Open Access Repository of Indian Theses

REDDY, K. RAGHAVENDER

English

SYNTHESIS OF SUBSTITUTED HETEROCYCLIC RING SYSTEMS β-HYDROXY 1,2,3-TRIAZOLES, PYRROLO [1,2-a]QUINOXALINES,

3,5-DISUBSTITUTED 1,2,4-THIADIAZOLES AND 1,2-

BENZISOXAZOLE BASED HYBRID MOLECULES

CHAKKA, VARAPRASAD

Page | 1  
 
Abstract 
Cell division is a fundamental process required for the propagation of life. It 
takes place either by mitosis (equational genome segregation) or meiosis (reductional 
genome segregation). This study deals with two important players of the genome 
segregation machinery, kinetochore and cohesin, using Saccharomyces cerevisiae as a 
model system.  
Kinetochore is a multiprotein complex required for connecting centromeres to 
the microtubules for the segregation of the chromosomes. Any defect in kinetochore 
assembly results in weak connections between centromere and microtubule, leading to 
the missegregation of chromosomes. In budding yeast, kinetochore is made up of 
around 100 proteins, categorized into eight complexes, which are further categorized 
as inner, central and outer complexes based on their relative position on the centromere-
microtubule interface. Ctf19 supercomplex, one of the central kinetochore complexes, 
is made up of biochemically distinguishable three subcomplexes: COMA, Iml3-Chl4, 
and Ctf3. However, the functional significance of each of these subcomplexes of Ctf19 
supercomplex is not known. In the first objective of this thesis, the main goal is to 
identify the significance of the COMA and the Iml3-Chl4 subcomplexes in meiosis. 
Systematic chromosome segregation analysis and meiotic progression analysis in the 
wild-type and the mutants of the COMA and the Iml3-Chl4 subcomplexes revealed 
their functional significance during meiosis, although they were found to be redundant 
during mitosis. The COMA subcomplex is epistatic to the Iml3-Chl4 subcomplex 
because absence of the COMA subcomplex proteins generates severe defects in 
comparison with iml3Δ or chl4Δ. Interestingly, meiotic progression analysis 
demonstrated that Ctf19 complex mutants arrest transiently during prophase I and 
metaphase I, indicating their importance during these stages of meiosis. Therefore, we 
aimed to observe the role of Ctf19 in executing different events of meiosis I (MI). 
In the second objective of this thesis, effects of absence of Ctf19 in various MI 
specific events were observed. Cell biological and biochemical analysis suggested 
impairment of many MI specific events, such as pairing of homologous chromosomes, 
bi-orientation of homologous chromosomes, mono-orientation of sister kinetochores, 
chiasmata resolution, sister chromatid cohesion and chromosome condensation, in 
absence of Ctf19. 
As the absence of Ctf19 affects meiosis severely than mitosis, we asked the 
question whether the absence of Ctf19 affects the kinetochore organization severely  
Page | 2  
 
during meiosis in comparison with mitosis. In the third objective of this thesis, live cell 
imaging and chromatin immunoprecipitation based experiments suggest that the 
faithful organization of the meiotic kinetochore depends more on Ctf19 in comparison 
with the mitotic kinetochore, as absence of Ctf19 failed to recruit many complexes at 
the centromere during meiosis, but not in mitosis. 
The fourth objective of this thesis deals with the cohesin biology to reveal the 
mechanism of stepwise loss of cohesin during meiosis. Preliminary cell biological 
analysis has been carried out to find out the interdependencies among Sgo1, PP2A and 
Spo13, key protectors of the centromeric cohesin, for their involvement in the 
protection of centromeric cohesin during MI. Our data suggests that Spo13 and 
Sgo1/PP2A act through independent pathways for the protection of centromeric 
cohesin. Although Sgo1 and PP2A have been shown to be involved in the same pathway 
for the protection of centromeric cohesin during meiosis I, sgo1Δ and rts1Δ (PP2A 
mutant) mutants do not show similar quantity of cohesin defect, suggesting that PP2A 
is involved in some but not all the functions of Sgo1 for the protection of centromeric 
cohesin. Additionally, there are several hypotheses regarding the mechanism of 
deprotection of centromeric cohesin during meiosis II (MII). Here, an attempt was made 
to test one such hypothesis, whether increased distance between cohesin (Rec8) and its 
protector (Sgo1) during MII is required for the deprotection of centromeric cohesin. We 
designed FRET-based analysis to observe the proximity between cohesin and its 
protector (Sgo1) during MI and MII, but due to limitations of the FRET approach, it 
failed to provide conclusive information. 
In summary, this work provides significant insight into the essential process of 
life, i.e. cell division. It increases the basic understanding of meiosis, the process 
required for the generation of sperm and egg cells in the human, which has a significant 
impact on human fertility and public health. 
 
 
 
 
 
 


