https://theses.gla.ac.uk/ Theses Digitisation: https://www.gla.ac.uk/myglasgow/research/enlighten/theses/digitisation/ This is a digitised version of the original print thesis. Copyright and moral rights for this work are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This work cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Enlighten: Theses https://theses.gla.ac.uk/ [email protected] À Thesis entitled PARTIAL SYNTHESIS AND REGIOSELECTIVE REDUCTION OF STEROIDAL 11,12-SEra-DIOIC ANHYDRIDES Submitted in part fulfilment of the requirements for admittance to the Degree of Doctor of Philosophy by HASSAN ABBAS HASSAN. B.Sc.. M.Sc.. January 1987 Department of Chemistry UNIVERSITY OF OLASOOV ProQuest Number: 10991907 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10991907 Published by ProQuest LLO (2018). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLO. ProQuest LLO. 789 East Eisenhower Parkway P.Q. Box 1346 Ann Arbor, Ml 48106- 1346 TO MY MOTHER AND THE MEMORY OF MY LATE FATHER ACKNOWLEDGEMENTS I would like to express my sincere gratitude to Professor C J W Brooks for his constant supervision and under whose guidance and encouragement this work was performed. Special thanks to Professor G W Kirby for providing the opportunity to carry out this research and also for his advice and criticism. My thanks also to all members of the Technical staff for their valuable assistance and in particular to Dr J Cole for running the mass spectra (by GC-MS) The Iraqi Ministry of Higher Education is warmly acknowledged for the award of the scholarship. I am especially grateful to my brother Hadi and to my friends Ms A McNeish, Dr G Mitchell and Dr Hamed J. Jaffer for their kind and generous support. Finally, I would like to thank Mrs J Anthony and Susie Q for carefully typing the manuscript. ******** CONTENTS Page Summary ^ Introduction 1 1.1 Steroids 1 1.2 Occurrence 3 1.3 Steroid Types 5 1.4 Nomenclature 7 1.5 The Biosynthesis of Steroids 10 1.6 Brassinolide and Related Steroids 22 (a) The Discovery of Brassinolide 22 (b) Brassinolide Isolation & Characterisation 24 (c) Synthetic Studies on Brassinolide 26 (d) Synthetic Analogues of Brassinolide 38 1.7 Steroidal Ring-C Lactones 57 1.8 Metal Hydride Reduction of Cyclic Anhydrides 66 1.9 Oxidative Cleavage of Steroid Rings 79 Results and Discussion 95 2.1 3a-Exthoxycarbonyloxy-11,12-seco-5g-Cholane 11.12.24-trioic acid 24-methyl ester 97 2.2 3a-Exthoxycarbonyloxy-11,12-seco-5p-Cholane 11.12.24-trioic acid 11,12-anhydride 24-methyl ester 100 2.3 Synthesis of Methyl 3a-Exthoxycarbonyloxy-1 la- bromo-12-oxo-5P-cholanoate 102 2.4 Oxidative Ring-Cleavage by Superoxide 107 2.5 Methyl 1 la-bromo-12-oxo-5P-cholanate 119 2.6 11,12-seco-5p-Cholane-11,12,24-trioic acid 24-methyl ester 123 2.7 11,12-seco-5p~Cholane-11,12,24-trioic acid 11,12-anhydride 24-methyl ester 125 2.8 3P-Acetoxy-12p-hydroxy-5a:2 5R-spirostan- 11-one 128 2.9 3p-Benzyloxy-12p-hydroxy-5a:25R-spirostan- 11 -one 132 2.10 11,12-Secotigogenin-11,12-dioic acid-3p- acetate 132 2.11 11,12-Secotigogenin-11,12-dioic acid anhydride- 3p-acetate 136 2.12 11,12-Secotigogenin-11,12-dioic acid anhydride- 3p-benzoate 137 2.13 Gas-Liquid Chromatography (GLC) Data for some bile acid and Hecogenin Derivatives 142 2.14 Borohydride Reduction of Cyclic Anhydrides 155 (a) Reduction of 2o,3p-Diphenylglutaric Anhydride 155 (b) Reduction of 3a-Ethoxycarbonyloxy-l 1,12- seco-5P-Cholane-11,12,24-trioic acid 11,12- anhydride 2 4-methyl ester 156 (c) Reduction of 11,12- seco-5p-Cholane-11,12, 24-trioic acid 11,12- anhydride 24-methyl ester 164 (d) Reduction of 11,12-secotigogenin-11,12-dioic acid anhydride 3p-acetate 165 2.15 Treatment of 11,12-secotigenin- 11,12-dioic acid anhydride 3p-acetate 175 2.16 Mechanism of Metal Hydride Reduction of Cyclic Anhydrides 176 Experimental General Analytical Techniques (i) Thin Layer Chromatography (TLC) 188 (ii) Gas-Liquid Chromatography (GLC) 188 (ill) Combined Gas-Liquid Chromatography-Mass Spectrometry (GC-MS) 189 (iv) Mass Spectrometry (MS) 189 (v) InfraRed (IR) 189 (vi) Nuclear Magnetic Resonance (NMR) 190 (vii) Melting Point Apparatus 190 Purification Techniques (viii) Column Chromatography 190 (ix) Vacuum Sublimation 190 3.1 Methyl Deoxycholate 191 3.2 Methyl 3a-Ethoxycarbonyl-Deoxycholate 191 3.3 Methyl 3a-Exthoxycarbonyloxy-5p-chol- 11 -enoate 191 3.4 3a-Exthoxycarbonyloxy-11,12-seco-5P- cholane-11,12,24-trioic acid 24-methyl ester 192 3.5 Treatment of Methyl 3a-Exthoxycarbonyloxy- 5P-chol-11 -enoate with NalO^-KMnO^ 193 3.6 Treatment of Methyl 3a-Exthoxycarbonyloxy- 5P-chol-11 -enoate with Ru02-NaI0^ 194 3.7 3a-Exthoxycarbonyloxy- 11,12-seco-5P- cholane-11,12,24-trioic acid-11,12-anhydride 24-methyl ester 194 3.8 Methyl 3a-Exthoxycarbonyloxy-12-oxo-5P- cholanoate 195 3.9 Methyl 1 la-bromo-3a-Ethoxycarbonyloxy- 12-oxo- 5p-cholanoate 195 3.10 Methyl 3,12-dibenzoyl-deoxycholate 196 3.11 Methyl 3-benzoyl-deoxycholate 196 3.12 Methyl 3«-benzoyloxy-12p-hydroxy-5p- cholanoate 197 3.13 Methyl 3ot-benzoyloxy-1 la-bromo-12-oxo- 5P-cholanoate 198 3.14 Treatment of Methyl 3ot-benzoyloxy-1 la- bromo- 1 2-0X 0- 5P-cholanoate with KOg 198 3.15 Methyl 3-tosyl-deoxycholate 199 3.16 Methyl 12a-hydroxy-5P-chol-3-enoate 200 3.17 Methyl 12a-hydroxy-5P-cholanoate 201 3.18 Methyl 12-oxo-5P-cholanoate 201 3.19 1 la-Bromo-12-oxo-cholanoic acid 202 3.20 Methyl 12p-hydroxy-l l-oxo-5P-cholanoate 202 3.21 11,12-seco-5p-cholane-11,12,24-trioic acid 24 methyl ester 203 3.22 11,12-seco-5p-cholane-11,12,24-trioic acid-11,12-anhydride 24-methyl ester 204 3.23 3P-Acetoxy-5a:25R-spirostan-12-one (Hecogenin acetate) 204 3.24 3P, 12p-Diacetoxy-5a:25R-spirostan-11 -one 204 3.25 3P, 12p-Dihydroxy-5a:25R-spirostan-11 -one 205 3.26 3p-Acetoxy-12p-hydroxy-5«:25R-spirostan- 11-one 206 3.27 3P-Benzoyloxy-12P-hydroxy-5a:25R-spirostan- spirostan - 11 -one 206 3.28 11,12-secotigogenin- 11,12-dioic acid-3P- acetate 207 3.29 11,12-secotigogenin- 11,12-dioic acid anhydride 3p-acetate 208 3.30 11,12-secotigogenin- 11,12-dioic acid anhydride 3p-benzoate 209 3.31 3P-Acetoxy-11,12-seco-dialdehyde-5a:25R- spirostan 209 3.32 Borohydride Reduction of Cyclic Anhydrides 210 (a) Reduction of 2,3-diphenylglutaric anhydride 211 (b) Reduction of 3a-ethoxycarbonyloxy-11,12- seco-5p-cholane-11,12,24-trioic acid-11,12- anhydride 24-methyl ester 211 (c) Reduction of 11,12-seco-5p-cholane-11,12, 24-trioic acid-11,12-anhydride 24-methyl ester 212 (d) Reduction of 11,12-secotigogenin-11,12- dioic acid anhydride 3P-acetate 213 3.33 Treatment of 11,12-secotigogenin- 11,12-dioic acid anhydride 3p-benzoate with K-selectride 215 Appendix 216 References 233 SUMMARY 11 12-sêffi-5p-cholane-l 1,12,24-trioic acid in 42% yield, along with two other compounds identified as 3a-hydroxy-l l, 12-sefio- 12-nor- 5p-cholane-11.24- dioic acid (25%) and 3a, 13-dihydroxy-11, 12-seco- 12-nor-5p-cholane- 11,24- dioic acid (32%). Ozonolysis of methyl 3a-ethoxycarbonyloxy-5p-chol-l 1- enoate afforded the3a-ethoxycarbonyloxy-11,12-seco- 5p -cholane-11,12, 24-trioic acid 24-methyl ester, in 25% yield, which was converted to the desired 11.12-seco-dioic anhydride by treatment with acetic anhydride. Reduction of the obtained anhydride with NaBH^ in THF gave in total regio- selectivity the 3a-ethoxycarbonvloxv-11.12-seco- 12-hvdroxv-5p- cholane- 11,24-dioic acid 24-methyl ester. Treatment of the hydroxy-acid with acetic anhydride led to the corresponding acetoxy-acid, 3a-ethoxycarbonyloxy- 11,12-seco- 12-acetoxy- 5P-cholane -11, 24-dioic acid 24-methyl ester. Oxidation of methyl 12p-hydroxy-11 -oxo-5p-cholanoate with NalO^ /CrOg afforded the corresponding 11.12-seco-dioic acid in good I l l yield. Treatment with acetic anhydride led to the desired 11.12-seco-5p-cholane-11,12,24-trioic acid-11,12-anhydride 24-methyl ester. Reduction of the anhydride with NaBH^ in THF gave exclusively the 11.12-seco- 12-hvdroxv-5p-cholane-11.24-dioic acid 24-methyl ester. Treatment of the latter with acetic anhydride afforded the corresponding lactone, methyl 12-oxa-C-homo-l l-oxo-5P-cholanoate, in only 6 % yield and the acetoxy-acid, 11,12-seco-12-acetoxy-5P-cholane- 11,24-dioic acid 24-methyl ester, as the major product.