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. 2015 Jun 4:5:10360.
doi: 10.1038/srep10360.

Activated carbon for aerobic oxidation: Benign approach toward 2-benzoylbenzimidazoles and 2-benzoylbenzoxazoles synthesis

Kai Bao  1 , Fuqing Li  2 , Hanjing Liu  2 , Zhiwei Wang  2 , Qirong Shen  2 , Jian Wang  2 , Weige Zhang  2
Affiliations

Activated carbon for aerobic oxidation: Benign approach toward 2-benzoylbenzimidazoles and 2-benzoylbenzoxazoles synthesis

Kai Bao et al. Sci Rep. .

Abstract

A general strategy involving a novel and highly efficient aerobic benzylic oxidation promoted by cheap, reusable activated carbon in water is developed. Application of this method has been demonstrated in the benign synthesis of bioactive 2-benzoylbenzimidazoles and 2-benzoylbenzoxazoles derivatives. Furthermore, the activated carbon catalyst could be recovered and reused at least three times without significantly losing its activity. Preliminary research suggests that the oxidation mechanism may involve intermediate hydroperoxidation and that a portion of the final carbonyl product is obtained through a secondary benzylic alcohol intermediate. Finally, theoretical calculations reveal that the oxidation yield is closely associated with the electric density at the benzylic position of the substrate.

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Figures

Figure 1
Figure 1
The aerobic benzylic oxidation of 2-benzylbenzo[d]imidazoles.
Figure 2
Figure 2
Time course for the substrate 4, products 5 and 6 using AC III. The yields were determined by HPLC analysis.
Figure 3
Figure 3
The proposed mechanism of the aerobic benzylic oxidation of 2-benzylbenzo[δ]imidazoles by AC in water.
See this image and copyright information in PMC

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