NATURAL 1,4-NAPHTHOQUINONE BASED NEW CHEMICAL ENTITIES: SYNTHESIS, ANTICANCER AND ANTI-INFLAMMATORY ACTIVITIES

MULUKA, Hemalatha

CHAPTER 5  SUMMARY AND CONLUSIONS 
 
118 
 
CHAPTER 5 
 
SUMMARY AND CONCLUSIONS 
A total of 450 bacterial cultures from In-house culture center were screened for nitrilase 
production by employing bromothymol blue (BTB) agar plate method as primary screening 
method and 17 strains were short-listed. Further, these isolates were screened for specific 
nitrilases towards bioconversion of acrylonitrile and iminodiacetonitrile (IDAN) using HPLC 
(high performance liquid chromatography) and UPLC (ultra-performance liquid 
chromatography), respectively and short-listed to 8. Out of 8 isolates, 6 strains were exhibited 
activity towards bioconversion of both the nitriles acrylonitrile and IDAN. Remaining two 
strains (IICT-A38 & IICT-akl387) have shown activity exclusively for bioconversion of 
acrylonitrile.  From both the above methods, it was observed that only 8 strains out of 17 BTB 
plate positives exhibited nitrilase activity. The false positives (9 isolates) obtained in BTB agar 
plate method might be due to other acidic metabolites. From the analysis of above screening 
methods it can be concluded that the direct screening methods like HPLC and UPLC asaays  are 
more reliable than indirect methods like BTB agar plate method because of the probability of 
getting more false positives in BTB agar plate method due to interference of other substances 
along with nitrilase produced by microbes.  Though HPLC and UPLC assays are final 
confirmation to assess nitrilase activity, inconvenient to use for screening of a large number of 
isolates as time consuming and expensive.  
The six strains which were positive for acrylonitrile and IDAN hydrolysis identified up to 
species level by morphological, physiological, biochemical characteristics and 16S rDNA 
sequence analysis. The isolated microorganisms were identified as Alcaligenes faecalis, Bacillus 
subtilis, Lysinibacillus boronitolerans and Bacillus sp. Among these isolates, a new 
microorganism, namely, Lysinibacillus boronitolerans was identified as new additions to the list 
of nitrilase producing microorganisms. Except Alcaligenes faecalis, remaining isolates were 
identified as new addendum to the list of IDAN hydrolyzing microorganisms. However, 4 strains 
were known for hydrolysis of nitriles other than IDAN. IICT-A3, identified as Alcaligenes 
faecalis, was promising with highest conversion rate for acrylonitrile while IICT-akl252 
CHAPTER 5  SUMMARY AND CONLUSIONS 
 
119 
 
(identified as Lysinibacillus boronitolerans) exhibited highest conversion rate for IDAN 
hydrolysis.  Hence, furtehr studies were carried out with these isolates. 
To develop a feasible industrial process, growth medium composition and reaction parameters 
are critical and need to be optimized for higher bioconversion. Thus, we have conducted studies 
towards the optimization of reaction and media parameters that play important role in production 
of acrylic acid and IDA by A. faecalis IICT-A3 and Lysinibacillus boronitolerans akl-252, 
respectively. Both the strains assimilated all the carbon sources tested, however, highest nitrilase 
activity for A. faecalis IICT-A3 was recorded when glucose used as carbon source at a 
concentration of 10 g/L where as in case of L. boronitolerans IICT-akl252 the highest nitrilase 
activity was observed in presence of sucrose at a concentration of 20 g/L. Nitrilases are generally 
inducible in nature; when a panel of inducers was tested acrylonitrile acted as the most suitable 
inducer for A. faecalis culture at 0.1% while highest production of nitrilase achieved with 0.2 % 
IDAN from L. boronitolerans IICT-akl252.  
Further, optimization studies with respect to reaction conditions were conducted including 
different concentrations of substrate, biomass, temperature and pH. The conversion of 
acrylonitrile to acrylic acid was optimum between 3 to 4 mM of acrylonitrile substrate for A. 
faecalis IICT-A3 while highest activity was achieved with 100 mM of IDAN substrate 
concentration with L. boronitolerans IICT-akl252 culture. The optimum pH and temperature for 
the highest nitrilase activity with A. faecalis IICT-A3 were at pH 8 and temperatures of 35°C, 
respectively. In case of L. boronitolerans IICT-akl252 isolate, nitrilase activity was higher at 
30°C while optimum pH recorded at 6.5. Amount of biomass in the reaction mixture also affects 
the degree of bioconversion as well as the reaction rate. The highest nitrilase activity was 
observed when 100 mg of wet cell weight of A. faecalis IICT-A3 was used whereas maximum 
activity attained with 150 mg of wet cell weight of L. boronitolerans IICT-akl252. 
After optimization of medium and reaction conditions the nitrilase activity of both the strains, A. 
faecalis IICT-A3 (8.5U increase) and L. boronitolerans IICT-akl252 (37U increase) was 
significantly improved. These results indicate that, these strains might be suitable candidates for 
production of acrylic acid and IDA at the industrial scale. 
CHAPTER 5  SUMMARY AND CONLUSIONS 
 
120 
 
Thermostability of the nitrilase from A. faecalis IICT-A3 and L. boronitolerans IICT-akl252 
investigated by pre-incubating the reaction mixtures at various temperatures ranging from 10 to 
70°C for 1h.  The nitrilase activity from A. faecalis IICT-A3 was intact up to 60°C while nitrilase 
from L. boronitolerans shown stability up to 50°C for indicating these both enzymes are fairly 
thermostable which is useful in industrial applications.  Both the enzymes exhibited broad 
substrate specificity i.e. for aliphatic, aromatic and heteroaromatic substrates, thus these strains 
further can be extended for bioconversion of other nitriles substrates as well as. 
Further, we aimed to purify the nitrilase from A. faecalis IICT-A3 and to this regard the nitrilase 
specific primers were adopted from the previous that was publised by Lie et al., 2011. Initially, a 
1.1 kb amplicon corresponding nitrilase gene was fished out from genomic DNA of A. faecalis 
IICT-A3 and cloned successfully into pTNOT vector using TA cloning strategy. Further, to 
express the desired gene encoding nitrilase was subcloned into an expression vector 
pET28a(+).The positive transformant containing recombinant plasmid was identified by double 
digestion. The production of enzyme from recombinant cell was achieved by inducing the cells 
at 0.6 OD (600 nm) with IPTG for 3 h. The nitrilase protein containing His-tag was purified 
using Ni-NTA affinity chromatography. The purified enzyme exhibited an apparent molecular 
weight of 44 kDa. This purified nitrilase shares higher similarity with the nitrilase protein of 
Alcaligenes faecalis ZJUTB10. Further studies are required to determine important properties 
like thermostability, substrate specifity, kinetic properties etc. 


