Open Access Repository of Indian Theses

Kamath, Sandesh

English

Biotechnological production of microalgal carotenoids with reference to astaxanthin and evaluation of its biological activity

Telang, Manasi

Chapter-I  
(General introduction
Tuberculosis is a dreadful disease caused by bacteria called Mycobacterium tuberculosis and responsible for more human deaths than any other single infectious disease. It is estimated that, about one third of the world’s population is infected with this disease. According to World Health Organization, approximately 8 million people contact TB annually with almost 2 million deaths. Furthermore, treatment of this disease caused by resistant bacteria is more difficult in immuno-compromised patients such as those infected with human immunodeficiency virus (HIV). For these reasons, there is an overwhelming need to develop novel antimycobacterial agents with different mechanism of action aimed at a better understanding of antimycobacterial resistance
Chapter-II
Synthesis and Antimycobacterial Evaluation of nitroheterocyclic Based 1,2,4-Benzothiadiazines

The importance of nitrofurans and the isosteric nitrothiophenes as antimicrobial agents is well documented. Although a lot of work has been done on these heterocycles, they still remained an active area of research interest. The antimicrobial activity of nitroheterocycles is mainly due to the metabolic reduction of their nitro group by a class of enzymes called nitroreductases.











Sulfonamide derivatives have demonstrated potential antibacterial, anticancer, anti-inflammatory activities in the literature and benzothiadiazines can be considered as cyclic sulfonamide class of molecules. These compounds have been extensively studied as potassium channel openers. Moreover, this ring system has also been known for antimicrobial activity. Based on these findings, recently we have reported the synthesis and evaluation of antimycobacterial activity of these molecules by coupling with pyrazine carboxylic acid derivatives. Keeping the importance of the nitroheterocycles in mind and in continuation of our studies on antimycobacterials particularly benzothiadiazines, herein we have reported the synthesis of 5-nitrofuran, 5-nitrothiophene and arylfuran coupled benzothiadiazines and evaluated them for their antimycobacterial and antibacterial activities.





Table 1. Antibacterial activity and antimycobacterial  activity of 3-benzothiadiazinyl hydrazone (5a-g) and hydrazide derivatives (7a-k) (MIC in μg/mL)


Compd	M. tuberculosis H37Rv	S. aureus	E. coli	P. aeruginosa	B. Subtilis
5a	8	37.5	18.75	150	37.5
5b	8	37.5	37.5	150	18.75
5c	8	37.5	18.75	150	9.37
5d	16	18.75	18.75	150	18.75
5e	4	18.75	18.75	150	18.75
5f	1	75	37.5	150	37.5
5g	4	37.5	18.75	150	37.5
7a	32	37.5	18.75	150	18.75
7b	32	150	18.75	150	18.75
7c	8	37.5	18.75	150	75
7d	4	37.5	18.75	150	18.75
7e	>100	18.75	37.5	75	37.5
7f	>100	9.37	18.75	150	18.75
7g	>100	18.75	75	150	37.5
7h	>100	75	18.75	150	37.5
7i	>100	18.75	18.75	75	37.5
7j	>100	75	75	150	37.5
7k	>100	18.75	18.75	150	37.5
NF	--	18.75	18.75	150	18.75
RMP	0.12	-	-	-	-
INH	0.5	-	-	-	-
NF, Nitrofurantoin; RMP, Rifampicin; INH, Isoniazid.



Chapter –III
Section-A
Synthesis and Biological Evaluation of a New Series of Benzothiazole-Benzothiadiazine Conjugates As Antibacterial Agents

Benzothiazole derivatives have shown diverse biological properties such as antibacterials, anticancer, antirheumatic, anti-inflammatory etc. Basing on the importance of benzothiazoles and benzothiadiazines, an attempt has been made to synthesize new hybrids of benzothiadiazines and benzothiazoles with the aim of improving the efficacy of the antibacterial activity.  
The synthesized compounds have also been evaluated for their DNA gyrase inhibition. Some of the tested compounds have exhibited moderate gyrase inhibitory activity in comparison to ciprofloxacin, thus indicating the possibility of somewhat similar mode of action. As far as we know, this is the first report for the DNA gyrase inhibition of these new hybrids. Therefore, we have investigated the molecular docking studies of these compounds in comparison to the ciprofloxacin using GOLD v 2.0 program and shown in ball and socket model (Fig. 2 and 3). Binding energy of benzothiazole hybrids with DNA gyrase is found to be 21.95 kcal/mol as compared to ciprofloxacin 42.31 kcal/mol. Moreover, one of the oxygen S=O (1.604 Å) atom of sulfone group is forming hydrogen bonding with minor groove of DNA, whereas two hydrogen bonds are formed, one from the C=O (1.622 Å) oxygen atoms of ring and another from the acid group C=O  (2.196 Å) between minor groove of DNA. However, it requires further detailed investigations for a larger number of compounds of this type of ring system to provide a clear understanding of the mechanism of action for this new class of hybrids.










	





Figure 2. Molecular docking of benzothiazole hybrid (9f) into DNA gyrase, one of the oxygen of sulfone group participates in hydrogen bonding with minor groove of the DNA. 




Figure 3. Molecular docking of ciprofloxicin into DNA gyrase, oxygen atoms of two C=O groups, one from the ring and another from the acid group are forming hydrogen bondings with minor groove of the DNA.































	Figure 1. DNA gyrase supercoiling inhibition assay. The assays were performed as described general procedure section. The enzyme was incubated with indicated concentrations of the compounds before the addition of rest of the components. In all the figures (1a, 1b and 1c) lane1: supercolied DNA, lane2: relaxed DNA substrate, lane 3: supercoiling reaction, lane 4: supercoiling reaction in presence of 10 g/ml ciprofloxacin. 5% DMSO was used as a solvent control in supercoiling reaction in lane 5.  (a) 50 g/ml of compounds 9g, 9f, 9e and 9d were used in lanes 6, 7, 8 and 9 respectively. (b) 40 g/ml of compounds 9g, 9f, 9e and 9d were used in lanes 6, 7, 8 and 9 respectively. (c) 30 g/ml of compounds 9g, 9f, 9e and 9d were used in lanes 6, 7, 8 and 9 respectively. R- relaxed DNA, S – supercoiled DNA. 




