1. Thesis Front Cover - Emboss -...

Chapter 1 Introduction

Chapter 1Chapter 1Chapter 1Chapter 1

1111

The chemistry of heterocyclic compounds is one of the most complex

branches of organic chemistry and has seen unparalleled evolution owing to their

ample natural occurrence, specific chemical reactivity and widespread utility in the

field of therapeutics. The study of heterocyclic compounds is of great concern both

from the theoretical and practical standpoint. It is equally interesting for its theoretical

implications, for the diversity of its synthetic procedures as well as for the

physiological and industrial significance of heterocyclic compounds.

Heterocycles form by far the largest of classical organic synthesis divisions of

organic chemistry and are of immense importance biologically and industrially.

Heterocyclic compounds consist of cyclic structures in which one or more of the ring

atoms are of elements other than carbon. The number of possible heterocyclic systems

is almost limitless, an enormous number of heterocyclic compounds are known and

this number is increasing very rapidly. It has been estimated that more than 65% of all

published chemical studies deal in one way or another with heterocyclic systems.

The imperative part of heterocyclic compounds is drugs, which forms a link

between the natural and the purely synthetic divisions of the subject. Most of the

natural products obtained from plants and animal origin containing heterocyclic

compounds such as alkaloids-nitrogenous bases and glycosides have been used since

historic age as remedial agents. Reserpine alkaloid from Indian Rouwolfia, Febrifuge

from ancient Chinese drug Chang Shan, Curar alkaloid from arrow poison, codeine,

Ψ-tropine and strychinine are the examples of heterocyclic compounds. Synthetic

heterocyclic drugs are used as hypnotics, anticonvulsants, antineoplastics,

antihistaminics, antithyroid agents, antiseptics, antimalarials, herbicides, pesticides,

fungicides, bactericides, antituberculars and vasopressor modifiers. They also find

applications as sensitizers, developers, antioxidants, copolymers etc.

The search for biologically active compounds is the driving force in

pharmaceutical synthesis. Since the majority of new molecules entering clinical

studies contains at least one heterocyclic moiety predominantly N-heterocyclic ones,

the modification of these ring systems plays an important role during drug

development. Thus, there is always a specific need for novel heterocyclic ring

systems, both for finding new hit structures and in optimization of lead compounds. In


2222

the pharmaceutical field, there has always been and will continue to be a need for new

and novel chemical entities with diverse biological activities. Our efforts are focused

on the introduction of chemical diversity in the molecular frame work in order to

synthesizing pharmacologically interesting compounds of widely different

composition.

Since past few decades, a significant increase in microbial diseases has been

witnessed. The incidence of fungal and bacterial infections has increased

dramatically. The infections have soundly affected humankind as well as animals. The

widespread use of antifungal and antibacterial drugs and their resistance against

fungal and bacterial infections has led to serious health hazards. The resistance of

wide spectrum antifungal and antibacterial agents has initiated discovery and

modification of the new antimicrobial drugs. Hence, this class of drugs is the greatest

contribution of the 21st century to medicinal chemistry. Extensive attention has been

focused on the development of more potent and effective antimicrobial agents as the

devotion to the antimicrobial medicine research.

The thesis at hand explores synthesis, characterization and biological studies

of some new biquinoline, pyranoquinoline, benzimidazole, benzothiazole,

benzoxazole and chromene, pyranopyarazole, pyridobenzimidazole derivatives from

the parent compounds 2-aryloxyquinoline and 2-phenyl indole respectively with an

expectation to have healthier biological activity. In favor of this reason, it is much

meaningful here to endow with brief depiction regarding the properties, synthesis and

medicinal applicability of quinoline and indol derivatives.

1.1 QUINOLINE:

Quinoline (1-azanaphthalene or benzo[b]pyridine) is an aromatic nitrogen

containing compound characterized by a double-ring structure where a ben zene ring is

fused to pyridine at two adjacent carbon atoms. Quinoline, a stable base, was first

isolated in an impure state in 1834 by Runge1 from coal-tar distillate. Shortly after the

isolation of quinoline from coal tar it was also recognized as a pyrolytic degradation

product of cinchonamine, an alkaloid closely related to quinine, from which name

quinoline is derived; the word quinine, in turn, derives from quina, a Spanish version

of a local South American name for the bark of quinine-containing Cinchona species.

Gerhardt2 obtained quinoline, probably contaminated by lepidine by distillation of


3333

cinchonine and quinine with caustic alkali and named it quinoleine. This name was

subsequently changed to quinoline by Berzelius.

Quinoline can be prepared from aniline with acrolein under heated sulfuric

acid (Skraup synthesis). Various quinoline compounds can be prepared by Skraup

synthesis using different oxidizing agents. The compounds of quinoline family are

widely used as a parent compound to make drugs (especially anti-malarial medicines),

fungicides, biocides, alkaloids, dyes, rubber chemicals and flavoring agents. They

also have antiseptic, antipyretic and antiperiodic properties. They are also employed

as catalyst, corrosion inhibitor, and preservative and as a solvent for resins and

terpenes as well as in the production of paints. They are used in transition-metal

complex catalyst chemistry for uniform polymerization and luminescence chemistry.

They are recognised as good antifoaming agent in refinery field. Quinaldine, 2-

methylquinoline, is used to synthesize antimalarial drugs and in manufacturing oil

soluble dyes, food colorants, pharmaceuticals, pH indicators and other organic

compounds.

1.1.1 NATURAL OCCURRENCE:

Quinine3 is natural white crystalline alkaloids having antipyretic, antimalarial,

analgesic and anti-inflammatory properties and a bitter taste. It is a stereoisomer of

quinidine. Quinine was the first effective treatment for malaria caused by plasmodium

falciparum, appearing in therapeutic in the 17th century. Raheem et al.4 and Stork et

al.5 have described sterioselective synthesis of quinine.

In 1959, Rao and Cullen6 disclosed the isolation of an initially un-named dark-

brown metabolite of Streptomyces flocculus that exhibited striking activity against

several animal tumors7. Subsequently, the same crystalline compound was isolated

from S. rufochromogenes and S. echinatus. The active agent of all these Streptomyces


4444

and Actinomyces species is streptonigrin8. Since then, intense efforts have been

undertaken towards the isolation of bioactive compounds with variations on the same

molecular framework9, two closely related antibiotics, streptonigrone10 and

lavendamycin, were also isolated. The synthetic chemistry of these natural products

has been extensively studied and discussed in literature11.

Two new pyrroloquinazolinoquinoline alkaloids12 Luotonin A (1) and B (2),

were recently isolated from the aerial parts of Peganum nigellastrum Bunge. Luotonin

A is cytotoxic against the murine leukemia P-388 cell line (IC50=1.8 p.g/mL).

A considerable number of medicinally important alkaloids have been isolated

from the Rutaceae family of plant13. Representative example of this class of

compound includes atanine, the angular alkaloid araliopsine and linear alkaloid

isoplatydesmine. These types of compounds have been shown to exhibit a variety of

pharmacological properties including antimicrobial14, antiviral15, mutagenic16 and

cytotoxic17 activities.


5555

Some of the therapeutically active quinoline alkaloids are reviewed here.

