Title:
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Identification and synthesis of hymenopteran pheromones
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GC-MS analysis of Camponotus floridanus revealed that queens and workers differ
significantly in their cuticular hyrdrocarbons (CHC's) and surface compounds of their
eggs. The CHC profiles comprised a complex mixture of straight and branched
alkanes. Bioassays showed that the hydrocarbons on queens and queen eggs carry a
signal that prevents workers from laying eggs and protects queen eggs from worker
policing. GC-MS analysis also showed that the CHC's of C.jloridanus queens and
workers and C. tortuganus workers differ between colonies. Synthesis of queen
specific compounds was carried out in order to prepare a synthetic queen blend for
use in bioassays. A synthetic route towards central-l ,5-dimethylalkanes was
developed employing 3-methyl thiophene as a building block being sequentially
acylated and reduced. A synthetic route towards 3-methyl carboxylic acids was also
developed utilising the Homer-Wadsworth-Emmons reaction. The thiophene
methodology was also used to prepare mono-methylalkanes and 3,X-dimethylalkanes.
The metapleural glands of Acromyrmex echinator and its associated parasite
Ainsinuator were analysed by GC-MS to compare the profiles of the two species. The
24 compounds identified included a range of carboxylic acids, lactones and ketoacids.
The gland contents of the two species were found to be very similar. This was
surprising as it was expected that the parasite would produce a lower number and
amount of compounds due to the energy costs associated with their production.
Attempts to further develop a synthetic route towards alkyl pyrazines was undertaken.
Nitroalcohols were prepared from nitroalkanes and aldehdydes using alumina as a
surface catalyst. Oxidation to nitroketones used pyridinium chlorochromate on silica
and ultrasound. Attempts at the synthesis of tri and tetra substitued pyrazines were
partially successful but not conclusive.
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