1989 Fiscal Year Final Research Report Summary
One-step Amination by Parent Nitrenium Ion and Alkylnitrenium Ion
| Project/Area Number |
63490013
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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 |
広領域
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| Research Institution | Shinshu University |
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Principal Investigator |
TAKEUCHI Hiroshi Shinshu University Faculty of Engineering Associate Professor, 工学部, 助教授 (00029258)
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| Co-Investigator(Kenkyū-buntansha) |
TSUCHIDA Teruko Shinshu University Faculty of Engineering Instructor, 工学部, 教務員
MITANI Michiharu Shinshu University Faculty of Engineering Associate Professor, 工学部, 助教授 (20021016)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Parent nitrenium ion / Alkylnitrenium ion / Alicyclic nitrenium ion / Aromatic N-substitution / Stabilisation singlet state / Promotion S-T conversion / Benzazepine / Dibenzoazepine |
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| Research Abstract |
Parent, alkyl, dialkyl, and alicyclic nitrenium ions were generated from photolyses of 1-aminopyridinium and S-aminosulphonium salts and the derivatives in arene-trifluoroacetic acid. The photolyses gave aromatic N-substitution pro- ducts via the singlet nitrenium ions and hydrogen abstraction products via the triplet nitrenium ions.
The mechanism was suggested by rho -2.1 for Hammett plot, an exclusion of a mechanism through an amino radical or aminium ion, and an effect of heavy atom or oxygen molecule. The result altering the reactivity upon the change of cationic and anionic portions of the reactant salt shows that the nitrenium ion interacts with both the unshared electron pair of the heteroatom of pyridine or sulphide and the Gegen anion. Thus the singlet nitrenium ion is stabilised by this interaction. The singlet nitrenium ion is also stabilised by interaction with 18-crown-6; the yield of N-substitution by the nitrenium ion was increased in the presence of the crown ether. The preferable ortho-attack of the nitrenium ion on anisole well supports the interaction between the nitrenium ion and the oxygen atom of anisole.
The S-T conversion of the singlet into the triplet nitrenium ion is promoted by heavy atom solvent and oxygen molecule. The more stabilised singlet nitrenium ions can undergo the more predominant promotion of the S-T conversion. The di- alkyl or alicyclic nitrenium ion having a lower singlet-triplet energy gap than the alkyl or parent nitrenium ion undergoes a fast S-T conversion in the presence of a good hydrogenatom donor such as toluene or mesitylene due to a fast equilibrium between the singlet and triplet states.
On the other hand, the triplet parent nitrenium ion with the.Gegen anion I^- is allowed to react with naphthalene or phenanthrene to yield novel compounds, 1H- and 9H-l-benzazepines or 9H- and 11H-dibenzo[d,f]azepines, via the ring- expansion of aziridine intermediates.
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