ALKALOID PHARMACOLOGY

Cusparine

Antileishmanial18

Ribalinine

Calcium channel blocker19

Galipeine

Antimalarial and cytotoxic activities20

Buchapine

HIV21

Aaptamine

Cardiac22

Semecarpifoline

Antiplatelet and aggregation23

Cryptolepine

Antimalarial24


6666

1.1.2 SYNTHETIC APPROACH:

Skraup synthesis

The Skraup synthesis25 is probably the most important synthetic route to

quinoline derivatives. Quinoline is produced when aniline, concentrated sulphuric

acid, glycerol and oxidizing agent are heated together. The reaction has been shown to

proceed by dehydration of glycerol to acrolein to which aniline then adds in conjugate

fashion. Acid-catalyzed cyclization produces a 1,2-dihydroquinoline finally

dehydrogenated by oxidizing agent to give the quinoline. The Skraup synthesis is the

best for the ring synthesis of quinoline unsubstituted on the hetero-ring.

Doebner-Von Miller synthesis

This is a modification of Skraup synthesis of quinolines and consists in

heating primary aromatic amine and aldehyde with sulfuric acid. In this synthesis

glycerol is replaced by two molecules of aldehydes26.

The α,β-unsaturated aldehyde, initially formed from two molecules of

aldehydes by acid-catalyzed aldol condensation, reacts with aniline to give secondary

amine. Its cyclization in presence of strong acid and dehydrogenation yields quinoline

homologue. It is believed that the oxidative step is brought about by the action of

schiff base produced in situ (from aniline and aldehyde).

Beyer’s modification of the Dobner-Von Miller synthesis

Substitution of a methyl ketone for the second molecule of aldehyde in

the Dobner- V. Miller synthesis27 results in the formation of a 2,4-disubstituted

quinoline.


7777

Conrad-Limpach Knorr synthesis

In Conrad-Limpach Knorr synthesis28, β-Keto ester, such as ethyl acetoacetate

can react with an aromatic amine in either of two ways. The factors governing the

manner in which the condensation takes place have been greatly clarified by Houser

and Reynolds29.

_______________

Combes method

Combes method30 resembles the Conrad-Limpach-Knorr synthesis so closely

that it must be classed as a variant of this method. Aromatic amines are condensed

with 1,3-diketones and the resulting substances are then ring-closed to 2,4-

disubstituted quinolines.

Friedlaender synthesis

Friedlaender31 obtained quinoline by the condensation of o-amino

benzaldehyde with ketone to form quinoline derivatives. The Friedlaender ring

closure involves two distinct reactions: (1) Schiff base formation between the amino

group of the aniline and the carbonyl group of the acetaldehyde and (2) An internal

Claisen type of condensation between the aryl aldehyde group and the α-hydrogens of

the acetaldehyde. Piperidine is a condensing agent.

Fischer et al.32 on the basis of Friedlaender’s synthesis of quinoline

demonstrated the mode of formation of flavaniline. When acetanilide is heated with


8888

zinc chloride, the acetyl group migrates in part to the ortho position and in part to the

para position. The resulting o-acetyl aniline and p-acetyl aniline then undergo

condensation in sense of Friedlaender’s synthesis of quinoline to yield flavaniline.

NH2

+ NH2N

CH3

Flavaniline

ZnCl2

NHCOCH3

COCH3

H3COC

NH2

Pfitzinger reaction

The reaction is carried out by Pfitzinger33 in 1886, by boiling Isatin with

sodium hydroxide solution and the resultant isatic acid is condensed directly with the

ketone. Isatin is hydrolyzed to an o-amino keto acid which condense with ketones or

acids that have a reactive methylene group.

Gould-Jacobs reaction

In Gould-Jacobs reaction34, aniline or an aniline derivative first reacts with

malonic acid derivative ethyl ethoxymethylenemalonate with substitution of the

ethoxy group by nitrogen. A benzannulation takes place by application of heat to a

quinoline. The ester group is hydrolyzed by sodium hydroxide to the carboxylic acid

followed by decarboxylation again by application of heat to 4-hydroxyquinoline.

Doebner Synthesis

The Doebner reaction35 is a three component coupling of aniline, pyruvic acid

and aldehyde to provide a 4-carboxyl quinoline. It is most commonly associated with

the preparation of 2-aryl quinolines.


9999

1.1.3 BIOLOGICAL SIGNIFICANCE:

A number of derivatives of quinoline serve as valuable therapeutic agents.

Some hundred years ago cinchona bark was introduced for the treatment of malaria

and until very recently quinine has remained the standard remedy for this disease.

Several other synthetic antimalarial drugs are based on quinoline nucleus e.g.

Chloroquine. Ciprofloxacin is effective antibacterial agent in the market.

Some of the therapeutically active quinoline derivatives are reviewed here.

THERAPEUTIC AGENT PHARMACOLOGY

Antimicrobial36

Anti-HCV37

Antimalarial38

Antioxidative39

Anti-hepatitis40


10101010

Antitubercular41

Antileishmanial42

Local anesthetic and

Antiarrhythmic43

Anticancer44

1.1.4 SYNTHESIS AND REACTIONS OF 2-CHLORO-3-FORMYL QUINOLINE:

As the quinoline compounds reported in the thesis have been derived from 2-

chloro-3-formyl quinoline, details regarding its synthesis and reaction are also

reviewed here.

1.1.4A Synthesis of 2-chloro-3-formyl quinoline

In the broad field of quinoline, 2-chloro-3-formyl quinoline possesses a

prominent position in the intermediate category as it can be utilized for the synthesis

of many heterocyclic compounds. There has been relentless interest towards the use

of Vilsmeier-Haack reagent in organic synthesis of several nitrogen and oxygen

heterocycles. The Vilsmeier-Haack reagent (VMH) (Halomethyleneiminium salt)

formed from the interaction of dialkyl formamides such as DMF with POCl3 has

attracted the attention of synthetic organic chemists since its discovery in 1927.45 It is

one of the most commonly used reagents for the introduction of an aldehydic (-CHO)

group into aromatic and heteroaromatic compounds. It is proved to be a mild and

efficient method for the formylation.46-50 The utility of this reagent also explores the

powerful route for the synthesis of substituted 2-chloro-3-formyl quinoline.


11111111

Meth-Cohn Quinoline Synthesis

Mechanism

In the Meth-Cohn quinoline synthesis, the acetanilide becomes a nucleophile

and provides the framework of the quinoline (nitrogen and the 2,3-carbons) and the 4-

carbon is derived from the Vilsmeier reagent. The reaction mechanism51 involves the

initial conversion of an acetanilide into an α-iminochloride by the action of POCl3.

The α-chloroenamine tautomer is subsequently C-formylated by the Vilsmeier reagent

derived from POCl3 and DMF. In examples, where acetanilides are employed, a

second C-formylation, subsequent cyclisation and aromatization by loss of

dimethylamine finally affords 2-chloro-3-formyl quinoline.

P T Perumal and R R Amaresh have reported synthesis of 4-chloro-3-

quinolinecarbaldehyde from o-aminoacetophenone using Vilsmeier reagent.52

M Kidwai and S Jindal have described the method for the preparation of

substituted 2-chloro-3-formyl quinoline starting from acetoacetanilide.53


12121212

P A Pawar, P B Bajare54 and coworkers have also reported synthesis of 2-

chloro-3-formyl-4-methyl quinoline from acetophenone oxime under the Vilsmeier

cyclization conditions.

Rajana et al.55 have recently demonstrated that acetanilides undergo rapid

cyclisation in micellar media to afford 2-chloro-3-formyl quinoline. Cyclisation in the

presence of cetyltrimethylammonium bromide (CTAB) under Vilsmeier-Haack

conditions afforded 2-chloro-3-formyl quinoline in good yield. As the current trend of

green chemistry, they have also synthesized the 2-chloro-3-formyl quinolines using

ultrasound in the presence of micelles like CTAB. Under ultrasonic irradiation the

reaction time were reduced with dramatic enhancement in the yield of reaction products.56

Gupta et al.57 reported the Vilsmeier-Haack cyclisation of acetanilides under

microwave-irradiation using silica as a solid support in solvent-free condition. This

method is rapid and efficient.

