Synthesis, Stability, and Photoreactivity of Diazirinyl-Substituted N-Heterocycles Based on Indole, Benzimidazole, and Imidazole
Synthesis, Stability, and Photoreactivity of Diazirinyl-Substituted N-Heterocycles Based on Indole, Benzimidazole, and Imidazole
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DOI：
10.1002/ejoc.201402354
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发表时间：
2014-09
影响因子：
2.8
通讯作者：
Björn Raimer;T. Wartmann;P. Jones;T. Lindel
中科院分区：
文献类型：
--
作者：
Björn Raimer;T. Wartmann;P. Jones;T. Lindel
研究了N-甲基吲哚杂环、N-甲基苯并咪唑杂环和N-甲基咪唑杂环上的三氟甲基二氮杂环化合物的合成、热稳定性和光反应活性。结果表明，N-甲酰基-3-二氮杂吲哚和N-甲基-2-二氮杂基苯并咪唑具有较好的热稳定性，而相应的2-二氮杂吲哚则不稳定。稳定性最差的是2-二氮杂咪唑，分解速度较快。乙醇猝灭表明生成了相应的卡宾。卡宾的放热开环使分解合理化。量子力学计算[B3LYP/6-311G(2d，2p)]预测了所有卡宾的单重态基态。相应地，在苯酚存在下，N-甲基苯并咪唑类二氮杂环化合物在350 nm的辐射下生成了Friedel-Craft烷基化产物。
The synthesis, thermal stability, and photoreactivity of trifluoromethyl diazirines installed at the heterocyclic section of N-methylindole, N-methylbenzimidazole, and at N-methylimidazole were investigated. N-Tosyl-3-diazirinylindole and N-methyl-2-diazirinylbenzimidazole proved to be thermally stable, whereas the corresponding 2-diazirinylindole was not. The least stable was 2-diazirinylimidazole, which underwent rapid decomposition. Quenching with ethanol indicated that the corresponding carbene was formed. Decomposition is rationalized by exothermic coarctate ring-opening of the carbene. Quantum mechanical calculations [B3LYP/6-311G(2d,2p)] predict singlet ground states of all carbenes. Accordingly, Friedel–Crafts alkylation products were formed on irradiation (350 nm, Rayonet) of the N-methylbenzimidazole-based diazirine in the presence of phenol.