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
Originalsprog | Engelsk |
---|---|
Tidsskrift | Molecules |
Vol/bind | 20 |
Udgave nummer | 10 |
Sider (fra-til) | 19605-19619 |
Antal sider | 15 |
ISSN | 1420-3049 |
DOI | |
Status | Udgivet - 2015 |
Emneord
- indoles
- Friedel-Crafts
- acylation
- green chemistry
- ionic liquids
- ytterbium triflate
- microwave