1.1.4B Reactions of 2-chloro-3-formyl quinoline

The substituted 2-chloro-3-formyl quinolines are the unique intermediates as

they can be utilized for various functional group interconversions (FGIs).58

The presence of electron rich nitrogen at 1-position and electron withdrawing

formyl group at 3-position activates the chlorine towards various displacement

reactions. Some examples of the displacement reactions of chlorine atom at 2-position

are cited below. Interestingly, these reactions are successful without protecting formyl

group at 3-position.


13131313

The displacement reaction at 2-position of 2-chloro-3-formyl quinoline by 3-

phenyl-5-mercapto-4H-1,2,4-triazole has been reported by Kalluraya et al.59

The displacement reaction at 2-position of 2-chloro-3-formyl quinoline by

allyl alcohol has been reported by Bhuyan et al.60

The formyl group of 2-chloro-3-formyl quinoline also undergoes various

addition and condensation reactions to afford variety of compounds. The formyl

group at 3-position is highly reactive towards hydrazine hydrate, phenyl hydrazine

and hydroxylamine hydrochloride61.


14141414

It also undergoes oxidation and Grignard reactions.

Shrivastava et al.62 described the Grignard reaction of 2-chloro-3-formyl

quinoline.

Rao et al. described the oxidation reaction of 2-chloro-3-formyl quinoline.63

It also reacts with the compounds bearing active methylene group.

B Bhat and coworkers64 have reported the reaction of 2-chloro-3-formyl

quinoline with nitromethane or nitroethane in the presence of sodium acetate in

methanol.

B Singh65 and coworkers have reported synthesis of some new thiopyrano[2,3-

b]quinolines. The reaction sequence involves initial formation of thioquinolone which

upon cyclisation through acrylonitrile affords thiopyrano[2,3-b]quinolines.

Singh et al.66 described the synthesis of pyrano[4,3-b]quinolines from

substituted 2-chloro-3-formyl quinoline.


15151515

I Cikotiene67 has reported the synthesis of new 3-aryl-2-

methoxycarbonylacridines of 2-chloro-3-formyl quinoline.

Synthesis of 2-amino-3H-pyrimido[4,5-b]quinolin-4-ones from cyclization

reaction of 2-chloroquinoline-3-carbonitriles and guanidine hydrochloride was reported

by Chandra et al.68

1.1.4C Reactions of 2-chloro-3-formyl quinoline as per current green chemistry trends

An efficient microwave-assisted synthesis of thienoquinolines is reported

under solvent free conditions from 2-chloro-3-formyl quinolines using K2CO3 as

catalyst.69


16161616

Kidwai et al.70 reported fluorination of 2-chloro-3-formyl quinolines using

microwave.

Naik et al.71 reported Biginelli reaction in which neat reactants were subjected

to react under microwave irradiation using TiO2 as a catalyst.

1.1.4D 2-Chloro-3-formyl quinolines as therapeutic agents

Some of the therapeutically active compounds derived from 2-chloro-3-

formyl quinoline derivatives are reviewed here.

Lamania et al.72 have reported carbodiimide-mediated synthesis and DNA-

binding studies of novel 2-chloro quinoline fused 1,3-thiazolidinones via one-pot

three-component condensation.

M Abdel-Aziz73 and co-workers have synthesized a series of pyrazine-2-

carboxylic acid hydrazide derivatives and screened for their activity against

Mycobacterium tuberculosis.


17171717

Abonia et al.74 have reported one-pot synthesis and antitumor studies of a

library of novel imidazol-2-yl-1H-quinolin-2-one derivatives by the direct reaction of

2-chloroquinolin-3-carbaldehyde with aromatic o-diamines in 70% aqueous acetic

acid.

N Cl

CHO

NH

+

NH2

NH2

70% AcOH

A-15 (20% w/w)

reflux for 1-4 h underair-oxygen

NH

N

O

Kumar et al.75 have synthesized a series of secondary and tertiary quinolinyl

amines by nucleophilic substitution reaction and screened in vitro for their

antimicrobial activity.

Kategaonkar et al.76 have reported synthesis and antimicrobial evaluation of

some new 2-chloro-3-((4-phenyl-1H-1,2,3-triazol-1-yl)methyl)quinoline derivatives

via click chemistry approach.

N ClR2

R3

R1

N

NN

R1 = H, CH3, OCH3, OEt

R2 = H, CH3, OCH3, OEt

R3 = H, CH3, OEt

El-Sayed77 and co-worker have reported the non-steroidal anti-inflammatory

agents derived from 2-chloro-3-formyl quinoline.

S M Roopan78 and co-workers have synthesized 2-(2-chloroquinolin-3-yl)-2,3-

dihydroquinazolin-4(1H)-ones as potential antitumor agents.


18181818

Pokalwar et al.79 have reported synthesis and antibacterial activities of α-

hydroxyphosphonates and α-acetyloxyphosphonates derived from 2-chloro-3-

formylquioline.

N Cl

R1 CHOP(OC2H5)3, TMSCl

Toluene, RefluxN Cl

P

OH

N Cl

R1

R2

R3

P

OCOCH3

DBURT

R2

R3

R1

R3

R2

(CH3CO)2O

OC2H5

OC2H5

OC2H5

OC2H5

O

O

1.1.5 2-ARYLOXYQUINOLINE

Aryloxyquinoline derivatives represent a new class of potent medicinal active

compounds, which prompted our continued endeavor to delineate a pharmacophoric

pattern, from which a putative target might be deduced. On the other hand, from the

synthetic point of view, the presence of a good leaving group ‘-chloro’ on 2-chloro-3-

formyl quinoline encouraged us to synthesize 2-aryloxyquinoline from an easily

available phenols viz. p-cresol, 4-chlorophenol and unsubstituted phenol. Herein we

developed hybrid molecules through the combination of pharmacophores (various 2-

chloro-3-formyl quinolines and different phenols) in one structure which lead to

compounds with increased pharmacological activity.

1.1.5A Synthesis, reactions and biological aspects of 2-aryloxyquinoline

In the large field of quinoline, 2-aryloxyquinoline is the inner core structure

for the synthesis of several bioactive heterocyclic compounds. As about the half of

quinoline compounds reported in the thesis at hand are derived from 2-

aryloxyquinoline, details regarding their synthesis, reaction and biological aspects are

as well reviewed here.

P Mandhane80 and co-workers have described synthesis and antimicrobial

screening of quiazolinones derivatives.


19191919

N Cl

p-cresol

DMF, K2CO3 N OR

NaBH4, MeOH

N OR

PBr3, DCM

OH

N OR

Br+

N

NH

O

NaH, DMF

15-20 minN O

N

N

O

R = H, 5-CH3, 6-CH3, 7-CH3

CHO

R

CHO

R

Mungra et al.81 have described synthesis and identification of 2-

aryloxyquinolines and their pyrano[3,2-c]chromene derivatives as a new class of

antimicrobial and antituberculosis agents.

S T Hazeldine82 and co-workers have described the synthesis of 2-(4-(7-

bromo-4-substituted-quinolin-2-yloxy)phenoxy)propanoic acid in basic reaction

conditions and also reported antitumor activity of synthesized derivatives.


