Fischer indole synthesis

Fischer indole synthesis
Named after Hermann Emil Fischer
Reaction type Ring forming reaction
Identifiers
Organic Chemistry Portal fischer-indole-synthesis
RSC ontology ID RXNO:0000064

The Fischer indole synthesis is a chemical reaction that produces the aromatic heterocycle indole from a (substituted) phenylhydrazine and an aldehyde or ketone under acidic conditions.[1][2] The reaction was discovered in 1883 by Emil Fischer. Today antimigraine drugs of the triptan class are often synthesized by this method.

The Fischer indole synthesis
The Fischer indole synthesis

This reaction can be catalyzed by Brønsted acids such as HCl, H2SO4, polyphosphoric acid and p-toluenesulfonic acid or Lewis acids such as boron trifluoride, zinc chloride, and aluminium chloride.

Several reviews have been published.[3][4][5]

  1. ^ Fischer, E.; Jourdan, F. (1883). "Ueber die Hydrazine der Brenztraubensäure". Berichte der Deutschen Chemischen Gesellschaft. 16 (2): 2241–2245. doi:10.1002/cber.188301602141.
  2. ^ Fischer, E.; Hess, O. (1884). "Synthese von Indolderivaten". Berichte der Deutschen Chemischen Gesellschaft. 17 (1): 559–568. doi:10.1002/cber.188401701155.
  3. ^ van Order, R. B.; Lindwall, H. G. (1942). "Indole". Chemical Reviews. 30 (1): 69–96. doi:10.1021/cr60095a004.
  4. ^ Robinson, B. (1963). "The Fischer Indole Synthesis". Chemical Reviews. 63 (4): 373–401. doi:10.1021/cr60224a003.
  5. ^ Robinson, B. (1969). "Studies on the Fischer indole synthesis". Chemical Reviews. 69 (2): 227–250. doi:10.1021/cr60258a004.