1. A Simple, Effective, Green Method for the Regioselective 3-Acylation of Unprotected Indoles.
- Author
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Tran PH, Tran HN, Hansen PE, Do MH, and Le TN
- Subjects
- Acylation, Catalysis, Green Chemistry Technology, Microwaves, Molecular Structure, Stereoisomerism, Indoles chemical synthesis, Indoles chemistry
- Abstract
A fast and green method is developed for regioselective acylation of indoles in the 3-position without the need for protection of the NH position. The method is based on Friedel-Crafts acylation using acid anhydrides. The method has been optimized, and Y(OTf)₃ in catalytic amounts is found to be the best catalyst together with the commercially available ionic liquid [BMI]BF₄ (1-butyl-3-methylimidazolium tetrafluoro-borate) as solvent. The reaction is completed in a very short time using monomode microwave irradiation. The catalyst can be reused up to four times without significant loss of activity. A range of substituted indoles are investigated as substrates, and thirteen new compounds have been synthesized.
- Published
- 2015
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