STUDIES ON PRODUCTION AND CHARACTERIZATION OF NITRILASE FROM ALCALIGENES FAECALIS IICT-A3 AND LYSINIBACILLUS BORONITOLERANS IICT-AKL-252

Puvvala, Nagarjuna

Abstract 
 
 vi 
 
The present thesis entitled "Molecular Engineering of Soluble Fullerene Derivatives for 
Organic Solar Cell Applications” emphasized on the design, synthesis of new highly soluble 
fullerene derivatives. These fullerene derivatives utilized as electron acceptor molecules for 
OSCs applications. The photophysical and electrochemical properties of these entire fullerene 
derivatives have been investigated by UV-absorption, cyclic voltammetry and the 
photovoltaic performance of all the derivatives were evaluated by fabricating devices with 
different polymer donors. The main objective of the thesis is laid on design and synthesis of 
new fullerene derivatives to increase solubility in common organic solvents and to improve 
PCEs.  
Statement of Problem: In BHJ solar cells the main components are electron donor and 
electron acceptor. Generally, fullerene and its derivatives are widely used as electron 
acceptors in organic photovoltaics (OPVs) because of their high electron affinity, high 
mobility and excellent properties on photoinduced electron transfer. Among them, [6,6]-
phenyl-C61-butyric acid methyl ester (PC61BM) and [6,6]-phenyl-C71-butyric acid methyl 
ester (PC71BM) are widely studied, with a remarkable power conversion efficiencies. 
However, the drawbacks associated with these derivatives like multi-step synthesis, less 
solubility in common organic solvents, low LUMO energy levels, purification difficulty and 
weak absorption in the UV-visible region. To overcome these problems, our research group 
involved in the design and synthesis of highly soluble fullerene derivatives. Similar problem 
are also chosen for present investigation as well as for thesis.  In this thesis, we describes 
different kinds of new fullerene derivative acceptors methanofullerene derivatives, 
diarylmethanofullerene derivatives,  fulleropyrrolidine derivatives which are derived through 
one-pot synthesis. These derivatives have high solubility in common organic solvents like 
chloroform, dichloromethane etc. We have purified the desired compounds with simple 
column chromatography technique with high purity using commercially readily available 
solvents (ethylacetate and hexane) as eluent. The synthesized derivatives have strong 
absorption in the visible region and also have high lying LUMO energy levels which decrease 
the biding energy gap at donor acceptor interface to make easy charge separation which 
results in high PCE in solar cells. The outcomes of all synthesized materials are explained by 
chapter wise in detail.  
 
Abstract 
 
 vii 
 
Methodology(s) used: The molecularly engineered soluble fullerene derivatives were 
synthesized by following different methodology(s). The methanofullerene derivatives and 
diarylmethanofullerene derivatives were synthesized by simple alkylation, Friedel-Craft 
acylation, formation of tosylhydrazine followed by isomerisation and fulleropyrrolidine 
derivatives were synthesized by Prato one-pot synthetic protocol. The hybrid molecule was 
synthesized through o-alkylation, Miyaura borylation reaction, Suzuki coupling then finally 
Prato synthesis. All the synthesized materials were systematically characterised by 
1
H and 
13
C NMR, FT-IR, Mass spectrometry. The absorption spectra of all derivatives recorded with 
UV-visible spectrometer and the HOMO and LUMO energy levels calculated from cyclic 
voltammetry and differential pulse voltammetry. The photovoltaic characteristics of all 
acceptor derivatives explained by fabrication experiments. 
Sample Results with Interpretation: The results are presented in five individual chapters, 
first chapter deals with the introduction to OSCs then 2
nd
, 3
rd
 , 4
th
  and 5
th
  chapter’s describes 
the synthetic work in detail. A brief, chapter-wise account of the results is presented below. 
First chapter is introduction to introduces the basics of solar energy which deals with 
conversion of solar radiation in to electrical energy by using organic based photovoltaic 
materials which established during past three decades. It explains the basic concepts and 
working principle of BHJs. Extensive literature survey has been carried out and major current 
issues relevant to organic photovoltaics and fullerene derivatives as electron acceptors have 
been discussed in detail. It discuss about various parameters which influence the 
photophysical properties, electrochemical properties and photovoltaic characteristics. 
In second chapter, three new fullerene derivative acceptors N3, N4 and N6, derived from 
fluorene have been design and synthesized for the organic photovoltaic applications. The 
molecules N3 (C60-derivative), N4 (C70-derivative) are diarylmethano fullerene derivatives, 
where as N6 contains a chromophore 4-nitro-cyanostilbene (NCS). Their optical, 
electrochemical, and structural properties were systematically studied by 
1
H and 
13
C-NMR, 
UV−visible absorption spectroscopy and cyclic voltammetry. A series of bulk heterojunction 
polymer solar cells was constructed from these newly developed acceptors using PBDTTT-
C-T and PTB7 as electron donors with different donor-to-acceptor weight ratios along with 
the variation in the volume percentage of DIO additive. The best solar cells made from 
PTB7:N3 and PTB7:N6 blends exhibited power conversion efficiencies of 4.1 and 3.6%, and 
Abstract 
 
