School of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming 650500, P.R. China.
Curr Org Synth. 2022;19(7):819-823. doi: 10.2174/1570179419666220225115017.
Benzoxazoles are of great importance in natural products, pharmaceutical agents as well as synthetic intermediates. Although many works on the construction of benzoxazoles by Cu-catalyzed intramolecular O-arylation of ortho-haloanilides have been reported, only a few reports about transition metal-catalyzed synthesis of benzoxazoles from inactive 2-chloroanilides so far. This work aimed to explore a green and cheap protocol for intramolecular O-arylation of inactive 2-chloroanilides to prepare 2-arylbenzoxazoles.
We found that Cu(acac)2/1,10-Phen complex was beneficial to intramolecular O-arylation of 2-chloroanilides using KCO as a base in EtOH at 90 °C to prepare benzoxazoles.
An efficient and green method was developed for Cu(II)-catalyzed intramolecular Oarylation of inactive 2-chloroanilides.
In this way, many 2-arylbenzoxazoles were prepared in good yields.
苯并恶唑在天然产物、药物试剂以及合成中间体中具有重要意义。尽管已经有许多关于邻卤代苯胺与 Cu 催化的分子内 O-芳基化反应构建苯并恶唑的研究，但目前仅有少数关于过渡金属催化的从惰性 2-氯苯胺合成苯并恶唑的报道。本工作旨在探索一种绿色、廉价的方法，用于通过分子内 O-芳基化反应，将惰性 2-氯苯胺转化为 2-芳基苯并恶唑。
我们发现，在 90°C 下，使用 KCO3 作为碱，在 EtOH 中，Cu(acac)2/1,10-Phen 配合物有利于 2-氯苯胺的分子内 O-芳基化反应，从而制备苯并恶唑。
开发了一种高效、绿色的方法，用于 Cu(II)催化的惰性 2-氯苯胺的分子内 O-芳基化反应。
通过这种方法，可以以良好的产率制备许多 2-芳基苯并恶唑。
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