Chemistry of Vanadium and Zinc Antiviral Tetra-aza Macrocycles

223 Pages·2010·6.97 MB·English

Chemistry of Vanadium and Zinc
Antiviral Tetra-aza Macrocycles

A Thesis Submitted for the Degree
of
Doctor of Philosophy
at
The University of Edinburgh
by
Allison Ross B.Sc.(Hons.)

Department of Chemistry
University of Edinburgh
September 2008
DECLARATION..............................................................................I
ACKNOWLEDGEMENTS...........................................................II
ABSTRACT....................................................................................IV
ABBREVIATIONS......................................................................VII
APPENDICES................................................................................XI

1. INTRODUCTION.................................................................... 1
1.1. Bioactivity of macrocycles........................................................................ 1
1.1.1. Synthetic Macrocycles.................................................................... 3

1.2. HIV and AIDS............................................................................................ 7
1.2.1. Polyoxometallates........................................................................... 8

1.3. Existing drug treatments........................................................................ 10
1.3.1. Reverse transcriptase inhibitors (RTIs)....................................... 10
1.3.2. Protease inhibitors (pharmacology)............................................. 13
1.3.3. Entry inhibitors............................................................................... 15
1.3.3.1. Fuzeon.............................................................................................. 15
1.3.3.2. Maraviroc..........................................................................................16
1.3.3.3. AMD3100..........................................................................................18
1.3.3.4. Metal Complexes............................................................................. 19

1.4. Cyclam and bicyclam................................................................................ 23
1.4.1. Configurational isomers and transition metal complexes........ 25
1.4.2. Constrained cyclam complexes.................................................. 27
1.4.3. Proposed mechanism of antiviral activity................................... 29
1.4.4. Metalloporphyrins.......................................................................... 30

1.5. Vanadium as a bioactive metal................................................................31
1.5.1. Vanadium......................................................................................... 31
1.5.2. Vanadium in macrocycles.............................................................. 34

1.6. Aims of thesis............................................................................................. 35

1.7. Bibliography............................................................................................... 37

2. MATERIALS AND METHODS............................................ 41
2.1. Chemicals and instruments......................................................................41
2.1.1. Chemicals......................................................................................... 41
2.1.2. I R spectroscopy.............................................................................. 41
2.1.3. Conductivity measurements......................................................... 41
2.1.4. Resonance Raman spectroscopy................................................... 42
2.1.5. NMR spectroscopy.......................................................................... 42
2.1.6. X-ray crystallography..................................................................... 43
2.1.7. CHN analysis.................................................................................. 43
2.1.8. Electrospray ionisation-mass spectrometry (ESI-MS)............... 43
2.1.9. Ultraviolet and visible spectroscopy (UV-Vis)........................... 43
2.1.10. pH measurements........................................................................... 44
2.1.11. EPR spectroscopy............................................................................ 44
2.1.12. X-ray absorption near edge structure (XANES) and
Extended X-ray absorption fine structure (EXAFS)................ 44
2.1.12.1. V K Edge XANES/EXAFS............................................................. 44
2.2. IR spectroscopy........................................................................................... 45

2.3. Resonance Raman spectroscopy.............................................................. 47

2.4. NMR spectroscopy..................................................................................... 48
2.4.1. Nuclear spin and chemical shift................................................... 49
2.4.2. Spin-spin coupling and quadrupolar relaxation........................ 51
2.4.3. Paramagnetic effects in NMR spectra.......................................... 52
2.4.4. 2D NMR spectroscopy................................................................... 52
2.4.4.1. COrrelation SpectroscopY (COSY) and TOtal Correlation
SpectroscopY (TOCSY)................................................................... 53
2.4.4.2. Heteronuclear Single-Quantum Correlation (HSQC)............... 54
15
2.4.4.3. N NMR spectroscopy................................................................... 55

2.5. EPR spectroscopy....................................................................................... 55
2.5.1. Spin-lattice relaxation..................................................................... 56
2.5.2. Hyperfine splitting.......................................................................... 56
2.5.3. Line widths and intensities............................................................ 57
2.5.4. Magnetic moment and g-factor..................................................... 57
4+ 2+
2.5.5. EPR of V and VO ....................................................................... 60

2.6. Bibliography............................................................................................... 62
3. OXOVANADIUM(IV) CYCLAM COMPLEXES.....................63
3.1. Experimental.....................................................................................................64
3.2. Materials............................................................................................................65
3.3. Results................................................................................................................65
3.3.1. Magnetic measurements.......................................................................65
3.3.2. X-ray crystallography............................................................................67
3.3.3. FTIR and resonance Raman spectroscopy..........................................78
3.3.4. Conductivity measurements.................................................................83
3.3.5. EPR spectroscopy...................................................................................84
3.3.6. EXAFS/XANES.......................................................................................87
3.3.7. Antiviral HIV Tests................................................................................89
3.3.8. In-silico docking with bovine rhodopsin template...........................93

3.4. Discussion.........................................................................................................97
3.4.1. Oxovanadium(IV) cyclam complexes in the solid state...................97
3.4.1.1. Magnetic measurements.......................................................................97
3.4.1.2. X-ray crystallography............................................................................97
3.4.1.3. Infrared and resonance Raman spectroscopy...................................99
3.4.1.4. EXAFS....................................................................................................100
3.4.2. Oxovanadium(IV) cyclam complexes in solution...........................101
3.4.2.1. Infrared spectroscopy..........................................................................101
3.4.2.2. Conductivity measurements..............................................................102
3.4.2.3. EPR spectroscopy.................................................................................103
3.4.3. Oxovanadium(IV) cyclam complexes in-silico................................104

