| dc.description.abstract | In this thesis some preliminary studies
have been described, which were aimed at the
synthesis of compounds in which a 3-substituted
furan is attached to a 6-lactone ring so as to
yield structures of the type observed in the
naturally occurring tetranortriterpenoids (e.g.
see structures [8] till [13] on pp. 2 and 3).
In an introductory literature survey various
types of naturally occurring 3-substituted furan
compounds have been described, and an outline has
been given of some of the possible approaches to
the synthesis of compounds containing a part
structure [12] (p.3).
Since 3-halofurans are essential starting
materials for such a synthesis, the effectiveness
of some preparations of 3-iodofuran and 3-bromofuran
as reported in the literature has been studied.
The reactions of 3-furyl^lithium and 3-
thieny1-lithium with aldehydes and esters led to
the isolation of coupling products, which were
studied in some detail.
Thus, oxidation of the alcohols obtained in
this way gave information on the relative stabilities of this type of compounds under oxidising conditions. A mass spectrometric study of these
model compounds led to the observation of some
interesting fragmentation patterns which are discussed
in detail.
Finally, various reactions are discussed
which were directed towards the preparation of
derivatives of a-tetralone, which could be used
in similar coupling reactions, in order to arrive
at the desired 3-furyl-lactone structure. These
modifications of the a-tetralone molecule were
largely unsuccessful. Therefore, the discussion
is concluded with an examination of the reasons
for these difficulties, and some suggestions are
made with respect to future studies in this area. | |
