Open Access Repository of Indian Theses

SHUKLA, PARSHURAM GAJANAN

PREFACE 
 
Study of atmospheric Aerosols is a vital problem in current environmental 
research due to its importance in atmospheric optics, energetics, radiative transfer 
studies, chemistry, climate, biology and public health. Aerosols can influence the 
energy balance of the terrestrial atmosphere, the hydrological cycle, atmospheric 
dynamics and monsoon circulations. Because of the heterogeneous aerosol field with 
large spatial and temporal variability and reduction in uncertainties in aerosol 
quantification is a challenging task in atmospheric sciences. Keeping this in view the 
present study aims to assess the impact of aerosols on coastal Indian station 
Visakhapatnam and the adjoining Bay of Bengal.  
 
In chapter I, brief introduction on the atmospheric aerosols and their 
importance in climate change studies was given with a logical conclusion on the 
scope of the research work incorporated in the thesis. Chapter II deals with the 
experimental techniques involved in the study. The equipment include 
MICROTOPS-II sun photometer, Multi Wavelength Radiometer to derive Aerosol 
Optical Depth, Quartz Crystal Microbalance for the measurements of size segregated 
near surface mass concentrations, Aethelometer for the  measurement of Black 
Carbon aerosols and Nephelometer for scattering coefficients at three wavelengths. 
The design of instruments, principle of working, and error estimation are described 
in detail. The methods used to determine various parameters that characterise the 
optical /physical properties of Aerosols, and the models utilized are explained 
briefly.  
 
Chapter III describes extensive study of aerosol intensive properties over 
Visakhapatnam. This presents for the first time results on seasonal variation in 
aerosol Single Scattering Albedo with the data for a period of one year. The inferred 
aerosol single scattering albedo was in the range of 0.7 and 0.9 showing a distinct 
seasonal variation. Relative variation of column and surface angstrom size index 
derived respectively from aerosol optical depth spectra and surface measurements 
with the SSA indicate that the in-situ measured SSA is applicable to column 
integrated estimation during winter and monsoon months while such applicability is 
limited during summer months due to the possibility of aerosol transport.  The 
measurements also indicate little variation in SSA during sunlit hours of all the 
seasons. The asymmetry parameter which represents the angular scattering in 
radiative forcing estimation is found to be around 0.65±0.1 for the location. The 
results are discussed in light of the aerosol physical and optical properties and the 
asymmetry parameter.   
In chapter IV, Advection induced short period anomalies and seasonal 
features in Aerosol Optical Depth over Bay of Bengal in the W- ICARB Region are 
presented with a statistical assessment of the regional short term perturbations in 
AOD over Bay of Bengal for the entire season. Seasonal features in AOD using 
MODIS level 3 data for the period of six years (2005-2010) are presented. Though 
several reports are available on the features of Aerosol Optical Depth (AOD) over 
BoB region based on cruise as well as satellite data, the day to day variability over 
the oceanic regions due to day to day variability at the aerosol source regions and 
advection pathways is yet incomplete.   The results indicate that the day to day 
variability in AOD could possibly be reflected as spatial variation when short period 
cruise measurements are made.  A statistical analysis of the short period variations 
using W-ICARB cruise data and the MODIS satellite data for the whole  winter 
2008-09 show that in 65% of the case,  the airmass pathways have the potential of 
inducing large day to day variability in AOD with  79 % of the cases over eastern 
BoB affected by east Asian airmass, 98% of the cases over western BoB affected by 
airmass pathways from the Indian region, while the western BoB is mostly affected 
by the east Asian aerosol transport, which is significant in altering the mean AOD 
features over the regions. Steady increase in AOD over the western BoB during 
2005 to 2010 is observed, while it is more or less stable over southern BoB.   
In Chapter V, the diurnal variation aerosol backscatter intensity profiles 
during typical days during winter, summer and monsoon are used to derive the 
vertical aerosol distribution in terms of scaling altitudes.   This information with 
simultaneous data on Aerosol Optical Depth (AOD) and surface mass concentrations 
are analyzed and discussed in light of mesoscale processes and advection.  The 
characteristics of the near surface aerosols are well in accordance with the mesoscale 
processes, but a possible advection of aerosols was suspected at higher altitudes 
while examining Lidar profiles.  For winter, the advection pathways are computed 
using HYSPLIT forward trajectory analysis and discussed. In the current study we 
also had an opportunity to examine a closure on aerosol characteristics with different 
measurements during the study period.  The correlation between columnar and 
surface fine mode aerosol fraction was also examined in view of column-surface 
coupling.   
Study comprises the results from the seasonal variation in the aerosol 
intensive properties using in situ measurements and vertical distribution using 
LIDAR measurements over a coastal urban location and day to day variations over 
supposed clean maritime environment which are exceptionally sparse. With 
measurements on aerosol optical properties this study reports that the mean SSA is 
about 0.79 indicating a marginal atmospheric warming over the study location 
Visakhapatnam.  The asymmetry parameter was found to be 0.65 compared to the 
value 0.7 used widely over the globe in climate modelling estimations. Even though 
the experimental campaigns over the oceanic regions using cruise based 
measurements fill the voids in aerosol data over the study regions and over oceans, 
given the extent of the anthropogenic influence on the clean maritime environment it 
is important to characterize the aerosol fields over oceans for climatic studies.  It is 
observed with cruise data and satellite data that short term variations in AOD, 
induced by seasonally varying advection pathways over Bay of Bengal adjacent to 
the Visakhapatnam contribute to significant deviations in AOD which cautions and 
suggests the requirement of long term campaigns over marine environment to reduce 
the uncertainties. Hence the study emphasizing the seasonal characterization of 
aerosol bulk and intensive properties over eastern peninsular Indian location and 
advection over adjoining Bay of Bengal could be considered important and can 
contribute to the field of atmospheric studies.  While column integrated aerosol 
properties give a general idea on aerosol environment, it is important to characterize 
the aerosol vertical distribution for maintaining accuracies in aerosol radiative 
transfer calculations.  Also the current study with aerosol vertical profiling   
provided information on aerosol scale heights and advection altitudes which are 
important in aerosol characterization.    
 
