Open Access Repository of Indian Theses

Agarwalla, Pritha

Synopsis 
 
viii 
 
Chapter 1: Introduction 
 Cancer, the age-old immortal illness, arises from uncontrolled division of a 
set of diseased cells which can be identified with a limitless replicative potential as 
well as the capacity of out-of-bound migration, invasion and metastasis. The loss of 
cellular regulation leading to cancer may often arise from mutations in two broad 
classes of genes, namely, oncogenes and tumor suppressor genes. Though cancer is 
often described as ‘The wound that never heals’, there have been intense efforts 
worldwide to bring a remedy including hormonal therapy, targeted chemotherapy, 
cancer immunotherapy, gene therapy, anti-angiogenic therapy etc. 
Chemotherapy usually refers to use of drugs (chemotherapeutics) that kill 
rapidly dividing cancer cells. While chemo drugs kill cancer cells, they also harm 
cells that divide rapidly under normal conditions. Such side effects are partly 
overcome by targeted therapy which is a special type of chemotherapy that takes 
advantage of small differences between normal cells and cancer cells (“molecular 
targets”), thereby selectively delivering drugs to cancer cells via suitable drug 
delivery systems.  
Drug delivery systems refer to approaches, formulations, and systems for 
transporting a pharmaceutical compound in the body to safely achieve its desired 
therapeutic effect. These include liposomes, microspheres, gels, polymers, 
nanoparticles, micelles, cyclodextrins etc. Liposomes, consisting of spherical lipid 
bilayers and enclosing a watery interior, have long been viewed as bio-compatible 
drug/gene delivery reagents owing to their structural similarity to cell membranes. In 
the field of targeted chemotherapy, specific targeting of liposomally encapsulated 
chemotherapeutics to tumor cells are often accomplished using liposomes made from 
lipids covalently conjugated with tumor targeting ligands. Past decade has also 
witnessed wide use of Gold nanoparticles (GNPs) in the field of nanomedicine with 
diverse biomedical applications such as drug delivery vehicles or theranostic agents.
 
Due to their small size, good biocompatibility, tailor-able surface chemistry, 
characteristic surface plasmon absorption, and ease of synthesis, gold nanoparticles 
serve as promising drug nanocarriers.  
Synopsis 
 
ix 
 
Despite significant advances, resistance to chemotherapy and molecularly 
targeted therapies is a major challenge in current cancer research. The resistance to 
‘classical’ cytotoxic chemotherapeutics and to therapies that are designed to be 
selective for specific molecular targets may be intrinsic or acquired. The most 
common reason for acquisition of resistance to a broad range of anticancer drugs is 
expression of one or more energy-dependent transporters that detect and eject 
anticancer drugs from cells, but other mechanisms of resistance including 
insensitivity to drug-induced apoptosis and induction of drug-detoxifying 
mechanisms also play an important role in acquired anticancer drug resistance. 
Multidrug based combination therapy sometimes helps to circumvent such resistance 
of cancer cells to chemotherapeutics. Rational drug combinations are often proposed 
on the basis of in vitro and in vivo synergy between agents; either hitting the same 
pathway at multiple points or targeting completely independent pathways. Thus, 
strategies to circumvent cancer drug resistance by targeting alternative pathways may 
improve cancer chemo therapy leading to efficient tumor management. 
Here, in my thesis, I report on the exploitation of two targets: Glucocorticoid 
receptor and N-end rule pathway as a strategy to induce drug sensitization in cancer 
cells and inhibit tumor regression (melanoma & colon).  
Chapter 2 
 The differentiation of epithelial cells to motile mesenchymal phenotype, a 
process known as epithelial-mesenchymal transition (EMT) is involved in drug 
resistance, cancer progression and metastasis. Therefore, inhibiting EMT could be an 
attractive therapeutic modality to overcome drug resistance and metastasis in cancer 
cells. Recent studies demonstrate that glucocorticoids (GCs), a class of steroid 
hormones can block EMT of mink lung epithelial cells, estrogen receptor (ER) 
negative breast cancer cells and human peritoneal mesothelial cells. However, 
elucidation of role of glucocorticoids in inducing EMT has just started and 
glucocorticoid receptor’s (GR) functional importance in this regard is not clear yet. 
Chapter 2 of my thesis delineates the development of a new glucocorticoid receptor 
(GR)-targeted gold nanoparticle formulation, that can stably carry anticancer drug 
Withaferin A (WFA) in its hydrophobic core. To achieve GR target-ability, we 
conjugated Dexamethasone (a synthetic Glucocorticoid) to GNP surface via thiol 
Synopsis 
 
x 
 
bond. The primary –OH group of dexamethasone was converted into thiol 
functionality (DSH) to ensure facile binding with gold nanoparticle surface. The 
presently synthesized gold nanoparticle formulation (GNP-DSH-WFA) showed GR-
dependent cancer cell selective cytotoxicity, inhibited growth of aggressive mouse 
melanoma tumor while reversing EMT in tumor-associated cells and reduced mice 
mortality. Same treatment also led to near-complete down-regulation of ABCG2 
drug transporter in tumor cells thereby attributing it to its drug sensitization ability. 
The present report thus demonstrates the design of a new metallic nano-formulation 
that reduces aggressive tumor growth through GR-mediated reversal of EMT and 
induction of drug sensitivity. 
 
 
Figure 1. Glucocorticoid receptor targeted gold nanoconjugates inhibit tumor growth in mice via 
EMT reversal. Schematic representation of Glucocorticoid receptor targeted gold-withaferin 
nanoconjugate and its application in inhibiting growth of melanoma tumor in mice while reversing 
EMT in tumor cells. 
Chapter 3A 
 Biotin (vitamin B7, vitamin H) is an essential micronutrient for normal 
cellular functions and is required in excess by various cancer cells to sustain their 
rapid proliferation. Biotin receptor is often found to be over expressed in a number of 
cancer cell lines of ovarian, colorectal etc. origins and has emerged as a promising 
Synopsis 
 
xi 
 
molecular marker for targeted drug delivery. This chapter reports on the synthesis of 
a biotin based amphiphilic lipid, BIO-C18, which along with appropriate co-lipids in 
particular mole ratios form stable liposome. Cellular uptake study demonstrates that 
Rhodamine PE labelled liposomes of BIO-C18 lipid efficiently internalize in CT26, 
A549 and Hela cells via biotin receptor. This liposome can also preferentially deliver 
a hydrophobic fluorescent molecule in mice bearing colon tumor (biotin receptor 
over-expressed) under in vivo settings. 
 
Figure 2. Cellular uptake of liposomes of biotinylated amphiphile are biotin receptor mediated. 
Structure of biotin derived amphiphile, BIO-C18 (A) and schematic representation of biotin receptor 
targeted liposome (B) of BIO-C18. Flow cytometric uptake analysis (C) of Rh-PE liposome of BIO-
C18 (red) which decreased considerably (blue) when cells were pre-saturated with biotin when 
compared to untreated (black). 
 Chapter 3B  
N-end rule pathway is an ubiquitin dependent protein degradation pathway 
that relates the in vivo half-life of a protein to the identity of its N-terminal residue. 
Recent study has shown that N-end rule pathway counteracts cell death by degrading 
many anti-survival protein fragments like BCLxL, BRCA1, RIPK1 etc. Inhibition of 
the N-end rule pathway can lead to metabolic stabilization of pro-apoptotic protein 
fragments like RIPK1, thereby sensitizing cells to programmed cell death. Receptor 
interacting serine-threonine protein kinase-1 (RIPK1) is one of the upstream 
regulators of programmed necrosis known as necroptosis. Necroptosis is particularly 
gaining attention of cancer biologists as it provides an alternate therapeutic modality 
to kill cancer cells, which often evolve multiple strategies to circumvent growth 
inhibition by apoptosis. Utilizing the over expression of biotin receptor in cancer 
Synopsis 
 
xii 
 
cells, herein, we report that co-administration of synthetic hetero-bivalent N-end rule 
inhibitor RFC11 & anticancer drug shikonin solubilized in a stable biotin receptor-
targeted liposome (described in Chapter 3A) exhibited significant synergistic anti-
tumor effect in both subcutaneous and orthotopic mouse colon tumor model through 
induction of necroptosis. Besides developing a newly targeted formulation for 
necroptosis induction, this report is the first in vivo evidence demonstrating that 
potent inhibition of N-end rule pathway can enhance therapeutic efficacy of 
conventional chemotherapeutics. 
 
