The Development of Novel Immunosuppressant Drugs: The
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University of Wollongong Research Online University of Wollongong Thesis Collection University of Wollongong Thesis Collections 2002 The development of novel immunosuppressant drugs: the synthesis of thiazole analogues of 2-acetyl-1', 2', 3', 4' - tetrahydroxybutylimidazole George Robert Jeoffreys University of Wollongong Recommended Citation Jeoffreys, George Robert, The development of novel immunosuppressant drugs: the synthesis of thiazole analogues of 2-acetyl-1', 2', 3', 4' - tetrahydroxybutylimidazole, Doctor of Philosophy thesis, Department of Chemistry, University of Wollongong, 2002. http://ro.uow.edu.au/theses/1204 Research Online is the open access institutional repository for the University of Wollongong. For further information contact Manager Repository Services: [email protected]. The Development of Novel Immunosuppressant Drugs: The Synthesis of Thiazole Analogues of 2-Acetyl-l', 2', 3', 4'- Tetrahydroxybutylimidazole. A thesis submitted in fulfilment of the requirements for the award of the degree Doctor of Philosophy from UNIVERSITY OF WOLLONGONG George Robert Jeoffreys, BSc (Hons I) Department of Chemistry December 2002 CERTIFICATION I, George Robert Jeoffreys, declare that this thesis, submitted in fulfilment of the requirements for the award of Doctor of Philosophy, in the Department of Chemistry, University of Wollongong, is wholly my own work unless otherwise referenced or acknowledged. The document has not been submitted for qualifications at any other academic institution. December, 2002 Publications Sections of the work published herein have been reported through the following presentations: Papers Jeoffreys, G.R., Ung, A.T., Pyne, S.G., Skelton, B.W. and White, A.H. "Synthesis of thiazole analogues of the immunosuppressive agent (1R, 2S, 3R)-2-acetyl-4 (5)- (1,2,3,4-tetrahvdroxybutyl)imidazole" Journal of the Chemical Society, Perkins Transactions 1,1999, 2281 -2291 Abstracts Jeoffreys, G.R. and Pyne, S.G., "Synthesis of Immunosuppressant Drugs: Giving Transplant Patients a Helping Hand", 1999 University of Wollongong Postgraduate Open Day Jeoffreys, G.R. and Pyne, S.G., "Development and Synthesis of Novel Immunosuppressant Drugs" 1999 Southern Highlands Heterocyclic Chemistry Conference, Bowral NSW. Jeoffreys, G.R. and Pyne, S.G., "Synthesis of Novel Immunosuppressant Compounds" 1998 RACI Conference, Leura NSW Jeoffreys, G.R. and Pyne, S.G., "Development and Synthesis of Novel Immunosuppressant Compounds" 1998 Departmental Conference (University of Wollongong, Chemistry Department), Kioloa NSW Jeoffreys, G.R. and Pyne, S.G., "Immunosuppressant Compounds: Dr Frankenstein's Favourite Drug" 1998 University of Wollongong Postgraduate Open Day Acknowledgements I would like to take this opportunity to thank my supervisor, Professor Steve Pyne, for his guidance, expertise and patience throughout the course of my project, and for the chance to do the project in the first place. Thanks also to J&J for their financial support which allowed me to carry out my research without the stress of working externally at the same time. To the other members of the Pyne research group I would also like to offer my thanks for their camaraderie and support. In particular many thanks to Dr Alison Ung, for whom I have the utmost respect, for her day-to-day supervision and for being there to stop me blowing myself up! And to Tien Pham, for his friendship and constant banter in the lab which helped keep me sane. Also deserving a mention are Dorothy David, Andrew Davies and Helen Witchard. From other research groups at UOW, thanks and best wishes to Glen Burley and Tien Liu who took the journey with me. To those within the department my thanks go especially to Larry Hicks and his team of merry Mass Spec'ers and to Ellen, Sandra and Yoke for their tireless efforts with the NMR's. Sincere thanks to Professor John Bremner without whom I would not have come to UOW in the first place. And to Will Price and again, John Bremner for their support as Heads of Department. Also, the unsung heroes - Mari Dwarte and Jenny Sheridan, without whom the Department would fall over itself on a regular basis. Finally, to my beloved wife Neisha, for whose patience, assistance and counsel I am eternally grateful. One down, one to go! Abbreviations Ac acetyl anhyd anhydrous Ar aryl Atm atmosphere(s) Bn benzyl BOC,Boc tert-butoxycarbonyl bp boiling point br broad (spectral) Bu butyl s-Bu .sec-butyl r-Bu fert-butyl rc-BuLi n-butyl lithium °C degrees Celsius calcd calculated CI chemical ionization (in mass spectrometry); configuration interaction (in MO theory) cm centimeter(s) coned concentrated COSY correlation spectroscopy 8 chemical shift in parts per million downfield from tetramethylsilane d day(s); doublet (spectral) DCC N,N-dicyclohexylcarbodiimide de diastereomeric excess DEAD diethyl azodicarboxylate DEPT