 viii 
 
the cells made from PBDTTT-C-T:N3 and PBDTTT-C-T:N6 blends exhibited power 
conversion efficiencies of 2.3 and 1.4%, respectively. 
3
rd 
chapter describes new acceptors synthesized at low-cost by using commercially readily 
available aldehydes and amines with high yield which is beneficial to large scale applications 
in organic solar cells. It presents six new soluble fulleropyrrolidine derivatives as electron 
acceptors for bulk heterojunction solar cells bearing general formula R-NCH3-C60. These 
derivatives are synthesised by one step synthetic protocol, where R= Substituted phenyl (di 
trifluoromethyl and di trifluoromethyl methoxy) or heterocyclic compounds (benozofuran, 
benzothiophene, benzopyridyl and benzothiazole). These derivatives are characterised by 
1
H-
NMR, and Mass spectrometry. Here the addition of high electronegative groups or 
heterocyclic atom to the pristine C60 increases the electron accepting nature of fullerene and 
enhanced the efficiency of the photovoltaic device. Their optical and electrochemical 
properties are systematically studied by UV- absorption spectrometry and cyclic 
voltammetry. A series of polymer solar cells have been constructed with these new 
fulleropyrrolidine derivatives using low band gap polymer donor PTB7 at different 
donor:acceptor ratios and achieved high PCE 6-8%. 
Chapter four includes two new methanofullerene acceptors BIT-C60, BIT-C70 derived from 
hexyl bis-thiophene. These molecules are systematically characterised by 
1
H, 
13
C-NMR, 
MALDI-TOF mass spectrometry. It discusses about new fullerene acceptors (BIT-C60, BIT-
C70) how they are important in the field of bulk heterojunction solar cells. The structural 
modification of fullerene acceptors shows dramatic changes in physical and electrochemical 
properties. The optical and electrochemical properties are studied by UV-absorption 
spectroscopy and cyclic voltammetry. We have also study the photovoltaic performance. 
In chapter five, we have design and synthesized new dumbbell kind of fulleropyrrolidine 
hybrid molecule as acceptor which derived from salicylaldehyde and fluorene. The molecule 
was fully characterised by 
1
H, 
13
C-NMR, MALDI-TOF mass spectrometry. The optical and 
electrochemical properties of this hybrid molecule evaluated from UV-absorption and cyclic 
voltammetry. This type of molecules improves the stability and avoids the nano scale 
aggregation at donor acceptor interface which helps to increase the PCE of the solar cells. 
Currently we are studying it photovoltaic properties.  
 


Molecular Engineering of Soluble Fullerene Derivatives

for Organic Solar  Applications

Gauravarapu Navlur, Nikhil

(h) Abstract/Synopsis The objective of work is to develop metal catalyzed reactions or metal
salt promoted reactions to achieve certain functionalized novel
heterocyclic scaffolds of biological importance where the application of
highly efficient simple, practical and environment friendly
methodologies are considered as the main interest. New catalytic
synthetic methods in organic chemistry that satisfy increasingly
stringent environmental constraints are of great demand by the
phannaceutical and chemical industries. In addition, novel catalytic
procedures are necessary to produce the emerging classes of organic
compounds that are becoming the targets of molecular and biomedical
research. This interest in the diverse aspects of the catalysis of organic
reactions for finer applications has been growing worldwide.
A simple and convenient protocol for the synthesis of O·aryloxime
ethers having coumarin nucleus has been explored. The efficient activity
of cupric chloride in promoting the cross coupling reaction of
arylboronic acids and (hydroxyimino)ethylcoumarins at room
temperature in the presence ofNEh as base has been studied in detail.
A series of novel coumarinyl 1,4-bel1zodioxanes, from electronically
diverse 2-[(o-iodophenoxy)methylloxirancs and different positional
lsomers of hydroxycoumarin via one-pot tandem nucleophilic
displacement and copper-mediated intramolecular C-O coupling reaction
using CuI and 1,IO-phenanthroline, has been synthesized. In addition,
the biological importance of the synthesized molecules was illustrated by
testing the in vitro free hydroxyl radical scavenging activity of a selected
set of compounds.
The direct synthesis of novel compounds containing pyrrole substituted
coumann molecules via three component condensation of 3-
bromoacetylcoumarin, acetyl acetone and amine derivatives by utilizing
an inexpensive, efficient, non-toxic and mild Lewis acid catalyst, alum,
m presence of water-PEG 400 binary solvent systems has been
investigated.
Highly efficient and general protocol for the facile synthesis of highly
diversified 1,3,5-trisubstituted pyrazoles and 3,5-disubstituted 2-
isoxazolines through one-pot tandem intermolecular as well as
intramolecular dipolar [3+2] cycloaddition reactions has been
investigated. A Chemoselective oxidation of aldohydrazone to nitrile
imine and a1doximes to nitrile oxides by iodosobenzene in neutral
aqueous media and their scope in regiocontrolled dipolar cycloaddition
with olefin in presence of PhlO toward highly substinlted pyrazole and
isoxazoline derivatives has also been demonstrated.
Finally, synthesis of functionalized 4-oxo-2-(phenylimino)thiazolidin-5-
ylideneacetate derivatives has been explored. Nano-CuFC:!O~ spinel
exhibits strong catal)'1ic activity in facilitating the cascade reaction
involving 1,4-addition and intramolecular electrophilic cyclization in a
perfectly regiocontrolled manner. The dual role of thiocarbonyl moiety
as an electophile and as nuc1eophile within two distinct precursors with
excellent chemoselectivity has also been investigated.


STRATEGIC INVESTIGATION OF BIOELECTRO-FERMENTATION FOR

GENERATION OF BIOENERGY AND TO RECOVER BIOBASED PRODUCTS

REDDY, ANUGU RAGHUNATH

Synopsis 
 
xii 
 
The thesis entitled “Synthetic studies towards bioactives (+)-Asenapine and (-)-
Englerin A” is presented in three chapters. 
General introduction of Ireland-Claisen rearrangement 
In 1972, for first time Ireland-Claisen rearrangement was introduced and since then 
this reaction is widely used in the synthesis of natural products. The starting materials 
can be prepared easily by the coupling an allylic alcohol with carboxylic acid with 
excellent yields, product diastereoselectivity and atom economy.Ireland-Claisen 
rearrangement is a [3, 3]-sigmatropic shift of allylic ester which produce γ, δ-
unsaturated acid. The rearrangement proceeds through chair like transition state. The 
allylic ester when subjected with base in presence of TBSCl initially forms an enolate 
which is stabilized by forming TBS ketene acetal. If there is a substitution at alpha 
positition of allylic ester, it can produce E and Z enolates which are responsible for 
the stereo chemical outcome. The formation of E and Z enolates are controlled by 
changing the reaction conditions.  
 