 
Figure 3. RFC11 & shikonin co-solubilised within the liposomes of BIO-C18 synergistically inhibit 
colon tumor growth via induction of necroptosis. Structure of RFC11 (A). Viability assay showing 
RFC11 could synergise anticancer effect of shikonin in colon cancer cell (B). Transmission electron 
micrograph of CT26 cell showing signs of necroptosis (C). Representative tumor size (D) in mice 
bearing orthotopic and subcutaneous colon tumor treated with glucose (I), biotinylated liposomes 
containing RFC11(II), shikonin (III), both RFC11 & shikonin (IV). 
Conclusion 
My thesis work thus focuses on the development of two different nano-
assemblies, one liposomal and other gold nanoparticle based, both when loaded with 
suitable adjuvant could sensitize cancer cells to chemotherapeutics leading to 
efficient tumor growth inhibition in melanoma and colon carcinoma. The present 
thesis work also demonstrates that inhibition of N-end rule pathway can act as a 
platform to enhance therapeutic efficacy of conventional chemotherapeutics, thus 
opening new prospects in the field of cancer chemotherapy. 


English

Development Of Glucocorticoid Receptor And N-end Rule

Pathway Targeted Nano-assemblies As Drug Sensitizers For

Cancer Therapy

Chiluveru, Ravi Kumar

STEREOSELECTIVE FORMAL SYNTHESIS OF (+)-, (-)-

CYCLOPHELLITOL, (-)-CONDURITOL-B, (-)-CONDURAMINE-B, AND

(-)-CLAVOSOLIDE A

Gaddam, Krishna

 
 
 
 
 
 
 
 
 
SYNOPSIS 
 
 
 
 
 
 
 
 
 
																																																																																
SYNOPSIS	
 
i	
 
SYNOPSIS 
The thesis entitled “Development of alkyne-assisted approaches to the synthesis of 
benzofurans, furan and furan-fragment of furanocembranoid-1, has been divided in 
to four chapters.  
CHAPTER-I: Introduction of benzofurans and furans. 
CHAPTER-II: Synthesis of 2, 3-disubstituted benzofurans from TBS-protected 
alkynols. 
Benzofurans are an important class of bicyclic heterocyclic compounds containing 
benzene ring fused with furan. Substituted benzofurans display diverse pharmacological 
activities. Among these, 2, 3-disubstituted benzofurans have great considerable attention 
as a synthetic targets due to the presence of their skeleton as an integral part of various 
biologically active natural products as well as pharmaceutical compounds. For example 
(Figure 1), the tetracyclic meroterpenoid natural product (+)-liphagal (1), a selective 
inhibitor of phosphatidylinositol 3-kinase (PI3K), isolated from the Caribbean sponge 
Aka coralliphaga; ii) amiodarone (2),  a clinically used drug for controlling intractable 
cardiac arrhythmias; iii) a phenolic compound (3), inhibitor against testosterone 5α-
reductase, isolated from the stems of Dalbergia cochinchinensis. In addition, numerous 
2, 3-disubstituted benzofurans have been reported to possess antifungal, antiviral, 
antidiabetic and antiparasitic activity. 
																																																																																												
SYNOPSIS	
 
ii	
 
O
O
I
I
O
N
amiodarone (2)
O
HO
OH
H
H
O
(+)-Liphagal (1)
O
O
MeO
OMe
Phenolic compound from
Dalbergia cochinchinensis (3)
OH
OMe
 
Figure 1: Structure of selected benzofuran-based molecules.   
Herein we describe the synthesis of substituted benzofurans from TBS-protected 
alkynols in one-pot reaction and this method involves sequential Lewis acid catalysed 
nucleophilic substitution and TBAF mediated desilylation followed by exo-dig-
cycloisomerization to give diversely substituted benzofurans in good yields shown in 
(Scheme 1 and Table 1).  
 
Scheme 1  
Table 1: One pot synthesis of 2,3-disubstituted benzofurans. 
																																																																																
SYNOPSIS	
 
iii	
 
 
Later, the reactivity of silylenol ether 27 with 4 also tested under the present one-pot 
reaction conditions and to our delight, the reaction provided the corresponding 
benzofurans 28 in 86% yield (Scheme 2). 
 
Scheme 2 
																																																																																												
SYNOPSIS	
 
iv	
 
In subsequent studies, we also investigated the reactivity of propargylic alcohols 29 and 
31, obtained from the reaction of TBS-protected salicylaldehyde with alkynes derived 
from Boc-protected prolinol and Garner’s  aldehyde, with allyltrimethylsilane (11). 
From these reactions, the corresponding 3-allylbenzofuran 30 and 32 were obtained in 
74% and 61% yields, respectively (Scheme 3, eq-1). The reaction of 29 with 11 
proceeded under the described reaction conditions, whereas in the case of 31, we found 
that 5 mol% B(C6F5) was a suitable acid catalyst for the nucleophilic substitution 
reaction; see (Scheme 3, eq-2) because the acid labile acetonide group was not stable in 
the presence of BF3
.EtO. 
 
Scheme 3 
CHAPTER-III: Synthesis of 5-substituted 3-furanoates from Morita-Baylis-
Hillman acetates of acetylenic aldehyde. 
Furans are among the most important five member heterocycles in organic and 
pharmaceutical chemistry. They are not only significant as key motifs in many natural 
products, but also as versatile building block for the construction of various complex 
																																																																																
SYNOPSIS	
 
v	
 
molecules. And appear as a subunit in many natural products, agrochemicals, functional 
materials and cosmetics, etc. Precisely, 5-substituted furan-3-carboxylate has been 
recognized as one of the important frameworks due to its occurrence in many bio-active 
natural products. For example, flufuran (33), tournefolin C (34), angelone (35) and 
pukalide class of molecules (36) are some of the representative natural products 
possessing furan-3-carboxylate skeleton embedded in their structures (Figure 2). 
Further, 5-substituted 3-furanoates were also present in valuable intermediates for the 
synthesis of bioactive molecules including pesticides such as pyrethroid resmethrin,  a 
synthetic insecticide (37, Figure 2). 
 
Figure 2: Structures of 5-substituted 3-furanoate molecules. 
Herein we describe the synthesis of 5-substituted furan-3-carboxylates from Morita-
Baylis-Hillman acetates of acetylenic aldehydes is reported. The process involves 
palladium-catalyzed isomerization followed by base-promoted deacetylation and 
																																																																																												
SYNOPSIS	
 
vi	
 
cycloisomerization reactions. The utility of this chemistry is further demonstrated by the 
synthesis of Elliott’s alcohol, a key intermediate of the pyrethroid resmethrins. 
Table 2: Synthesis of 5-substituted 3-furanoates. 
 
Additionally, MBH acetate 64, obtained from the reaction of 3-phenylpropiolaldehyde 
with t-butyl acrylate, was found to be good substrate in providing 5-benzyl t-butyl 
furan-3-carboxylate in 90% yield. Interestingly, MBH acetate 65, derived from methyl 
																																																																																
SYNOPSIS	
 
vii	
 
vinyl ketone, underwent tandem isomerization/deacetylation/cycloisomerization 
reactions to give the corresponding aceto-furanone 68 in 83% yield. Similarly, the 
present protocol was also extended to MBH acetate 66, prepared from cyclohexenone, 
which successfully furnished the tri-substituted furanone 69 in 78% yield (Table 3). 
Table 3: Synthesis of substituted furanones 
 
Encouraged by the above success, we turned our attention to show the applicability of 
the obtained 3-furanoates having ester as a handle for further elaboration towards the 
useful derivatives. In this direction, methyl 5-benzylfuran-3-carboxylate 51, achieved 
from MBH acetate 38, was converted to (5-benzylfuran-3-yl)methanol (70), Elliott’s 
alcohol, by reduction of the ester using DIBAL-H in dichloromethane (Scheme 5). The 
resulting Elliott’s alcohol (70) is a key intermediate for the manufacture of resmethrins, 
pyrethroid insecticides (Figure 2). 
																																																																																												
SYNOPSIS	
 
viii	
 
 
                      Scheme 4 
CHAPTER-IV: Synthesis of furan-fragment of furanocembranoid-1.     
In 2007, Khanitha Pudhom et al. isolated a class of furanocembranoids  47-50 (Figure 3) 
from the hexane extract of croton oblengifolius roxb sp. Furanocembranoids-1 was 
obtained as colorless oil. It showed cytotoxicities againest  BT474 (human breast ductol 
carcinoma), CHAGO (human undifferentiate lung carcinoma), Hep-G2 (human liver 
hepatoblastoma),  KATO-3 (human gastric carcinoma) and SW-6 (human colon adreno 
carcinoma). 
 
