Gramine (also called donaxine) is a naturally occurring indole alkaloid present in several plant species. Gramine may play a defensive role in these plants, since it is toxic to many organisms.^[1]

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1 Uses
2 Biology
3 Synthesis
4 References

Uses

Gramine is used mostly in synthetic organic chemistry as a starting material for tryptophan syntheses.

All reactions of gramine follow the same general reaction scheme. Gramine is reacted with a strong electrophile, such as methyl iodide, to form the quaternary ammonium salt 2. The ammonium salt will undergo a Hofmann elimination or retro-Michael addition to give the very active intermediate 3, which can accept a wide range of nucleophiles to give the desired product 4.

Biology

Gramine has been found in the Arundo^[2], silver maple^[3], Hordeum, and Phalaris plant species.

Synthesis

Despite being widely available in several plant species, gramine is far easier to synthesize directly from indole via a Mannich reaction with dimethylamine and formaldehyde.

References

The references in this article would be clearer with a different or consistent style of citation, footnoting, or external linking.

^ Corcuera, L. J.; Biochemical basis of the resistance of the barley to aphids. Phytochemistry 1993, 33, 741-747.
^ Orechoff; Norkina; Ber. 1935, 68, 670.
^ Pachter et al. J. Org. Chem. 1959, 24, 1285.

Category: Indoles

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Gramine". A list of authors is available in Wikipedia.