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.
Potassium ethoxide has been shown to give better results than sodium ethoxide.
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.
References
Reissert indole synthesis Wikipedia(Text) CC BY-SA