																																																																																
SYNOPSIS	
 
ix	
 
Figure 3: Structures of furanocembranoids 71-74. 
The presence of two stereogenic centers and a network of diverse and distributed 
functionalities on its novel framework, together with its potential bioactivity, make 
furanocembranoid-1 (71) a challenging and attractive target molecule for synthetic 
chemists. Strategically, the most challenging problem is the construction of the furan 
ring system as well as the structural moiety possessing the asymmetric centers bearing a 
isopropyl group and trans double bonds. In continuation of our focus on the synthesis of 
bioactive natural products, we herein, developed the synthetic approach toward 
construction of furan-fragment of furanocembranoid-1. 
The retrosynthetic analysis of 71 was outlined in scheme 6. As indicated, our initial 
disconnections of the target molecule involved C2-C3 and C7-C8 double bonds to give  
fragments 76 and 77. In requisite fragment 76, could be accessed from coupling of 
fragments 78, 79 and 80. These three fragments are synthesized from glycolic acid, L-
phenylalanine and 2-methyloxirane respectively. In this, Horner-Wittig, asymmetric 
Aldol and Gilman epoxide opening type reactions are involved as on key steps. On the 
other hand, fragment 77 was synthesized from 2-methylallylalcohol. 
																																																																																												
SYNOPSIS	
 
x	
 
 
Scheme 5: Retrosynthetic analysis of furanocembranoid-1.  
Synthesis of fragment of 78 
The preparation of fragment 78 was accomplished by readily available glycolic acid 81 
with known procedure. As shown in (Scheme 6), the acid group of glycolic acid 
subjected to esterification in presence of CSA and methanol to give ester 82 which was 
further subjected to protection of primary alcohol with tert-butyl dimethyl silylchloride 
in presence of imidazole and dichloromethane result furnish 83 in good yield. Than 
ester was treated with dimethyl methylphosponate in presence of n-butyl lithium to give 
fragment 78.  
																																																																																
SYNOPSIS	
 
xi	
 
 
Scheme 6 
Synthesis of fragment 79 
Synthesis fragment 79 was accomplished by from readily available L-phenylalanine 
with known procedure (Scheme 7). Initially, L-phenylalanine was reduced under iodine 
and NaBH4 in tetrahydrofuran at reflux 12 h to give alcohol and which upon cyclization  
furnished chiral auxiliary 84. The auxiliary  was reacted with isovalaric acid in the 
presence of DCC, DMAP in dichloromethane to give compound 85. The compound 85 
was subjected to chiral aldol reaction in presence of s-trioxane, TiCl4 and DIPEA in 
dichloromethane to give compound 86 in 95% yield. The primary alcohol of compound 
86 was protected with MOMCl in presence of DIPEA and dichloromethane at reflux for 
12 h to furnish compound 87 in 94% yield, Next the auxiliary was removed by 
reduction of compound 87 with lithium borohydride in presence of tetrahydrofuran at 
room temperature for 12 h to offer compound  88 in 92% yield. Finally, the alcohol 
undergoes oxidation with Dess-Martin periodinane in dichloromethane at room 
temperature to provide aldehyde 79 in 98% yield. 
 
																																																																																												
SYNOPSIS	
 
xii	
 
Scheme 7 
Synthesis of fragment 80 
Synthesis of fragment 80 was achieved starting from methyloxirane as shown in scheme 
9, in which the epoxide opening with trimethylsilyl acetylene in presence of n-BuLi and 
tetrahydrofuran at -78 oC to give compound 89 in 86% yield. The secondary alcohol of 
compound 89 was protected with p-Methoxybenzyl trichloroacetamide (synthesized 
from p-Methoxy benzylalcohol treated with trichloroacetonitrile in presence of sodium 
hydride and dichloromethane) in presence of  CSA and dichloromethane  to give 
compound 90 in 74 % yield. Trimethylsilyl removed by potassium carbonate in 
methanol at room temperature to offered fragment 80 in 97% yield. 
O OH TMS OPMB
OPMB
TMS
89 90 91
80
TMS-acetylene
n-BuLi, BF3 Et2O
THF, -20 oC, 6h
86%
PMB-acetamide
CSA
CH2Cl2, rt, 12h
74%
K2CO3, MeOH
rt, 2h, 97%
Scheme 8 
																																																																																
SYNOPSIS	
 
xiii	
 
Synthesis of furan-fragment 76 
Synthesis of main fragment 76 demonstrate in scheme 10. Initially the phosponate 78 
react with aldehyde 79 in presence of barium hydroxide and tetrahydrofuran to offered 
α, β- unsaturated ketone 92 in 87% yield. Next the double bond of compound 92 
reduction with Hexahydrate nickel chloride and sodium borohydride in presence of  
methanol to provide saturated ketone 93 in 98% yield. The ketone of compound 93 was 
treated with terminal alkyne 79 in presence of n-butyl lithium and Tetrahydofuran at -78 
oC to provide compound 94 in 92% yield. Finally deprotection of tert-butyldimethylsilyl 
ether with tert-butyl ammonium fluoride in presence tetrahydrofuran followed by furan 
formation under silver nitrate reaction condition to offered furan-fragment 76 of 
furanocembranoid-1(71) in 94% yield. 
Scheme 9 
Conclusion 
By utilizing the high yielding chemical transformations, we have delineated a 
stereoselective and convergent approach towards the synthesis of furan-fragment 76 of 
furanocembranoid-1 (71).  Initial retrosynthetic analysis on scheme 6 identified three 
																																																																																												
SYNOPSIS	
 
xiv	
 
key segments 78, 79 and 80. The preparation of furan-fragment 76 a perpouse of 
providing an advanced intermediate towards the synthesis of furanocembranoid-1(71) 
by usin alkyne chemistry.  
 
 


DEVELOPMENT OF ALKYNE-ASSISTED APROACHES TO THE

SYNTHESIS OF BENZOFURANS, FURANS AND FURANFRAGMENT

OF FURANOCEMBRANOID-1

BEGUM, ZUBEDA

 
 
                                                          Synopsis 
 
The thesis entitled “Functionalisation of Indoles, Aminoquinolines, Glucal via C-
H activation and a Formal synthesis of (+)-Neopeltolide” is divided into five 
chapters 
 
Chapter I  : This Chapter deals with  the  Pd(OAc)2 catalysed C-H Activation of 
Indoles, A Facile  Synthesis  of   3-Cyano  Indoles.      
Chapter II : This Chapter deals with metal-free remote C-5 oxytosylation of 8-
aminoquinoline amides with koser’s reagent. 
Chapter III : This Chapter deals with the Pd(OAc)2  catalyzed Direct cross coupling 
reaction between the Glycals and Benzoic Acids promoted by PhI(OAc)2 as an 
Oxidant.   
Chapter IV :  This Chapter deals with the development of synthetic method for the 
Aza Ferrier rearrangement of Glycals with amides promoted by molecular iodine. 
Chapter V :  This chapter deals with the introduction, Previous approaches and 
present work wherein a Formal Synthesis of  (+)-Neopeltolide, is described. 
 
Chapter I:  Pd(OAc)2 Catalysed C-H Activation of Indoles, A Facile Synthesis of 
3- Cyanoindoles. 
The indole ring system is the most important heterocycle in nature, owing to the great 
structural diversity of biologically active indoles.
 
The indole ring is found in many 
natural products such as the alkaloids, fungal metabolites and marine natural products.
 
Indoles constitute as a diverse array of biologically significant natural compounds  
which occur in various forms from simple derivatives such as the essential amino acid 
tryptophan to complex alkaloids like antihypertensive compound. Indole is a nitrogen-
containing heterocycle with a central position in organic chemistry and is considered 
to be a “privileged” structure in medicinal chemistry. 
Aryl nitriles are extraordinary important organic compounds  in chemistry as well as 
biology, and they are widely used in the production of pharmaceuticals, agricultural 
chemicals, and fine chemicals. Aryl nitriles also exhibit  an important class of 
compounds in medicinal science. 
In continuation of our interest on the functionalization of indoles , we herein report 
the direct Pd(II)-catalyzed cyanation of indoles through C–H bond activation using 
CuCN (2) as the cyanating agent. We first attempted the cyanation of indole (1) with 
CuCN (2) using 0.1 equiv of Pd(OAc)2 and 0.4 equiv of CuBr2 in DMF resulting 
cyano indoles (3).  
                
N
H
+ CuCN
Pd(OAc)2 (20 mol%)
(CuBr2) (40 mol%)
DMF, 130oC
N
H
CN
1 2 3
70%
 
                                                     (Scheme 1) 
Conclusion: 
In summary, we have developed a novel protocol for the cyanation of indoles at C-3 
position via C–H activation. This method provides an easy access to a wide range of 
potentially valuable 3-cyanoindoles (3) thereby providing the precursors for the 
synthesis of natural products. 
 
Chapter II: Metal Free Remote C-5 Oxytosylation  of 8-Aminoquinoline amides 
                       with KOSER’s  reagent. 
The quinoline skeleton is one of the most important aromatic heterocycles present in 
various natural products and pharmaceuticals. Quinolines can also be employed as 
ligands and directing groups in organic synthesis, as well as fluorescence probes in 
analytical chemistry. Thus, considerable efforts have been directed toward the 
formation and modification of quinoline-based scaffolds. 
The first 8-amino quinolines to be extensively clinically investigated were pamaquine 
and pentaquine. The 8-aminoquinoline primaquine is a key antimalarial drug for both 
Plasmodium falciparum and P. vivax . It is postulated that the efficacy and toxicity of 
8- aminoquinolines, such as primaquine, are ultimately related to the generation of 
reactive oxygen intermediates. 
 
