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Synthesis, EPR Characterization and Chitosan Labelling of Triarylmethyl Radicals

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Synthesis, EPR Characterization and Chitosan Labelling of Triarylmethyl Radicals Synthesis, EPR characterization and chitosan labelling of triarylmethyl radicals Dissertation Zur Erlangung des akademischen Grades Doctor rerum naturalium (Dr. rer. nat.) vorgelegt der Naturwissenschaftlichen Fakultät I Biowissenschaften der Martin-Luther-Universität Halle-Wittenberg von M.Sc. Marwa Aly El-metwaly Mohamed Elewa Geboren am 16. August 1982 in Port Said, Ägypten Gutachter: 1. Prof. Dr. habil. Peter Imming 2. Prof. Dr. habil. Karsten Mäder 3. Prof. Dr. habil. Klaus Müller Halle (Saale), den 30.07.2015 Verteidigt am 06.11.2015 TO MARYAM & TAMER Table of contents Table of contents Table of contents _________________________________________________________ A List of abbreviations ______________________________________________________ E Abstract ________________________________________________________________ G English version ______________________________________________________________ G German version ______________________________________________________________ I 1. Introduction ___________________________________________________________ 1 1.1. Electron paramagnetic resonance (EPR) _____________________________________ 1 1.2. Spin probes _____________________________________________________________ 5 1.2.1. Tetrathia-TAM radicals as spin probes for oxygen, pH, redox status and thiol concentration measurements __________________________________________________________________________ 7 1.2.1.1. Tetrathia-TAM radicals and oxygen mapping ____________________________________ 7 1.2.1.2. Tetrathia-TAM radicals metabolism and reactions ________________________________ 11 1.2.1.3. Tetrathia-TAM radicals and interaction with biological macromolecules ______________ 15 1.2.1.4. Tetrathia-TAM radicals as pH-sensitive spin probes ______________________________ 16 1.2.1.5. Tetrathia-TAM radicals and redox status determination ___________________________ 19 1.2.1.6. Tetrathia-TAM radicals and thiol concentration measurement ______________________ 20 1.2.1.7. Tetrathia-TAM radicals and superoxide radical measurement _______________________ 21 1.2.2. Tetrachloro-TAM radicals _______________________________________________________ 22 1.2.2.1. Synthesis of tetrachloro-TAM radicals _________________________________________ 22 1.2.2.2. Stability of tetrachloro-TAM radicals __________________________________________ 24 1.2.2.3. Reactivity of tetrachloro-TAM radicals ________________________________________ 24 1.2.2.4. Different derivatives of tetrachloro-TAM radicals ________________________________ 25 1.2.2.5. Tetrachloro-TAM radicals as spin probes for various pharmaceutical applications ______ 27 1.3. Aim of the work _________________________________________________________ 31 2. Tetrathiatriarylmethyl radicals ___________________________________________ 32 2.1. Introduction ____________________________________________________________ 32 2.2. Experimental ___________________________________________________________ 33 2.2.1. Materials and general methods for synthesis and analytical characterization _______________ 33 2.2.2. Sample preparation for EPR spectroscopic characterization. ____________________________ 33 2.2.3. EPR spectroscopy _____________________________________________________________ 33 2.3. Results and Discussion ___________________________________________________ 33 A Table of contents 2.3.1. Synthesis of different tetrathia-TAM radicals ________________________________________ 33 2.3.2. Characterization of hydrophilic trityl radicals in aqueous solutions ______________________ 35 2.3.2.1. Influence of ion strength, osmolarity, and pH value _______________________________ 35 2.3.2.2. Impact of viscosity _________________________________________________________ 35 2.3.3. EPR spectroscopic characterization of lipophilic tetrathia-TAM radicals in an oily solution __ 36 2.3.4. Oxygen sensitivity _____________________________________________________________ 37 2.3.5. Encapsulation of tetrathia-TAM esters and properties of the resulting nanocapsules (NCs) ___ 38 2.4. Conclusion _____________________________________________________________ 39 2.5. Syntheses ______________________________________________________________ 39 3. Tetrachlorotriarylmethyl radicals _________________________________________ 51 3.1. Introduction ____________________________________________________________ 51 3.2. Experimental ___________________________________________________________ 51 3.2.1. Materials and general methods for synthesis and analytical characterization _______________ 51 3.2.2. Sample preparation for EPR spectroscopic characterization ____________________________ 51 3.2.3. EPR spectroscopy _____________________________________________________________ 51 3.3. Results and Discussion ___________________________________________________ 52 3.3.1. Synthesis of different tetrachloro-TAM radicals _____________________________________ 52 3.3.2. EPR characterization ___________________________________________________________ 53 3.3.3. Oxygen calibration of radicals 24 and 25 in an oily solution ___________________________ 55 3.3.4. Spin labelling of a nucleoside ____________________________________________________ 56 3.4. Syntheses ______________________________________________________________ 64 4. PTMTC and 13C-PTMTC _______________________________________________ 83 4.1. Introduction ____________________________________________________________ 83 4.2. Experimental ___________________________________________________________ 83 4.2.1. Materials and general methods for synthesis and analytical characterization _______________ 83 4.2.2. Sample preparation for EPR spectroscopic characterization ____________________________ 83 4.2.3. Continuous wave (CW-EPR) spectra ______________________________________________ 84 4.2.4. Pulse X-band EPR _____________________________________________________________ 84 4.3. Results and discussion ___________________________________________________ 84 4.3.1. Synthesis of tetrachlorotriarylmethyl tricarboxylic acid (PTMTC) and its 13C labelled analog (13C-PTMTC) _________________________________________________________________________ 84 4.3.2. EPR characterization ___________________________________________________________ 85 4.3.3. CW-EPR spectrum _____________________________________________________________ 86 B Table of contents 4.3.4. Influence of pH value on 13C-PTMTC line width _____________________________________ 87 4.3.5. Influence of viscosity on 13C-PTMC line width ______________________________________ 88 4.3.6. Influence of oxygen on PTMTC line width _________________________________________ 89 4.3.7. Influence of temperature on 13C-PTMTC line width __________________________________ 91 4.3.8. The accelerated aging (by increasing temperature) method _____________________________ 93 4.3.9. Cell lysate study _______________________________________________________________ 95 4.4. Conclusion _____________________________________________________________ 95 4.5. Syntheses ______________________________________________________________ 96 5. Spin labelling of polymers (chitosan and carboxymethyl chitosan) _____________ 100 5.1. Introduction ___________________________________________________________ 100 5.1.1. Structure of CS and CMC ______________________________________________________ 100 5.1.2. Properties of CS and CMC _____________________________________________________ 102 5.2. Experimental __________________________________________________________ 103 5.2.1. Materials and general methods for synthesis and analytical characterization ______________ 103 5.2.2. Characterization of CS and CMC conjugates _______________________________________ 103 5.2.2.1. UV-Vis spectroscopy ______________________________________________________ 103 5.2.2.2. EPR measurements _______________________________________________________ 103 5.3. Results and discussion __________________________________________________ 103 5.3.1. Preparation of CS and CMC conjugates ___________________________________________ 103 5.3.2. UV-Vis spectroscopy __________________________________________________________ 104 5.3.3. EPR spectroscopy ____________________________________________________________ 106 5.4. Conclusion ____________________________________________________________ 107 5.5. Syntheses _____________________________________________________________ 107 6. Tetraoxatriarylmethyl radicals __________________________________________ 109 6.1. Introduction ___________________________________________________________ 109 6.2. Results and Discussion __________________________________________________ 110 6.3. Syntheses _____________________________________________________________ 114 7. Summary and Outlook _________________________________________________ 118 8. References __________________________________________________________ 128 9. Appendices ____________________________________________________________ I C Table of contents 9.1. Materials ________________________________________________________________ I 9.2. General methods for synthesis and analytical characterization ____________________ I 9.3. LDH-release and cell activity/proliferation ___________________________________ II 9.4. Acknowledgement ________________________________________________________ III 9.5. Curriculum vitae _________________________________________________________ IV 9.6. List of publications _______________________________________________________ V 9.6.1. Research articles _______________________________________________________________ V 9.6.2. Conference
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