| Reissert indole synthesis | |
|---|---|
| Named after | Arnold Reissert |
| Reaction type | Ring forming reaction |
TheReissert indole synthesis is a series ofchemical reactions designed to synthesizeindole or substituted-indoles (4 and5) fromortho-nitrotoluene1 anddiethyl oxalate2.[1][2]
Potassium ethoxide has been shown to give better results thansodium ethoxide.[3]
The first step of the synthesis is the condensation of o-nitrotoluene1 with a diethyl oxalate2 to give ethyl o-nitrophenylpyruvate3. Thereductive cyclization of3 withzinc inacetic acid gives indole-2-carboxylic acid4. If desired,4 can bedecarboxylated with heat to give indole5.
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]
