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Phenethylisoquinoline - derived alkaloids and related systems


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Paano, Anamy Maria Caterial 1986 , 'Phenethylisoquinoline - derived alkaloids and related systems', Unspecified thesis, University of Tasmania.

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The phenethylisoquinoline alkaloids comprise a relatively
new class of alkaloids. They are structurally related to the very
vast group of alkaloids based on the 1-benzylisoquinoline skeleton.
Most of these alkaloids follow a biosynthetic pathway analogous to
the benzylisoquinoline series. That is, they are biosynthesized
from the 1-phenethylisoquinoline autumnaline (Table 1, A-1) and its
relatives by phenolic oxidative coupling and subsequent reactions.
At present, nine groups of alkaloids are identified as of the
phenethylisoquinoline type (Scheme 1). This includes the simple
1-phenethylisoquinoline (1), homomorphinane (2), colchicine (3),
homoproaporphine (4), homoaporphine (5), bisphenethylisoquinoline
(6), dibenz[d,fJazecine (7), homoerythrina (8), and cephalotaxine
(9) groups. The bold lines in Scheme 1 represent biosynthetic
pathways indicated by tracer studies. No tracer studies have been
done on those shown with dotted lines. One can see in the Scheme
that, biosynthetically, homoerythrina and cephalotaxinemay be related
by a common precursor, the dibenz[d,fJazecine-type alkaloid (7). 177
Colchicine on the other hand is derived biosynthetically from a
homomorphinane (2), specifically Q-methylandrocymbine 92
(Table 1, C-2).
The homoprotoberberine-type alkaloid skeleton (10), which
may also be biosynthetically derived from a 1-phenethylisoquinoline
precursor by a Mannich-type reaction, and which was anticipated by
Battersby3 to occur in plants, has not yet been isolated. However, a
homoprotoberberine (11) was isolated from Berberis acticantha4
but differs from (10) in the ring C structure. That is, nitrogen and ring
D are joined together by an ethylene group in (11) instead
of a methylene group as in (10), the latter being characteristic of
a Mannich-type ring closure. A complete list of the phenethyli
soquinoline-derived alkaloids from plants, their sources, and their
physical properties is given in Table 1 and summarised in Table 2.
All the isolated alkaloids presented in Kamentani's review5 are
included in Table 1 to provide a better view of the alkaloid profile.

Item Type: Thesis - Unspecified
Authors/Creators:Paano, Anamy Maria Caterial
Keywords: Alkaloids, Botanical chemistry
Copyright Holders: The Author
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Copyright 1986 the author - The University is continuing to endeavour to trace the copyright
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Additional Information:

Thesis (M.Sc.(Reading))--University of Tasmania, 1987. Includes bibliographical references

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