Reissert indole synthesis
| Reissert indole synthesis | |
|---|---|
| Named after | Arnold Reissert |
| Reaction type | Ring forming reaction |
The Reissert indole synthesis is a series of
Potassium ethoxide has been shown to give better results than sodium ethoxide.[3]
Reaction mechanism
The first step of the synthesis is the condensation of o-nitrotoluene 1 with a diethyl oxalate 2 to give ethyl o-nitrophenylpyruvate 3. The reductive cyclization of 3 with zinc in acetic acid gives indole-2-carboxylic acid 4. If desired, 4 can be decarboxylated with heat to give indole 5.
Variations
Butin modification
In an intramolecular version of the Reissert reaction, a furan ring-opening provides the carbonyl necessary for cyclization to form an indole. A ketone side chain is present in the final product, allowing further modifications.[4]
See also
- Leimgruber-Batcho indole synthesis
References
- .
- ^ Noland, W. E.; Baude, F. J. Organic Syntheses, Coll. Vol. 5, p. 567 (1973); Vol. 43, p. 40 (1963). (Article)
- .
- .