Standard Article

Fischer Indole Synthesis

(Fischer Indolization)

Published Online: 15 SEP 2010

DOI: 10.1002/9780470638859.conrr233

Comprehensive Organic Name Reactions and Reagents

Comprehensive Organic Name Reactions and Reagents

How to Cite

2010. Fischer Indole Synthesis. Comprehensive Organic Name Reactions and Reagents. 233:1069–1075.

Publication History

  1. Published Online: 15 SEP 2010

Chemistry Terms

Choose one or more boxes to highlight terms.


The synthesis of indole derivatives by the treatment of aryl hydrazones coupled from aromatic hydrazines and ketones or aldehydes with either a mineral or Lewis acid is generally known as the Fischer indole synthesis. Although the mechanism of this reaction has been extensively studied, the one formulated by Robinson and Robinson is now generally accepted. Thioether is often used to direct the regiochemistry and it has also been reported that Eaton's reagent (P2O5/MeSO3H) and diethylaluminum 2,2,6,6-tetramethylpiperidide (DATMP) can facilitate the regioselectivity. A solid-phase supported synthesis of indole has been developed. Several modifications of this reaction have been applied to achieve the optimum yield. This reaction has been widely applied to pharmaceutical and medicinal chemistry as well as in organic synthesis.


  • Lewis acid;
  • mineral acids;
  • Eaton's reagent (P2O5/MeSO3H);
  • diethylaluminum 2,2,6,6-tetramethylpiperidide (DATMP)