Statement of problem 
Chapter I: Total synthesis of (+)-Asenapine 
 This chapter describes the total synthesis of (+)-asenapine which is approved by FDA 
in 2009 for the treatment of schizophrenia. Asenapine is a synthetic drug which is 
developed by altering the structure of mianserin. Mianserin is an anti psychoactive 
drug which belongs to tetracyclic antidepressant (TeCA) therapeutic family. 
Asenapine is used for treatment of schizophrenia and acute manic or mixed episodes 
(bipolar disorders). This drug, when administered, enhances the extracellular 
dopamine concentration in the medial prefrontal Cortex (mPFC) and is also found to 
enhance the transmission of NMDA in the mFPC. The total synthesis of asenapine in 
racemic form is reported in the literature. The chemical structure of (±)-asenapine can 
be described as tetracyclic framework, where in N-methylpyrrolidine ring fuses at 3
rd
 
and 4
th
 positions with chlorophenyl, phenyl ether in a trans geometry. Interestingly, 
the (+)-isomer has exhibited better plasma concentration than (-)-isomer. However, 
Synopsis 
 
xiii 
 
based on preclinical data, the FDA has approved the market launch with the racemic 
version. It would be worthy an effort to develop a strategy which enables one to 
synthesise any of the possible four isomers by choosing the appropriate starting 
materials albeit the same synthetic sequence. The synthetic challenges posed by the 
asenapine structure were influencial in taking up its total synthesis.  
Chapter II: Synthesis of Asenapine analogues as neurotrophic agents 
Schizophrenia is a disorder characterized to be both neuro-degenerative and neuro- 
developmental. Research in this area has identified the role of genes in the 
manifestation of this disease from what appears to be a normal childhood. In addition 
to genetic factors, environmental factors play a substantial role in the development of 
neurons. It has been thought that psychotropic drug molecules act through their 
neurotransmitter action. Bodnar et al. have reported that chronic activation of post 
synoptic 5-HTLA receptor may encourage neurite growth in hippocampus and 
regulation of BDNF. As asenapine is a 5-HT eceptor and we envisioned to explore the 
relation between BDNF and 5-HT receptor activity. To determine this some of the 
advanced intermediates, their derivative and asenapine analogues were screened for 
BDNF signaling. 
 
Chapter III: Synthetic efforts towards (-)-Englerin A 
Beutler et al. isolated guanine sesquiterpene from the stem bark of Phyllanthus sp in 
2009, and named them as englerin A (1), englerin B (2) and englerin B acetate (3). 
Englerin A (1) is characterized as a tricyclic (5-6-5) skeleton with ether bridge and it 
has cinnamic acid (C6) and glycolic acid (C9) residue. Englerin B (2) and englerin B 
acetate (3) showed significant loss of potency and selectivity toward renal cancer 
cells. Englerin A (1) has been used as a lead compound for drug discovery, due to its 
significant cytotoxic activity against six human cancer cell lines. It binds to TRPC 
protein tetramers (four cylinders) in a kidney cancer cell membrane. This opens the 
central ion channel, which allows Ca
2+
 into the cell and leads to cell death. Our 
group’s interest in the total synthesis of natural products and the synthesis of 
bioactives of marine origin is the driving force which embarks on the total synthesis 
of Englerin A (1).  
 
 
 
Synopsis 
 
xiv 
 
Methodology used 
Chapter I: The total synthesis of (+)-asenapine 
The retrosynthetic analysis of the (+)-asenapine framework could be obtained from 
synthon (2) through Ullmann coupling, which could be built from (3), which in turn 
could be realised from ester (4) via Ireland-Claisen rearrangement. The intermediate 
(4) could be built from alcohol (5) and 2-bromo phenyl acetic acid (6). Alcohol 
synthon (5) can be accessed from commercially available (S)-ethyl lactate (7) 
(Scheme 1). 
Scheme 1 
The synthetic plan was executed by choosing commercially available (S)-ethyl lactate 
(7), which was protected with TBSCl and reduced to alcohol (8). The alcohol in 
compound (8) was converted to thiotetrazole (9) under Mitsunobu conditions in 92% 
yield. A smooth oxidation of (9) with ammonium molybdate and H2O2 yielded 
sulfone (10) in 87% yield.  
 
 
Scheme 2 
Reagents and conditions: a) TBSCl, imidazole, DCM, 0 
o
C to rt, 2 h, 96%; b) DIBAL-H, DCM, 0 
o
C 
to rt, 4 h, 62%; c) TPP, DIAD, PTSH, THF, 0 
o
C to rt, 3 h, 92%; d) (NH4)6Mo7O24 .4H2O, 30% H2O2, 
EtOH, 0 
o
C to rt, 12 h, 87%; e) 5-chloro-2-methoxy benzaldehyde (11), KHMDS, THF, -78 
o
C, 2 h, 
70%; f) TBAF, THF, 0 
o
C to rt, 6 h, 86%. 
 
