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Structural studies on alkaloids from Peripentadenia MearsII and Hedycarya Angustifolia

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Gunawardana, YAGP (1983) Structural studies on alkaloids from Peripentadenia MearsII and Hedycarya Angustifolia. PhD thesis, University of Tasmania.

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Abstract

A detailed phytochemical investigation of the alkaloids of two
plant species: Peripentadenia mearsii (Elaeocarpaceae) and
Hedycarya angustifblia (Monimiaceae) has been undertaken.
P. mearsii was found to be a rather rich source of alkaloids:
nearly thirty different alkaloids were detected in the bark and leaf
extracts. A total of twenty bases and three non-alkaloidal compounds
were isolated during this investigation.
The structural elucidation of the major alkaloid, peripentadenine,
was carried out by spectroscopic methods and by degradation. Detailed
PMR and 13C NMR spectral assignments of peripentadenine and some of
its twenty derivatives or degradation products are described.
Approaches to the synthesis of EZaeocarpus alkaloids are reviewed.
The structure of peripentadenine was finally confirmed by two different
syntheses.
Structures of three minor bases from the bark: dinorperipentadenine,
peripentamine and dehydroperipentamine were also established.
Dinorperipentadenine was synthesised, and the other two bases were
converted to one of the Hofmann degradation products of peripentadenine.
Tentative structures have been assigned for three other bases
(PBXM2, PLM2 and PLM3) and partial structural analysis was carried
out on two further bases (PBVMD and PLM4).
The identities of the non-alkaloidal compounds isolated were
established by spectroscopy as dimethylsulphone, methylgallate and
2-hydroxy-6-methylacetophenone.
The remaining twelve bases were isolated in minute amounts,
and only their mass spectra were recorded. Possible biosynthetic origins for Peripentadenia bases have been
discussed. The presence of a three-carbon unit between two
nitrogens was considered to be an interesting structural feature of
these alkaloids and a list of compounds with similar features has
been compiled.
Nine alkaloids including four new compounds were isolated from
Hedycaria angustifoZia. The new compounds include a benzylisoquinoline
whose structure was established by X-ray crystallography
(by Professor Allan H. White, University of Western Australia), a
tetrahydrobenzylisoquinoline, a phenanthrene and a dehydraporphine.
The known compounds isolated are all aporphines. Two non-alkaloidal
compounds, 2,3-camphanediol and eudesmol, were also isolated from the
same plant.
The isolation of the alkaloids of Macademia integrifolia was
also attempted but a successful method could not be developed.

Item Type: Thesis (PhD)
Keywords: Alkaloids, Peripentadenine
Copyright Holders: The Author
Copyright Information:

Copyright 1983 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

Thesis (Ph.D)--University of Tasmania. 1984. Bibliography: l. 214-216

Date Deposited: 08 Dec 2014 23:56
Last Modified: 14 Mar 2017 05:16
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