 
 
 
 
 
 
 


English

STUDIES IN ENCAPSULATION WITH STARCH DERIVATIVES

VYAS, PRANAV R.

STUDIES ON CHITINOLYTIC ENZYMES

S., PRASAD

Undetermined

STUDIES ON ALUMINOSILICATE AND ALUMINOPHOSPHATE MOLECULAR

SHARMA, ARCHANA

Abstract
Fine Particulate Characterization and Source Apportionment
Increasing ambient levels of fine particles due to anthropogenic activities are leading to adverse effects on human health and climate change.  Indian subcontinent has witnessed high levels of air emission and its increasing concern. Air quality management in India is being studied with more rigor, in recent times 
due to immense pressure from public to clean the ambient air. India has also progressed in understanding TSP and PM10 sources but the amount of information available on fine particulate pollution in India is very limited. 

The ‘Auto Fuel Policy Report’ submitted to the Government of India by the ‘Committee’ in 2002, identified many gaps in available knowledge about the sources and recommended a need to carry out “Source Apportionment”. The present research is an attempt to address this issue with a view to fill the scientific gap. 

In the present study, outdoor and indoor fine particles were measured at four locations in Mumbai city, India, during 2007-2008. The fine particles were measured using a MiniVol PM2.5 Sampler. After gravimetric measurement, ions, elements, elemental carbon and organic carbon and organic markers were analyzed. The present research tried to assess air quality status for different land use patterns but the research shows that sites, though associated with particular zone are in a broader sense mixed zones. Reconstruction of mass of PM2.5 in Mumbai city indicate highest contribution from organic matter (36-52%) followed by secondary inorganic aerosols (21-27%). Contribution by crustal (6-12%), noncrustal (4-8%) and sea salt (6-11%) were low as compared to organic matter and SIA. 

The sources to fine particles in Mumbai were quantified using receptor technique like ‘Chemical Mass Balance’ (CMB) modeling and ‘Principal Component Analysis’. The source apportionment was attempted using source profiles developed in India and organic marker source profiles from Asia and the United States. Multiple sources identified were estimated for Mumbai city. The factor analysis helped to 
improve the understanding of fine aerosol qualitatively but not quantitatively. Chemical Mass Balance model using local source profiles and organic marker indicated vehicles, biomass burning and secondary inorganic aerosol as major sources.

 The source contribution estimated using CMB with Indian profiles were road dust- 8-18%, biomass- 10-22%, diesel- 8-35%, gasoline- 8%, Secondary Inorganic Aerosol (SIA)- 7-32% and marine- 10-17% in the city. Other site specific sources identified were industry- 10%, Liquid Petroleum Gas (LPG)- 14-18%, 3 Wheeler Compressed Natural Gas (CNG)- 20% and kerosene, coal and wood- 2-4%. On the other hand CMB using organic marker shows road dust- 4-20%, biomass burning- 6-24%,  diesel- 17-28%, gasoline- 7-12% and SIA 11-28%. Both the techniques showed that fossil fuel contribution dominates over biomass combustion. Secondary inorganic aerosol contribution by both techniques agreed well.

The research was mainly focused on source apportionment outdoors; though, a brief study to understand indoor air quality was also attempted. The contribution of outdoor particles to indoors is estimated using the Random Component Superposition Model (RCS). The model results indicate that indoor fine particles are derived from outdoor by 3, 79, 43 and 16% at Control (C), Kerb (K), Residential (R) and Industrial (I) respectively. It shows that maximum particles are derived from indoor sources itself at C and I, whereas at K and R, outdoor sources contribute to indoor.
The present study on PM2.5 characterization and source apportionment for four different land use patterns attempt to improve spatial understanding of sources in Mumbai city. The present study aims to improve the scientific understanding of aerosols in Mumbai city.



