Reissert indole synthesis
The Reissert indole synthesis is a series of chemical reactions designed to synthesize indole or substituted-indoles (4 and 5) from ortho-nitrotoluene 1 and diethyl oxalate 2.[1][2]
Potassium ethoxide has been shown to give better results than sodium ethoxide.[3]
Reaction mechanism
The first step of the Reissert indole 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.
References
- ^ Reissert, A. Ber. 1897, 30, 1030.
- ^ Noland, W. E.; Baude, F. J. Organic Syntheses, Coll. Vol. 5, p.567 (1973); Vol. 43, p.40 (1963). (Article)
- ^ Johnson, J. R.; Hasbrouck, R. B.; Dutcher, J. D.; Bruce, W. F. J. Am. Chem. Soc. 1945, 67, 423.