Skraup reaction

The Skraup synthesis is a chemical reaction used to synthesize quinolines. It is named after the Czech chemist Zdenko Hans Skraup (1850-1910). In the archetypal Skraup, aniline is heated with sulfuric acid, glycerol, and an oxidizing agent to yield quinoline.^[1][2][3][4]

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In this example, nitrobenzene serves as both the solvent and the oxidizing agent. The reaction, which otherwise has a reputation for being violent, is typically conducted in the presence of ferrous sulfate.^[5]

Reaction mechanism

The mechanism is unclear, yet there is good reason to believe that acrolein (obtained by dehydration of glycerol) is an intermediate.

References

1. ^  Skraup, Z. H. "Eine Synthese des Chinolins" Berichte 1880, 13, 2086-7.
2. ^  Manske, R. H. F. Chem. Rev. 1942, 30, 113. (Review)
3. ^  Manske, R. H. F.; Kulka, M. Org. React. 1953, 7, 80-99. (Review)
4. ^  Wahren, M. Tetrahedron 1964, 20, 2773. (Review)
5. ^  Clarke, H. T.; Davis, A. W. “Quinoline” Organic Syntheses Collective Volume 1, page 478 (1941). http://www.orgsyn.org/orgsyn/pdfs/CV1P0478.pdf.

See also

• Bischler-Napieralski reaction
• Doebner-Miller reaction