Reissert indole synthesis

The Reissert indole synthesis is a series of chemical reactions designed to synthesize indole or substituted-indoles (4 and 5) from ortho-nitrotoluene 1 and diethyl oxalate 2.^[1][2]

Additional recommended knowledge

How to quickly check pipettes?

Recognize and detect the effects of electrostatic charges on your balance

What is the Correct Way to Check Repeatability in Balances?

Potassium ethoxide has been shown to give better results than sodium ethoxide.^[3]

Reaction mechanism

The first step of the Reissert indole synthesis is the condensation of o-nitrotoluene 1 with a diethyl oxalate 2 to give ethyl o-nitrophenylpyruvate 3. The reductive cyclization of 3 with zinc in acetic acid gives indole-2-carboxylic acid 4. If desired, 4 can be decarboxylated with heat to give indole 5.

References

1. ^ Reissert, A. Ber. 1897, 30, 1030.
2. ^ Noland, W. E.; Baude, F. J. Organic Syntheses, Coll. Vol. 5, p.567 (1973); Vol. 43, p.40 (1963). (Article)
3. ^ Johnson, J. R.; Hasbrouck, R. B.; Dutcher, J. D.; Bruce, W. F. J. Am. Chem. Soc. 1945, 67, 423.

See also

• Leimgruber-Batcho indole synthesis