The olefination between 2-methoxy-4-chloro benzaldehyde (11) and sulfone (10) was 
accomplished with KHMDS as base to isolate the (E)-styrene derivative (12) in 70% 
yield. The silyl ether in (12) was unmasked to alcohol (5) with TBAF (Scheme 2). 
The Mitsunobu reaction between alcohol (5) and o-bromophenylacetic acid (6) was 
performed in presence of DIAD and PPh3 at 0 
o
C 
 
to yield allyl acetate derivative (4) 
in 83% yield. The anionic Claisen rearrangement
 
was enforced on (4) with LDA, 
Synopsis 
 
xv 
 
TBSCl and HMPA as additive, in THF and subsequent esterification (after CH2N2 
reaction) provided a diastereomeric mixture of esters (3) and epi-(3) (9:1 ratio), in 
85% yield. The additive HMPA is known to stabilize the (Z)-transition state of enolate 
to furnish the anti-product in major ratio which can be separated by column 
chromatography. With The olefinic functionality in (3) was subjected to oxidative 
cleavage under OsO4/ NaIO4 conditions to obtain aldehyde (13) in 75% yield which 
was further reduced with excess of DIBAL-H to diol (14) in 53% yield. The N-
methylpyrrolidine ring was constructed via tosylation followed by treatment with 
aqueous methylamine in acetonitrile to generate the tricyclic core (2) in 57% yield 
over two steps. Demethylation was achieved with BBr3 in CH2Cl2 to provide phenol 
derivative (15) in 83% yield. The oxepine ring was constructed from (15) using 
Cs2CO3 and CuI resulted in (+) asenapine (1) in enantiopure form in 71% yield. 
 
 
Scheme 3 
Reagents and conditions: a) DIAD, PPh3, THF, 0 
o
C, 4 h, 83%; b) i) LDA, TBSCl, HMPA THF, -78 
o
C to rt 12 h; c) CH2N2, Et2O, 0 
o
C 0.5 h, 85%; d) OsO4 (cat), NaIO4, THF/H2O, (3:1), 0 
o
C, 12 h, 75%; 
e) DIBAL-H, CH2Cl2, 0 
o
C to rt, 6 h, 53%; f) i) TsCl, Pyridine, -15 
o
C to -10 °C, 12 h; ii) aq. 40% 
CH3NH2, CH3CN  60 
o
C, 12 h, 57%; g) BBr3, CH2Cl2, -78 
o
C to  0 
o
C to rt, 3 h, 83%; h) Cs2CO3, CuI, 
1,4-dioxane, reflux, 12 h, 71%.  
Conclusion 
In summary, enantiopure (+)-asenapine has been synthesized employing Julia 
olefination and Ireland-Claisen rearrangement as key reactions. The synthesis was 
successfully completed utilizing commercially available (S)-ethyl lactate with 4.6% 
overall yield. 
 
 
Synopsis 
 
xvi 
 
Chapter II: Synthesis of asenapine analogues as neurotrophic agents 
The synthetic plan was executed by choosing commercially available (S)-ethyl lactate 
(7), which was converted to the alcohol derivative (5) in 28.6% overall yield. 2-
bromophenylacetic acid (6) was coupled with chiral alcohol (5) in the presence of 
DCC/DMAP to furnish ester (4a).  
 
                                                                                       Scheme 4 
Reagents and conditions: (a) 2-bromo phenylaceticacid (6), DCC, DMAP, CH2Cl2, 0 
o
C, 4 h, 88%; (b) 
LHMDS, TMSCl, THF, -78 
o
C to rt 12 h, 80%; (c) CH2N2, Et2O, 0 
o
C, 0.5 h, 85%; (d) OsO4 (cat), 
NaIO4, THF/H2O (3:1), 0 
o
C, 12 h; (e) DIBAL-H, CH2Cl2 0 
o
C to rt, 6 h, 51%. 
Enolic ester (4a) was then subjected to sigmatropic rearrangement by using 
LiHMDS/TMSCl for a smooth reaction to give an acid (16b) with an excellent 
diastereoselectivity. The esterification of acid 16b in the presence of CH2N2 afforded 
ester (3b) in 85% yield. Compound (3b) was dihydroxylated by using osmium 
tetroxide and NMO followed by oxidative cleavage using sodium periodate provided 
an aldehyde. The resultant aldehyde was subjected to DIBAL-H reduction to produce 
diol (14a) (Scheme 4). Free acid (16b) was coupled with two bases N-methyl 
piperidine and morpholine under EDC/HOBt conditions to get amide analogues (17) 
and (18) (Scheme 5). In addition to these compounds all advanced intermediates were 
screened for their neurotrophic activity (Figure 1). 
 
                                                                
 
Scheme 5 
 
 
Synopsis 
 
xvii 
 
Figure 1 
Conclusion 
A set fifteen closely related compounds derived from asenapine were synthesized. 
Screening against 5-HT inhibition has been taken up. BDNF inhibitory studies on the 
fifteen compounds indicated that asenapine and intermediate (3) showed comparable 
activity. 
Chapter III: Synthetic efforts towards (-)-Englerin A 
The retrosynthetic analysis of Englerine A (19) is depicted in scheme 6. The ether 
bridge could be accessed from intramolecular epoxide opening of compound (20). 
The tetrasubstituted double bond of compound (20) could be derived from bicyclic 
compound (21) by aldol condensation. Compound (21) could be achieved from 
commercially available (R)-Limonene. 
 
                                                                   Scheme 6 
The synthesis began with (R)-Limonene (22) as a chiral starting material. Thus, 
controlled ozonolysis of (R)-Limonene (22) followed by intromolecular aldol 
condensation of the resultant ketoaldehyde furnished the aldehyde (24). The aldehyde 
Synopsis 
 
xviii 
 
(24) on treating with 4-bromobut-1-ene yielded alcohol (25) which was oxidized with 
Dess-Martin periodinane (DMP) to give ketone (26). The formation of bicyclic enone 
was mediated by RCM reaction using Grubbs 2
nd
 generation catalyst which was 
further subjected to admix-β yielded diol (27). This diol (27) was protected with 2,2-
DMP to furnish compound (28). The selective hydrogenation of the compound (28) 
with 10% palladium over charcoal as a catalyst in ethyl acetate furnished the saturated 
bycyclic enone (21) in 80% yield. The relative stereochemistry of compound (21) was 
established by NOESY correlations. The aldol condensation between bicyclic 
compound (21) and acetone in the presence of LDA and ZnCl2 in THF at -78 
o
C 
afforded bicyclic alcohol (30). Dehydration of alcohol (30) with Burgess reagent 
(MeO2CN-SO2NEt3) gave alkene (31) in 95% yield. The migration of double bond 
was observed using K2CO3 in methanol under reflux condition to produce conjugated 
enone (20). Epoxidation of (20) with hydrogen peroxide gave compound (32). 
Unfortunately regioselective opening of epoxide (32) to give (38) was not successful; 
however formation of (33) was observed (Scheme 7).Deprotection of (20) with p-
methyl sulphonic acid produced diol which on epoxidation with hydrogen peroxide 
gave compound (35) in 85% yield. Secondary alcohol (35) was coupled with acid 
chloride (36) in the presence of pyridine to furnish ester (37) in 86% yield. The 
etherification of compound (37) in presence of Lewis acid gave tricyclic alchohol (39) 
(Scheme 8).  
      