20202020

Ries et al.83 have reported a design and synthesis of novel Amidino-phenoxy

quinoline derivatives as a new class of potential thrombin inhibitors with good

selectivity and remarkably low molecular weight (MW: 335-391) by employing

Suzuki-type coupling and Heck reaction conditions.

NBr

CH3

Cl NBr

CH3

O

CN

NBr

CH3

O

NH2

NH

N

CH3

O

NH2

NH

COOEt

N

CH3

O

NH2

NH

COOEt

H3C

N

CH3

O

NH2

NH

CH3

(a) 4-Hydroxybenzonitrile, DMF, 160 0C, 1 h (b) 2-methyl-phenylboronic acid, Pd(PPh3)4, Na2CO3, toluene, 110 0C, 6 h(c) (E)-ethylcrotonate, Pd(OAc)2, tris-(o-tolyl)phosphine, TEA, xylene, 32 h, 150 0C (d) (1) HCl (g), EtOH, 25 0C; (2)

(NH4)2CO3, EtOH, 12 h, 25 0C (e) allyltributyltin, Pd(PPh3)4, toluene, 15 h, 120 0C(f) RuCl3, NaIO4, H2O/CH2Cl2/CH3CN, 24 h, 25 0C (g) carbonyldiimidazole, THF, EtOH, 2 h, 25 0C

(h) Br(CH2)4Br, NaH, DMSO, 1 h, 40 0C

NBr

CH3

O

CN

a

d

c,d

b,d

e,f,g,h,d

Upadhayaya et al.84 have reported the base catalyzed etherification reaction

and antituberculosis activity of synthesized compounds incorporating 2-

aryloxyquinoline nucleus.

Y Liu85 and coworkers have reported the synthesis quinoline-4-

formamide/acetamides bearing 2-ether linkage as potential phospholipase A2

inhibitors.


21212121

1.2 INDOLE:

The name indole is portmanteau of the words indigo and oleum, since indole

was first isolated by treatment of the indigo dye with oleum. Indole chemistry began

with the study of the dye indigo. Indole is an aromatic heterocyclic nucleus. It has a

bicyclic structure, consisting of a six-membered benzene ring fused to a five

membered nitrogen containing pyrrole ring through the 2- and 3-positions of the

pyrrole nucleus. Indole is called as benzopyrrole. The I.U.P.A.C. name of indole is

1H-benzo[b]pyrrole

The principal commercial source of indole is extraction from coal tar, although

the feasibility of industrial synthesis from starting materials such as aniline, ethylene

glycol and others has also been demonstrated86. Indole itself was first obtained by

Adolf Baeyer by pyrolysis of oxindole with zinc dust in 186687. Oxindole was

obtained from the reduction of isatin which was obtained from oxidizing the natural

insoluble dark blue dye called indigo.

1.2.1 NATURAL OCCURRENCE:

The isolation of tryptophan was first reported by Frederick Hopkins in 1901.88

Tryptophan is one of the 22 standard amino acids, as well as an essential amino acid

in the human diet. It is encoded in the standard genetic code as the codon UGG. Only

the L-stereoisomer of tryptophan is used in structural or enzyme proteins, but the D-

stereoisomer is occasionally found in naturally produced peptides (for example, the

marine venom peptide contryphan).89 The distinguishing structural characteristic of

tryptophan is that it contains an indole functional group. It is an essential amino acid

as demonstrated by its growth effects on rats.


22222222

Tryptamine is a monoamine alkaloid found in plants, fungi, and animals. It

contains an indole ring structure, and is structurally similar to the amino acid

tryptophan, from which it derives its name. Tryptamine is found in trace amounts in

the brains of mammals and is believed to play a role as a neuromodulator or

neurotransmitter.90 The tryptamine chemical structure is the backbone for a group of

compounds termed collectively tryptamines. This group includes many biologically

active compounds, including neurotransmitters and psychedelic drugs.

Serotonin is a monoamine neurotransmitter. Biochemically derived from

tryptophan, serotonin is primarily found in the gastrointestinal (GI) tract, platelets,

and in the central nervous system (CNS) of animals including humans. It is popularly

thought to be a contributor to feelings of well-being and happiness.91

Melatonin is a naturally occurring compound found in animals, plants, and

microbes.92 In animals, circulating levels of the hormone melatonin vary in a daily

cycle, thereby allowing the entrainment of the circadian rhythms of several biological

functions.93 Many biological effects of melatonin are produced through activation of

melatonin receptors94 while others are due to its role as a pervasive and powerful

antioxidant95 with a particular role in the protection of nuclear and mitochondrial

DNA.96

β-Carboline alkaloids are widespread in plants and animals, and frequently act

as Benzodiazepine inverse agonists. As components of the liana Banisteriopsis caapi,

the β-carbolines harmine, harmaline, and tetrahydroharmine play a pivotal role in the

pharmacology of the indigenous hallucinogenic drug ayahuasca by preventing the

breakdown of dimethyltryptamine in the gut by inhibiting monoamine oxidase, thus

making it psychoactive upon oral administration. Some β-carbolines, notably

tryptoline and pinoline, are formed naturally in the human body. The latter is

implicated along with melatonin in the role of the pineal gland in regulating the sleep-


23232323

wake cycle. The β-carboline can link to cerebral benzodiazepine receptors and induce

inverse agonist effects to benzodiazepines, like convulsive, anxiogenic and memory

enhancing effects.97

Physostigmine (also known as eserine from éséré, West African name for the

Calabar bean) is a parasympathomimetic alkaloid, specifically, a reversible

cholinesterase inhibitor. It occurs naturally in the Calabar bean. Physostigmine acts by

interfering with the metabolism of acetylcholine. It is a covalent (reversible - bond

hydrolyzed and released) inhibitor of acetylcholinesterase, the enzyme responsible for

the breakdown of acetylcholine in the synaptic cleft of the neuromuscular junction.98

It indirectly stimulates both nicotinic and muscarinic receptors.

Lysergic acid, also known as D-lysergic acid and (+)-lysergic acid, is a

precursor for a wide range of ergoline alkaloids that are produced by the ergot fungus

and found in the Hawaiian Baby Woodrose and the seeds of Morning glory. Amides

of lysergic acid, lysergamides, are widely used as pharmaceuticals and as psychedelic

drugs (LSD). Lysergic acid received its name as it was a product of the lysis of

various ergot alkaloids.99


24242424

1.2.2 SYNTHETIC APPROACH:

Fischer indole synthesis

The Fischer indole synthesis is a chemical reaction that produces the aromatic

heterocycle indole from a (substituted) phenylhydrazine and an aldehyde or ketone

under acidic conditions.100 The reaction was discovered in 1883 by Hermann Emil

Fischer. Today antimigraine drugs of the triptan class are often synthesized by this

method.

Buchwald modification of the Fischer indole synthesis

Using palladium chemistry developed at MIT by Stephen Buchwald, the

Fischer indole synthesis can be completed using aryl bromides as starting materials.101

Note that this also gives evidence to the fact that hydrazones are potential

intermediates in the classical Fischer indole synthesis.

