Abstract
Anilines react with alkanolammonium chlorides in an aqueous medium (H2O-dioxane) at 180°C in the presence of a catalytic amount of a ruthenium catalyst together with SnCl2·2H2O to afford the corresponding indoles in moderate to good yields. Especially, when triisopropanolammonium chloride is employed to react with anilines, 2-methylindoles are formed regioselectively. The presence of SnCl2·2H2O is necessary for the effective formation of indoles. A reaction pathway involving alkanol group transfer from alkanolamines to anilines, N-alkylation of anilines by anilinoalkanols and heteroannulation of 1,2-dianilinoalkanes is proposed for this catalytic process.
Original language | English |
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Pages (from-to) | 3321-3329 |
Number of pages | 9 |
Journal | Tetrahedron |
Volume | 57 |
Issue number | 16 |
DOIs | |
State | Published - 16 Apr 2001 |
Keywords
- Amine exchange reaction
- Aqueous medium
- Catalyst
- Heteroannulation
- Indoles
- Ruthenium