 
Scheme 7 
Reagents and conditions: (a) O3, MeOH, -78 
o
C, 86%; (b) AcOH, piperidine, benzene, reflux, 85%; 
(c) Li, 4-bromobut-1-ene, THF, 0 
o
C 1 h, 71%; (d)  IBX, DMSO, rt, 3 h, 85%; (e) Ti(OiPr)4, Grubbs' 
catalyst (II), CH2Cl2; reflux, 3 h 79% (f) Admix-β, tBuOH/H2O, 24 h, 73% (g) 2,2-DMP, CH2Cl2, rt, 4 
Synopsis 
 
xix 
 
h, 97% (h) Pd-C/H2, EtOAc, 4 h, 81% (i)  LDA, ZnCl2, acetone, -78 
o
C, 4 h, 85% (j) Burgess reagent, 
PhCH3, 110 
o
C, 1 h, 95% (k) K2CO3, MeOH, reflux, 6 h, 95% (l) 30% H2O2, 10% NaOH, CH3OH  0 
o
C 
to r.t 6 h, 72% (m) In(OTf)3, CH3CN, H2O (20:1), 80 
o
C,  4 h, 63%.  
 
 
Scheme 8 
Reagents and conditions: a) pTSA, MeOH, rt, 12  h, 92%; (b) 30% H2O2, MeOH, 0 °C to rt, 6 h 85% 
(c) 11, pyridine, 0 °C to rt 1 h, 86% (d) InCl3, CHCl3, reflux, 4 h, 60%. 
Conclusion 
In conclusion enantioselective synthesis of fully functionalized tricyclic skeleton of (-
)-Englerin A is completed. 
 


SYNTHETIC STUDIES TOWARDS BIOACTIVES: (+)-ASENAPINE AND (-)-ENGLERIN A

Reddy, L Hanuma

  
 
     
         
        
  
      
         
         
     
  
    
     
    
       
        
     
  
   
        
      
        
      
 
        
         
        
      
ABSTRACT
Salinity and drought are the two major environmental constraints that
affect plant growth and in turn crop productivity, a problem that has been
increased by improper land usage and irrigation practices. Thorough
understanding of the salt tolerance adaptations of plants in terms of biochemical
and molecular levels can provide tremendous knowledge about their tolerance
strategies. Salinity stress in plants induces the formation of reactive oxygen
species (ROS) and plants have formulated an array of ROS scavenging system
(enzymatic and nonenzymatic antioxidants) to mitigate the cellular components
from oxidative burst. 
Mangroves are intertidal plants inhabiting the coastal zones of tropical
and subtropical regions and possess unique characteristics of tolerating high-
salinity of seawater and also tidal currents. Recent progresses in understanding
the physiological mechanism of salinity adaptation in mangroves on molecular
level indicate that the phenomenon is indeed tightly linked to the regulation of 
gene expression. Recent studies on salinity tolerance in mangroves like
Avicennia marina, Aegiceras corniculatum, Bruguiera gymnorrhiza, Bruguiera
cylindrica, Ceriops tagal, Acanthus species have identified number of 
differentially expressed stress regulated genes. Rhizophora apiculata Blume. is
a highly salt tolerant mangrove species inhabiting the coastal belts of Kerala.
The present work proposes to examine the ROS cycle and also gene
expression in Rhizophora apiculata in response to NaCl stress by suppression
subtractive hybridization and gene cloning analysis.
Salt stress was imposed on R. apiculata seedlings with five different
concentrations of NaCl (0, 100, 200, 300, 400 and 500 mM) and also with time
slots such as 3, 6, 12 and 24 h durations. NaCl induced remarkable changes in
total protein levels and is visualized with protein banding by SDS-PAGE. NaCl
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stress induced the profile of superoxide anion and hydrogen peroxide content.
Further, the activities of NADPH oxidase, superoxide dismutase (SOD),
catalase (CAT) and peroxidae (GPOX) showed varied levels of expression with
concentrations and durations. Different isoenzyme of SOD, CAT and GPOX
were detected with the NaCl treatment. Enhancement in antioxidant enzyme
activities could be an induced response against cellular damage due to NaCl
stress. Significant ascorbate-glutathione cycle (in terms of activities of 
ascorbate peroxidase (APX), regenerating enzymes and isozymes of APX)
supports the efficiency of the mangrove to detoxify the ROS hydrogen peroxide
from cells. Ascorbate, reduced glutathione and α-tocopherol increase the
capacity of the species to neutralize the toxic effects of NaCl stress.
The molecular part includes Subtractive hybridization using PCR Select
TM Subtraction kit (Clontech, CA, USA). Several stress genes were isolated,
which were then classified to nine functional categories viz., Metabolism,
Protein degradation and folding, Secondary metabolism, Cell rescue and
defense, Transport facilitation, Signal transduction, Transcription and
translation, Photosynthesis and Unclassified genes of unknown function. The
expression patterns of twelve of the genes thus obtained were studied at 6 h,
12 h and 24 h time points of salinity stress using Real time PCR. Most genes
were found to be upregulated under salt stress and showed maximum
upregulation at the 6 h time point. Two of the genes studied were down
regulated after 6 h, implying that the pattern of gene expression varies with time
of application of stress.
The most important gene identified by SSH and upregulated in Real time
RT PCR is Cytochrome P450 monooxygenase (S)-N-methylcoclaurine 3′-
hydrolase (CYP80B3), which acts in the hydroxylation of (S)-N-
Methylcoclaurine to yield (S)-3'-Hydroxy-N-methylcoclaurine.The full length
gene (1.5 Kb) was isolated and its expression in planta was attempted. The
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promoter sequence of the gene was also isolated by genome walking approach.
The size of the amplified product was ~0.5Kb. Several domains were identified
in the promoter region such as CAAT box, TATA box, Myb Binding Site (MBS)
etc.
Another gene that was highly upregulated in the real time PCR analysis
was that of Hevamine A precursor.The gene (1.1Kb) was isolated, cloned into a
binary vector, pMDC 139 and expressed in onion epidermal cells. Syringe
infiltration of the binary vector construct into onion peels showed blue colour
due to gus activity.
The present results suggest that the synergistic effect of different ROS-
scavenging enzymes and compounds effectively improve the biochemical
caliber of plants, thereby reducing the degree of oxidative injuries. Similarly, the
genes and the gene elements thus isolated may be used to confer the trait of 
salt tolerance to non – tolerant genotypes, which can ultimately prove beneficial
for crop improvement programmes.
Key words: Antioxidant enzymes, Mangrove, NaCl, Oxidative stress, Reactive
oxygen species, Rhizophora apiculata, Salinity, Stress genes
xi