MODELLING BIOLOGICAL SYSTEMS: A FRACTAL APPROACH

PATHAN, NUZHAT

Abstract


HETEROGENEOUS CATALYSTS FOR ORGANIC TRANSFORMATIONS
This thesis mainly deals with the synthesis and applications of heterogeneous catalysts for various organic transformations. Heterogeneous catalysis for the synthesis of fine chemicals is particularly attractive as it allows production and ready separation of large quantities of products with the use of a small amount of catalyst. Majority of the reported supports for catalytic applications are based on pure inorganic materials or functional polymers in which the synthesis of the supports involves either high temperature calcinations or polymerization of petrochemical feed stocks. In recent years, the emphasis of science and technology is shifting more towards environmentally friendly and sustainable resources and processes, in this regard biopolymers are attractive candidates to explore for supported catalysis.
Chapter I highlights the importance of heterogeneous catalysis and various options for the synthesis of heterogeneous catalysts. An overview about polymer supported catalysts is also configured. The need and development of "cleaner" and "greener" alternative technologies using especially cellulose as a support for the preparation of fine chemicals and pharmaceuticals is also discussed in this chapter. Chapter II mainly deals with preparation and characterization of cellulose supported copper(0) catalyst and its application for the N-arylation of nitrogen heterocycles with aryl halides and arylboronic acids. Chapter III presents the efficacy of cellulose supported copper(0) catalyst for the aza-Michael addition of unsaturated compounds to amines and imidazoles. Chapter IV details the preparation and characterization of cellulose supported palladium(0) catalyst and its application for the  C-C coupling reactions such as Heck and Sonogashira coupling reactions. Chapter V details an efficient and eco-friendly process for the nitration of o-xylene with high regio-selectivity in liquid phase using beta zeolite as a catalyst.
CHAPTER I  
INTRODUCTION                                                                                                
This chapter describes the various catalyst/process options available for an industrial chemist to effect different organic transformations. It includes a brief introduction of homogeneous, heterogeneous catalytic systems and basic concept commonly encountered in catalysis such as selectivity, turnover number, atom economy etc. A brief discussion of polymer supported catalysts and the advantages in using polymer supported catalysts is discussed. A detailed discussion about cellulose is also described. The importance of selective organic transformations and the need for the design and development of environmentally cleaner catalytic methodologies is also highlighted. The origin of zeolites, properties of zeolites and their application in catalysis was described. 
CHAPTER II
 Synthesis and Characterization of Cellulose Supported Copper(0) Catalyst and its Application for N-Arylation of Nitrogen Heterocycles
This chapter is divided into two sections.
Section I deals with preparation and characterization of cellulose supported Cu(0) catalyst [CELL-Cu(0)] 
Section II deals with the application of CELL-Cu(0) catalyst for N-arylation reactions.
Section II is divided into two topics:
 Topic I deals with CELL-Cu(0) catalyzed  for the  N-arylation of imidazole with aryl boronic acids.
Topic II deals with CELL-Cu(0) catalyzed N-arylation of nitrogen heterocycles with    
aryl halides.
Section I 
Preparation and Characterization of Cellulose Supported Copper(0) Catalyst 
Cellulose, a linear -1, 4-linked glucose polymer synthesized by plants and some species of bacteria, is the most abundant naturally occurring biopolymer.  Cellulose and its derivatives are widely used in chemical and bio-chemical applications and also as a support for the synthesis of organic molecules. It is also observed that cellulose fibers acts as nanoreactor for the stabilization of metal nanoparticles. Cellulose and modified cellulosic materials can be used as sorbents of metal ions from aqueous solutions. Furthermore, cellulose can be used as a matrix for platinum, palladium, and silver aggregates in catalysts or antimicrobial materials.
In this section, a new heterogeneous catalyst consisting of active copper species using cellulose as a support [CELL-Cu(0)] was prepared for the first time and well characterized by XRD and XPS. 
X-Ray Diffraction pattern of cellulose support and Cu(0) supported catalyst indicates the presence of Cu (111) and Cu(200) phases, which are attributed to Cu(0). The high resolution XPS narrow scan of CELL-Cu(0) catalyst show a peak at 932.72 of Cu 2p3/2, which is attributed to Cu (0). ICP-AES analysis of the catalyst indicates the presence of 0.368 mmol/g of copper. 
Section II, Topic I 
Cellulose Supported Copper(0): An Efficient Reusable Catalyst for C-N Coupling of Imidazole with Aryl Boronic Acids
N-Aryl azoles are important substructures in natural products and industrial chemicals, such as pharmaceuticals, dyes, and agricultural products. N-Aryl azoles such as N-aryl pyrrole, N-aryl carbazole, and N-aryl indole, display biological activity such as antimicrobial activity, dopamine D-2 and serotonin 5-HT2 antagonist activity, analgesic activity and antiallergy activity. N-Aryl imines, on the other hand, are protected anilines, which are useful in the synthesis of pharmaceuticals, polymers and oligomers.
N-Arylimidazoles and other N-Arylheterocycles are common motifs in pharmaceutical research because of their biomedical use as thromboxane synthase inhibitors. They are not only important structures in biological systems, but also common moieties in pharmaceutical research. A significant number of N-arylimidazole derivatives have been reported to have biomedical applications, serving as cyclic AMP phosphodiesterase inhibitors, AMPA receptor antagonists, cardiotonic agents and topical antiglaucoma agents. For example, 6-(1H-imidazol-1yl)-7-nitro-2,3-(1H,4H)-quinoxalinedione (YM90K), displays anti-AMPA-induced toxicity in cultured neurons and anti convulsive activity and antiischemic effects in both global and focal ischema models. N-arylimidazoles are found in broad array of imidazolium quaternary salts used as key precursors to imidazolylidines, the largest class of N-heterocyclic carbenes (NHCs). 
Ullmann and Goldberg arylation of amines, amides, and anilines with aryl halides using copper catalysts are popular methodologies before the Pd and Ni catalyzed protocols reported by Hartwig and Buchwald. Chan, Evans, Lam and others reported the synthesis of arylamines, aryl ethers and N-arylheterocycles (scheme 1) using boronic acids and cupric acetate under mild conditions compared to that of conventional methods. Collman has demonstrated the first catalytic version of the reaction using [Cu(OH).TMEDA]2Cl2 and later Buchwald and Lam using Cu(OAc)2 as catalyst in presence of base and additive.
In this topic, cellulose supported Cu(0) was used as a reusable catalyst for the N-arylation of imidazole with aryl boronic acids using methanol as solvent and triethylamine as base under reflux conditions (Scheme 1).


Scheme 1



Section II, Topic II
Cellulose Supported Cu (0) Catalyzed C-N Coupling of Nitrogen Heterocycles with Aryl halides
The Ullmann reaction, initially reported in 1901, has long been employed by chemists to generate a C-C bond between two aromatic nuclei. Typically two molecular equivalents of aryl halide are reacted with one equivalent of finely divided copper at high temperature (above 200 °C) to form a biaryl and a copper halide. This procedure and variants were comprehensively reviewed several decades ago. Considerable improvements have been made through the last century.  Dimethylformamide is a solvent, which permits the use of lower temperatures and a lower proportion of copper. 
The methods commonly used for constructing C-N bonds are 
1.	Nucleophilic aromatic substitution, which requires that the aryl halide substrate possesses electron-withdrawing substituents and
2.	Ullmann-type coupling of imidazoles with aryl halides, which has a broader substrate scope with respect to the aryl halide.
The development of more improved synthetic methods for the preparation of N-arylimidazoles still remains an active research area. It is highly desirable to develop a ligand free new recyclable heterogeneous copper catalyst system to promote easy commercialization and dispense the use of expensive diamine ligands for copper catalyzed coupling reactions of haloarenes.  
In this topic, cellulose supported Cu(0) [CELL-Cu(0)] was used as a reusable catalyst for the N-arylation of imidazole with aryl halides in dimethylsulfoxide solvent and K2CO3 base at 130 0C (Scheme 2).