Table 1. Antibacterial activity of 3-[4-(1,3-benzothiazol-2-yl)anilino]-4-alkyl-1,4-dihydro-1λ6,2,4-benzothiadiazine-1,1-diones (9a-g) (MIC in μg/mL)
Compd	X	Y	R	Gram positive	Gram negative	DNA gyrase(MIC μg/mL).
				BS	SA		EC	PA	
9a	H	H	C2H5	18.75	18.75		9.37	150		-
9b	H	Cl	CH3	18.75	9.37		9.37	150		-
9c	H	H	CH3	18.75	18.75		9.37	150		-
9d	H	H	(CH3)2CH	75	18.75		75	150		30
9e	Br	H	(CH3)2CH	18.75	18.75		37.5	150		30
9f	OH	H	(CH3)2CH	37.5	18.75		37.5	150		30
9g	OH	H	CH3	18.75	9.37		37.5	150		30
Amp				18.75	9.37		9.37	150		-
Cipro				-	-		-	-		10
The organisms tested are as follows: BS = Bacillus subtilis, SA = Staphylococcus aureus, EC = Escherichia coli, PA = Pseudomonos aeruginosa. Amp = ampicillin; Cipro = ciprofloxacin; -, not tested.

a new series of 3-[4-(1,3-benzothiazol-2-yl)anilino]-4-alkyl-1,4-dihydro-1 λ6,2,4-benzothiadiazine-1,1-diones derivatives (9a-g) has been synthesized and evaluated for their antibacterial activity. Most of the compounds were found to be equipotent in activity with ampicillin against all the bacterial strains tested.These findings will assist the researchers in the development of new class cyclic sulfonamide based antibacterial agents
Chapter –III
Section - B
    Design, Synthesis And Anti bacterial Activity Of  Novel Quinolone Hybrids
Quinolones are synthetic antibacterial compounds based on a 4-quinolone skeleton. Fluoroquinolones have been clinically successful and are used to treat bacterial infections in both community and hospital settings. Quinolones target bacterial type II topoisomerases, generally DNA gyrase in Gram-negative bacteria and DNA topoisomerase IV in Gram-positive bacteria. Most of the quinolones currently on the market or under development have only moderate activity against many Gram-positive cocci, including Staphylococci and Streptococci. This insufficient activity has not only limited their use in infections caused by these organisms, such as respiratory tract infections, but has also been believed to be one of the reasons for the rapidly developing quinolone resistance. Therefore, recent efforts have been directed toward the synthesis of new benzothiazole derived quinolone antibacterials that can provide improved Gram-positive antibacterial activity, some of the quinolone based structure are




	





ChapterIVA
Section -A
Oxathioacetalization, thioacetalization and transthioacetalization of carbonyl compounds by N-bromosuccinimide: selectivity and scope
The protection of carbonyl compounds as acetals, dithioacetals and oxathioacetals is an important aspect of the total synthesis of complex natural products. Among these, oxathioacetals and dithioacetals are important because they are considered more stable than the corresponding O,O-acetals under acidic conditions and are also useful in organic synthesis as acyl carbanion equivalents in C-C bond forming reactions.2 Moreover, S,S-acetals can be used as intermediates for the conversion of the carbonyl function to the parent hydrocarbons. In view of the potential applications of 1,3-oxathiolanes and thiolanes, it is important to search for newer and efficient synthetic methodologies for the preparation of these compounds. In general they are prepared by protic or Lewis acid-catalyzed condensation of carbonyl compounds with 2-mercaptoethanol, thiols and dithiols.10 Transthioacetalization of acetals is a useful transformation for the preparation of S,Sacetals and in comparison with thioacetalization of carbonyl compounds, it is a faster and cleaner reaction
In spite of a number of reports employing conventional catalysts for the protection of carbonyl compounds, the search for new catalysts is still actively pursued to address such problems as harsh reaction conditions and poor chemoselectivity. In addition, environmental and economic considerations have prompted us to redesign these commercially important processes. As a result, there is further scope to explore mild and efficient methods for oxathioacetalization and transthioacetalization. N-Bromosuccinimide (NBS) is an important reagent not only for bromination, but also for a range of other reactions. Depending upon the nature of the reactant and reaction conditions in solution, NBS reacts differently with many organic compounds and recently, we have reported dithioacetalization of carbonyl compounds using NBS.








Table 1. Oxathioacetalization of carbonyl compounds
Entry 	Product 	Time 	Yield %
a		2.0	75
b		2.5	80
c		2.0	70
d		2.5	75
e		2.0	76
f		2.0	68
g		2.5	63
h		1.5	73
i		3.0	80
j		2.5	78
k		3.0	58
l		3.0	64

































	












Table 2.
Thioacetalization and trans thioacetalization of carbonyl compounds
Entry	Acetal (1)	Product (2)	Time (min)	Yield (%)
a			10	91
b			12	87
c			15	90
d			10	78
e			10	90
f			20	75
g			20	85
h			20	73
i			15	80
j			25	57
k			20	85
l			25	79


Section - B

Bi(OTf)3-Catalyzed regioselective ring opening of epoxide with phenols: facile synthesis of 1,3-diaryloxy-2-propanols
Substituted aryl oxiranes undergo the facile ring opening with phenols in presence of catalytic amount of bismuth (III) triflate to afford 1,3-diaryloxy-2-propanols in excellent yields under mild conditions. Bismuth (III) triflate is relatively non-toxic, easy to handle and inexpensive, which makes this procedure particularly attractive for large scale synthesis


The high regioselectivity in the epoxide ring opening with bismuth (III) triflate can be explained by the in situ formation of complex between epoxide and bismuth (III) triflate, which undergoes SN2 attack of phenols at less hindered C-3 carbon to give secondary alcohol exclusively (Scheme 2). In the present investigation among the various solvents examined for the epoxide ring opening with phenols, dichloromethane was better solvent under these conditions. However, in the absence of bismuth (III) triflate the reaction did not proceed even under reflux conditions and prolonged reaction time (1, 2 days).










