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Structural systematics of halogenated benzamides

Hehir, Niall (2017) Structural systematics of halogenated benzamides. PhD thesis, Dublin City University.

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This PhD Thesis, entitled "Structural Systematics of Halogenated Benzamides", describes the synthesis, characterisation and analysis of a series of 3×3 isomer grids. A range of bromo- and iodo- substituted compounds based on both the benzamide and carboxamide backbones were synthesised and fully characterised by 1H NMR, ATR-IR and X-ray crystallography. The goal of this work was to explore the effect of different functional groups and their position on small drug-like molecules and analyse the trends noted in the compounds, including the formation of an imide moiety, following placement of the pyridine nitrogen and bromine moiety in close proximity in the ortho- position. Further work was carried out on the benzamide backbone, with two isomer grids synthesised in which the positions of both a difluoro- and methyl moiety were varied and trends in 1H NMR, 19F NMR and solid state structure were analysed and rationalised. This data allowed us to observe how the addition and position of various functional groups drive or inhibit the formation of mixed amide/imide (foldamer) structures. A number of modifications to the benzamide backbone were carried out, with a carbamate based alternative being the primary backbone investigated. The reactions, combined with the previous data gathered from the isomer grid analysis, allowed us to rationalise an approach using the most suitable compounds from our earlier work to synthesise larger conformationally constrained foldamers. Using this information, compounds with a mixed imide/amide backbone were synthesised and a number of interesting variations on the basic 2:1 fluoroaminopyridine: pyridinedicarbonyl structural motif found in the earlier isomer grids, were found. Compounds containing 3:2 and 4:3 ratios were synthesised and characterised fully.

Item Type:Thesis (PhD)
Date of Award:January 2017
Supervisor(s):Gallagher, John F.
Uncontrolled Keywords:Chemical Crystallography; Organic synthesis; X-ray diffraction; Benzamides; Pyridinecarboxamides; Carbamates; imides; Isomer grids; Hydrogen bonding; Halogen bonding; Foldamers
Subjects:Physical Sciences > Organic chemistry
Physical Sciences > Chemistry
Physical Sciences > Crystallography
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Chemical Sciences
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 3.0 License. View License
Funders:Meath VEC
ID Code:21616
Deposited On:07 Apr 2017 15:07 by John Gallagher. Last Modified 20 Apr 2017 12:00

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