Scheme 2
CHAPTER III
Cellulose Supported Copper(0) Catalyst for aza-Michael Addition of -Unsaturated Compounds to Amines and Imidazoles
The β-amino ketone functionality is an important segment for the synthesis of biologically active natural products and it also serves as an essential intermediate in the synthesis of β-amino acids and β-lactam antibiotics [1-4]. On the other hand, N-substituted imidazoles and their derivatives, obtained through alkylation reactions [5] or Michael additions [6] are of interest in the pharmaceutical chemistry because of their pharmacodynamic properties. Tinidazole and metronidazole, which belong to the 5-nitro-N-substituted imidazole derivatives, have been widely used in the treatment of protozoal infections, such as trichomoniasis. The 4-nitro-isomeric compounds are also gaining pharmacological significance as immunosuppressants, aldehyde dehydrogenase inhibitors and radiotherapy synergists.
The most common method for the preparation of β-amino ketones is the Mannich reaction. Classical Mannich type reactions are certainly very powerful but need quite severe reaction conditions and are rather sluggish. Conjugate addition of amines to ,-unsaturated compounds which is also known as aza-Michael is on  the contrary, atom economic and quite easy to carry out. However, these reactions require either basic conditions or acidic catalysts, which can be detrimental to the desired synthesis. Moreover, most Lewis acid catalysts are likely to be poisoned by alkyl and arylamine reagents. In order to overcome some of the disadvantages, a wide range of alternative procedures have been reported over the past few years using stoichiometric or catalytic Lewis acids such as Yb(OTf)3, InCl3, CeCl3.7H2O, Bi(NO)3, Bi(OTf)3, Cu(OTf)2, FeCl3.7H2O/Co(OAc)2, H3BO3, SmI2, LiClO4 and copper nanoparticles. Although the recent advances made this route attractive, the development of simple, convenient and environmentally benign recyclable approaches are highly desirable.
In this chapter, the catalytic activity of cellulose supported copper catalyst [CELL-Cu(0)] for aza-Michael addition of unsaturated compounds  to amines and imidazoles is described (Scheme 3).

Scheme 3
CHAPTER IV
Synthesis and Characterization of Cellulose Supported Palladium(0) Catalyst and its Application for C-C Coupling Reactions
This chapter is divided into two sections.
Section I deals with preparation and characterization of cellulose supported Pd(0) catalyst [CELL-Pd(0)] 
Section II deals with the application of CELL-Pd(0) catalyst for C-C coupling reactions.
Section II is divided into two topics:
 Topic I deals with CELL-Pd(0) catalyzed  Heck coupling of olefins with aryl iodides
Topic II deals with CELL-Pd(0) catalyzed Sonogashira coupling of phenylacetylene with aryl iodides. 
SECTION I
Preparation and Characterization of Cellulose Supported Pd(0) Catalyst
This section describes the synthesis of a new heterogeneous catalyst consisting of active palladium species using cellulose as a support [CELL-Pd(0)] and its characterization  by XRD, XPS  and TEM.
The catalyst CELL-Pd(0) is prepared by simple in situ reduction of methanolic solution of palladium chloride in the presence of microcrystalline cellulose support. The X-ray diffraction pattern of CELL-Pd(0) catalyst clearly indicates the presence of Pd (111) and Pd (110) phases which are attributed to Pd(0) Further, the high resolution XPS narrow scan [Fig 2.] of the CELL-Pd(0) catalyst shows two peaks at 335.4 eV of Pd 3d5/2 which is attributed to Pd (0) and 336.5 of Pd 3d5/2 which is attributed to Pd(II). Metal content in CELL-Pd(0) catalyst was analyzed by ICP-AES, which shows the presence of 4.94 % of palladium. TEM image shows the formation of palladium particles in the range of 10-20 nm.
SECTION II, TOPIC I
Cellulose Supported Pd(0) Catalyzed Heck Reaction of Olefins with Aryl Iodides
The Pd-catalyzed arylation or vinylation of olefins, universally referred to as the “Heck Reaction (HR)” has received increasing attention in the last decade, as it is a selective method to form new C–C bonds in a single operational step. The reaction is appealing because of its tolerance of nearly any solvent and functional group on the substrates, its high selectivity, and its moderate toxicity. It constitutes a powerful and versatile method for the synthesis of polyfunctional compounds, e.g., dienes, cinnamic esters, and other variously substituted olefinic compounds, which are primarily applied as dyes, UV absorbers, and intermediates for pharmaceuticals, agrochemicals, and fragrances.
Currently, the Heck reaction is a landmark in small-scale organic preparations. However, a suitable, versatile and reusable heterogeneous catalyst might increase the applicability of Heck chemistry in commercial processes. Among the various works on heterogeneous Heck catalysis, several approaches deserve particular attention to overcome the problems concerning thermal stability (high reaction temperatures), separation, and recovery of the Pd complexes. 
Nanopalladium catalysts, as such or stabilized by poly-(vinylpyrrolidone), block copolymer micelles of polystyrene b-poly-4-vinylpyridine, propylene carbonate, mesoporous MCM- 41, and silica supported poly-g-mercaptopropylsiloxane, exhibit higher catalytic activity in the Heck olefination of bromo- and iodoarenes because of the larger surface areas. The preparation of these stabilized colloids involves invariably difficult protocols using exotic reagents. 
In this section, the Heck arylation of olefins mediated by cellulose supported palladium(0) catalyst without addition of any phosphine ligand is described. (Scheme 4).

