Alkaloids Derived from Tryptophan

L-Tryptophan is an aromatic amino acid containing an indole ring system, having its origins in the shikimate pathway via anthranilic acid. It acts as a precursor of a wide range of indole alkaloids, but there is also definite proof that major rearrangement reactions can convert the indole ring system into a quinoline ring, thus increasing further the ability of this amino acid to act as an alkaloid precursor.