1996 Fiscal Year Final Research Report Summary
Synthesis and Biological Evaluation of Thiophene Derivatives containing a Silicon Atom
| Project/Area Number |
07672295
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Chemical pharmacy
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| Research Institution | Science University of Tokyo |
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Principal Investigator |
HOSHINO Osamu Science University of Tokyo, Faculty of Pharmaceutical Sciences, Professor, 薬学部, 教授 (40084420)
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| Project Period (FY) |
1995 – 1996
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| Keywords | vinylsilylmethylthiophene / silylated thiophene / (substituted methyl) silylmethylthiophene / MO calculation / PM3 method / intramolecular cyclization / Grignard reaction / biological evaluation |
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| Research Abstract |
(1) Synthesis of Vinylsilyl- and (Substituted methyl) silyl-methylthiophenes In 1995, it was found that vinylsilylmethylthiophenes were obtained by addition of thienylmethyl chlorides to a suspension of Mg and trichlorovinysilane in THF.In 1996, this method was developed to the synthesis of various vinylsilylmethylthiophene derivatives. Furthermore, chloromethylsilylmethylthiophenes were synthesized by the modified method, in which a mixture of thienylmethyl chlorides and chloro (chloromethyl) silane was added to a suspension Mg in THF.Chloromethylsilyl derivatives thus obtained were converted into the Grignard reagents in a usual manner, which were treated with dry ice or dialkyl carbonates to give the corresponding (substituted methyl) silylmethylthiophene derivatives in fair to good yield. Among them, the mass spectra of hydroxy -and alkoxycarbonylsilyl derivatives showed characteristic fragment peaks. Silylmethylthiophenes except dichlorosilylmethylthiophenes are stable at ambident
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temperature and all of them thus obtained are novel compounds.
(2) Attempts for Intramolecular Cyslization Intramolecular cyclization of vinylsilylmethylthiophenes under the conditions similar to those for vinylsilylmethylbenenes failed. In order to document this discrepancy in the cyclization, molecular orbital (MO) calculations of vinylsilylmethyl-benzenes and -thiophenes using PM3 method were done. The calculations suggested that in the transition state the over-lappings of the pi-orbital (HOMO) of the carbon atom at 2-position in thiophene and the pi-orbital (LUMO) of the terminal carbon atom of vinyl group are in anti-bonding. Although the cyclization of vinylsilylmethylthiophenes was unfruitful, a product, which was formed by the cyclization followed by the cleavage, was obtained by the cyclization of acetoxyethysilylmethylthiophene. The present findings can offer a novel information on the synthesis of heterocyclic compounds containing a silicon atom.
(3) Biological Evaluation This works are now in progress. Less
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