Scheme 4
Section II, Topic II
Cellulose Supported Pd(0) Catalyzed Sonogashira Coupling of Aryl Halides with Phenylacetylene
The ever-growing search for new drugs and polymers is bringing alkyne chemistry forward. In the fine chemical industry, C–C triple bonds are sought because they can be easily functionalized using multiple addition reactions. In materials science, polyalkyne derivatives are used to make Organic Light Emitting Diodes (OLEDs), new carbon allotropes and carbon-rich materials. The key reaction here is the formation of an alkyne–carbon bond, i.e. the attachment of an alkyl or aryl group onto the triple bond without destroying it. In 1963, Stephens and Castro demonstrated the coupling of aryl halides with alkynylcopper(I) species to obtain arylacetylenes. Since then, much effort has been directed to elucidate the mechanism of the Stephens–Castro reaction, and to develop synthetic protocols that would not require stoichiometric copper. Sonogashira and co-workers found that combining catalytic amounts of Pd(PPh3)4 and CuI enabled the same coupling without the need for stoichiometric copper or for isolating the alkynylcopper(I) intermediate. 
In this section, cellulose supported palladium(0) catalyst was utilized successfully for the Sonogashira coupling reaction to afford corresponding coupled products in good to excellent yields. The catalyst was recovered by simple filtration and reused for several cycles (Scheme 5). 

Scheme 5
CHAPTER V
Beta Zeolite: an Efficient and Eco-Friendly Catalyst for the Nitration of o-Xylene with High Regio-selectivity in Liquid Phase
The mononitro derivatives of o-, m- and p-xylene isomers are used as intermediates for the production of vitamins, agrochemicals, fragrances and dyes. Although 4- and 3-nitro-o-xylenes are useful starting materials for the production of riboflavin (Vitamin B2) and mefenamic acid, a nonsteroidal anti-inflammatory and analgesic drug, respectively, the former is required in large tonnage. Selective nitration of o-xylene, thus, assumes higher importance. Nitroxylenes on reduction give the corresponding xylidines, which have much industrial importance. 3,4- and 2,6- xylidines are the starting materials for the production of riboflavin and agrochemicals respectively. Other isomers are used as colorant intermediates. The most important of these are 2,4-xylidine, used as diazo compound (e.g. in C.I. Solvent Orange and C.I. Acid Red) and 2,5-xylidine used as a coupling component (e.g. in Dispersol Orange and C.I. Solvent Red). Conveniently, mixed xylidines can be used for some colorants.
Nitration of aromatic compounds is a widely used reaction to realize organic intermediates required in large tonnages for the fine chemical industry. The conventional eco-unfriendly nitration process, employing a nitrating mixture of nitric acid and sulfuric acid, for the last two centuries has remained unchallenged in the commercial arena owing to the uneconomical alternative options. Research in dispensing the use of sulfuric acid in general in the nitration of aromatic compounds and selective synthesis of the desired isomer in the nitration of substituted benzenes in particular is of topical interest, since it reduces pollution caused by spent acid and unwanted isomers and more specifically to respond to market demand. 
The excellent applications of nitroxylene isomers in general and the poor isomeric selectivity towards 4-nitro-o-xylene or large amounts of oxygenates expressed in the nitration of o-xylene in particular prompted us to undertake the present the nitration of xylenes using beta zeolite in an effort to evolve eco-friendly and high atom utilization process. 
In this chapter, the nitration of o-xylene was performed with highest isomeric selectivity for 4-nitro-o-xylene using beta zeolite as a catalyst (Scheme 6) in liquid phase with reuse of the solid acid catalyst being possible by azeotropic removal of water formed in the reaction and present in nitric acid is described. Influence of various reaction parameters viz., effect of solvents, influence of rate of addition of nitric acid on the conversion as well as the selectivity of 4-nitro-o-xylene, influence of Si/Al ratio and consistent activity of the catalyst were discussed in detail.

Scheme 6
















PAGE  



i





BIOTRANSFORAMATIONS: STEREOSPECIFIC ESTER HYDROLYSIS USING Bacillus Subtilis

GADE, NARSINGA RAO

Abstract/Synopsis: 
     A variety of hypervalent iodine compounds have presently secured a firm 
place as reagents in organic synthesis as witnessed by more than 4800 
references, 3400 journal articles, 1100 patents, 192 reviews which appeared in 
chemical literature since year 2000 onwards (SciFinder Scholar Data on March, 
2011). Hypervalent iodine compounds are generally defined as “ions or 
molecules of iodine bearing more electrons than the octet within a valence 
shell”. 
 
      It has been recognized that there are many similarities between 
hypervalent iodine reagents and organic transition metal complexes.  The 
reactions of hypervalent iodine molecules are commonly discussed in terms of 
oxidative addition, reductive elimination, ligand exchange, and ligand coupling, 
which are typical of the transition metal chemistry.  Exploration and practical 
utilization of these similarities may lead to the development of new useful 
methodologies for modern organic synthesis. 
 
 
 
 
 
 
 
 
 
 
 


SYNTHESIS, CHARACTERIZATION AND CATALYTIC PROPERTIES OF EU-1 ZEOLITES

WAGHAMARE, KASHINATH J.