Gassman indole synthesis

The Gassman indole synthesis involves an one-pot process in which hypohalite,

a β-carbonyl sulfide derivative and a base are added sequentially to an aniline or a

substituted aniline to provide 3-thioalkoxyindoles Raney nickel-mediated

desulfurization produces the parent indole.102


25252525

Bartoli Indole Synthesis

In 1989, Bartoli reported that vinylmagnesium bromide reacted with 2-

nitrotoluene at -40°C in THF to furnish 7-methylindole in 67% yield. The reaction

process also proceeded well with other 2-substituted nitrobenzenes. However, the 3-

or 4-substituted nitrobenzenes provided either no indole products or indoles in poor

yield.103

Madelung Indole Synthesis

In 1912, Madelung reported that o-acetotoluidine and o-benzotoluidme

provided the corresponding 2-methylindole and 2-phenylindole respectively when

heated to 360-380°C with 2 molar equivalents of sodium ethoxide.104

1.2.3 BIOLOGICAL SIGNIFICANCE:

The indole nucleus is found to be very active nucleus in pharmacy field as

several natural alkaloids having indole as their basic ring are found to be

therapeutically active agent. In recent years a lots of synthetic drugs have been

synthesized and used in various disease.

Some of the therapeutically active indole drugs are reviewed here.

THERAPEUTIC AGENT PHARMACOLOGY

Antimicrobial105

Cutaneous TCell

Lymphoma106


26262626

Anti-hypertensive107

Antidepressant108

Anti-psychotic109

Schizophrenia110

Analgesic111

Anti Viral112

Toxin113

1.2.4 SYNTHESIS AND REACTIONS OF 2-PHENYL-1H-INDOLE-3-

CARBOXALDEHYDE:

As the indole compounds reported in the thesis have been derived from 2-

phenyl-1H-indole-3-carboxaldehyde, details regarding its synthesis and reaction are

also reviewed here.


27272727

1.2.4A Synthesis of 2-phenyl-1H-indole-3-carboxaldehyde

In the broad field of indole, 2-phenyl-1H-indole-3-carboxaldehyde possesses

a prominent position in the intermediate category as it can be utilized for the synthesis

of many heterocyclic compounds.

J Qu and coworkers have reported synthesis of 2-phenyl-1H-indole-3-

carboxaldehyde from 2-phenyl-1H-indole using Vilsmeier Haack reaction.114

R S Chavan and A P Khadke, have reported synthesis of 2-phenyl-1H-indole-

3-carboxaldehyde from 2-phenyl-1H-indole using N,N-dimethylformamide and

trichlorophosphate.115

S Paul and coworkers have reported synthesis of 2-phenyl-1H-indole-3-

carboxaldehyde from 2-phenyl-1H-indole using silica gel, N,N-dimethylformamide

and trichlorophosphate under microwave irradiation.116

1.2.4B Reactions of 2-phenyl-1H-indole-3-carboxaldehyde

V N Pathak117 and coworkers have synthesized isooxazole derivatives from

reaction of chalcone and indolylaldoximes resulted from reaction of 2-phenyl-1H-

indole-3-carboxaldehyde with hydroxylamine hydrochloride and triethylamine in

ethyl alcohol.


28282828

W Wang118 and coworkers have prepared 2-phenyl-substituted tryptophan

analogues.

T Janosik119 and coworkers have reported indole-3-carbonyl nitrile via a

masked cyanohydrins silylether as the intermediate followed by oxidation with 2,3-

dichloro-5,6-dicyano-1,4-benzoquinone (DDQ).

S Paul and M Gupta120 have reported chalcone from reaction of 2-phenyl-1H-

indole-3-carboxaldehyde and acetone in water.

B S Hansen121 and coworkers have patented the reaction of 2-phenyl-1H-

indole-3-carboxaldehyde and malonitrile in the presence of piperidine as a catalyst to

give indole-3-ylidenemalononitrile.

S Kumar122 and coworkers have carried out the reaction of 2-phenyl-1H-

indole-3-carboxaldehydes with allyl bromide and indoles afforded unsymmetrical

bis(indolyl)alkanes.


29292929

LG Life Sciences Ltd.123 has patented condensation reaction of 5-chloro-3-

formyl-7-nitro-2-phenyl-1H-indole with 2-oxopiperazine in 1,2-dichloroethane using

sodium tris(acetoxy)borohydride and acetic acid as a catalyst.

1.2.4C 2-Phenyl-1H-indole-3-carboxaldehyde as therapeutic agents

Some of the therapeutically active compounds derived from 2-phenyl-1H-

indole-3-carboxaldehyde derivatives are reviewed here.

R M Rao124 and coworkers have reported pyrazolo-pyrazole derivatives of 2-

phenyl-1H-indole-3-carboxaldehyde which shows antimicrobial activity.

H M Patel125 and coworkers have reported anticancer activity of 2-phenyl-1H-

indole derivatives.

M G Bursavich126 and coworkers have prepared a series of benzofuran-3-one

derivatives as phosphatidylinositol-3-kinases (PI3K) inhibitors.

NH

R1

O

O OH

OH

R2R1 = H, Me, Ph, 4-ClPh, 4-FPh, 2-Pyridyl,

3-Pyridyl, 2-Napthyl

R2 = H, Cl, Br, OMe, OBn


30303030

J S Biradar and B S Sasidhar127 have reported antioxidant and cytotoxic

activity of 2,5-disubstituted indole analogues.

J S Biradar128 and coworkers have evaluated antioxidant and DNA cleavage

activities of indole derivatives.

Indole-3-ylidenemalononitriles have been sythesised and evaluated as inhibiter

for the growth of breast cancer cells by cell cycle arrest in G2/M phase and apoptosis

by Pojarova et al.129

S Vogel130 and coworkers have reported aroyl hydrazones of 2-phenylindole-

3-carbaldehydes as novel antimitotic agents.

R Gupta131 and coworkers have repoted the synthesis and antimicrobial

activity of 5-indolylpyrimido[4,5-d]pyrimidinones.

NH

NH

NH

NHHN

Y

OZ

X

X = H, CH3

Y = Z = O, S


31313131

1.3 ANTIMICROBIAL STUDY:

Humankind has been subjected to infections by microorganisms since before

the dawn of recorded history. Untill after the discovery of bacteria 300 years ago and

subsequent understanding of their role in infection about 150 years ago, there was no

hope for the rational therapy. The past few decades have witnessed a significant

increase in microbial diseases. The infections caused by bacteria and fungi has

affected human as well as animals. Control of microbial population is necessary to

prevent transmission of disease, infection, decomposition, contamination and spoilage

caused by them. Humankind’s personal comforts and convenience depend to a large

extent on the control of microbial population. It has been estimated that the life

expectancy of humans has increased by atleast 10 years since the discovery of

antimicrobial agents for the treatment of microbial infections. Substantial attention

has been focused on developing a more potent and effective anti-microbial agents.

1.3.1 Pathogens:

The microorganisms, or infectious agents or more commonly germs, are

biological agents capable of producing diseases in host are known as pathogens.

There are several substrates and pathways whereby pathogens can invade a host; the

principal pathways have different episodic time frames, but soil contamination has the

longest or most persistent potential for harboring a pathogen.

Pathogens have certain characteristics that they need and use, to cause disease.

These so-called virulence factors have specific functions in the successive steps that

result in an infection. An infection can be seen as a miniature battle between pathogen

and host, the first trying to remain present and to feed and multiply, while the host is

trying to prevent this. The resulting infection is a process with three possible

outcomes: the host wins and the pathogen are removed (possibly with the help of

medication) so that the host can recover; the pathogen win the ultimate battle and kill

their host; or an equilibrium is reached in which host and pathogen live involuntarily

together and damage is minimized.


