Page 73 - phytochemistry general program
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7- Gelsemium alkaloids.
Almost all these alkaloids are biogenetically derived from the amino-acid
Tryptophan-derived alkaloids”.“ tryptophan. So, they are also referred to
Being derivatives from tryptophan, most of the indole alkaloids contain two
nitrogen atoms in their molecule.
Indole
N
H
NH2 NH2
H2C CH2 H2C CH
COOH
N Tryptamine N Tryptophane
H
H
The clavine alkaloids of Ergot as well as the lysergic acid moiety of all Ergot
alkaloids are products of condensation of tryptophan with an isoprenyl moiety;
where the two carbon side chain of trptophan together with the C5 prenyl moiety
provided rings C and D.
NH
N
H
Ergot alkaloids
(Tryptophan with one prenyl moiety)
On the other hand, Rauwolfia and Yohimbe alkaloids are examples of the
latter classes, where ring C is formed by cyclization of the two carbon side chain of
tryptophan, upon condensation with the C10-geranyl portion that provides rings D
and E.
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