Abstract
Studies on in silico modeling and Xanthine oxidase (XO) inhibitory activities of Novel flavones derivatives with reference to gout

Hyperuricemia is a condition of defective purine metabolism characterized with elevated serum uric acid level (7 mg/dl) that further leads to Gout. One of the factors contributing to overproduction of uric acid is xanthine oxidase (XO) catalysis. XO is a complex metalloflavoprotein that catalyses the conversion of hypoxanthine to xanthine and xanthine to uric acid with concomitant production of hydrogen peroxide and super oxide anions.  Increase in uric acid level in serum eventually leads to the deposition of micro and macroscopic deposits of sodium hydrogen urate monohydrate crystals in the joints of humans that leads to the hyperuricemic condition called Gout. Deposition of urate crystals initiates an inflammatory reaction at the joints that includes swelling, redness and pain, the hallmark of inflammation. In addition a large amount of superoxide anion generation by XO has been involved in the pathogenesis of inflammation, mutagenesis, cancer, aging and ischemic reperfusion injury. Therefore XO inhibitors along with free radical scavengers may prove to be promising agents to treat Gout and hyperuricemic conditions and associated side effects. Purine analog Allopurinol is used as drug for inhibiting XO activity that blocks the synthesis of uric acid in Gout. Use of Allopurinol however is associated with adverse effects that include allergy, hypersensitivity reactions, gastrointestinal upset, skin rashes and acute interstitial nephritis due to lack of free radical scavenging activity against superoxide anions produced. Therefore there is a need for the development of novel compounds with better safety profiles that could be used to relieve associated side effects. Flavones are well known for their pharmacological activities including antitumor, antipyretic, anticancer, antioxidant, anti-inflammatory and XO inhibitory.
	Therefore present study was undertaken to synthesize some novel derivatives of flavones able to inhibit XO and scavenge the free radical produced.
As an attempt thiazolo derivatives V(a-z) and pyrazolo derivatives M(1-9) were designed using PASS, synthesized and characterized by using IR and NMR. In vitro evaluation of all synthesized derivatives for XO inhibitory and antioxidant activity was done using different assay conditions.  XO from rat was isolated and characterized for inhibitory assays having 17.2 U/mg of specific activity. Results in the form of IC50   values were recorded. Derivatives Vq, Vo, Vx, Vu, Vk, Vg, Vh, M6, M7 and Ve demonstrated satisfactory XO inhibitory and antioxidant activities in terms of IC50 values, in which Vq, Vo, Vh was more potent inhibitor. In silico docking studies were performed to have an insight of binding. In case of absence of 3D structure of XO, computational structure was constructed based on the homology with other sequence. Constructed model Model was validated using Verify 3D, Prosa and Ramchandran plot. Docking was done using BioMed Cache software. Results indicated presence of nonpolar amino acid in binding. Hydration number of binding of two most potent derivative Vq and Vo was derived using dielectric study using Time Domain Refractometer (TDR).  




STUDIES ON PETROLEUM REFINING CATALYSTS CONTAINING PENTASIL ZEOLITES

ZOPE, UMESH

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APPROACHES TOWARDS STEREOCONTROLLED MEDIUM CYCLIC RINGS AND RELATED STUDIES

SHINDE, UJWAL

SYNOPSIS OF THESIS
The breathtaking discoveries of today’s biology not only revolutionize our views about living 
things but also make a profound impact on science and engineering. Genetic engineering, which 
came into existence about 10-15 years ago, has made it possible to change in a purposeful way the 
machinery of inheritance to design the liv ing matter. This recent upsurge of interest in biotechnology 
has aroused renewed consideration of the range of products of commercial value that might be 
produced from biological systems. The techniques by which such products are produced and isolated 
from organisms often is the major bottleneck in their application to modern industry. A major task 
of today’s science is to expand and deepen basic research and make it’s findings work in practical 
fields. With extensive utilization of experimental methods, simulation studies and system analysis 
may promote biology to the rank of an exact science. In the present thesis, an emphasis on some of 
these points has been made.
Affinity separations utilizing immobilized antibodies is a technique that is now being used 
for the purification of proteins for use as pharmaceuticals or in other applications where the purity 
of the product is an important consideration. The technique involves the immobilization of antibodies 
to inert supports in order to form biospecific adsorbents that can be used in purification processes. 
The biospecific adsorbents that have a high affinity for a single compound are ideally suited for the 
purification of proteins from a variety of biological sources.
Chapter one introduces the subject matter of the thesis. The literature on the various topics 
covered is reviewed in order to justify the work presented. Briefly, the problems associated with 
the purification of proteins on a large scale have been presented and highlights of the potential of 
affinity separations as industrial unit operations for this purpose are discussed. The reasons for using 
immobilized antibodies, their advantages and disadvantages are also discussed.
In chapter two, details of procedures by which polyclonal antibodies against a protein (Ga- 
lactosyltransferase) are raised, purified and characterized are presented. These antibodies are then 
immobilized and used to study the process of deactivation of the adsorbed antibodies.
(viii)
Chapter three presents an analysis of antibody deactivation. The effect of deactivation over 
a large number of cycles for various types of reactors has been studied in order to give clues for 
designing reactors using immobilized antibodies for large scale separations.
Chapter four presents a mathematical model for checking the feasibility of continuous affinity 
separations using a magnetically fluidized bed.
Chapter five presents the use of novel matrix for immobilization of a hydrophobic antigen 
rice prolamin and using it to estimate easily but accurately the content of prolamin in rice.
The processes by which antibodies and other different secretory proteins are made to cross 
the membrane barrier in cells are discussed in chapter six. Details of the signal that are recognized 
by the translocation apparatus are discussed.
Chapter seven presents detailed analysis of structural aspects of signal peptides. Based on 
this analysis, a mechanism has been postulated for the initiation of protein export across membranes.
Chapter eight comprises aspects of specific degradation of signal peptide inside the lipid 
bilayer of the membrane. A detailed analysis of differences existing between transmembrane 
sequences and signal peptides has helped to identify regions which may be playing a vital role in 
specificity of signal peptide peptidases.
Application of the above analysis to Escherichia co li has been undertaken in chapter nine. 
Regions in Protease IV, a signal peptide peptidase, have been identified by topological studies on 
the probable membrane spanning regions of this protein. A model for protein degradation in the 
membrane has been postulated.
Membranes are known to be fractal in nature. Each component of the membrane, namely the 
different types of lipids and proteins, constitute a part of the fractal shape. These components are 
mobile in shape leading to a time based evolution of the fractal shape, however, maintaining the
(ix)
over all fractal dimension. The effects of mobile shapes o f  fracta ls  on biological processes and its 
relevance to processes often encountered in other disciplines of science and engineering have been 
evaluated in chapter ten.
Chapter eleven finally concludes the thesis giving a concise summary of the results obtained 
and brings out the importance of the work. In the end, a brief discussion on further research that 
should be carried out is given.
(x)


