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Title: Studies on Pyridine n-oxides
Author: Knott, Jane Marie
ISNI:       0000 0001 3601 1447
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 1995
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The work described herein is directed towards the Claisen rearrangements and [3+2] cycloaddition reaction of pyridine N-oxide systems. The pyridine N-oxide molecule is a very versatile and useful synthetic intermediate for the construction of more complex pyridines. Chapter 1 contains a review of work carried out within the group towards Claisen rearrangement of benzene-type systems. The acid catalysed rearrangement of these systems affords a high degree of regioselectivity. A literature survey of the [3+2] cycloaddition reaction of both aliphatic nitrones and aromatic N-oxides with various dipolarophiles is also included. Access to many stereochemically pure products demonstrates that the [3+2] cycloaddition has become a very important ring-forming reaction. Chapter 2 describes development of two Claisen rearrangement precursors and their subsequent attempted Claisen rearrangement is outlined. Chapter 3 details the construction of a range of 3-substituted pyridine N-oxides. Their attempted intermolecular cycloaddition, by thermal means and at high pressure, with mono- and di-activated dipolarophiles is described. Chapter 4 outlines attempts towards and the final synthesis of the ester cycloaddition precursors. Attempted intramolecular [3+2] cycloaddition of these substrates both thermally and under high pressure is summarised. Chapter 5 describes approaches towards [3+2] cycloaddition precursors that contain mono- and di-activated dienophiles. The synthesis of a variety of 3-substituted pyridines is detailed.
Supervisor: Harwood, Laurence M. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Pyridine ; Derivatives ; Synthesis ; Claisen rearrangement ; Ring formation (Chemistry)