32323232

1.3.1A Bacterial Pathogens

Bacteria that cause disease are called pathogenic bacteria. Bacteria can cause

diseases in humans, in other animals and also in plants. Some bacteria can only make

one particular host ill; others cause trouble in a number of hosts, depending on the

host specificity of the bacteria. The diseases caused by bacteria are almost as diverse

as the bugs themselves and include infectious diseases such as pneumonia, foodborne

illnesses, tetanus, typhoid fever, diphtheria, syphilis and leprosy and even certain

forms of cancer. Bacterial cells grow and divide, replicating repeatedly to form large

numbers present during an infection or on the surfaces of the body. To grow and

divide, organisms must synthesize or take up many types of biomolecules.

In 1928, a German scientist C. E. Chrenberg first used the term “bacterium” to

denote small microscopic organism with a relatively simple and primitive form of the

cellular organization known as “prokaryotic”. The Danish physician Christian Gram

in 1884 discovered a stain known as Gram stain, which can divide all bacteria into

two classes “Gram positive” and “Gram negative”. The Gram-positive bacteria resist

decolouration with acetone, alcohol and remain stained (methyl violet) as dark blue

color, while Gram-negative bacteria are decolorized. We have used following listed

bacterial pathogens for antibacterial study of synthesized title derivatives.

Gram positive bacterial pathogens

(i) Streptococcus pneumoniae132:

They are lancet-shaped cocci, fermentative aerotolerant anaerobe. Usually,

they are seen as pairs of cocci (diplococci), but they may also occur singly and in

short chains. When cultured on blood agar, they are alpha hemolytic. Individual cells

are between 0.5 and 1.25 micrometers in diameter. They do not form spores and they

are nonmotile. Individual bacteria are between 0.5 and 1.25 micrometers in diameter.

They do not form spores and are non-motile. They are mesophillic, living optimally at

temperatures between 30 and 35 °C. It was isolated in 1881 by Louis Pasteur. The

species was then known as pneumococcus due to its role in the disease, pneumonia. It

was termed Diplococcus pneumonia in 1926 due to its propensity to exist in pairs of

cells and renamed Streptococcus pneumoniae in 1974 because of its formation of

chains in liquid.They are found normally in the upper respiratory tract, including the

throat and nasal passages. It infects the upper respiratory tract and can cause


33333333

pneumonia, as well as infections in other parts of the body such as in the bloodstream

(bacteremia), lining of the brain and spinal cord (meningitis), bones (osteomyelitis),

joints (arthritis), ears (otitis media) and sinuses (sinusitis).

(ii) Clostridium tetani133:

It is a mobile, spore-forming, obligate anaerobic, cannot survive in high

oxygen situations, rod-shaped bacterium, found as spores in soil or as parasites in the

gastrointestinal tract of animals. The rods arrange themselves as pairs and chains as

well as single-celled and do not contain any membrane-bound organelles, such as a

nucleus. Its appearance on gram stain is said to resemble tennis rackets or drumsticks.

It is a non-halophilic bacterium with an optimal temperature of 37 °C, making it

mesophilic. In 1884, Arthur Nicolaier isolated the strychnine-like toxin of tetanus

from free-living, anaerobic soil bacteria. C. tetani produces a potent biological toxin,

tetanospasmin and is the causative agent of tetanus, a disease characterized by painful

muscular spasms that can lead to respiratory failure and, in up to 40% of cases, death.

(iii) Bacillus subtilis134:

They are rod-shaped with rounded ends, more or less strictly, aerobic, found in

soil and vegetation. They are motile and sporulating. They are small in size, occurring

single or in short chains. B. subtilis produces the proteolytic enzyme subtilisin.

Bacillus subtilis grow in the mesophilic temperature range. The optimal temperature

is 25-35 °C and a basic pH of 8. In 1835, the bacterium was originally named Vibrio

subtilis by Christian Gottfried Ehrenberg and renamed Bacillus subtilis by Ferdinand

Cohn in 1872. They can contaminate food; however, they seldom result in food

poisoning. B. subtilis spores can survive the extreme heating that is often used to cook

food and it is responsible for causing ropiness — a sticky, stringy consistency caused

by bacterial production of long-chain polysaccharides — in spoiled bread dough.

Gram negative bacterial pathogens

(i) Salmonella typhi135:

This rod-shaped food born pathogen has adapted to grow under both an

aerobic and anaerobic conditions. It grows best between 35 and 37 °C and pH range

of 3.8 to 9.5. It was discovered by C. J. Eberth in 1880. Its infections cause systemic

infections and typhoid fever in humans. It is killed by heating, 70 °C for 1 min or less.


34343434

Transmission of disease is mainly through food, water or human carriers. S. typhi

usually invades the surface of the intestine in humans, but have developed and

adapted to grow into the deeper tissues of the spleen, liver and the bone marrow.

Symptoms most characterized by this disease often include a sudden onset of a high

fever, a headache and nausea. Other common symptoms include loss of appetite,

diarrhea and enlargement of the spleen (depending on where it is located).

(ii) Vibrio cholerae136:

It has a "comma" shaped cell body and contains a singular polar flagellum

used for motility. It enters the human body through injestion of contaminated food or

water. The bacteria enter the instestine; imbed itself in the villi of absorptive intestinal

cells and releases cholera toxin. The bacteria infects the intestine and increases

mucous production causing diarrhea and vomiting which results in an extreme

dehydration and, if not treated, death. It is usually transmitted through the feces of an

infected person, often by way of unclean drinking water or contaminated food results

in epidermic cholera. Filippo Pacini first discovered V. cholerae in Italy in 1854,

though it was originally believed to be Robert Koch who discovered it thirty years

later in Berlin in 1884.

(iii) Escherichia coli137:

They are rods, 2 to 4 micro by 0.4 micro in size, commonly seen in

coccobacillary form and rarely in filamentous form. Colonies are circular, raised and

smooth and emit a faecal odour. It grows best at 37 °C, through a pH range of 4.4 to

9.0, in the presence or absence of oxygen. Escherichia is discovered by T. Escherich

in 1885. They are normally present in the intestine without causing problems, but a

few types cause illness after consuming contaminated food or water, when the

bacteria produces toxin in the intestine causing diarrhoea. It causes infantile

diarrhoea, gastroenteritis, traveller’s diarrhoea, causes bacillary dysentery, causes

Haemorrhagic colitis, Haemolytic uraemic syndrome (HUS), or Thrombocytopaenic

purpura. It does not form toxin in food, this is formed in the intestine of infected

people. Illness is caused after ingestion of a sufficient number of E.coli when the

bacteria travels through the stomach and small intestine, attaches itself to the inside

surface of the large intestine and causes inflammation of the intestinal wall.


35353535

1.3.1B Fungal Pathogens

Fungi are one of the five kingdoms of life. They are plant-like organisms that

lack chlorophyll. Since they do not have chlorophyll, fungi absorb food from others.

Since they don't use light to make food, they can live in damp and dark places. Fungi

are saprophytic organism, as they grow on dead organic matter such as soil or dead

plant material. Fungi are nonphotosynthetic eukaryotes growing either as colonies of

single cells (yeasts) or as filamentous multicellular aggregate [molds]. Fungi comprise

a eukaryotic kingdom of microbes that are usually saprophytes but can cause diseases

in humans, animals and plants.