3.5. Conclusion........................................................................................................107
3.6. Bibliography.....................................................................................................109

4. OXOVANADIUM(IV) BICYCLAM COMPLEXES.................111
4.1. Experimental.....................................................................................................112
4.1.1. Materials................................................................................................112
4.1.2. Synthesis of Xylyl-bicyclam, 16..........................................................113
4.1.3. Syntheses of oxovanadium(IV) cyclam complexes with aromatic
pendant arm substituents...................................................................114
4.1.3.1. Synthesis of oxovanadium(IV) bicyclam complexes......................114
4.1.3.2. Synthesis of oxovanadium(IV) naphthyl complexes......................116
4.1.4. FTIR and resonance Raman spectroscopy.......................................117
4.1.5. UV-Vis spectroscopy...........................................................................120
4.1.6. EPR spectroscopy.................................................................................121
4.1.7. EXAFS/XANES.....................................................................................126
4.1.8. Anti-HIV activity..................................................................................130

4.2. Discussion.........................................................................................................132
4.3. Conclusion........................................................................................................137

4.4. Bibliography.....................................................................................................139

5. ZINC(II) CONSTRAINED CYCLAMS.....................................140
5.1. Experimental.....................................................................................................143
5.1.1. Materials..............................................................................................144

5.2. Results................................................................................................................144
5.2.1. Infrared spectroscopy........................................................................144
5.2.2. X-ray crystallography.......................................................................145
5.2.3. Comparison of bond lengths and angles.......................................154
5.2.3.1. Zinc-oxygen bonds, (Zn(II)-HMC, 36)............................................154
5.2.3.2. Zinc-nitrogen bonds, (Zn(II)-HMC, 36)..........................................154
5.2.3.3. Zinc-chloride bonds, (Zn(II)-NHMC, 41).......................................156
5.2.3.4. Zinc-nitrogen bonds, (Zn(II)-NHMC, 41).......................................156
5.2.4. NMR spectroscopy.............................................................................158

5.3. Antiviral testing...............................................................................................165
5.3.1. Anti-HIV.............................................................................................165
5.3.2. Antibody binding competition tests...............................................167

5.4. Discussion.........................................................................................................168
5.4.1. Infrared spectroscopy......................................................................168
5.4.2. NMR spectroscopy of Zn(II)-hexyl-Me -cyclams........................171
2

5.5. Conclusion........................................................................................................172
5.6. Bibliography.....................................................................................................174

6. CONCLUSIONS AND FUTURE WORK..................................176
6.1. Conclusions......................................................................................................176
6.2. Future work......................................................................................................178
6.2.1. Oxovanadium(IV) complexes......................................................178
6.2.2. Zinc(II) constrained cyclam complexes......................................181

6.3. Conferences attended.....................................................................................182
6.4. Bibliography.....................................................................................................184

7. EXPERIMENTAL...........................................................................185
7.1. General experimental......................................................................................185
7.1.1. Materials........................................................................................185
7.1.2. Infrared spectroscopy .................................................................185
7.1.3. Thin layer chromatography........................................................185
7.1.4. Flash column chromatography..................................................186
7.1.5. Mass spectrometry.......................................................................186
7.1.6. Nuclear magnetic resonance spectroscopy..............................186
7.1.7. Evaporation of solvents...............................................................186
7.1.8. Nomenclature...............................................................................187
7.1.9. Crystallographic data .................................................................187
7.1.10. Glassware......................................................................................187

7.2. Synthesis of oxovanadium(IV) and zinc(II) complexes...........................188

7.3. Antibody competition binding tests...........................................................202
7.3.1. Cell cultures.................................................................................202
7.3.2. Antibodies, chemokines and fluorescent dyes......................203
7.3.3. Assay to measure displacement of antagonist......................203

7.4. Bibliography....................................................................................................204
Declaration

I hereby declare that except where specific reference is made to other
sources, the work contained in this thesis is the original work of the author.
It has been composed by myself and has not been submitted, in whole or in
part of, for any other degree, diploma or other qualification.

Allison Ross
September 2008
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Acknowledgements

I would like to thank my supervisor, Professor Peter J Sadler, FRS, for
his support, advice and encouragement throughout the project and for
always being available when needed. It has been a most enjoyable three
years and I am privileged to have worked for him.
My sincere thanks go to the Sadler research group for members past
and present, both in Edinburgh and Warwick, for their continued support
and friendship. In particular, special thanks are due to Dr Ana Pizarro and
Dr Abraha Habtemariam for invaluable assistance and discussions on many
occasions. I would also like to thank Dr Neil Robertson for acting as my
second supervisor in Edinburgh when Professor Sadler moved to Warwick
University.
Thanks are also due to Professor Simon Parsons and his research
group, and the EPSRC National Crystallographic Service at the University of
Southampton for the crystallography work in this thesis. I also thank
Mr Juraj Bella for assistance with NMR experiments. I am very grateful to
Dr Daniel Stone, National EPR Service, University of Manchester for all his
help with EPR data simulations and Miss Danielle Covelli, University of
British Columbia, for her assistance with the EXAFS/XANES data.
A very special thank you is due to Dr Peter J Kirsop of the University
of Edinburgh for many invaluable discussions, and for his support, patience
and understanding throughout the project.
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