Synthesis of Optically Active alpha, alpha-Disubstituted Cyclohexanone Derivatives and Their CD Spectra
| Project/Area Number |
09672181
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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 | Tokushima Bunri University |
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Principal Investigator |
TORI Motoo Tokushima Bunri University, Faculty of Pharmaceutical Sciences, Professor, 薬学部, 教授 (90163956)
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| Co-Investigator(Kenkyū-buntansha) |
NAKASHIMA Katsuyuki Tokushima Bunri University, Faculty of Pharmaceutical Sciences, Assistant, 薬学部, 助手 (80299338)
SONO Masakazu Tokushima Bunri University, Faculty of Pharmaceutical Sciences, Assistant, 薬学部, 助手 (10221342)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1998: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1997: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | CD spectrum / cyclohexanone derivatives / optical activity / absolute configuration / conformation / X-ray crystallography / 合成 |
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| Research Abstract |
In the first year, a research work on the reaction of the imine from (S)-(-)-phenylethylamine and 2-methylcyclohexanone and 2-ethylcyclohexanone with methyl acrylate has been carried out. In the second year, this extended to 2-allyl-, 2-isopropyl-, 2-octylcyclohexanone, and disubstituted cyclohexanones, 2-methyl-4-t-butyl and 2-ethyl-4-t-butylcyclohexanones. The absolute configurations of keto esters obtained in these reactions were established by X-ray crystallography. The stereochemistries of keto esters with three substituents have been examined by 600 MHz NMR spectroscopy, and the conformations were thus determined. The sign of the CD spectra for derivatives of 2-methylcyclohexanone series was (+), while those for 2-ethyl series and other derivatives examined was (-). The difference is not due to the misassignment of the absolute configuration, nor the front octant. The difference of the sign of the CD spectra between 2-methyl and 2-ethylcyclohexanones must be due to the conformation of the 6-membered ring. Compounds having three substituents must adopt the conformation that two of them are in the equatorial position. The sign of the CD spectrum is predictable from this assumption. The most stable conformations were calculated by MM2 with CONFLEX.
In the case of 2, 3-dimethylcyclohexanone, matching and mismatching combinations exist due to the 3-methyl group and thus this reaction is highly useful for synthesis of cic-2, 3-dimethyl-2-substitutedcyclohexanone derivative because it is easy to operate and ee's of the products are usually high. This is the first example of the application of this reaction to the trisubstituted cyclohexanones.
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Report
(3 results)
Research Products
(2 results)