SOME ASPECTS OF DESIGN AND ANALYSIS OF BIOLOGICAL SEPARATION PROCESSES

SHAH, SUBODH

Structural and functional studies on crystallins and their homologues

α-, β- and γ-crystallins are the major water-soluble components of a vertebrate eye lens.  While α-crystallins act as a molecular chaperone, the β- and γ-crystallins are considered the major structural proteins. In some species, several enzymes, such as aldehyde dehydrogenase class 3 (ALDH3) or gelsolin accumulate in the eye tissues (such as in cornea) at unusually high concentrations. Based on the analogy with lens crystallins, these enzymes are called as taxon-specific or tissue-specific crystallins. These enzymes are found abundantly in the corneal epithelium; and because of their high expressions in the cornea, they are thought to be functioning as structural proteins rather than enzymes, thus referred to as corneal crystallins. The first part of the thesis deals with the major corneal proteins of anurans.  
Among the major two sub-classes of lens crystallins, the βγ-crystallin superfamily comprises a class of structurally related members implicated in a wide variety of functions. The characteristic feature of these proteins is the Greek-key motif topology with anti-parallel β-sheets, called the βγ-crystallin fold. This fold is structurally conserved from lower microbes to high order vertebrate lens crystallins. The pattern of Ca2+ coordination by the double clamp motif with a signature sequence of N/D-N/D-X-X-S/T-S motif is conserved in this superfamily. With increasing numbers of sequences in the databases, a few novel sequences from eukaryotes were identified containing the uncharacteristic Greek key crystallin motif (without proper signature sequences). In the second part of the study, a novel  but diverse βγ-crystallin domain of fungus Neurospora crassa annotated as APP has been characterized for the Ca2+-binding and spectral properties.
The last part of the thesis describes the connection between bacterial immunoglobulin like domains (Big), with its structural homolog, i.e., the βγ-crystallin domain. From our studies, it has been found that Big domain of Lig (Leptospira immunoglobulin-like) proteins also possesses Ca2+-binding property since both βγ-crystallin and Big domains have the similar Greek key topology. To demonstrate that Ca2+-binding could be an inherent and important characteristic of Big superfamily, two diverse proteins from different bacterial species have been studied. The spectral and conformational aspects have been addressed using biophysical tools.
Chapter 1: Introduction
This chapter introduces the crystallins, βγ-crystallin domain and taxon-specific crystallins. This chapter also discusses about the general features of Big domain, a structural homologue of βγ-crystallin domain. The last portion of the chapter outlines objectives of the research work to be described in this thesis.
Chapter 2: Experimental Procedures
All experimental procedures used in the following study have been described in this chapter. Cloning, overexpression and purification procedures of individual proteins have been mentioned in their respective chapters. A set of common biochemical, spectroscopic and calorimetric techniques applied to this study has been described.
The results of the work are divided into the following three Sections in the thesis.
Section I: Corneal and nictitans crystallins
Chapter 3: Accumulation of lens crystallins in anuran cornea
Crystallins are responsible for the transparency of lens, but the molecular basis of corneal transparency has not been very clear. It is known that after lentectomy, anurans exhibit a unique property of regenerating a lens by transdifferentiation of the corneal epithelium. However, the molecular basis behind this lens-forming competence of the corneal epithelium is not understood. This study was directed towards identification of the abundant proteins in anuran cornea which may help to obtain insights into this mechanism. 
Water soluble corneal proteins were isolated and resolved on two-dimensional gel electrophoresis. Selected protein spots were excised and analyzed with MALDI-TOF/TOF and MS/MS analysis. Peptide mass fingerprinting was generated and proteins were identified using various databases. Localization and further confirmation of interesting proteins were performed using immunofluorescence, western immunoblot and RT-PCR. It has been observed that anuran cornea is made up of full complement of ubiquitous lens α-, β-, and γ-crystallins, which remain localized mainly in the corneal epithelium. In addition, some taxon-specific lens crystallins and novel proteins, such as α- or β-enolase/τ-crystallin, have also been identified. High levels of lens α-, β-, and γ-crystallins may offer a possible explanation for their ability to regenerate a lens after lentectomy. These data present a unique case of the anuran cornea where the same crystallins are used in the lens and in the cornea, thus supporting the earlier idea that crystallins are essential for the visual functions of the cornea as they perform for the lens. Our data that anuran cornea has abundant quantity of almost all the lens crystallins is consistent with the cornea’s ability to form a lens and thus presents a plausible explanation for the propensity of corneal trans-differentiation into lens.
Chapter 4: Semi-transparency of anuran nictitans
Anuran is an order in the class amphibia that includes frogs and toads. Frog and toad have an extra optical tissue as compared to the non-amphibians: nictitating membrane (NM). NM has been least studied. This chapter is possibly the first attempt to present the list of major soluble proteins expressed in nictitating membrane: a semi-transparent tissue, which has not been explored. 
Section II: βγ-crystallin domains
Chapter 5: A divergent βγ-crystallin type protein from Neurospora crassa
