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Title: Investigations of new synthetic routes to fused tricyclic heteropines and related heterocycles
Author: Bell, Ian Alexander Weston
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1996
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The subject matter of this thesis is concerned with investigations into the synthesis of tricyclic heteropine systems. In particular Lewis acid-catalysed and carbanion-induced cyclisation reactions of suitably substituted isothiocyanate and carbodiimide derivatives were investigated for the synthesis of dibenzoxazepines, pyridobenxoxazepines, dibenzothiazepines, dibenzodiazepines and benzonapthoxazepines. These studies were also expanded to investigate the synthesis of benzoxazepinodibenzoxazepines and benzoxazepinobenzonapthoxazepines via the double-cyclisation of the appropriate bis-isothiocyanate derivatives. The description of the results obtained in these studies is preceded by a review on the use of tricyclic heteropine derivatives as chemotherapeutic agents in the areas of schizophrenia and Alzheimer's disease. The synthetic strategies currently available for the synthesis of tricyclic heteropines are also included in this review. It highlights the need for a flexible, widely applicable route to this class of compound and how the present studies could address this problem. The syntheses of the appropriate 2-isothiocyanatodiphenyl ether derivatives were readily accomplished, and in most cases their subsequent reaction with a Lewis acid catalyst resulted in the formation of the desired tricyclic heteropine. These compounds were also synthesised in high yield via a carbanion-induced cyclisation involving reaction of appropriate halogen derivatives with butyl lithium, the first examples of intramolecular carbanion addition to a heterocumulene. The attempted transition metal-mediated and radical -induced cyclisation of the isothiocyanate precursors, however, proved unsuccessful, with no formation of the desired tricyclic heteropine-system. The attempted functionalisation of the tricyclic heteropines, via thiomethylation of the thiolactam moiety and subsequent displacement of the thiomethyl-group, proved unsuccessful.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available