(b)

(c)

(a)

S

R

S

R

S

R

   1        2        3         4        5       6         7         8        9  

   1         2         3       4        5        6        7        8        9  

   1        2        3        4        5        6       7         8          9  





Molecular analysis of plant-pest interaction with special reference to Helicoverpa armigera and proteinase inhibitors from host and non-host plants

S., ANAND

MICROBIOLOGICAL AND MOLECULAR METHODS FOR THE STUDY OF OCHRATOXIN A IN FOODS AND ITS CONTROL

C., RADHA

SYNOPSIS
      
	Gene therapy uses genes as medicine and is a promising approach for the treatment of genetic defects as well as many acquired diseases. It involves transfer of a normal functioning copy of a non-functional gene into our body cells in order to repair the faulty gene. Putting it differently, this therapeutic modality replaces a faulty gene or introduces a new gene whose function is to cure or to favorably modify the clinical course of a disease. However, this is easier said than done. Since both the macromolecular nucleic acids (genes) and the biological cell surfaces are negatively charged, spontaneous entry of naked genes into body cells is unlikely to be an efficient process.  This is why developing a promising gene therapeutic approach and designing safe and efficient gene delivery reagents are two inseparable problems.
   
The success of gene therapy critically depends on the efficiency with which the functioning copy of the genes is delivered into our body cells. Broadly speaking, two methods are used for delivering genes. One is viral gene delivery and the other is non-viral gene delivery. In general, the transfection efficiencies of viral vectors are higher than their non-viral counterparts. The exquisite natural ability of viruses to transfer their genetic payload into humans has inspired scientists to use viruses for delivering therapeutic genes in gene therapy. However, there are practical limitations of viral gene delivery systems including difficulties of their large scale production, lack of selectivity, insertional mutagenesis, and immunogenic responses raised against virus structural components etc. All these alarming bio-safety concerns associated with the use of viral vectors are increasingly making the non-viral gene delivery reagents as the alternative vectors of choice. Non-viral methods include DNA delivery using physical and chemical methods. Among the existing arsenal of non-viral gene delivery reagents, the distinct advantages associated with the use of cationic liposomes (used generally in combination with neutral molecules like cholesterol, DOPC or DOPE) as gene carrier include their robust manufacture, ease in handling and preparation techniques, ability to inject large lipid-DNA complex and low immunogenic response. 

       Cationic lipid molecules are amphiphilic in nature containing a lipid anchor, a linker group, and a positively charged head group. These are soluble in organic solvents such as chloroform and methanol, and are usually dissolves as monomers in these organic solvents. However, when dissolved in water these cationic amphiphiles spontaneously form multilamellar vesicular structures (MLV) called liposomes above a certain critical vesicular concentration (CVC). On sonication or extrusion through various pore size membranes, the multilamellar liposome (MLV) assumes the size of small unilamellar vesicle (SUV, 20-100 nm) or large unilamellar vesicle (LUV, 150-250 nm) respectively (Figure 1).


         The transfer of DNA (containing the gene of interest) into a cell with the subsequent expression of its encoded protein is called “transfection”. In liposomal gene delivery, cationic liposomes are mixed with DNA and the resultant lipid-DNA complexes (popularly known as lipoplexes) are simply incubated with the cells (in vitro) or injected intravenously (in vivo). The intracellular transfection pathway in lipoplex mediated transgene expression consists mainly of three steps: initial endocytotic cellular uptake of lipoplex by plasma membrane; escape of DNA from the endosome (endosomal release) into the cell cytoplasm and efficient transport of the endosomally released DNA to the cell nucleus (Figure 2). If the DNA (containing the gene of interest) is taken up by cells and eventually reaches the nucleus, the encoded protein gets finally expressed through transcription and translation. Quantitative assay of the expressed protein indicates the degree of efficiency of the transfection procedure.

                              Figure 2: Lipofection pathway.
         
         The transfection efficiency of any given liposomal formulation is highly dependent on the cell line, type of cationic lipid and the ratio of lipid:DNA. Interestingly majority of the efficient contemporary cationic amphiphiles such as, DOTMA, DMDHP, DMRIE, etc. (Figure 3) possess a common structural element in their molecular architecture, namely a glycerol backbone (highlighted by the rectangular boxes in figure 3) linking the cationic head-group and the hydrophobic tail region. Covalent grafting of hydroxyl moiety in the head group region of cationic lipids has been demonstrated to be capable of imparting efficient transfection properties of cationic lipids.  It was suggested that the hydroxyl group could improve the compaction of DNA by several mechanisms. For example, DNA can form hydrogen bonds with the lipids, and the hydroxyl group can enhance the membrane hydration. Detailed structure-activity investigations in cationic lipid mediated gene delivery using such glycerol based cationic transfection lipids with varying chain lengths hydrophobic tails, ether linker regions, unsaturated hydrophobic tails with membrane reorganizing capabilities etc. have been reported. The corresponding structure-activity studies using non-glycerol based cationic transfection lipids have previously been reported from our lab.



                    




Figure 3: Representative structures of Glycerol based cationic lipids with Hydroxyalkyl head group.      




