transduced into H+ signal ; H+ is released from outer membrane of photoreceptor organelle so that evoked depolarization of cell membrane. Less
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