Upon analyzing the genomic sequence of Neurospora crassa, a sequence has been identified which was annotated earlier as hypothetical protein, and later on named as abundant perithecial protein (APP). At some stages of reproductive life cycle, this protein constitutes up to 30% of the total perithecial proteins. The sequence features indicates that it might harbor Greek key motifs, though only some indications for the signature sequences were seen, specifically for a single Greek key motif, while the signature sequences were absent for the second motif. To understand its spectral properties, the full length protein (which appeared to have two-domains) was prepared and studied for Ca2+-binding. Role of Ca2+ on its conformation and stability was delineated. Since the possibility that N-terminal region might be a βγ-crystallin like domain (NTD), it was also cloned and prepared. Interestingly, this domain binds Ca2+, however, there is no ambiguity about the presence of the βγ-crystallin motif though Ca2+-binding as consensus sequence of N/D-N/D-X-X-S/T-S motif is not clearly noted. To explore the limits of relationship between the sequence diversity and structural features of this highly diverse βγ-crystallin fold, its crystal structure in Ca2+-bound form was solved which clearly demonstrate the presence of one Ca2+-binding site, whereas other site is disabled due to the presence of unfavorable amino acids at the ligation positions for side chain coordination. This work thus classifies this protein towards a sub-family of βγ-crystallins fused with a putative immunoglobulin domain at its C-terminal. Efforts to solve the structure of full protein failed due to problems in obtaining suitable crystals. 
Section III: Structural homologues of βγ-crystallins: the Bacterial immunoglobulin-like (Big) domain
Chapter 6: Lig proteins are Ca2+-binding proteins 
The Big domains possess Greek key motifs, thus could be considered as structural homologues of βγ-crystallins domain, though both are two different families without any connection. In order to correlate any functional similarities between these two domains, Ca2+-binding to Big domains of the proteins from Leptospira interrogans (called as Leptospira immunoglobulin-like or Lig) proteins was explored. In this chapter, Ca2+-binding properties vis-à-vis spectral features of various Lig domains was described. In addition, the response of Ca2+ on conformation and domain stability has also been studied. 
Chapter 7: Ca2+-modulates N-terminal domain of fibronectin binding to LigBCen2
Lig proteins which possess bacterial immunoglobulin-like (Big) domains are surface exposed proteins; the interaction between the bacterium and host cells is the first step in the establishment of a productive infection. It has been shown that Lig proteins interact with ECM proteins such as fibronectin, laminin, elastin or collagen and this is one of the strategies, the bacterium uses to adhere to host cells. A domain of Lig i.e., LigBCen2, is shown to interact with NTD of fibronectin (Fn). Absolute requirement of calcium and magnesium ions for the growth and survival of this bacterium has been known for a long time; however this work set up the indication of their role as Big domain of Lig binds Ca2+. Further, Fn binding with LigBCen2, is enhanced in the presence of Ca2+, demonstrating a direct functional consequences of ion binding.
Chapter 8: Excited-state interaction and doublet fluorescence of Big_2 domains
Trp fluorescence spectrum of a Big domain has an uncommon doublet spectrum (two peaks at ~320 and ~330 nm). The origin of such unique spectral feature not only in Big domains but also in proteins with similar spectra is not known. It has been observed that in most of the Big_2 domains, a conserved Phe is located 19 residues apart from the invariant Trp. The first peak of a doublet spectrum disappears without affecting the 2nd peak when this Phe is mutated to Ala in a Big_2 domain. Our results suggested that the Phe-Trp pair forms a complex during excitation via hydrophobic interaction, forming the basis for a doublet in the emission spectrum. LigBCen2 is known to interact with fibronectin through some unknown mechanism. Mutating a conserved Phe to Ala in LigBCen2 severely attenuates fibronectin binding, suggesting this Phe to be a hot-spot residue. Hence, the Phe-Trp interaction in Lig proteins is necessary for Leptospira virulence, and thus may play a role in other Big domains or proteins with similar aromatic pairing.
Chapter 9: Big: a novel superfamily of Ca2+-binding proteins
The data that Lig proteins bind Ca2+ were extrapolated further to generalize the results. Big domains, the Big_2 domain to be specific, spread over a large number of proteins. To test the ability and generality of Ca2+ binding in the context of Big_2 domain, two diverse proteins from different organisms were tested for Ca2+-binding. Both proteins bind Ca2+ with similar affinities, thus letting to propose that the proteins with Big domains form a novel, superfamily of Ca2+-binding proteins. 
Concluding remarks and future prospects
This part concludes the thesis with a brief summary of salient findings, and several unanswered question as future prospective. In brief, an anuran cornea is made up of full complement of ubiquitous lens α-, β- and γ-crystallins which are mainly localized in the corneal epithelium. Proteomic studies of nictitating membrane provide an overview of protein composition and some possible candidates to be classified as nictitans crystallin. One member of βγ-crystallin superfamily from Neurospora has one degenerate Ca2+-binding site. Studying diverse members of this superfamily has a huge potential to help understanding not only the basis of Ca2+-dependent functions in some microbial species, but also a requirement for fold. Recruitment of individual domains into multi-domain proteins indicates the modular roles of βγ-crystallins in affecting activity of other functional domains in these proteins in a Ca2+-dependent manner. Big domain, a homologue of βγ-crystallin domain, is a novel superfamily of Ca2+-binding proteins though the exact motif need to be defined. The properties and functional role of diverse members of Big family remain to be investigated. 




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