Carbolines naturally occurring indoles

Indole chemistry has already been discussed in Chapter 4. This is one of the major groups of naturally occurring bioactive alkaloids, and can be classified into three main categories tryptamine and its derivatives, ergoline and its derivatives, and (3-carboline and its derivatives. 

Of the more than 4500 known naturally occurring organohalogen compounds, a large fraction are alkaloids [1,3]. Most of these halogenated pyrroles, indoles, carbazoles, carbolines, tyrosines, and others have a marine origin. The present chapter surveys the occurrence, structure, and biosynthesis of these fascinating natural products. However, given their sheer number, this review focuses mainly on recent examples. 

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