2002 Fiscal Year Final Research Report Summary
1, 3-DIPOLAR CYCLOADDITIONS OF AZOMETHINE YLIDE WITH ELECTRON-RICH OR NORMAL OLEFINS
| Project/Area Number |
13672239
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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 | MEIJI PHARMACEUTICAL UNIVERSITY |
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Principal Investigator |
ISHII Keitaro MEIJI PHARMACEUTICAL UNIVERSITY FACULTY OF PHARMACY PROFESSOR, 薬学部, 教授 (70167245)
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| Project Period (FY) |
2001 – 2002
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| Keywords | AZIRIDINE / PYRROLIDINE / PHOTOREACTION / ELECTRON-DEFICIENT OLEFIN / ELECTRON-RICH OLEFIN / CYCLOADDITION / BIRADICAL / DIOXAZOLIDINE |
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| Research Abstract |
1. Effects of the N-Substituent in Aziridine on the Reaction
The photochemical and thermal reactions of (α, β-unsaturated γ, δ-epimino esters 1 and 2 possessing respectively N-phenyl or N-benzoyl group and olefins were studied. The photoreaction of 1 with acrylonitrile gave the adduct in 45% yield. On the other hand, the thermal reactions of 1 and 2 and the photoreactions of 2 afforded no adduct, but enamines formed via C(γ), O-bong cleavage. The N-substituents conjugated with the aziridine ring tend to cleave the C(γ), O-bong in aziridine.
2. Effects of the α-Substituent in the side chain on the Reaction
The reactions of α, β-unsaturated γ, δ-epimino system possessing two electron withdrawing groups in α-position and olefins were investigated. The photoreactions of the dinitrile 3 and the diester 4 and acrylonitrile gave the adducts as obtained before. Furthermore, the novel photocycloadditions of the dinitrile 3 proceeded with isoprene and vinyl acetate successfully.
The yields of the acrylonitrile adducts decreased with increasing the electron deficiency in the side chain of aziridine.
3. Reactions of Aziridines Possessing Substituent at 3-Position
In order to clarify the reaction mechanism, the reactions of 3-methyl and 3-phenyl substituted aziridines 5 and 6 and olefins were performed. The photochemical and thermal reaction of 5 shows that the ring-opening of aziridine and cycloaddition with olefins did not proceed concertedly. On the other hand, on the photochemical and thermal reactions the aziridine 6 underwent ring-opening and cycloaddition concertedly leading to adducts. The 3-p-cyanophenyl (more electron deficient substituent) aziridine did not react with isoprene and vinyl acetate.
The aziridines 5 and 6 react with molecular oxygen photochemically affording the dioxazolidine and its decomposed compounds. The results may suggest that the reaction intermediate possesses biradical character.
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