                 
In continuation of our interest in developing new C-H activation methodologies under 
mild conditions and site selective, we attempted a reaction between 
Aminoquinolinamide (4)  and Kosers reagent (5) . Strangely, oxytosylation reaction 
did not occur at the phenyl part of the aromatic acid group but at the C5–H position of 
the quinoline ring in DCM at rt within 15 min resulting the oxytosylated 
product(6).                    
                                         
                                                 
                                                                 (Scheme 2) 
In conclusion, we have established a site-selective C–H oxytosylation approach for 
the construction of a variety of quinoline derived sulfones. The reaction require 
commercially available and inexpensive substrates as the Oxytosylation  agents. More 
importantly, our work complements the research area concerning the functionalization 
of remote C–H bonds. 
Chapter III:  Pd(OAc)2  catalyzed direct cross coupling reaction between the 
glycals and benzoic acids promoted by PhI(OAc)2 as an oxidant.  
Sugar pyranoses are one of the most abundant pyrans that are fully substituted with 
specific chiral centers. Among the many sugar pyranose derivatives, glycals are 
preeminent. Glycals are extremely useful carbohydrate derivates, which are not only 
versatile as glycosyl donors, or as substrates for Ferrier type rearrangements, but find 
extensive application for many other synthetic purposes, particularly as chiral 
building blocks for the synthesis of natural products. Unlike C-1 glycoside 
derivatives, the synthesis of C-2 substituted carbohydrate derivatives is not very 
common. To achieve C-2 carbohydrate derivatives some very well-known reactions 
such as the Suzuki–Miyaura, Wittig and Heck-type reactions have been 
applied.Although it is uncommon, the formation of the C– C bond at C-2 of glucal 
derivatives has synthetic importance and it has played a key role in the synthesis of 
some very interesting and biologically important glycoside derivatives. C2-
functionalized glycals could provide access to a large number of natural products and 
sugar derivatives.  
To the best of our knowledge, there are no reports on the  Palladium Catalysed cross 
coupling reaction of glucal with aromatic acids. In continuation of our interest in 
developing new methods on C-H activation, we herein report a versatile approach for 
a cross coupling reaction between aromatic acids and  glucal. Palladium catalysed 
Cross Coupling reaction(Scheme 3) of glucal (8) with aromatic acid (10) with (0.75 
equiv) of PhI(OAc)2 as oxidant in acetonitrile as solvent furnished the product (9) and 
the product (7) with  (3 equiv) of PhI(OAc)2 is shown as below. 
                                                                           (Scheme 3) 
Conclusion: 
In conclusion, we have reported an efficient and highly regioselective protocol for 
direct acyloxylation and benzoylation  of glucals  at the C-2  position via palladium-
catalyzed C–H activation. This protocol provided a convenient synthesis of C-2 
Functionalised Glucals. 
Chapter  IV:  Aza-Ferrier rearrangement of glycals with amides  promoted by 
                                                   molecular iodine 
Carbohydrates play a crucial role in many biological processes such as cell 
development, cell−cell and cell−viral recognition, cell adhesion, inflammation, the 
immune response, etc., and have become a central theme in glycochemistry and 
glycobiology. Glycals are amongst the most versatile carbohydrate chiral building 
blocks that provide oxygen-rich stereochemically pure scaffolds. One of the most 
important reactions to produce diversity in glycal chemistry is the Ferrier 
rearrangement, which plays a very important role in carbohydrate chemistry. 
Azaglycosylation is an important reaction in the synthesis of N-glycosides, due to the 
increasing importance of nucleosides having N-glycosidic linkages as 
pharmacological agents such as antibiotics, antineoplastic and antiviral compounds. 
Among the N-glycosides, glycols having the double bond between C(2) and C(3) (N-
pseudoglycals), represent a very important class of compounds because the double 
bond may be easily modified.    
In continuation of our interest in developing methodologies with mild conditions, 
inexpensive and readily available reagents or catalysts, we developed a protocol 
where in  a metal-free approach was utilized for the preparation of N-glycosyl amides 
from glucal using molecular iodine. 
We developed a protocol where in sulfonamidoglycosilation was carried out not only 
on the acetylayed glucals but also on benzylated glucals making this as the first report 
of ferrier reaction  with benzyl substituted glycals.   (Scheme 4) 
 
 
 
 
 
 
 
Conclusion: 
In summary, we have demonstrated molecular iodine promoted aza-Ferrier 
rearrangement for the synthesis of 2,3-unsaturated N-pseudoglycals from glycals and 
amides under mild and neutral conditions. This method provides good yields of N-
glycosyl amides/sulfonamides in short reaction time with good α-anomeric selectivity, 
which makes it an attractive process.  
Chapter V:  A Formal Synthesis of  (+)-Neopeltolide from D-Glucal 
Natural products including plants, animals and minerals sometimes exhibit 
pharmacological or biological property that can be of therapeutic benefit in treating 
diseases.As such, natural products are the active components not only of most 
traditional medicines but also of many newer medications. Furthermore, synthetic 
analogs of natural products with improved potency can be prepared and therefore 
natural products are often used as lead compounds for drug discovery.  
Tetrahydropyrans are structural motifs that are abundantly present in a range of 
biologically important marine natural products. Neopeltolide, a potent 
antiproliferative marine natural product, has been an attractive target compound for 
synthetic chemists because of its complex structure comprised of a 14-membered 
macrolactone embedded with a tetrahydropyran ring, an oxazole having an 
unsaturated chain appended through an ester linkage and six stereogenic centers.  
 Neopeltolide (14), a new member of marine macrolide natural products, was 
identified by Wright and co-workers from a deep-water sponge of the family 
Neopeltolide, collected off the north coast of Jamaica. The gross structure including 
the relative configuration was proposed on the basis of extensive 2D-NMR analyses. 
Later, total syntheses by Panek et al. and Scheidt et al. partially reassigned the 
relative configuration and established the absolute configuration.  
 
 
 
                                                                                                                                                                     
                                                        
                                                                 
(+) Neopeltolide (14) 
 
The structure of Neopeltolide resembles with that of Leucascandrolide A, another 
marine macrolide natural product isolated from a calcareous sponge collected along 
the east coast of New Caledonia. Wright reported that Neopeltolide showed potent 
antiproliferative activity against several human cancer cell lines at nanomolar 
concentrations. The Kozmin group has reported that Neopeltolide specifically inhibits 
the complex III of the mitochondrial electron transport chain. Fuwa et al. have 
recently described the apoptosis-inducing activity of a synthetic analogue of 
Neopeltolide in HL-60 human promyelocytic leukemia cells. However, the mode-of-
action of this natural product have not been fully elucidated. The intriguing structure 
and potent biological activities of Neopeltolide have attracted considerable attention 
from the synthetic community, and twenty total and formal syntheses of this natural 
product have been reported so far  Furthermore, several groups have reported the 
structure-activity relationships of Neopeltolide by evaluating the antiproliferative 
activity of synthetic analogues against cancer cells. These efforts have culminated in 
the elucidation of the pharmacophoric structural elements for potent antiproliferative 
activity. 
Retro synthetic analysis: 
The retrosynthetic analysis of Neopeltolide (14)  is depicted in (Scheme 5). The 
synthesis 
                      
                                                           (Scheme 5) 
was envisioned from coupling of  fragments (20) and (19), Fragment(20) and (19) are 
obtained from the tetrahydropyran ketone (18) and tetrahydropyran Ester (17)  
respectively, which in turn  are obtained from Lactol (16) .The Lactol (16) moiety was 
successively achieved from the Tri-O-Acetyl-D-Glucal (15). 
Results and Discussion: 
The synthesis commenced from Tri-O-acetyl-D-Glucal (15) following  the reported 
procedure resulting the compound(AIBN) (21). AIBN(21) compound underwent 
oxymercuration  with Mercury acetate and sodiumborohydride in THF:Water in 9:1 
ratio from  0°C to rt to achieve compound(16).                             
              
 
                                                                    (Scheme 6) 
Synthesis of acid  fragment: 
The synthesis of acid fragment began with the lactol (16) fragment.The lactol 
fragment underwent one pot Intramolecular two carbon  wittig homologation in 
dioxane under reflux at 110
°
C for 12 hours  and insitu OxaMichael addition in the 
presence of K2CO3.  
 