distortionless enhancement by polarization transfer DIBALH diisobutylaluminum hydride DMAP 4-(dimethylamino)pyridine DME 1,2-dimethoxyethane DMF dimethylformamide DMSO dimethyl sulfoxide DNA deoxyribonucleic acid El unimolecular elimination E2 bimolecular elimination EE enantiomeric excess EI electron impact (in mass spectrometry) Et ethyl FT Fourier transform G gram(s) GC gas chromatography h hour(s) HPLC high-performance liquid chromatography HRMS high-resolution mass spectrum Hz hertz JR infrared / coupling constant (in NMR) K kilo L litre(s) V- micro m multiplet (spectral), meter(s), milli M moles per litre m-CPBA m-chloroperoxybenzoic acid Me methyl MHz megahertz min minute(s) mM millimoles per litre mol mole(s) MOM methoxymethyl mp melting point mRNA messenger RNA MS mass spectrometry m/z mass to charge ratio (in mass specti NMR nuclear magnetic resonance NOE nuclear Overhauser effect Nu nucleophile NOESY nuclear Overhauser effect spectros< PCC pyridinium chlorochromate PDC pyridinium dichromate Ph phenyl ppm parts per million (in NMR) Pr propyl i-Pr isopropyl q quartet (spectral) Rf retention factor (in chromatograph' rRNA ribosomal RNA rt room temperature s singlet (NMR); second(s) SNI unimolecular nucleophilic substitution SN2 bimolecular nucleophilic substitution t triplet (spectra) TBDMS tert-butyldimethylsilyl TFA trifluoroacetic acid Th thiazole THF tetrahydrofuran TLC thin layer chromatography TM0F trimethyl-O-formate TMS trimethylsilyl, tetramethylsilane Torr ImmHg, l/760atm tRNA transfer RNA TS transition state tR retention time (in chromatography) UV ultraviolet Abstract This thesis presents the synthesis of several structural analogues of the immunosuppressant compound THI. A number of the synthesised analogues were found to have higher levels of biological activity of the same type as THI. Chapter 1 presents an introduction and summary of some of the fundamental principles behind immunosuppression and the modes of action of a range of known commercial immunosuppressants. This chapter also looks at the role of immunosuppression in modern medicine and presents some potential new immunosuppressants yet to reach the commercial market. The final part of the chapter provides an introduction to, and background of THI, which leads into the aims of the project. Chapter 2 presents the synthesis of five-carbon side chain, 5-thiazole analogues of THI, with the aim of determining the effect of increasing the length of the pendant side-chain. The promising biological screening data generated for these compounds is presented towards the end of the chapter. Chapter 3 investigates the consequences of reversing the orientation of the thiazole heterocycle. This synthesis proceeds via a lithium-bromide exchange reaction to overcome the lower reactivity of the 4-thiazole position (compared to the 5- position). Chapter 4 provides a logical extension of the successful increase in side chain length from 4 to 5 carbons, by further extending this functionality out to 6 carbons. This Chapter also includes a more detailed study of metal hydride reductions and the stereochemical factors associated with these reactions. In order to determine the role of the absolute configuration of the polyhydroxyl side chain, Chapter 5 presents the synthesis of another range of 6- carbon side chain analogues with different absolute configurations. A brief summary of the work is presented in Chapter 6, along with some general observations brought about by the results of the project. Table of Contents 1 Table Of Contents CHAPTER 1 INTRODUCTION. 7 1.1 Defences of the Human Body , 8 1.1.1 Non-Specific Defences 9 1.1.1.1 Passive Non-Specific Defences 9 1.1.1.2 Active Non-Specific Defences 10 1.1.2 Specific Defences 13 1.1.2.1 The Immune System 13 1.1.2.2 Humoral Immunity 13 1.1.2.3 Cellular Immunity 15 1.1.3 The Leukocyte Cascade Mechanism 17 1.1.3.1 Lymphocyte Rolling 18 1.1.3.2 Lymphocyte Triggering 19 1.1.3.3 Lymphocyte Adhesion 20 1.1.3.4 Lymphocyte Transmigration 20 1.2 Conditions Involving the Immune System 22 1.2.1 Allergies 22 1.2.2 Allergic Disease - Hypersensitivity 23 1.2.2.1 Asthma 24 1.2.3 Autoimmunity 25 1.2.3.1 Insulin Dependent Diabetes Mellitus 25 1.2.3.2 Rheumatoid Arthritis 27 1.2.3.3 Multiple Sclerosis 28 1.2.4 Transplant Procedures 28 Table of Contents 1.2.4.1 Transplant rejection 31 1.3 Immunosuppression and Immunosuppressant Drugs 31 1.3.1 Calcineurin Inhibition 34 1.3.1.1 Immunophilins 34 1.3.1.2 Cvclosporine 35 1.3.1.3 Tacrolimus 37 1.3.2 Sirolimus 39 1.3.3 Corticosteroids 40 1.3.4 Adjunctive Treatments 41 1.3.5 Antibody Therapy 43 1.3.6 Gusperimus 44 1.3.7 New Immunosuppressant Agents 45 1.3.7.1 Leflunomide 45 1.3.7.2 Brequinar Sodium 46 1.3.8 2-Acetvl-4(5H 1,2.3,4-tetrahvdroxvbutyl)imidazole (THI) 46 1.3.8.1 Established Syntheses of THI 48 1.3.8.2 New Syntheses of THI 50 1.3.8.3 Analogues of THI 51 1.4 Aims of Project................ 54 CHAPTER 2 THE SYNTHESIS OF V,2'-SYN- AND 1\2--4iV77-2-ACETYL-5- rtT.