Alkaloids Derived by Amination Reactions
The majority of alkaloids are derived from amino
acid precursors by processes that incorporate into
the final structure the nitrogen atom together with
the amino acid carbon skeleton or a large proportion
of it. Many alkaloids do not conform with
this description, however, and are synthesized primarily
from non-amino acid precursors, with the
nitrogen atom being inserted into the structure at a
relatively late stage. Such structures are frequently
based on terpenoid or steroidal skeletons, though
some relatively simple alkaloids also appear to
be derived by similar late amination processes. In
most of the examples studied, the nitrogen atom
is donated from an amino acid source through a
transamination reaction with a suitable aldehyde
or ketone . |