Abstract
The isoquinoline alkaloids and their biosynthetic relatives include many compounds
which show important physiological properties in animals: dopamine, mescaline, morphine,
papaverine, and narcotine are pertinent examples.
The biosynthetic routes to the members of this family start from the essential aminoacids
tyrosine or phenylalanine. Decarboxylation gives a phenethylamine building block (C6–C2) which then combines with an additional building block to form an isoquinoline ring.
This stage of the general biosynthetic scheme is illustrated by the biosynthesis of
the cactus alkaloid anhalonidine.
Many important classes of alkaloid are produced by further transformation of simple
isoquinoline systems. In the opium poppy the benzylisoquinoline reticuline is converted
to the two very different alkaloids morphine and narcotine. More recently it has been
estblished that two of the alkaloids of Stephania, japonica, protostephanine and hasubanonine are also produced by modification of a benzylisoquinoline
precursor.
These varied biosynthetic pathways and the methods used in their elucidation are discussed
in detail.
Key Word Index
Biosynthesis - Isoquinoline Alkaloids