Microwave-assisted solution combustion synthesis and characterization of ceria-based oxides for CO oxidation

REDDY AREKUTI, MAHESWARA

SYNTESIS OF CRYPTOPYRANMOSCATONES A2, A3, B4, CRYPTOCONCATONE H AND TETRAHYDROPYRAN RING CONTAINING MACROLACTIN

REDDY, CHADA NARSIHMA

viii 
 
Abstract 
With the advances in electronics, a large number of electronic appliances and 
applications are developed for field applications, power sources for such applications has been 
of much interest now a days. Batteries are routinely used as power sources, but they have the 
serious drawback of limited recharge cycles. Solar power along with battery is used now a day 
for powering field applications. But here also the problem of battery exists. Here we examine 
the use of fuel cell as a sustainable power source for powering field deployed electronic 
applications.  
Micro-SOFC model was created using COMSOL Multiphysics® with hydrogen anode 
fuel. The O2- ion transport properties were modelled and the model was validated with the 
experimentally reported data. Post validation, this model was employed to model the effects 
of hydrocarbon anode fuels on the O2- ion transport properties. It was remarked that the 
transport is hampered due to the formation of GIIB at the EEI because of CO2 being a by-
product in the electrochemical reaction taking place in the reaction sites present in the EEI as 
we change to low H: C ratio anode fuels. 
Nanopowdered rice husk based nano-gasifier cum catalytic reformer has been 
proposed to function as a solid organic / biomass anode fuel substitute to be utilized in portable 
devices with μ-SOFC which will work as a self-sustainable uninterruptable power source. It 
is noted from the TG/DTA analysis that, nanopowdered rice husk is more efficient combusted 
than the raw rice husk since the surface to volume ratio gets increased, likewise it is 
understood that it is compact and uses up less space. On gasification of the nanopowdered rice 
husk, it produced syngas, which mainly constituted CO2 and could create performance issues 
with the μ-SOFC. Inorder to avoid such fatal situations, a Nano catalytic reformer is being 
utilized in conjunction with the nano-gasifier which breakdowns CO2 to CO. 
ix 
 
A scheme for in-vivo power generation has been proposed for powering various body 
implants using waste body fluids based on nano biofuel cell. These waste fluids constitute 
waste glucose, which is decomposed to high H:C ratio alcohols using bioenzymes. These 
alcohols serve as the anode fuel for the nano biofuel cell. Further, this whole power generation 
system is enclosed in a biocompatible packaging material. This material was examined for 
both Hemolysis and Cytotoxicity which confirmed it to be biocompatible as per the FDA limit. 
Ultra-portable μ-SOFC testing setup was fabricated using machined graphite as the 
high temperature chamber. Novel design was used to machine this graphite chamber. It has 
embedded microheater to raise its temperature from 1000˚C which is needed for the operation 
of a μ-SOFC. Both the anode and cathode fuels are fed using portable canisters to benchmark 
the performance of the μ-SOFC. It was observed that the μ-SOFC (ASC-2.0) had poor 
performance for syngas anode fuel because of the CO2 presence resulting in the formation of 
GIIB. Biomethane, methane and propane anode fuels also showed the GIIB impact, but not 
so much significant as when syngas anode fuel was fed. 
 
  


PHENACYLAZIDE: A VERSATILE INTERMEDIATE FOR THE SYNTHESIS OF IMIDAZO[1,2-a]PYRIDINES, PYRROLO[1,2-a]IMIDAZOLES, β-ENAMINOES, PYRROLIDIN-2-ONES AND AMIDES; DIASTEREOSELECTIVE SYNTHESIS OF SPIRO[CYCLOPROPANE-1,3’-INDOLIN]-2’-ONES AS POTENTIAL ANTICANCER AGENTS

RASALA, MAHESH

Synthesis and anticancer potential of combretastatin sulfonamide/sulfonates, quinazolinone derivatives and green synthesis of spirooxindole, pyrazolo-pyrimidine derivatives

Not a member yet

SYNTHESIS OF SUBSTITUTED HETEROCYCLIC RING SYSTEMS β-HYDROXY 1,2,3-TRIAZOLES, PYRROLO [1,2-a]QUINOXALINES, 3,5-DISUBSTITUTED 1,2,4-THIADIAZOLES AND 1,2- BENZISOXAZOLE BASED HYBRID MOLECULES