Baeyer oxindole synthesis

What is Baeyer oxindole synthesis?

The Baeyer oxindole synthesis, originally discovered by von Baeyer (Nobel Prize in Chemistry 1905) in 1878, involves the synthesis of oxindole through the acidic reduction of o-nitrophenylacetic acid with tin, followed by the cyclization of the resulting reduced intermediate.

Baeyer oxindole synthesis
Baeyer oxindole synthesis

R = H, Br, NH2, alkyl (see list of acronyms)

In addition to these reaction conditions, various other acidic reducing combinations, such as Zn + H2SO4, Zn + HOAc, Fe + HOAc, and SnCl2 + NH4Cl, can also be employed to produce oxindole. Nevertheless, new methods have emerged for the synthesis of oxindoles in recent years.


Baeyer, A. (1878), Synthese des Oxindols. [Synthesis of oxindole.] Ber. Dtsch. Chem. Ges., 11: 582-584.