Present Thesis.
       The molecular architectures of cationic amphiphiles consist of a positively charged water-loving polar head-group region and a non-polar hydrophobic tail region (usually consisting of either two long aliphatic hydrocarbon chains or a cholesterol skeleton) often tethered together via a linker functionality such as ether, ester, amide, amidine group, etc.  Understanding the structural parameters capable of influencing the gene delivery efficiencies of cationic transfection lipids is important. To this end, the focus of many prior structure-activity investigations have been centered around probing the influence of each of the above mentioned three lipid structural components in modulating the gene transfer efficacies of cationic amphiphiles.  For instance, a number of prior reports have demonstrated that the gene transfer efficiencies of cationic amphiphiles critically depends on their molecular architectures including hydrophobic alkyl chain-lengths, nature of head-groups as well as on the nature of linker and spacer functionalities used in covalent tethering of the polar head-groups and the non-polar tails of cationic amphiphiles. Toward probing the hitherto unexplored influence of linker orientation in cationic lipid mediated gene delivery, we have designed & synthesized two structurally isomeric remarkably similar cationic amphiphiles 1 & 2 (Figure 4) bearing the same hydrophobic tails and the same polar head-groups connected by the same ester linker group.  The only structural difference between the cationic amphiphiles 1 & 2 is the orientation of their linker ester function. Synthesis, dramatic contrasting in vitro gene delivery efficacies and physiochemical properties of these novel cationic lipids are described in Chapter 1. 


Figure 4. Structure of two cationic amphiphiles differing only in linker orientation
Transfection efficacies of the Lipids 1& 2 were checked in COS-1 (SV 40 transformed African green monkey kidney cells), CHO (Chinese hamster ovary cells), HepG2 (Human hepatocarcinoma) and A549 (human lung carcinoma cells) using p-CMV-SPORT-β-gal plasmid DNA. While lipid 1 showed high efficacies in delivering reporter genes into multiple cultured mammalian cells including CHO, COS-1, HepG2 and A549, lipid 2 was found to be essentially incompetent in transferring genes into any of these cells. To obtain deeper insights into the origin of poor gene transfer efficacies of cationic transfection lipid 2, we have conducted differential scanning calorimetry, fluorescence anisotropy and conventional dye entrapment experiments. Our findings are consistent with the supposition that the significantly more membrane fluidity of the lipid 1 liposomes than that of lipid 2 liposomes are likely to play a dominant role behind the strikingly superior transfection efficacies of lipid 1.
 
	Many previous reports shown that, cationic liposomes bearing various covalently grafted cell specific ligands (the so-called “homing” device) are capable of delivering their genetic pay-loads to specific body cells.  To this end, perhaps, the most elegant uses of cationic transfection lipids have been demonstrated for targeting genes to liver cells (hepatocytes). Hepatocytes over express the high affinity cell-surface receptors that can bind asialoglycoproteins and then internalize them into the cell cytoplasm. Interestingly, design of many of the previously reported liver-specific cationic glycol-lipid based tranfection vectors has been based on the covalent grafting of only the cyclic pyranose form of D-galactose (the high affinity ligand for asialoglycoprotein receptors) into their polar head-group regions.  To this end, inspired by our previous findings that cationic glycolipids with open-sugar heads are also capable of efficiently transfecting cultured cells in vitro, I have addressed an yet unexplored structure-function issue in the area of cationic glycol-lipid mediated gene delivery namely, “Does the polar sugar-head of the galactosylated cationic lipids necessarily need to be in the cyclic pyranose forms?”. Toward finding an answer, I have designed and synthesized two novel series of cationic glycoamphiphiles 1-5 and 6-10 (Figure 5) containing the cyclic- and open-galactose heads respectively, at increasing covalent bond distances from the quaternary nitrogen centers and evaluated their relative in vitro efficiencies in transfecting five cultured mammalian cells including human hepatocarcinoma (HepG2) and human lung carcinoma (A549) cells. As delineated in chapter 2, the cationic glycol-lipids 3 (pyranose form) and 6 (acyclic form) to be the most promising cationic glycol-lipids.  The cellular uptake of the lipid:DNA complexes for both the glycol-lipids 3 & 6 were found to be mediated through asialoglycoprotein receptors in both cultured HepG2 and primary hepatocytes. Importantly, the in vitro transfection efficacies of the glyco-lipids 3 and 6 were also found to be highly serum compatible (up to 60% added serum). Finally, towards probing the systemic potentials of these two most promising cationic glycol-lipids (3 & 6), the lipid:DNA complexes were intravenously injected in C57 balbC mice and degree of transfection in various organs including lung, liver, heart, spleen and kidney were measured.  Contrary to usual high lung transfection efficacies of cationic lipids, both the lipids failed in transfecting mouse lungs and instead exhibited remarkable liver specificity. Thus, the novel cationic glycolipids 3 & 6 hold promise for future use in liver-specific systemic gene delivery.





    








Figure 5: Chemical structures of glycolipids with cyclic and open of the sugar heads.


















PAGE  



V





ENZYMATIC AND PHYSICAL MODIFICATIONS FOR THE PREPARATION AND UTILIZATION OF SOY FLOUR FOR BETTER FUNCTIONAL PROPERTIES

S, MICHAELRAJ

Studies on Pre-harvest Infestation and Management of Key Pests of Stored Maize by Plant Products and Insecticides

Shukla, Shastri Prasad

SYNOPSYS                                                                                             

CHAPTER- I                                                                                         		
Introduction and earlier synthesis approaches of Leptomycin-B and Synthesis of the C13-C24 fragment of Leptomycin-B,

Chemistry is a very broad subject and can justly claim to encompass many aspects of the study of biological molecules. To most researchers in the chemistry field, the term “chemistry” is often used in a much narrower way and is synonymous with synthetic chemistry as a tool for the discovery of anticancer drugs. Drug discovery requires knowledge of the structure and reactivity of small molecules and macromolecules and the ways in which molecules interact by means the both covalent and non-covalent reorganization during signal transfer.