 
                                                               (Scheme 7) 
base furnished the ester compound (22) with 80% yield..Further the ester compound 
(22) is treated with CSA, MeOH  at 0°C for 15min resulting the TBS deprotected 
alcohol(23). Absence of signals corresponding to tert-butyl and dimethyl  groups in 
its 
1
H NMR spectrum confirmed the transformation. The StereoChemistry of the THP 
compound was confirmed with NOE. Further the alcohol (23)was subjected to Parikh-
Doering oxidation at 0°C to the corresponding aldehyde which insitu was treated with 
PPh3=CH2 and n-BuLi in presence of Toluene to give the C-1Wittig Compound(24). 
This Wittig compound is subjected to olefin Metathesis with Styrene using Grubbs 2
nd
 
Generaration Catalyst which furnished the product (25). The Olefin compound was 
subjected to TBDPS deprotection using HF.Py in dry THF which was next subjected 
to BOMCl and DCE under reflux for 12hours resulting the BOM protected 
compound(26). With this compound in hand we subjected this compound to 
LiOH.monohydrate in THF:H2O:MeOH in the ratio of (4:2:2) as solvent for 12hours 
furnished the ACID Fragment (19).  
The product was confirmed by ESI-HRMS and it was further supported by  
comparing the data from the reported literature and all the 
1
H, 
13
C, specific rotation 
values were in full agreement with the literature. 
Synthesis of Alcohol Fragment : 
The synthesis of alcohol compound (20) was initiated with the conversion of lactol 
(16) compound to ketone (27) compound through one pot Two carbon Wittig 
olefination with dimethyl (2-oxopropyl)phosphonate with K2CO3 as base with 
dioxane as solvent 
                                                     (Scheme 8) 
under reflux conditions for 12hours. The keto compound was subjected to 
CSA,MeOH  at 0
°
C for 15min resulting the TBS deprotected alcohol(28). The 
stereochemistry of the THP was confirmed with NOE. The Alcohol compound was 
subjected to iodination with TPP, I2, Pyridine in THF as reflux for 12hours afforded 
the iodo compound (29) with 80% yield.This Iodo compound was in situ subjected to 
activated Zn, MeOH, NaI under reflux conditions for 12hours resulted the olefin 
compound(30).The olefin(30) compound was saturated with Palladium on charcoal 
with dry MeOH as solvent for 12hours resulted the saturated compound(31). The 
saturated compound(31) was O-methylated with Silver Oxide and MeI furnishing the 
compound (32). Next the compound was subjected to one carbon Wittig olefination 
with PPh2=CH2 with NaHMDS as base in Toluene as solvent at rt for 5 hours 
furnished the compound(33). The obtained olefin (33) compound was treated with 
TBAF in dry THF to obtain the alcohol.(20). The 1H, 13C, specific rotation values 
were in full agreement with the Literature. 
The fragments 19 and 20   following the reported procedure  results  the target, the 
core synthesis of Neopeltolide.                                  
           
 
                                                       (Scheme 9) 
Conclusion 
In summary, we described a convergent stereoselective formal synthesis of (+)-
Neopeltolide via Glycal approach. Our route requires total 16 steps from Glucal. 
Oxymercuration, one pot Wittig and oxa Michael addition, Parikh-Doering oxidation, 
and Grubbs Cross metathesis are the key reactions involved. 


FUNCTIONALIZATION OF INDOLES, AMINOQUINOLINES, GLUCAL VIA C-H ACTIVATION AND A FORMAL SYNTHESIS OF (+) – NEOPELTOLIDE

UREDI, DILIPKUMAR

TOTAL SYNTHESIS OF BIOACTIVE MACROLIDES, SEIMATOPOLIDE B & (+)-CLADOSPOLIDE D AND DEVELOPMENT OF NOVEL [4+2]-BENZANNULATION REACTIONS

Reddy, M. Rajashekhar

v 
 
ABSTRACT 
 The study attempted to mimic the state of obesity in vitro using 
3T3-L1 adipocytes, since they represent white adipose tissue which is 
responsible for obesity and related disorders. 3T3-L1 adipocytes were 
exposed to various conditions occurring during obesity in vivo such as (a) 
hyperglycemia (using high glucose), (b) hypoxia (using cobalt chloride 
(CoCl2)) and (c) macrophage infiltration (using RAW 264.7  conditioned 
medium (RCM). The study also attempted to assess the effect of a potential 
anti-adipogenic phytochemical (chlorogenic acid (CGA) - isolated from 
Cichorium intybus) and plant extract (Gymnema sylvestre methanol extract 
(GSM)) for their activity on the above conditions mimicking obesity.   
 A state of 25 mM glucose has been known to induce insulin 
resistance and hypertrophy in 3T3-L1 cells. To probe the role of glucose 
during hyperglycemia in adipocytes, the effect of various concentrations of 
glucose (45 mM, 65 mM, 85 mM and 105 mM glucose) were analyzed on 
3T3-L1 adipocytes. Differentiation of preadipocytes in the presence of 105 
mM glucose (high glucose) exhibited a significant decrease in adipogenesis 
through inhibition of CCAAT/enhancer-binding proteins (C/EBP?), sterol 
regulatory element binding protein 1c (SREBP1c) and peroxisome 
proliferator-activated receptor (PPAR?). Cells in the presence of high glucose 
(105 mM) showed increased cell proliferation through phosphotidyl inositol 3 
kinase (PI3K) / protein kinase B (Akt) dependent pathway. Furthermore, 
inhibition of p27 validated the induction of hyperplasia of activated 
preadipocytes under the state of high glucose. Nitric oxide and reactive 
oxygen species (ROS) production was induced at this condition leading to an 
increase in the expression of toll-like receptor 4 (TLR4), tumor necrosis factor 
vi 
 
? (TNF?) and nuclear factor kappa-light-chain-enhancer of activated B cells 
(NF?B), thereby decreasing adiponectin production. This condition also 
showed insulin resistance through decrease in insulin receptor ? (IR?), 
whereas an increase in glucose uptake was observed through activation of 
glucose transporter 1 (GLUT1). To summarize, 3T3-L1 adipocytes treated 
with 105 mM glucose mimicked the state of hyperplasia during obesity. 
 In this study, hypoxia condition was mimicked by treating 
differentiated adipocytes with 150 µM CoCl2 for 6, 12 and 24 h wherein, 
CoCl2 when treated for 12 h showed maximum expression of HIF1?. In 
comparison to control, cells under the state of hypoxia were found to inhibit 
lipid accumulation via C/EBP?, leading to a decrease in adiponectin levels. 
Although, cytotoxicity was observed in cells treated with CoCl2, the 
expression of ROS was reduced in response to metabolic alteration during 
hypoxia. However, the levels of stress targets such as phosphorylated c-Jun 
N-terminal kinases (pJNK) and NF?B were found to increase. Also, CoCl2 
treatment showed no significant change in GLUT1 levels however, glycogen 
synthesis was found to increase showing signs of hypertrophy. To 
recapitulate, 3T3-L1 adipocytes treated with 150 µM CoCl2 exhibited 
conditions imitating hypoxia during obesity. 
 To mimic the condition of macrophage infiltration in adipocytes 
during obesity, the effect of RCM on differentiated adipocytes was 
investigated for 6, 12 and 24 h. Maximum NO and ROS release along with an 
increase in inflammatory markers such as TNF?, pJNK and phosphorylated 
extracellular regulated kinase (pERK1/2) was observed at 24 h of RCM 
treatment. Further, RCM treatment induced cytotoxicity in adipocytes and the 
increase in lipid content due to significant increase in lipofuscin content 
vii 
 
indicated the state of senescence.  This was validated by an increase in 
senescence markers such as p53, p21, retinoblastoma protein (pRb), p27 and 
cyclin D1. The cells treated with RCM showed an inhibition of insulin 
signalling, since expression of insulin receptor substrate 1(IRS1) and PI3K 
were found to decrease. The study clearly shows that RCM induced 
inflammation and senescence in adipocytes, thereby mimicking the state of 
macrophage infiltration induced senescence. 
 CDK5 is a protein kinase specifically expressed in the adipose 
tissue during obesity and is known to be activated by TNF? and various 
cytokines. Cells differentiated in the presence of 105 mM glucose and 
adipocytes treated with RCM for 24 h increased CDK5 levels significantly in 
comparison to control cells. But differentiated adipocytes when treated with 
150 µM CoCl2 for 12 h showed reduced levels of ROS and TNF? with no 
significant change in CDK5 levels, signifying the role of ROS and TNF? in 
the regulation of CDK5 expression. 
 As obesity is a complex disorder, it would be advisable to use 
treatments possessing multiple effects, thereby minimizing side effects. 
Bioactive molecules have an advantage of optimisation of the dosage for 
consumption. In contrast, the plant extracts are expected to show strong 
potential as activities are exhibited from a mixture of active molecules. Hence 
the study attempts to study the bioactivity exhibited by a CGA and GSM.    
 CGA (100 ng/ml) exhibited significant down regulation of PPAR?, 
C/EBP?, phosphorylated hormone sensitive lipase (pHSL) and CDK5 along 
with an increase in adiponectin level. CGA (100 ng/ml) showed effective 
regulation of targets involved during obesity, and hence was selected for 
understanding its role on the three in vitro conditions mimicking obesity. The 
viii 
 
