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Synthesis 2011(6): 873-880  
DOI: 10.1055/s-0030-1258445
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

A Practical Synthesis of 2-Aroylindoles from N-(2-Formylphenyl)trifluoro­acetamides in PEG-400

Yu Zhaoa, Deyao Lia, Liwen Zhaoa, Jiancun Zhang*a,b
a Guangzhou Institute of Biomedicine and Health, CAS, 190 Kai Yuan Avenue, Science Park, Guangzhou 510530, P. R. of China
Fax: +86(20)32015323; e-Mail: zhang_jiancun@gibh.ac.cn;
b State Key Laboratory of Respiratory Diseases, Guangzhou Medical College, Guangzhou 510120, P. R. of China
Further Information

Publication History

Received 18 November 2010
Publication Date:
18 February 2011 (online)

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Abstract

A one-pot and environmentally benign approach to the synthesis of highly functionalized 3-unsubstituted 2-aroylindoles is described. Moderate to good yields were obtained through the reaction of easily accessible N-(2-formylphenyl)trifluoroacetamides and α-bromoacetophenones in the presence of K2CO3. PEG-400 was found to be an efficient and reusable solvent in the process.

Key words

2-aroylindoles - PEG-400 - N-(2-formylphenyl)trifluoro­acetamides - heterocycles - cyclization

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11

The only reaction condition reported by Jones’ group was that DMF was used as the solvent. We examined different solvents including acetone, acetonitrile, toluene, DMF and PEG-400, and different bases including NaHCO3, Na2CO3, K2CO3 and Et3N. Only a trace amount of 2-aroylindole was obtained.

14

No attempt was made to free the PEG-400 of salts because the salts did not hamper the rate of the reaction