2003 Fiscal Year Final Research Report Summary
STRUCTURE ELUCIDATION OF NATURAL MEDICINAL RESOURCES BASED ON THE NEW NMR TECHNOLOGY
| Project/Area Number |
14207096
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | The University of Tokushima |
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Principal Investigator |
KUSUMI Takenori TOKUSHIMA UNIVERSITY, FACULTY OF PHARMACEUTICAL SCIENCES, PROFESSOR, 薬学部, 教授 (70015882)
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| Co-Investigator(Kenkyū-buntansha) |
OOI Takkashi TOKUSHIMA UNIVERSITY, FACULTY OF PHARMACEUTICAL SCIENCES, ASSOCIATE PROFESSOR, 薬学部, 助教授 (00203696)
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| Project Period (FY) |
2002 – 2005
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| Keywords | chirality / modified Mosher's method / NMR / stereochemistry / absolute configuration / chiral anisotropic reagent / chiral allenes / solvent effect |
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| Research Abstract |
Solvent effects in the NMR spectroscopy had been actively discussed more than three decades ago, although they were seldom noticed in the modern NMR argument. The modified Mosher's method is a convenient means for determination of the absolute configurations of chiral secondary alcohols. It has been long believed that the method is valid only when deutero-chloroform is used as a solvent. In this study, we proved that the solvents such as deutero-benzene, methanol, and pyridine were usable in the modified Mosher's method.
Deutero-chloroform, the most popular NMR solvent, is known to have some problems : (1)It decomposes to produce hydrochloric acid that can destroy a valuable sample. (2)Water signal appears at δ1.5 and the signal may obscure important sample signals. Use of deutero-benzene in the modified Mosher's method may add a benefit to the method, because separation of signals are more excellent in benzene than in chloroform in many cases.
A cyclopropane ring is encountered in many terpenes. There has been no general methodology to determine the absolute configurations of the cyclopropane compounds. We found that the oxidation of cyclopropane compound with ruthenium oxide produces a carbonyl function at the methylene position that is adjacent to the three-membered ring. Because the carbonyl is convertible to a secondary alcohol, this finding led to a new methodology to the stereochemical study of cyclopropanes via the modified Mosher's method.
An allene has an axis of symmetry and it can exist as an enantiomer. For the purpose of developing a new NMR method to elucidate the chirality of the optically active allenes, an enantiomer of a nitrone has been synthesized. 1,3-Dipolar addition of the chiral nitrone to allenes turned out to be a convenient way for determining the absolute configurations of chiral allenes.
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