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Herquline A and B were isolated from the fungal strain \(Penicillium\) \(herquei\) Fg-372 and have been shown to exhibit potent platelet aggregation inhibitory activities. The unusual and strained structure of herquline A makes it a highly attractive and challenging synthetic target. Herquline B is conceived to be an analogue of herquline A, even though its absolute structure has not been elucidated. A biomimetic approach was initially investigated in Chapter 2, featuring an intramolecular direct oxidative phenol coupling strategy. While extensive experimentation failed to afford the desired coupling products, an advanced piperazine intermediate possessing a similar ring system to that in herquline A was accessed. Chapter 3 describes the transition metal-mediated intramolecular aryl coupling strategy. Small amounts of biaryl coupling products were fashioned. The conformational analysis of diketopiperazines and piperazines is also introduced. Chapter 4 describes the efforts in the synthesis of analogues of herquline B. The intramolecular coupling at the piperazine stage was found to be challenging and only trace amounts of the desired products were obtained.

Hurricanes are the most destructive of all weather systems. Conditions necessary for their formation are well known, but not those sufficient to guarantee their occurrence. A thorough understanding of their structure, the physical and dynamical processes which operate within them, and their interactions with the large-scale environmental flow are necessary if accurate forecasts are to be made of their development and tracks. In the present study, both 2-D (axisymmetric) and 3-D (asymmetric), two-layer (plus the boundary layer) numerical models have been developed. The 2 -D model is used to investigate the essential characteristics of the symmetric flow component of tropical cyclones. The heating rate, which is computed at the mid-level in the model, is related to the vortexflow itself. It consists of three parts: moisture convergence over the whole column, Ekman pumping and surface evaporation. The moisture convergence is found to be crucial in providing latent heating released by condensation of water vapour sufficient to compensate adiabatic ascent cooling. The Ekman pumping plays an important role as a 'contractor', i.e. to cause the maximum winds to concentrate towards the centre, and consequent intensification of the modelled vortex. The surface evaporation, although relatively S11UJU, spreads over a larger area than the other two. It is found to beessentialformaintenance of the mature stage.