1987 Fiscal Year Final Research Report Summary
Characteristics of photoreactions of heteroaromatic compounds. Multiple photoreactivities and simultaneous participation of several kinds of excited states
| Project/Area Number |
60470028
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
有機化学一般
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| Research Institution | Sophia University |
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Principal Investigator |
SUGIMORI AKIRA Department of Chemistry, Faculty of Science and Technology, Sophia University, 理工学部・化学科, 教授 (40053590)
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| Project Period (FY) |
1985 – 1987
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| Keywords | Parallel occurrence of ionic and radical reactions in photoreaction / Change of photoreaction by oxygen / Chemical utilization of visible light catalyzed by transition metal ion / Photoalkylation / Photoalkoxylation / Photo-trifluoromethylation / 放射線によるアルキル化 |
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| Research Abstract |
We found that the derivatives of pyridinecarboxylic acid show remarkable photoreactivities both in terms of the reaction types and the reaction mechanisms.
1) Ionic and radical reactions occur in parallel. Parallel occurrence of a variety of reactions is due to the simultaneous participation of several kinds of excited states: In the photoreaction of nicotinamide in alcohol, the alkoxylation (ionic reaction) derives from an excited singlet state and the alkylation (radical reaction) derives from an excited triplet state.
2) In addition to the above characteristics, the photoreactions of isonicotinic ester and its analogs show a unique oxygen effect. The presence of O_2 brings about a compete change of the orientation of the photosubstitution (alkoxylation). This oxygen effect cannot be explained by any established mechanisms, such as the oxidation of an intermediate, the formation of singlet oxygen, or the acceleration of the intersystem crossing.
3) On the basis of the above knowledge on the photoreactions of the N- heteroaromatic compounds, the introduction of the (functional) groups into the heteroaromatic rings with radical species have been studied. We succeeded in the alkylation and trifluoromethylation of pyridine and pyrimidine rings by visible light irradiation in the presence of transition metal ions, by UV-irradiation, and by gamma-irradiation. 5-(Trifluoromethyl)uracil (a pharmaceutically important compounds) can be synthesized in a one-step photochemical reaction.
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