cells differentiated with 105 mM glucose (hyperplasia model) when treated 
with CGA (100 ng/ml) showed significant decrease in GLUT1 expression and 
induced glycogen synthesis through increase in phosphorylated glycogen 
synthase kinase (pGSK3? - inactive form). CGA also inhibited CDK5 protein 
which was induced during hyperplasia. Treatment of CGA (100 ng/ml) in 
cells induced with hypoxia, showed an inhibition of HIF1?, pJNK and NF?B 
leading to an increase in adiponectin levels. Adipocytes treated with RCM in 
the presence of CGA (100 ng/ml) reduced ROS production and lipofuscin 
levels along with decrease in p53, p21 and pRb levels, showing reversal of 
senescence. The increased expression of CDK5 in RCM treated adipocytes 
was also reduced during CGA treatment. 
 GSM (10 µg/ml) exhibited optimum bioactivity by inhibition of 
adipogenesis through down regulation of PPAR?, SREBP1c and CDK5; 
however, an increase in C/EBP? and adiponectin was observed. GSM also 
inhibited the lipid protecting protein, perilipin with no significant change in 
pHSL levels. GSM was also investigated for its role on the three developed 
conditions mimicking obesity and results from the study clearly showed the 
potential of GSM in alleviating the various targets of obesity.  
 In conclusion, the present study has established in vitro models 
mimicking the conditions of obesity, characterized by hypertrophy/ 
hyperplasia, hypoxia and macrophage infiltration using 3T3-L1 adipocytes. 
The molecular programming involved during these conditions has also been 
elucidated through gene and protein expression studies. The therapeutic 
options for the developed conditions of obesity have been evaluated wherein 
CGA (100 ng/ml) and GSM (10 µg/ml) have been shown to be effective in 
alleviating various cellular targets involved during obesity. 


Cooperative multicatalytic Prins cyclization for the synthesis of octahydrospiro-β-carboline, tetrahydropyranoquinoline and spirotetrahydropyrano morpholine derivatives

Reddy, A. BAL

 | 1  
 
SYNOPSIS  
In sickness and in health: Exploring the evolution of immune response using Drosophila 
melanogaster  
Most organisms are likely to face pathogenic challenge in their life time. The ability to mount an 
immune response has direct consequences on the host’s fitness. Therefore, organisms have 
evolved an elaborate and complex immune response system. While the molecular mechanisms 
underlying immune response have been worked out in relatively great detail, the evolution of 
immune response has received relatively less empirical attention. The aim of my study was to 
understand the evolution of immune response using laboratory populations of Drosophila 
melanogaster. Towards this end, I first quantified the genetic variation in immune response using 
isofemale approach. Then, I successfully selected replicate populations of Drosophila 
melanogaster for increased ability to survive pathogenic infection using experimental 
approaches. I used the selected and control populations to explore the correlation of immune 
response with life-history traits, reproductive activity and resistance to multiple pathogens. I also 
addressed the mechanistic and genetic basis of evolved immune response.  
Various studies have found genetic variation for immunity in populations of Drosophila 
melanogaster. This variation can be maintained due to a number of reasons like varying 
environment that the hosts inhabit, genetic correlation across host traits or due to differences in 
the pathogens. Most of these studies have used chromosome extraction lines or inbred lines to 
assess genetic variation. Using a set of isofemale lines of D.melanogaster, I addressed the 
following questions – a) Is there any genetic variation for immune response, fecundity and 
longevity, b) how are these life-history traits correlated with each other, c) does sexual activity 
have an effect on these traits and d) how do fecundity and immune response change with age. 
For the experiment, I used 18 isofemale lines that were established from flies caught in wild 
from Blue Ridge Mountains, USA. The immune response and fecundity of these lines was 
measured at three different ages. I measured immune response against bacteria Providencia 
stuartii by estimating the bacterial CFUs (Colony forming Units) present in the flies 24 hours 
post-infection. Longevity of un-infected flies was assayed by monitoring mortality in cohorts till 
the death of the last fly. My results indicate that there was a significant genetic variation across 
isofemale lines for immune response, longevity and fecundity. I found a negative correlation of 
 | 2  
 
fecundity with both longevity and immunity. I observed that sexual activity had an effect on life-
span but not on the immune response. I found that age specific changes in immune response 
varied across lines- an evidence for variation in immunosenescence across lines. Therefore, I 
concluded that substantial genetic variation exists in all the three traits and that senescence rates 
are not uniform across lines.  
After this, I established a new laboratory population (Blue Ridge Baseline, BRB) of Drosophila 
melanogaster by mixing the flies from 19 isofemale lines and maintained them in the laboratory 
for ten generations to allow adaptation to laboratory conditions. I then used this newly created 
laboratory population (BRB) along with a long-term laboratory adapted population (LH) and 
inbred population (Canton S) to assess the effect of sexual activity on immune response. I 
subjected these populations to infection from two pathogens (Pseudomonas entomophila and 
Staphylococcus succinus). Previous studies with Drosophila melanogaster show that male’s 
ability to clear bacteria decreases with increase in sexual activity. However, I found that sexual 
activity enhanced male survivorship in a pathogen specific manner. Sexually active males 
showed higher resistance than virgins upon infection with Pseudomonas entomophila. 
Interestingly, the beneficial effects of sexual activity increased with time of co-habitation with 
females and declined when access to females was restricted. I did not observe change in male 
survivorship upon experimentally varying the number of sexual interactions. My results showed 
that the sexual activity-immunity trade-off in males cannot be generalised. The trade-off is 
potentially mediated through complex interactions between the host, pathogen and the 
environment experienced by the host.  
In the next part of my work, I studied the evolution of immunity by using long term 
Experimental Evolution protocol. For the study, I created three selection regimes using the BRB 
populations: – I (Infected with pathogen Pseudomonas entomophila), U (Unhandled Controls) 
and S (Sham Infected). Each selection regime consists of four independent replicate populations. 
I populations are challenged with bacterial infection through septic injury every generation. Flies 
are held for 4 days post infection during which time about 50% of the flies die. The next 
generation is started from the survivors. Flies from S populations are subjected to injury without 
infection while U populations are the unhandled controls. Within ten generations of selection, I 
observed that selected I males and females had higher survivorship post-infection compared to 
 | 3  
 
controls. I have carried on the selection for more than 60 generations. After 45 generations of 
forward selection, I also established a set of reverse selected populations. The forward selected 
and reverse selected populations were maintained separately and were used to address several 
questions:  
1. What is the mechanistic basis of evolved immune response?  
2. Is cost of evolved immune response manifested in other life-history traits?  
3. Is the evolved immune response generic or specific?  
Protection against pathogenic attacks can be achieved by either eliminating the pathogen 
(resistance) or by protecting own system from the pathogenic damage (tolerance). Experimental 
and theoretical evidence suggest that tolerance and resistance have different fitness consequences 
along with variable effect on disease prevalence in the population. Therefore, these mechanisms 
can shape the life-history of populations differentially. In this study, I looked at evolution of 
resistance and tolerance mechanisms in Drosophila melanogaster populations evolved for 
increased ability to survive infection by a gram-negative pathogen Pseudomonas entomophila. 
After 29 generations of selection, I quantified mortality and bacterial load post infection in the 
selected and control populations. I found that males have evolved increased tolerance to 
infections whereas females have evolved increased resistance. To understand the genetic basis of 
the evolved response I also looked at gene expression of humoral genes. I did not find any effect 
of selection on the expression of the genes studied. I conclude that immune mechanisms in the 
same population can evolve in a sex-specific manner which might not be mediated by humoral 
immune response.  
Maintenance and deployment of immune system are costly and are hence predicted to trade-off 
with other resource demanding traits, such as reproduction. However, very few empirical studies 
have investigated this trade-off. I subjected this long standing idea to test using laboratory 
experimental evolution approach. In the present study, three selection regimes: I, S and U were 
used. After 30 generations of selection, a number of life-history traits such as longevity, 
fecundity, egg hatchability or development time were assayed. However, contrary to 
expectations and previous reports, I did not find any evidence of trade-offs between immunity 
and any of the studied life-history related traits. In order to understand the fitness consequences 
 | 4  
 