                   
CHAPTER-II                                                                                       	            
 Introduction and earlier synthesis approaches of Litsealactone –B and Synthesis Towards the Litsealactone -B	         
Synthetic organic chemistry is perhaps the most expensive branch of the science of chemistry in view of its creative power and limited scope. T o apprecite its impact on modern humanity one only has to look around and recognize that science is a pillar behind pharmaceuticals, high-tech materials, polymers, fertilizers, pesticides, cosmetics and clothing1   The engine that drives forward and sharpness of our ability to create such a molecules through chemical synthesis. It request to construct the most complex and challenging of natures products, this endeavor-perhaps more that any other- becomes of the art of synthesis2

 Although theme of the natural product synthesis is attracting a lively interest in research laboratories around the world today, the reason for practicing it vary. Advances in the elucidation of biological process have generated a demand for the efficacious synthesis of biologically active compounds in enantiomerically pure form. Isolation from natural sources usually dpes not provide sufficient amount of material to complete biological studies. In addition, structural modification of a natural substrate often provides valuable information about a system not afforded by the parent molecule. In order to fulfill these needs, a major focus of synthetic organic chemistry has been the enatiomeric synthesis of molecules and analogues for the study of the expanding number of biological pathways that continued to be investigated.

         
CHAPTER-III                                                                                                        
Development of novel synthetic methodologies      


Section A:	                                                                                                              
 Previous approaches on KSF clay and Montomorillinite clay catalysed cleavage of Aziridines with alcohols 

One of the major current challenges before chemists to develop synthetic methods that 
are less polluting i.e. to design clean or green chemicals transformations. The chemical manufacturing processes should be such that they don’t cause permanent damage to the environment or disturb the ecological balance. Way to minimize the consumption of energy and raw materials used in the synthesis must be devised so the optimal value of resources could be realized. There by environmentally benign products are obtained at afford able costs such that a concept though has received enormous attention in recent times. The desire to make chemicals manufacturing environment friendly is not a new one. Such awareness is there not even among the nineteenth century chemists industrialists and law makers. The problem has become more acute in recent times and has received wider and scientific organization have put clean technology as an important R$D concern. The area of chemistry, which is particularly directed to achieve goals, is termed as green chemistry and is defined , according to us award programmed, process –including synthesis catalysis, analysis ,monitoring , separations and reaction conditions-that reduce impact on human health and environment relative to the current state of the care of the community and art.


Section B:                                                                                                            
 Previous approaches I2  and Chemoselective hydrolysis of tert -butylesters in acetonitrile using molecular iodine as catalyst.

The use of molecular iodine in organic synthesis has been known for a long time, such as in the Grignard reaction.  In recent years, molecular iodine has received considerable attention as an inexpensive, non-toxic, readily available catalyst for various organic transformations under very mild and convenient conditions to afford the corresponding products in excellent yields with high selectivity.  This is because of the mild Lewis acidity    of iodine.  




In-vitro studies on some threatened and economically important ferns

KUMARI, MAYA

Variability, Genetic and Molecular Characterization of Staygreen trait and its Association with Resistance to Spot Blotch Disease and Terminal Heat Stress in Spring Wheat (Triticum aestivum)

Patidar, B.

	Pulicaria is a genus of the family Compositae. The species belong to this genus are annual or perennial herbs distributed in different parts of India. The species are generally 30-60 cm in height and their leaves are linear-oblong.46,47
	Various species of Pulicaria are known for their medicinal properties. P. wightiana is used by the tribals to get relief from diarrhoea.48 P. dysenterica is used as tonic, astringent and diuretic.46,47 The alcoholic extract of P. orientalis exhibits significant hypoglycemic and anti-inflammatory properties.49 P. salviaefolin exhibits hypolipidemic  effect.35
	The metabolites obtained from diffirent species of Pulicaria are also chemically and biologically interesting. These metabolites are of varied types, viz., sesquiterpenoids,15 diterpenoids,2 triterpenoids,59 flavonoids,37 steroids49 and fatty compounds.50 The flavonoids of P. orientalis exhibit hypoglycemic activity,4 pulicarian, a new flavonoid of P. salviaefolia demonstrated promising hypolipidemic property.35 The essential oil extracted from P. undulata is antibacterial.60 The constituents of Pulicaria species are thus both chemically and biologically interesting.     	



The genus Jatropha belongs to the family Euphorbiaceae. The family Euphorbiaceae is generally endemic to tropics. This family also known as the spurge family, contains 300 genera and 800 species.1,2 The plants of the family are familiar for important medicinal values and for producing various drugs, which possess interesting pharmacological actions. 
The genus Jatropha is very important in the family of Euphorbiaceae as the plants belonging to the genus are reputed in the Indian Ayruvedic System of medicine for their medicinal properties and also contain various metabolites, which are chemically and biologically interesting. The compounds isolated from the plant were found to be of varied types viz., diterpenoids, triterpenoids, coumarins, coumarino-lignoids, flavonoids, alkaloids, cyclic peptides and steroids. This is indeed a reflection on the versatility of the enzymatic system present in the plants belonging to Euphorbiaceae. 
There have been a number of important advances in the practical aspects of organic synthesis during the past twenty years. Use of supported reagents has now been developed to a fairly sophisticated level. Yet little mechanistic or kinetic works have been carried out so far with supported reagents. The effectiveness of the inorganic supports in the reactions discussed appears to be due to a combination of factors.
1.   An increase in the effective surface area for reaction.
2.  The presence of pores, which contain both substrate and reactant and thus, lower the entropy of activation of reaction.
3.  A synergism (for displacement reactions) resulting from bringing electrophile and nucleophile into proximity, while at the same time enhancing the nucleophilicity (and basicity) of the latter. The synthetic utility of the reagents however is readily demonstrated.