The incidence of fungal infections has increased dramatically in the past 20

years. Accordingly, the increase in rates of morbidity and mortality because of fungal

infections has been now recognized as a major problem. Most fungal infections are

due to opportunistic pathogens; these affect people who are already ill or have a

suppressed immune system (e.g. in patients who have been given an organ transplant,

or in AIDS patients), although fungi are common problems in the immunocompetent

population as the causative agents of skin, nail or yeast infections. Most commonly,

fungi grow as pathogen on the skin of animals or people. This is sometimes called

Ringworm symptom. Fungi also cause a number of plant and animal diseases: in

humans, ringworm, athlete's foot and several more serious diseases are caused by

fungi. Because fungi are more chemically and genetically similar to animals than

other organisms, this makes fungal diseases very difficult to treat. Plant diseases

caused by fungi include rusts, smuts and leaf, root and stem rots and may cause severe

damage to crops. Most antibiotics that function on bacterial pathogens cannot be used

to treat fungal infections due to the fact that fungi and their hosts both have eukaryotic

cells. The typical fungal spore size is 1-40 micrometer in length. We have used

following listed fungal pathogens for antifungal study of synthesized title derivatives.

(i) Candida albicans138:

It is a dimorphic fungus. That is, it grows as both mycelium and yeasts. This is

one reason why there were so many names given to this fungus. This fungus is found

among the normal flora of the mouth, digestive tract and vagina of perfectly healthy

people, but under some circumstances and for reasons unknown, it may cause severe

and even fatal infections, with lesions and eruptions of the skin, nails, mouth,


36363636

bronchial tubes and lungs. The reason for this outbreak is difficult to pinpoint since

the fungus is generally present on and within the body of healthy individuals. There

are suggestions that there are special strains of this species that are pathogenic. This is

suggested by the fact that this disease can be contagious and epidemics have occurred.

Predisposition may also play a role in infection. An oral infection known as thrush is

relatively common. There are various infections on the body due to it.

(ii) Aspergillus fumigatus139:

It is a species complex rather than a single species. It is actually composed of

ten species. These species are commonly found in decaying vegetation, especially

when the latter is undergoing microbiological heating, because this complex is

thermophilic, adapted to growing at high temperatures 50-55 ºC. Aspergillus

fumigatus sometimes parasitizes animals, especially birds, infecting mainly lungs and

causing heavy mortality - up to 50% in young turkeys and up to 90% in young chicks.

Heavy losses have also been reported in herring gulls, ostriches and diving ducks in

the wild and in penguins in zoos. The fungus can also invade the embryos of eggs in

incubators and probably does the same in eggs in nest in the wild. It also invades the

uterus of pregnant cattle and grows through the placenta into the fetus, which then

dies and is aborted. It has been estimated that 64% of bovine abortion investigated

were due to infection of A. fumigatus. In people, the disease can lead to a chronic lung

infection which is apparently very contagious. The fungus is thought to cause death,

but that is not certain. In patients that have died and A. fumigatus has been isolated,

many have also had underlying disease that possibly lowered their resistance to the

fungus.

1.3.2 Antimicrobial agents:

The modern era of antimicrobial chemotherapy began following Fleming's

discovery in 1929 of the powerful bactericidal substance penicillin and Domagk's

discovery in 1935 of synthetic chemicals (sulfonamides) with broad antimicrobial

activity. In 1939, Gerhard Domagk, a german Bacteriologist and Pathologist, awarded

the Nobel Prize for discovery of the first synthetic antibacterial compound

“prontosil”.

Antimicrobial agents may be either bactericidal, killing the target bacterium or

fungus or bacteriostatic, inhibiting its growth. Bactericidal agents are more effective,


37373737

but bacteriostatic agents can be extremely beneficial since they permit the normal

defenses of the host to destroy microorganisms. Antimicrobial agents may be

classified according to the type of organism against which they are active i.e.

antibacterial, antiviral, antifungal, antiprotozoal and anthelmintic drugs. It can also be

useful to combine various antimicrobial agents for broadening the activity spectrums

and to minimize the possibility of the development of bacterial resistance. Some

antibiotic combinations are more effective together than the combine effectiveness of

the single agent. This is termed as Synergism. Combination therapy has proved its

value as latest therapy for antimicrobials. Some bacteriostatic agents on novel

combination give bactericidal activity. Sulphamethoxazole is bacteriostatic and

Trimethoprime is also bacteriostatic but combination of both the drugs is now widely

used as a bactericidal combination. Two such bactericidal drugs are also used in

combination therapy. Refampin + Dapsone are used in leprosy, Refampin +

Isoniazide in Tuberculosis. WHO has also approved this type of combination.

Most microbiologists explain that the antimicrobial agents are used in the

treatment of infectious disease: antibiotics, which are natural substances produced by

certain groups of microorganisms. A hybrid substance is a semisynthetic antibiotic,

wherein a molecular version produced by the microbe is subsequently modified by the

chemist to achieve desired properties. Furthermore, some antimicrobial compounds,

originally discovered as products of microorganisms, can be synthesized entirely by

chemical means. In the medical and pharmaceutical worlds, all these antimicrobial

agents used in the treatment of disease are referred to as antibiotics, chemicals that are

produced by living organisms which, even in minute amounts, inhibit the growth of or

kill another organism.

Characteristics of antimicrobial agent

• It should have a wide spectrum of activity with the ability to destroy or inhibit

many different species of pathogenic organisms.

• It should be nonallergenic and nontoxic to the host and without undesirable side

effects.

• It should not eliminate the normal flora of the host.

• It should be able to reach the part of the human body where the infection is

occurring.


38383838

• It should be inexpensive and easy to produce.

• It should be chemically-stable (have a long shelf-life).

• Microbial resistance is uncommon and unlikely to develop.

• It must have solubility in body fluids to be active and can rapidly penetrate body

tissues.

1.3.3 Antimicrobial Susceptibility Testing:

The goal of antimicrobial susceptibility testing is to predict the in vivo success

or failure of antibiotic therapy. Tests are performed in vitro and measure the growth

response of an isolated organism to a particular drug or drugs. The tests are performed

under standardized conditions so that the results are reproducible. The raw data are

either in the form of a zone size or Minimum Inhibitory Concentration (MIC). i.e.

antimicrobial susceptibility testing methods are divided into types based on the

principle applied in each system. All techniques involve either diffusion of

antimicrobial agent in agar or dilution of antibiotic in agar or broth. Even automated

techniques are variations of the above methods. The evaluation can be done by the

following methods:

Diffusion Dilution Diffusion & Dilution

Stokes method

Kirby-Bauer method

Minimum Inhibitory Concentration:

E-Test method i) Broth Dilution Method

ii)Agar Dilution Method

We have used the Broth Dilution method for antimicrobial study

recommended by the National Committee for Clinical Laboratory Standards

(NCCLS) 140.

NCCLS is an international, interdisciplinary, non-profit, non-governmental

organization composed of medical professionals, government, industry, healthcare

providers, educators etc. It promotes accurate antimicrobial susceptibility testing

(AST) and appropriate reporting by developing standard reference methods,

interpretative criteria for the results of standard AST methods, establishing quality

control parameters for standard test methods, provides testing and reporting strategies

that are clinically relevant and cost-effective. Interpretative criteria of NCCLS are


39393939

developed based on international collaborative studies and well correlated with MIC’s

and the results have corroborated with clinical data. Based on study results NCCLS

interpretative criteria are revised frequently. NCCLS is approved by FDA-USA and

recommended by WHO.

1.3.3A Broth Dilution Method:

Dilution susceptibility testing methods are used to determine the minimal

concentration of antimicrobial to inhibit or kill the microorganism i.e. aim of broth

dilution methods is to determine the lowest concentration of the assayed antimicrobial

agent (MIC) that, under defined test conditions, inhibits the visible growth of the

pathogen being investigated. MIC values are used to determine susceptibilities of

pathogen to drugs and also to evaluate the activity of new antimicrobial agents.