of evolved immunity, I established two reverse selection regimes where I and S populations were 
returned to U-type of regime. I observed that reverse selected I populations continued to exhibit 
higher post-infection survivorship even after ten generations of relaxed selection. I speculate that 
either evolved immune response has a feeble negative effect on fitness of the selected 
populations or that trade-offs occur with respect to traits like reproductive behaviour or other 
immune mechanisms that I have not investigated in this study.  
All organisms are susceptible to pathogenic attack and most organisms face attack from more 
than one kind of pathogen. It is often observed that immune response against a pathogen affects 
the immune response against another pathogen. Therefore, directional selection of a population 
for better immune response against one pathogen may affect the ability to mount immune 
response against other pathogens. However, direct empirical evidence that validate whether 
evolved immune response against one pathogen would confer protection against other unrelated 
pathogens or not is scanty and inconsistent. For this study, I subjected the populations from the 
three selection regimes – I, S and U to two other pathogens – Providencia retgerii (gram-
negative pathogen) and Staphylococcus succinus (gram-positive pathogen) to address whether 
evolved resistance is general or specific. Interestingly, I found that both males and females of 
selected I populations survived better than controls when challenged with these pathogens. Also, 
I observed that I females clear more bacteria compared to controls. However, even though I 
males showed increased survivorship against both pathogens, I observed a pathogen specific 
response in terms of their ability to clear bacteria. I also quantified mRNA expression of two 
genes from the humoral pathway and did not find any effect of selection. I conclude that evolved 
immune response against pathogen selected for, can result in better immune response against 
multiple pathogens.  
In my thesis I have tried to address some of the long standing questions related to evolutionary 
ecology of immunity. I have used different approaches to understand evolution of immune 
response. From my work, I establish that substantial genetic variation for immune response 
exists in the population which can further be subjected to selection under laboratory conditions. 
This thesis provides the first empirical evidence that immunity can evolve in a sex-specific 
manner. My results indicate that trade-offs between immunity and other life-history traits should 
 | 5  
 
be generalized with caution. Overall, my thesis has important implications in evolution of 
immunity, its trade-offs with other life-history traits and effect of sexual activity on immunity. 
 


STUDIES TOWARDS THE SYNTHESIS OF

BIOACTIVE LACTONES, HELICASCOLIDE A, B, C, (‒)-CLEISTENOLIDE AND ETNANGIEN

Arukula, Ravi

Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  i 
 
SYNOPSIS 
 
The thesis entitled “Conducting polyurethanes and polyureas with 
oligoanilines: Synthesis, characterization and their electrochemical 
applications” has been divided into six chapters.  
 
CHAPTER-I  : Introduction of polyurethanes, conducting polyaniline and 
conducting oligoanilines: application prospects 
CHAPTER-II : Conducting polyurethanes with trianilines and tetraaniline   
CHAPTER-III : Moisture curable polyurethanes with tetraaniline 
CHAPTER-IVA : Electro active hybrid polyurethane with tetraaniline pendant groups 
CHAPTER-IVB : Investigations on anticorrosive, thermal and mechanical properties 
of conducting polyurethanes with pendent tetraaniline groups 
CHAPTER-V : Aniline-nonamer segmented polyurea-electrochemical sensing and 
corrosion evaluation  
CHAPTER-VI       :    Summary and conclusions 
 
 
 
 
 
 
 
 
 
 
 
 
Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  ii 
CHAPTER I: Introduction 
New hybrid conducting polyurethanes: 
The conventionally known polymers, such as polyethylene, polyesters, epoxy 
polymers, polyurethane and PVC are highly processable with good mechanical and 
thermal properties. However these are electrical insulators barring them for 
applications in electrical conducting devices. There have been many attempts in 
literature to bring electrical conductivity to these insulating polymers, so that the 
application prospects of these robust polymers are widened. 
Binary composite systems, comprising of conductive fillers such as carbon 
black (CB), carbon nanotubes (CNTs), or metal powder in the polymer matrix, resulted 
in materials that are tough, flexible, and electrically conductive. These distinctive 
materials are suited for mainly antistatic layers, electromagnetic interference shielding 
(EMI) chemical vapour sensors, and thermal resistors. Three main important 
applications of electrical conducting plastics are (a) antistatic, (b) electrostatic 
dissipation (ESD), and (c) electromagnetic interference shielding (EMI). Antistatic 
applications involve materials that exhibit surface resistivity of 10
12
–10
6
 ohm cm and 
ESD applications involve imparting sufficient conductivity to plastics to reduce their 
surface resistivity to the range 10
6
–10
4 
ohm cm. Usually conductive polymeric 
materials offer conductivity in the range 10
-3
–10
-6
 S
 
cm
-1
, which is also optimum 
conductivity sufficient for the electromagnetic interference shielding (EMI) and ESD 
applications. The conductive polymer composites/blends are useful materials for 
sensors, electrostatic dissipaters, EMI shielding components, shape memory and 
corrosion protection coatings. The chapter-I gives insights into literature of 
polyurethanes and conducting polymers and gives rationale for taking this work which 
formed basis of thesis. 
An attempt has been made to understand the structure-property relationship 
through the extensive characterization of synthesized molecules such as oligomers 
(oligoanilines) and conducting polyurethane materials. The spectroscopic techniques 
such as Fourier transform infrared spectroscopy (FT-IR), 
1
H nuclear magnetic 
resonance spectroscopy (NMR), UV-Vis spectroscopy, mass spectrometry techniques 
such Matrix-assisted laser desorption/ionization (MALDI), X-ray diffraction (XRD) 
etc. have been used to obtain the structural information wherever required. The surface 
Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  iii 
of the samples was analyzed by using X-ray photoelectron spectrometer (XPS) at room 
temperature. Similarly, the microscopic techniques such as optical microscopy (OM), 
field emission scanning electron microscope (FE-SEM), transmission electron 
microscopy (TEM) and atomic force microscope (AFM) have been used for 
morphological evaluation wherever required. The techniques such as the thermo 
gravimetric analysis (TGA) for degradation profile, universal testing machine (UTM) 
for tensile properties and differential light scattering (DSC) for determination of glass 
transition temperature have been used in this study. The mechanical properties have 
been studied by DMTA experiments on the films. Conductivity of the powder/films of 
conducting polymers is measured by four probe method using. The electrochemical 
studies (such as cyclic voltammetry (CV)) for sensing behaviour were performed using 
in a three-electrode electrochemical cell using SCE as the reference electrode and 
platinum wire as the counter electrode. The anti-corrosive studies of the coating films 
have been carried out on selective coating films as per the requirement. Thus an attempt 
has been made to understand the structure property relationship through the extensive 
characterization of synthesized molecules, oligomers and hybrid conducting materials 
developed in this study. 
 
CHAPTER II: Conducting polyurethanes with trianilines and tetraaniline   
This chapter reports a novel conducting polyurethanes (CPUs) containing 
oligoanilines, namely tetraaniline (TAni) (PU-1 to PU-6) or trianiline (TriAni) (PU-7 to 
PU-12), in the backbone of polyurethane and these have been synthesized and 
characterized by formal spectral techniques. The unique properties of these CPUs, viz., 
electronic conductivity and electrochemical activity arising from the presence of 
oligoaniline units have been evaluated. The basic polyurethane backbone is derived 
from toluene diisocyanate (TDI), Isophorone diisocyanate (IPDI) or hexamethylene 
diisocyanate (HMDI), and polypropylene glycols of molecular weight 425 and 2000. In 
the first category of polyurethanes, the prepolymer obtained from the above reactants 
were chain terminated by TAni in emeraldine base. The conductivity of these CPUs 
films ranged from 1.2×10
-5
 to 1.77×10
-3
 S/cm. These polymers showed lower 
conductivity due to the presence of nonconjugated polyurethane segments. The second 
category of CPUs is obtained from prepolymers by chain extension with TriAni. The 
conductivity of these polymers is similar to the TAni analogues but are 
Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  iv 
electrochemically inactive. The anticorrosion properties of two of these polymers have 
also been evaluated in this study. The syntheses of CPUs are shown in Scheme-2.1 and 
Scheme-2.2. 
 
Scheme-2.1 Synthesis of Tetraaniline containing conducting polyurethanes 
All the conducting polyurethanes obtained by Scheme-2.1 and Scheme-2.2 were 
characterized by various spectroscopic techniques. Amine capped tetraaniline and 
trianiline oligomeric units in emeraldine base (EB) oxidation state have been used as 
chain terminator/ or extendor. The PU-TAnis exhibited irreversible two electron 
transfers whereas the PU-trianilines did not show electrochemical activity. The 
conductivity of the films of these new polymers is lower to their oligomeric anlaogues. 
The corrosion protecting ability is more for tetraniline containing polyurethane  
compared to trianiline containing polyurethane.  
 
Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  v 
 
Scheme-2.2 Synthesis of Trianiline containing conducting polyurethanes 
CHAPTER III: Moisture curable polyurethanes with tetraaniline 
In general moisture-curable polyurethanes are widely known for protective and 
decorative coatings in a broad range of application because of their wide range of 
physical properties. The work described in the previous chapter, it was observed that 
the film formation was very slow and the films were brittle. The corrosion protection 
was moderate, not high as expected. The electrochemical properties were not uniform. 
Hence polymers with better improved properties are designed and synthesised in this 
chapter-III. 
This chapter reports preparation of new series of electrochemically active 
conducting polyurethanes (CPU) using tetraaniline as conducting unit with IPDI-
PTMG as urethane prepolymer segment. These films are robust and formed as a 
consequence of moisture curing of excess isocyanate. The films are novel in the sense 
that the conductivity is found to be in the higher side of the order of 10
-3
 S/cm and the 
tetraaniline segments are electrochemically oxidiazable and/or reducible. The formed 
films have been subjected for thermal and mechanical tests such as TGA, DSC, DMTA 
Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  vi 
and tensile tests to explore into the understanding of structure–property relations. The 
nano/microstructure of the polymers has been investigated by TEM analysis. These 
CPUs are found to be excellent anti-corrosion barrier coatings for mild steel. The 
synthesis has been carried out using Scheme-3. The results are presented and discussed 
in this chapter-III.  
 
Scheme-3.1: synthesis of tetraaniline containing moistre curable conducting 
polyurethane  
CHAPTER IV(A): Electro active hybrid polyurethane with tetraaniline pendant 
groups 
To further enlarge applications of conducting polyurethanes, there have been 
attempts to bring conductivity and electrochemical activity to this insulating polymer. 
There is no report available in literature in which tetraaniline is bonded via a –O-
C(=O)-NH- (urethane) bond to give polyurethane.   
Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  vii 
Chapter-III describes, synthesis of a novel hybrid polyurethane from 
tetraaniline-diol (TAni-(OH)2) and hexamethylene diisocyanate (HMDI) with pendant 
tetraaniline units on the back bone. The synthetic procedure shown in Scheme-4A.1 and 
Scheme-4A.2. The striking property of this unprecedented polyurethane is its 
electrochemical sensing of ascorbic acid and self-assembly into core-shell type 
microstructures (microcapsules) in presence of aqueous acetic acid/noctane interface. 
These microcapsules exhibited a wide range of pH responses in their absorption 
spectrum. The synthesized polyurethane containing pendant tetraaniline units showed 
good surface conductivity to the tune of 3.4×10
-4 
S/cm. The electrochemical 
investigation showed two single electron oxidations and two single electron reductions 
reversibly.  
 
Scheme 4A.1 Chemical Synthesis of TAni-(OH)2  
We also investigated electrochemical sensing details of carbon paste electrode 
(CPE) fabricated with conducting polyurethane (TANI-PU) as ascorbic acid sensor 
(vitamin C, AA) in 0.2 M and pH 7 phosphate buffer solution. The fabricated electrode 
is useful in sensing as low as 1 mM of ascorbic acid. Self-assembly property was 
probed by optical and TEM studies which established the core-shell structure of the 
assembled species. The self-assembled microcapsules exhibited pH dependent doping 
and dedoping processes as established by UV-Visible study. The results are presented 
and discussed in thesis chapter-IV(A).   
Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  viii 
 
Scheme 4A.2 Chemical Synthesis of TAni-PU  
CHAPTER-IV(B): Investigations on anticorrosive, thermal and mechanical 
properties of conducting polyurethanes with pendent tetraaniline groups  
This part of the chapter reports synthesis of novel conducting polyurethanes 
synthesized from tetraaniline-diol namely Gly-TAni. In the earlier chapter-IV(A) we 
successfully functionalised the TAni with bis-MPA (2,2-bis(methoxyl) propionic acid 
in two step process namely Bis-TAni and in this part another new diol Gly-TAni is 
synthesised in easy process by using tetraaniline(TAni) and glycidol through SN
2 
 
reaction in single step process. The reparations of Gly-TAni containing conducting 
polyurethanes (GCPU-5%, GCPU-10%, GCPU-12.5% and GCPU-15%) were carried 
out in two step reaction sequence. The synthetic procedure shown in Scheme-4B.1 and 
Scheme-4B.2. The synthesized polyurethane containing pendant tetraaniline units (both 
Gly-PU) showed good surface conductivity to the tune of 5.41 x 10
-3 
to 3.69 x 10
-4 
S/cm. The electrochemical investigation showed two single electron oxidations and two 
single electron reductions reversibly. The anticorrosion properties of these polymers 
have also been evaluated in this study and better corrosion resistance performed by 
Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  ix 
GCPU-15% which is assigned to 1.84 x 10
-3 
mm/yr. The films have been subjected for 
thermal and mechanical tests such as TGA, DSC, DMTA and tensile tests to explore 
into the understanding of structure–property relations. 
 
Scheme-4B.1 Synthesis of Gly-TAni 
 
Scheme 4B.1 Chemical Synthesis of conducting polyurethanes of Gly-TAni 
 
Synopsis 
 
Arukula Ravi, Ph.D. Synopsis  x 
CHAPTER V: Aniline-nonamer segmented polyurea-electrochemical sensing and 
corrosion evaluation 
The previous Chapter-III and Chapter-IV(A) described couple of electroactive 
polymers bearing oligoaniline (tetraaniline) segments, which exhibited high corrosion 
resistance on mild steel (MS) and excellent electrochemical sensing for ascorbic acid 
and self-assembly into core shell type microstructures (microcapsules) in presence of 
aqueous acetic acid/n-octane interface. In this chapter, we synthesized an A-B-A type 
block copolymer polyurea with Tetraaniline dimer (TD) with 1, 4-Phenylenediamine by 
oxidative coupling, resulting in aniline nonamer in the main chain. The corrosive 
protection of EPU for MS, as the main part, was investigated and results are presented 
and discussed below in detail.  
 
Scheme 5 Chemical Synthesis of Electroactive polyurea  
 
CHAPTER-VI:    Summary and conclusions 
This chapter summarizes the important findings of this work and also explains 
the scope of the future perspectives. 


CONDUCTING POLYURETHANES AND POLYUREAS WITH OLIGOANILINES: SYNTHESIS, CHARACTERIZATION AND THEIR ELECTROCHEMICAL APPLICATIONS

Chirke, Sahadev Shrihari

		Abstract

The majority of conventional plastics are produced based on fossil fuels. Conventional plastics are durable and degrade slowly and their incineration releases pollutants, they contribute to environmental problems. In response to the world’s growing awareness about environment and limited fossil fuel resources, intensive research have focused on the production of bioplastics as “green” alternatives to synthetic plastics. Bioplastics such as polyhydroxyalkanoates (PHA) have attracted great interest due to their biodegradable nature. PHA are high molecular weight carbonaceous compounds produced as cellular reserve storage products under excess carbon and nutrient deprived conditions to protect bacteria against starvation. PHA has special physical traits, such as the elasticity, high crystallization rate, high degree of polymerization and can be converted to a wide range of finished products for application in industry, agriculture and medicine. 

One of the major drawbacks for commercialization of PHA production is the high production cost, in which feedstock accounts for 50% of the overall price. Hence, there is a big interest in the use of cheap renewable resources. PHA production from renewable resources and their complete biodegradability make them promising from an environmental point of view. A considerable effort has gone in production of PHA using mixed cultures of microorganisms and cheaply available wastewater. The merits of PHA production with mixed culture include an enhanced economy, a simpler process control, non sterile conditions and an improved use of wastes. Mixed culture utilization can lower the input costs by allowing for large scale fermentations to occur without overhead costs of sterilization. It also allows for a greater variety of substrates to be used due to the presence of several PHA producing organisms. As an alternative to sugars, to attain commercial viability as well as to further improve the sustainability profile of PHA production by fermentation, cheap renewable resources or secondary raw materials must be used instead of expensive carbohydrates such as glucose. Utilization of wastewater as substrate and mixed culture as biocatalyst makes these technologies as sustainable for bioplastics production as well as waste management. Waste/wastewater generally contains good amount of organic matter which can be considered as an ideal commodity to produce bioplastics. 

Various studies have already been conducted in the direction of utilizing wastewater as substrate, but many other organic waste streams are available as well and are currently not valorized. However, there still remain certain limitations to overcome these technologies to become alternatives for the traditional energy production processes. Lower substrate conversion efficiency, enhancement of bioplastics production, production of co-polymer instead of homopolymer is the major concerns which should be addressed prior to the up scaling of bioplastics production. In this context present thesis deals with some of the strategies to reduce the substrate cost, and regulate microbial metabolism towards enhancement of bioplastics production. Mixed culture bioplastics production process was understood by optimizing different critical factors and PHA production was enhanced using Taguchi – DOE methodology. PHA was produced using different types of pure substrates and waste streams with pure and mixed type of bacteria. PHA production was enhanced by employing bioaugmentation strategy and by addition of co-factor (molybdenum). Bioelectrochemical behavior of biocatalyst during PHA production was evaluated using cyclic voltammetry. Microbial diversity analysis was done for mixed culture to know the organisms involved in PHA production process by using molecular biology techniques. Bioplastics production process was integrated with acidogenic fermentation to utilize the acid rich effluents generated during hydrogen production process towards reduce production cost along with additional waste remediation. 




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