	As illustrated many reactions can be carried out rapidly and in high yield under mild conditions using supported reagents, whereas attempts to carry out the same reaction with unsupported reagents frequently either fail or result in the formation of mixture of products.
	One important aspect of reaction with supported reagents is that in many cases both the substrate and the product into which it is converted during reaction are strongly absorbed on the surface of the inorganic support or remain intercalated in it. Hence there is very little or no contamination of organic products or solvents by inorganic materials. Reactions are normally carried out in common organic solvents like toluene, ethanol, carbon tetrachloride, dichloromethelene, etc., and isolation of the organic products simply involves decantation or filtration to remove the spent support system followed by evaporation of the solvent. Furthermore, it is possible to remove the active reagents directly from the spent support system by standard inorganic reactions. 
	It is important to realize that the concept of support reagents is not new. Catalytic hydrogenation and numerous other processes which occur at metal and other solid surfaces can properly be classified as examples of supported reagents. Moreover ion exchange resins have been used routinely for esterification, hydration, dehydration, addition and Aldol condensation. Consider, for example the case of reactions run on the surfaces of solids. Though this field is relatively new, it is already apparent to practitioners that one can carryout many synthetically usefully reactions on solids often going faster and/or generally with higher yields than the solution counterparts.
	Organic reactions have been carried out on the surfaces of many solids,1-3  notably zeolite,4,5 clays,6-9 silica gel,10,11 alumina12,13 and polymers,14  all of which have distinctive surface character. Zeolite, both naturally occurring and synthetic is aluminosilicates which possess three dimensional structures with inter connecting channels and cavities. Reactions may take place in the channels or in the cavities if the substrates is small enough or on the exterior of the surface if it is not. Zeolites, which also have exchangeable metal cations have found wide use in the manufacture of gasoline. Clays are aluminosilicate minerals with exchangeable cations but unlike zeolite they possess lamellar or layered structures with interiors available to reactants. 
By contract silica gel and alumina which are widely used in chromatography do not contain accessible channels or cavities. Instead these materials have large surface areas and highly porous exteriors which are available to surfaces. What is more interested to the organic chemist is that alumina and silica gel can be used as catalyst, support and reagent because surface of alumina and silica gel can be modified in a variety of ways and the number of potential environment available for organic reactions is also very large.
As the canidate has carried out some reactions on solid surfaces it is relevant to describe some representative reactions with reagents supported on alumina, silica gel, clay, zeolite and celite







Application of remote sensing and GIS in the analysis of environment of Bay of Bengal

KHAN, MOHAMED

As all sciences in nature, chemistry and biology have become unified at a finer level of specification than that provided by their founding fathers like Darwin and Mendel. Owing to this inter-relation, antiviral chemotherapy has grown out of its infancy and has gone through phenomenal changes in recent times. 
Viruses are not simple cells but are entities of genetic materials (the genome) that possess a nucleic acid that replicates inside the living cells and also have an intrinsic ability to mediate its transfer from one host to another. So, viruses are intracellular parasites that use the machinery of the host to replicate. Hence, basing on the nature of the host cells, the viruses have been subdivided into the plant viruses, animal viruses and bacterial viruses. The animal viruses were further sub classified into the RNA viruses and DNA viruses.
Five DNA viruses are of medical interest and they are Parvoviridae, Papoaviridae, Adenoviridae, Herpesviridae and the Poxviridae.
The herpes viridae comprises of a family of viruses that are widespread in both cold-blooded and warm-blooded animals and they are extremely important pathogens. The diseases caused by herpes viruses are of ever increasing significance as serious medical problems.
Herpes viruses derive their name from the Greek term ‘herpes’ meaning creeping. The earliest herpes viruses were named after the clinical conditions and the diseases that they caused. It was initially used to describe a variety of skin conditions and diseases.
A large family of viruses is currently classified into three subfamilies-the alpha, beta and gamma herpes viridae. Though there is a vast range of non-human herpes viruses, three human herpes viruses, are of considerable medical interest and they belong to alpha sub-family. They are herpes simplex virus type-1 (HSV-1), herpes simplex virus type-2 (HSV-2) and varicella-zoster virus (human herpesvirus-3) Human herpes virus-5 (cytomegallovirus, HCMV), the prototype of beta sub-family is a significant human pathogen. Human herpes virus-4 is the Epstein-Barr (EBV), which is an important member of the gamma sub-family.
The most important biological feature of the herpes virus is that it may remain latent in its primary host for the lifetime. The clinical involvement and medical impact of herpes infection is increased substantially for patients with either drug or disease induced immunodeficiency. Herpes viruses of medical interest also vary greatly in biological properties including the host-range and rate of replication.
Viruses utilize the biochemical machinery of the host cells for their multiplication and in some cases the nuclear apparatus of the host cells. The chemicals that interfere with the virus growth also interact with the normal functions of the host cells. So, the earlier inhibitory drugs used in infection control showed no preferential action on the virus-controlled synthesis compared to host cell synthesis and hence had to be abandoned as antiviral chemotherapeutic agents. This inter-relationship, at many times, frustrated many workers in finding drugs that specifically disrupt the viral replication leaving the host cells undisturbed.
The general strategy for developing successful antiviral drugs owes much to fundamental research into mechanisms of virus replication. It is these efforts that lead to the recognition of target macromolecules suitable for chemical attack. Hence the work continues in the drug discovery process with the ultimate hope of finding antiviral agents for practical use.
Structure activity relationship (SAR) studies are used to optimize the pharmacophore and maximize antiviral activity. Developmental work, new synthetic routes and prodrugs are for improving pharmacokinetic behaviour, increasing metabolic stability or targeting drug delivery. 
The two fundamental approaches that compromises the methodologies of the drug discovery are:
1. Exploration directed towards the comprehension of basic biological mechanisms and rational design of novel therapeutic agents based on this information.
2. Rational pursuit of serendipitous discoveries and mass screening of compounds of varying origins and chemical structure.
However, to date, only the second approach has been proved to be effective in yielding better drugs for antiviral chemotherapy.
The leaves and bark of the South African plant Cryptocarya latifolia have been long sought after for their legendary magical and medicinal properties.1 These properties range from the treatment of headaches and morning sickness to that of cancer, pulmonary diseases, various bacterial and fungal infections. In search to find the molecular origins of these effects, Horn found a series of related 6-substituted 5,6-dihydropyran-2-ones in biologically active hexane and acetone extracts.2 The first isolated was cryptofoline, the simplest structures isolated was the cryptocarya diacetate and cryptocarya triacetate.  The much more complex 1,3-polyol/5,6-dihydro-pyran-2-one natural products3, like Passifloricin A having antifungal activity are also isolated.



