Baeyer–Emmerling indole synthesis explained

Baeyer–Emmerling indole synthesis is a method for synthesizing indole from a (substituted) ortho-nitrocinnamic acid and iron powder in strongly basic solution.^{[1] [2]} This reaction was discovered by Adolf von Baeyer and Adolph Emmerling in 1869.^{[3] [4]}

Reaction mechanism

The reaction of iron powder with o-nitrocinnamic acid reduces the nitro group to a nitroso. The nitrogen then condenses with a carbon on the alkene chain with loss of a molecule of water to form a ring. Decarboxylation gives indole.

See also

• Baeyer–Drewson indigo synthesis

References

1. Bayer, A. . Emmerling, A. . Synthese des indoles . Synthesis of indoles . . 2 . 1. 679–682 . 1869 . 10.1002/cber.186900201268.
2. http://www.pmf.ukim.edu.mk/PMF/Chemistry/reactions/baeyer5.htm Baeyer 5
3. Book: Chamberlain, Joseph Scudder . A Textbook of Organic Chemistry . 1921 . Blakiston . 874.
4. 10.1038/024227c0 . Indigo and its Artificial Production. 1881. Nature. Lockyer. Sir Norman. 24. 610. 227–231. 1881Natur..24..227H. 4100142. free.