Part I: Synthesis of Cyclobutyl Nucleoside Analogs That Mimic AZT for Inhibition of the K65R HIV-1 Reverse Transcriptase Mutant Part II: Synthesis and Evaluation of Truncated Triptolide Analogs to Suppress Chronic Inflammation Público

Bluemling, Gregory Richard (2011)

Permanent URL: https://etd.library.emory.edu/concern/etds/wm117p17w?locale=es
Published

Abstract

Part I of this dissertation describes the synthesis and biological activity of novel
3'-azido cyclobutyl nucleoside analogs. These analogs were developed for inhibition of
both the WT HIV RT and the K65R HIV RT mutant. The nucleoside analogs were
prepared from cyclobutenones which were generated via a [2+2] cycloaddition reaction.
The azide was installed through a Michael reaction, and both thymine and adenine were
coupled to the cyclobutyl ring through a SN2 reaction via a brosylate. The nucleosides
GB119, GB120, GB123, and GB124 did not show any anti-HIV activity in human PBM
cells and were not toxic to PBM, CEM, and Vero cells up to 100 μM.
Part II of this dissertation describes the synthesis and biological activity of
truncated analogs of the diterpenoid triepoxide natural product triptolide. Triptolide
possesses potent anti-inflammatory activity but is highly cytotoxic. In an effort to retain
the desired anti-inflammatory properties of triptolide while reducing cytotoxicity, a series
of truncated analogs were synthesized from phenols. Triptolide showed cytotoxicity at
50 nM in Jurkat cells. None of the analogs tested showed cytotoxicity in PMBCs or
Jurkat cells up to 1000 nM. The analogs GB67B, GB97, and GB187D were screened in
a carrageenan edema model in mice. GB67B was found to reduce TNF-α levels and
reduce paw inflammation. To further study this compound, GB67B at 10 mg/kg and 30
mg/kg was given orally to rats once daily for 28 consecutive days in an adjuvant arthritis
model. GB67B was found to give a dose-dependent reduction of paw volume and
arthritic score. A luciferase reporter gene assay showed that unlike triptolide, GB67B did
not inhibit NF-κB activation. However, GB67B was found to inhibit TNF-α levels from
LPS stimulated mouse splenocytes in a dose-dependent manner supporting the carrageenan edema model results. Triptolide is known to be lethal to mice and rats at a single dose of 1 mg/kg. In order to observe toxicity of the truncated analogs, GB67B was
dosed at 30, 90, and 180 mg/kg in rats for 7 days. While no animals died during the
study there were signs of clinical intolerance for GB67B in the 180 mg/kg group.

Table of Contents

Table of Contents

Part I: Synthesis of Cyclobutyl Nucleoside Analogs That Mimic AZT for Inhibition of the K65R HIV-1 Reverse Transcriptase Mutant

1.1 Statement of purpose ……………………………………….. 1

1.2 Introduction ………………………………………....……… 4

1.2.1 Current status of the HIV/AIDS pandemic ………………...... 4

1.2.2 The HIV replication cycle …………………………………... 6

1.2.3 FDA approved anti-HIV therapeutics ………………….…… 10

1.2.4 Drugs currently in clinical trials …………………………...…. 15

1.2.5 Additional classes of anti-viral therapies ………………...…... 19

1.2.6 HIV RT ……………………………………………...…….. 22

1.2.7 NRTI mechanism of action …………………………….…… 26

1.2.8 HIV RT NRTI resistance mechanisms …………….…….….. 28

1.3 Background ……………………………………..……..…... 33

1.3.1 3'-Azido-2',3'-dideoxynucleoside analogues ......................... 33

1.3.2 Syntheses of AZT and AZA …………………………….…. 34

1.3.3 Anti-viral natural product oxetanocin ……………….....…… 34

1.3.4 Syntheses of oxetanocin A and cyclobut-A ……..……..…… 36

1.3.5 Synthesis of cyclobutenones ……………………..…....…… 38

1.3.6 Methods for the Michael addition of azide ………...…..…… 41

1.3.7 Methods for coupling nucleoside bases to a cyclobutyl

ring ………………………………………...………….….. 46

1.3.8 Methods for synthesizing nucleoside triphosphates ……..….. 50

1.3.9 Synthesis and anti-HIV activity of 3'-hydroxymethyl

cyclobutyl nucleosides ……………………………...…….. 53

1.4 Results and discussion ……………………………...…….. 56

1.4.1 Design and synthesis of 3'-azido-3'-hydroxyethyl

cyclobutyl adenine ………………………………..……… 57

1.4.2 Design and synthesis of 3'-azido-3'-hydroxyethyl

cyclobutyl thymine………………………………..…….…. 60

1.4.3 Anti-viral activity…………………………………..……... 62

1.5 Conclusion …………………………………………….… 63

1.6 Experimental …………………………………….………. 64

1.7 References ………………………………………….…… 96

Part II: Synthesis and Evaluation of Truncated Triptolide Analogs to Suppress Chronic Inflammation

2.1 Statement of purpose ……………………………………… 103

2.2 Introduction ……………………………………………….. 106

2.2.1 Current status of autoimmune and inflammatory diseases ........ 106

2.2.2 Overview of the immune system ……………………..…….. 107

2.2.3 Autoimmunity ……………………………………………... 121

2.2.4 Inflammation …………………………………….………… 124

2.2.5 Drugs used to treat autoimmune/inflammatory diseases .....…. 128

2.3 Background ………………………………………...…….. 136

2.3.1 Triptolide as a potent immunosuppressant ……….…..…….. 136

2.3.2 Inhibition of the NF-kB signaling pathway by triptolide ......... 136

2.3.3 Synthesis of triptolide …....................................................... 140

2.3.4 Design and synthesis of monocyclic truncated

triptolide analogs…………………………………………… 143

2.3.5 Methods for o-formylation of phenols ……….………..…… 144

2.3.6 Methods for oxidative dearomatization ………………....….. 146

2.3.7 Epoxidation of electron deficient olefins …………….…....…. 148

2.4 Results and discussion ……………………………….……. 150

2.4.1 Synthesis of 2,5-substituted phenols ………………..….... 150

2.4.2 Synthesis of salicylic alcohols ……………………..…..…... 152

2.4.3 Oxidative dearomatization of salicylic alcohols ……….....…. 153

2.4.4 Synthesis of diepoxide analogs ………………………..….... 154

2.4.5 Triepoxide formation ………………….……………….…. 156

2.4.6 Deprotection of the triisopropylsilyl protected analogs …....…158

2.4.7 Design and synthesis of bicyclic truncated triptolide

analogs …………………………………………….......…. 158

2.4.8 Minimization of reactive functional groups …..………......…. 162

2.4.9 Synthesis of deuterated analogs for use as biological

standards …………………………………………..….…. 169

2.4.10 Biological evaluation of truncated triptolide analogs ….....…. 171

2.5 Conclusion …………………………………………..….. 206

2.6 Experimental ………………………………………......... 208

2.7 References ………………………………………..…….. 368

3.1 Appendix …………………………………………..…… 376

About this Dissertation

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
School
Department
Degree
Submission
Language
  • English
Research field
Palabra Clave
Committee Chair / Thesis Advisor
Committee Members
Última modificación

Primary PDF

Supplemental Files