	

Drews et al2 in 1995 reported the isolation of cryptocarya diacetate, whose spectral characteristics listed are [α]D +55.8 (c 1.06, CHCl3), IR shows carbonyl frequency at 1733 cm-1 and HRMS shows its M+ as 284.1250. The structure of cryptocarya diacetate was established by using spectral techniques COSY, HECTOR, DQFCOSY, HSQC and HMBC were applied in order to give an unambiguous result. Using above techniques the 1H/1H correlations and all relevant 1H/13C correlations were made. Based on the spectral data they assigned the structure as shown in the Figure 3 without the stereochemical assignment.

	


After two years of its isolation the same group4 assigned the stereochemistry of cryptocarya diacetate. The diacetate was converted to its acetonide, which possesses a chair conformation and 13C NMR data reveals that with one methyl group at axial at δ 19.9 and the other equatorial at δ 30.2. Accordingly the acetoxy groups in cryptocarya diacetate are assigned as syn. Because it is not possible to correlate the stereochemistry of the lactone hydroxy and the neighbouring acetate by NMR due to the intervening freely rotating methylene group, so the absolute stereochemistry at that particular carbon atom of cryptocarya diacetate remains unknown. However the absolute stereochemistry of cryptocarya triacetate was unequivocally determined to be 5R, 7R, 9S, 11S based on Moscher’s method using 1H NMR of the MTPA ester and Rychnovesky’s method using 13C NMR of the acetonide. Although the stereochemistry at C-5 of cryptocarya diacetate was R and 7, 9-syn configuration of diacetate was determined, the absolute stereochemistry at C7 and C9 remains unknown; however, because of the proven stereochemistry of cryptocarya triacetate, it was assumed that the diacetate probably possess a 7S, 9S configuration by an anology.





The chemistry of natural products attracts a very lively interest. New substances, more or less complicated, useful are constantly discovered and their properties investigated. In the course of investigation of complicated substances, the investigator is sooner or later is confronted by the problem of synthesis or the preparation of the substance by chemical method. There can be various motives; perhaps the chemists want to check the correctness of the structure that has been isolated through the synthesis of that molecule. If the substance is of practical importance, one may hope that the synthetic compound will be less expensive or more easily accessible than the natural product. It can also be desirable to modify some details in the structure of the molecule. An antibiotic substance of medicinal importance is often first isolated from a microorganism, perhaps a mould or a germ. There ought to exist a number of related compounds with similar effects. They may be more or less potent. Some may have undesirable secondary effects. It is by no means, or even probable, that the compound produced by the microorganism most likely as a weapon in the struggle for existence is the very best from the medicinal point of view. If it is possible to synthesize the compound, it will also be possible to modify the details of the structure and to find the most effective remedies.
Unlike many one-time discoveries or inventions, the endeavor of total synthesis1 is in a constant state of effervescence and flux. It has been on the move and center stage throughout the twentieth century and continues to provide fertile ground for new discoveries and inventions. The harvest of chemical synthesis touches upon our everyday lives in myriad ways, medicines, high-tech materials for computers, communication and transportation equipment, nutritional products, vitamins, plastics, clothing and tools for biology and physics.
The synthesis of a molecule is however, a very difficult task. Every group, every atom must be placed in its proper positions and this should be taken in its most literal sense. It is sometimes said that organic synthesis is at the same time an exact science and a fine art.
The practice of total synthesis is being enriched constantly by new tools such as new reagents and catalysts as well as analytical instrumentation for the rapid purification and characterization of compounds.
Thus the original goal of total synthesis is to confirm structure of a natural product and exploration and discovery of new chemistry along the pathway to the target molecule.
-Keto enol ethers have been extensively used as key intermediates in organic synthesis. In particular, they have been employed as synthons of natural products 
incorporating a cyclohexenone skeleton (i.e. 4-(2-p-methoxyphenyl)- cyclohexen-2-one isolated from gametophitic tissues of Plagiochila longispina-Lindenb & Gottsche).
-Keto enol ethers are important intermediates in organic synthesis 1-4 and have been used for the preparation of enantiomerically pure compounds 5,6. The synthesis of -keto enol ethers has been reported from -diketones by treatment with diazomethane (1) etherification of cyclic -diketones with alcohols using PTSA under reflux (2) TiCl4 in methanol 7. Another method has been reported from 3-chlorocycloalk-2-enones with methoxide 3,4. Recently Iodine 8 has been used for the synthesis of -keto enol ethers. 
However these methods suffer from the use of toxic reagents and cause environmental problems due to strongly acidic streams. Therefore, a need still exists for versatile, simple and environmentally friendly processes whereby -keto enol ethers may be formed under milder and practical conditions. Over recent years, lanthanide salt mediated Lewis acid reactions 9 have attracted tremendous interest throughout scientific communities due to their low toxicity, ease of handling, low cost and recoverability. Earlier we have shown the catalytic activity of CeCl3.7H2O 10 in synthetic methodology. 



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STUDIES ON TISSUE CULTURE SYSTEM FOR THE PRODUCTION OF FOOD COLOURS FROM BETA VULGARIS L.

