Lysergic acid derivatives biosynthesis

Ergot.—Experiments directed towards solving the outstanding problem of the biosynthesis of the peptide lysergic acid derivatives from lysergic acid have not yet proved definitive, and the recent results for ergotamine and ergometrine represent little advance on those reviewed previously. 

Biosynthesis. In Claviceps purpurea, and presumably also in higher plants, E.a. are biosynthesized from tryptophan and isopentenylpyrophosphate (see Terpenes). Synthesis proceeds via 4-dimethylallyl-tiyptophan, which is converted into the alkaloid chanoclavine (by hydroxylation, methylation, decarboxylation and formation of a new C-C bond). All the other clavine alkaloids and the lysergic acid derivatives are derived from chanoclavine. The peptide moieties of the ergotamine and ergotoxin alkaloids are formed by a multienzyme complex (Fig. 2). E.a. are prepared from the sclerotia of rye, previously inoculated with Claviceps and they are also produced by culture of the fungus on artificial growth media. 

Floss, H.G., Giinthei H., Groger, D. and Erge, D (1966) Biosynthesis of ergot alkaloids. Biogenetic relationships between clavine and lysergic acid derivatives. Z. Naturforschg., 21B, 128-131 (1966). 

Fig. 8. Biosynthesis of lysergic acid amide derivatives as proposed by Agurell.

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