190
12
stimulant. A carbonyl reduction of cathinone leads to norephedrine and norpseudoephedrine. From Khat also cathine (norpseudoephedrine) can be isolated with similar functions.
A similar compound, ephedrine, is found in Ephedra (Ephedraceae), and can be used as
a nasal decongestant and bronchial dilator against asthma. Ephedrine has already been
described in Chinese medicine. Some dietary supplements also include ephedra, with the
most popular uses being for improvement of weight loss and athletic performance (see
7 Sect. 7.2).
12.6 Alkaloids from Condensation of Tyrosine and Phenylalanine
12.6.1 Amaryllidaceae (Norbelladine)
Tyramine (from tyrosine) and 3,4-dihydroxybenzaldehyde (from phenylalanine) are condensed to norbelladine, and after different phenol coupling reactions, either galantamine
Tyrosine
Dopamine
Tyramine
2-DOPA
Mescaline
Noradrenaline
Adrenaline (Epinephrine)
mainly
humans
HO
HO
HO
OH
OH
OH
O
H 2 N
NH 2
NH 2
NH 2
O
O
O
HO
COOH
NH 2
. Fig. 12.4 Schematic overview of the biosynthetic pathway of phenethylamine alkaloids and representative members
Chapter 12 · Alkaloids