SISTLA, SRINIVAS

Many of the global wheat growing areas are subjected to heat stress at some stage of the development. Among these, terminal heat stress causes the maximum damage. In wheat, terminal heat stress reduces grain filling duration, biomass production, and seed weight which affects yield significantly. Stay green trait has been reported to be beneficial in many crops under various stress conditions. 963 germplasm lines from various sources, including Indian and CIMMYT, Mexico, were screened for three consecutive years for stay green expression. Stay green was judged based on single reading at late dough stage using 0-9 scale and leaf area under greenness (LAUG). Out of these germplasm, 5.50% were found to be stay green, 10.59% moderately stay green, and the rest showed some or no stay green. From the above screened germplasm, 100 germplasm lines were selected based on presence and absence of stay green and sown under three different showing dates (timely, late and very late) for three consecutive years, in three replications to find out the association of stay green and heat tolerance. Canopy temperature depression (CTD) was used as selection criteria for heat tolerance, using hand held Infra red thermometer (IRT), at 12h, 14h and 16h at 7days interval, on bright sunny days. Correlation study showed that LAUG and CTD were strongly correlated (r=+0.90). LAUG was also found to be significantly associated with yield traits like grain filling duration (GFD), grain yield, biomass, but its association with test weight was low. CTD showed significant correlation with GFD, grain yield and biomass. It was observed that there was significant association between these traits, under all the sowing dates but the association between CTD, LAUG and test weight was significant only under very late sown conditions. Analysis of variance showed that the difference between genotypes for all the traits under study was significant at both 5% and 1% level of significance. Genotype x Year interaction was found to be non-significant for LAUG and CTD. Genotype x Year x Sowing date was non-significant for LAUG but significant for CTD. T-test done to compare stay green and non-stay green genotypes was found to be significant for all the traits for all the years and under all sowing dates, except for test weight, under timely sown condition. 
Two crosses (stay green resistant verses non stay green susceptible) were studied to establish the genetics of stay green trait and it was found that stay green trait in wheat is governed by more than one genes and show additive gene action. Heritability was moderate (0.73). Also positive association between stay green and resistance to spot blotch disease was found.
This investigation reveals that there exists significant difference between stay green and non-stay green genotypes hence stay green trait along with CTD can be used as an effective selection criteria for tolerance to heat stress and also as an indicator for resistance to spot blotch disease. 
219 pairs of microsatellite markers were used to tag stay green gene in two F7 RILs (stay green vs. non stay green) as mapping population. In Yangmai 6 x Sonalika the markers BARC 109 and BARC 20 and in Ning 8201 x Sonalika WMC 10, WMC 74, and WMC 76 were found to be significantly (p>0.001) linked with stay green trait.

One thousand four hundred and seven spring wheat germplasm lines belonging to Indian and CIMMYT wheat programs were evaluated for stay green (SG) trait and resistance to spot blotch caused by Bipolaris sorokiniana during three consecutive crop seasons, 1999–2000, 2000–2001 and 2001–2002. Disease severity was recorded at six different growth stages beginning from tillering to late milk stage. SG trait was measured by following two approaches: difference for 0–9 scoring of green coloration (chlorophyll) of flag leaf and spike at the late dough stage (GS 87) and a new approach of leaf area under greenness (LAUG). Germplasm lines showed a wide range (7–89) for LAUG and were grouped into four viz., SG, moderately stay green, moderately non-stay green and non-stay green (NSG). However, very few (2.2%) lines showed high expression of SG trait, i.e., LAUG >60. LAUG appeared to be a better measure of SG trait than a 0–9 scale. Mean spot blotch ratings of SG genotypes were significantly lower than those of NSG genotypes at all growth stages. Two spot blotch resistant genotypes (Chirya 3 and Chirya 7) having strong expressions of SG trait were crossed with NSG, spot blotch susceptible cv. Sonalika. Individually threshed F2 plants were used to advance the generations. SG trait and spot blotch severity were recorded in the parents and F1, F3, F4, F5, F6 and F6–7 generations under disease-protected and inoculated conditions. SG trait in the F1 generation was intermediate and showed absence of dominance. Evaluation of progenies (202–207) in the segregating generations revealed that SG trait was under the control of around four additive genes. Lines homozygous for SG trait in F4, F5, F6 and F6–7 generations showed significantly lower mean area under disease progress curve (AUDPC) for spot blotch than those with NSG expression. A positive correlation (0.73) between SG trait and AUDPC further indicated a positive influence of SG on severity of spot blotch. The study established that variation for SG trait exists in spring wheat; around four additive genes control its inheritance in the crosses studied and there is positive association between SG trait and resistance to spot blotch.


Nine hundred and sixty three wheat advanced lines from various sources, including Indian and CIMMYT germplasm, were screened for the presence or absence of staygreen (SG) trait during two cycles, 2003–05. Staygreen was evaluated based on visual scoring (0–9 scale) and a new parameter, Leaf Area under Decline (LAUD). Approximately 5.5% of the lines were found to show staygreen character, 10.6% were moderately staygreen, and the remaining showed some or no expression of this trait. From this germplasm, one hundred lines were selected with the objective to find the effect of staygreen on yield and yield traits. These lines were sown under three different sowing dates (timely, late and very late) for three consecutive years to find the association between staygreen trait and heat tolerance. Canopy Temperature Depression (CTD), used as selection criteria for heat tolerance, was recorded at 12h, 14h and 16h at 7days interval, on bright sunny days. Correlation study showed that LAUD and CTD were strongly correlated (r=0.90). LAUD was also found to be significantly associated with yield traits like grain filling duration (GFD) (r=0.83), grain yield (r=0.89), biomass (r=0.84), but its association with test weight was non-significant. CTD also displayed significant correlation with yield traits like GFD (r=0.78), grain yield (r=0.84) and biomass (r=0.81). There was significant association between grain yield, biomass, and GFD under all the sowing dates but the association between CTD, LAUD and test weight was significant only under very late sown conditions. Genotype x Year interaction was found to be non-significant for LAUD and CTD. Genotype x Year x Sowing date was non-significant for LAUD but significant for CTD. T-test done to compare SG and non-SG genotypes was found to be significant for all the traits for both the years and under all sowing dates, except for test weight, under timely sown condition. This investigation revealed that substantial variation exists for SG trait in wheat and there is significant difference between SG and non-SG genotypes for CTD. Hence, SG trait along with CTD can be used as effective selection criteria for tolerance to heat stress




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