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Title: Continuous photo-oxidation with 1O2 in CO2
Author: Bellamy, Jessica Faye Barrett
ISNI:       0000 0004 6348 3775
Awarding Body: University of Nottingham
Current Institution: University of Nottingham
Date of Award: 2014
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This Thesis describes the application of supercritical carbon dioxide as a solvent for conducting continuous flow reactions using photochemically generated singlet oxygen. Model reactions have been explored, to develop the experimental procedure, and this technology has subsequently been applied to the synthesis of a series of antimalarial 1,2,4-trioxanes. Chapter 1 introduces the concepts of green chemistry as well as singlet oxygen, including a review of its known reactions. A summary of the work previously conducted in this field at the University of Nottingham is also presented. The reactors used to conduct the high pressure experiments discussed in this Thesis are presented in Chapter 2. Experimental results are split into two parts: Part I encompasses the efforts made to improve the photo-oxidation procedure, which includes Chapters 3 and 4; Part II describes the application of this technology to a series of 1,2,4-trioxanes including the important antimalarial artemisinin, discussed in Chapters 5 and 6. A fluorous biphase technique was developed to allow for the continuous recycling of a fluorinated photocatalyst, during flow photo-oxidation experiments, and is described in Chapter 3. Chapter 4 discusses the modifications to the continuous flow photo-oxidation reactor, to allow for an increase in productivity and applicability. Chapter 5 presents the continuous flow synthesis of the 1,2,4-trioxane artemisinin using CO? as the reaction solvent. Photo-oxidation with singlet oxygen is a key step in this synthesis and a novel bifunctional heterogeneous catalyst has been developed. Chapter 6 discusses the synthesis of a series of synthetic 1,2,4-trioxanes via three key steps. Each step, including the photo-oxidation of an allylic alcohol, has been adapted to a continuous flow process and thus the feasibility of the scale-up of such syntheses is investigated. Finally, Chapter 7 summarises the work described in this Thesis and examines the success of the techniques and approaches discussed. A summary of potential routes for further study is also presented.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available