This classic method yields a quantitative result for the amount of antimicrobial

agents that is needed to inhibit growth of specific microorganisms. The tube dilution

test is the standard method for determining levels of resistance to an antibiotic.

Following is the typical procedure to carry out Broth Dilution Method.

Procedure for Performing the Broth Dilution Method

• The in vitro antimicrobial activity of the synthesized compounds and standard

drugs were assessed against three representative of Gram-positive bacteria viz.

Streptococcus pneumoniae (MTCC 1936), Clostridium tetani (MTCC 449),

Bacillus subtilis (MTCC 441), three Gram-negative bacteria viz. Salmonella typhi

(MTCC 98), Vibrio cholerae (MTCC 3906), Escherichia coli (MTCC 443) and

two fungi viz. Aspergillus fumigatus (MTCC 3008) and Candida albicans (MTCC

227) and the strains employed for the activity were procured from (MTCC –

Micro Type Culture Collection) Institute of Microbial Technology, Chandigarh.

• Inoculum size for test strain was adjusted to 108 CFUmL-1 (Colony Forming Unit

per milliliter) by comparing the turbidity (turbidimetric method).

• Mueller Hinton Broth was used as nutrient medium to grow and dilute the

compound suspension for the test bacteria and Sabouraud Dextrose Broth used for

fungal nutrition.


40404040

• Ampicillin, Chloramphenicol, Ciprofloxacin and Norfloxacin were used as

standard antibacterial drugs, whereas griseofulvin and nystatin was used as

standard antifungal drugs.

• DMSO was used as diluents / vehicle to get desired concentration of synthesized

compounds and standard drugs to test upon standard microbial strains.

• Serial dilutions were prepared in primary and secondary screening. Each

synthesized compound and standard drugs were diluted obtaining 2000 µgmL-1

concentration, as a stock solution. In primary screening 1000, 500 and 250 µgmL-1

concentrations of the synthesized drugs were taken. The active synthesized

compounds found in this primary screening were further diluted to obtain 200,

125, 100, 62.5, 50, 25, 12.5 and 6.250 µgmL-1 concentrations for secondary

screening to test in a second set of dilution against all microorganisms.

• The control tube containing no antibiotic is immediately sub cultured (before

incubation) by spreading a loopful evenly over a quarter of the plate on a medium

suitable for the growth of the test organism. The tubes are then put for incubation

at 37 °C for 24 hr for bacteria and 48 hr for fungi. The highest dilution (lowest

concentration) showing at least 99 % inhibition or preventing appearance of

turbidity is considered as Minimal Inhibitory Concentration (µgmL−1) i.e. the

amount of growth from the control tube before incubation (which represents the

original inoculum) is compared. A set of tubes containing only seeded broth and

the solvent controls were maintained under identical conditions so as to make sure

that the solvent had no influence on strain growth. The result of this is much

affected by size of the inoculum. The test mixture should contain 108 CFUmL-1

organisms. The protocols were summarized and compared with standard drugs as

the Minimal Inhibitory Concentration (µgmL-1).

1.3.3B Factors Influencing Antimicrobial Susceptibility Testing:

• Choice of media: Consistent and reproducible results are obtained in media

prepared especially for sensitivity testing. Satisfactory media will provide

essentially clear, distinct zones of inhibition 20 mm or greater in diameter.

Unsatisfactory media will produce no zone of inhibition, growth within the zone, or

a zone of less than 20 mm.


41414141

• Size of inoculums: Although large numbers of organisms do not markedly affect

many antibiotics, the ideal inoculum is one, which gives an even dense growth

without being confluent. Overnight broth cultures of organisms and suitable

suspensions from solid media can be diluted appropriately to give optimum

inoculum for sensitivity testing.

• pH: The medium used should have a pH between 7.2 and 7.4 at room temperature

after gelling. If the pH is too low, certain drugs will appear to lose potency (e.g.,

aminoglycosides, quinolones and macrolides), while other agents may appear to

have excessive activity (e.g., tetracyclines). If the pH is too high, the opposite effects

can be expected.

• Moisture: The surface should be moist, but no droplets of moisture should be

apparent on the surface of the medium or on the petri dish covers when the plates are

inoculated.

• Effects of Variation in Divalent Cations: Variations in divalent cations affect

results. Excessive cation content will reduce zone sizes, whereas low cation content

may result in unacceptably large zones of inhibition.

• Testing strains that fail to grow satisfactorily: Only aerobic or facultative

bacteria that grow well on unsupplemented media should be tested on that medium.

Certain fastidious bacteria do not grow sufficiently on unsupplemented media.

These organisms require supplements or different media to grow and they should be

tested on the media.

1.3.3C The Following Conditions must be met for the Antimicrobial

Susceptibility Testing:

• There should be intimate contact between the test organisms and substance to be

evaluated.

• Required conditions should be provided for the growth of microorganisms.

• Conditions should be same through the study.

• Aseptic / sterile environment should be maintained.


42424242

1.4 ANTIMYCOBACTERIAL STUDY:

Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium

tuberculosis, which is responsible for the deaths of about 1 billion people during the

last two centuries. According to world health organization (WHO), approximately

1.86 billion people, that is, 32%, of the world population is infected with

Mycobacterium tuberculosis (MTB). WHO estimates about 8 million new active

cases of tuberculosis (TB) per year and nearly 2 million deaths each year, that is, 5000

people every day. In India alone, one person dies of TB every minute. HIV positive

patients are more susceptible to MTB with a 50-fold risk increase over HIV negative

patients. TB is currently to blame for 13% of the number of deaths due to HIV

infection.

1.4.1 Mycobacterium tuberculosis

General Characteristics

Mycobacterium tuberculosis is the etiologic agent of tuberculosis in humans.

Humans are the only reservoir for the bacterium. First discovered in 1882 by Robert

Koch, Mycobacterium tuberculosis is a fairly large nonmotile rod-shaped bacterium

distantly related to the actinomycetes. Many non pathogenic mycobacteria are

components of the normal flora of humans, found most often in dry and oily locales.

The rods are 2-4 micrometers in length and 0.2-0.5 um in width.

Mycobacterium tuberculosis is an obligate aerobe. For this reason, in the

classic case of tuberculosis, MTB complexes are always found in the well-aerated

upper lobes of the lungs. The bacterium is a facultative intracellular parasite, usually

of macrophages, and has a slow generation time, 15-20 hours, a physiological

characteristic that may contribute to its virulence.

M. tuberculosis requires oxygen to grow. It does not retain any bacteriological

stain due to high lipid content in its wall, and thus is neither Gram positive nor Gram

negative; hence Ziehl-Neelsen staining, or acid-fast staining, is used. Mycobacterium

species, along with members of a related genus Nocardia, are classified as acid-fast

bacteria due to their impermeability by certain dyes and stains. Despite this, once

stained, acid-fast bacteria will retain dyes when heated and treated with acidified

organic compounds. One acid-fast staining method for Mycobacterium tuberculosis is


43434343

the Ziehl-Neelsen stain. When this method is used, the MTB, smear is fixed, stained

with carbol-fuchsin (a pink dye), and decolorized with acid-alcohol. The smear is

counterstained with methylene-blue or certain other dyes. Acid-fast bacilli appear

pink in a contrasting background.

M. tuberculosis divides every 15-20 hours, which is extremely slow compared

to other bacteria, which tend to have division times measured in minutes (Escherichia

coli can divide roughly every 20 minutes). Tubercle bacilli are aerobes, grow slowly

(generation time 14-15 hours), optimum temperature 370C, pH 6.4-7.0. They grow

only in specially enriched media containing egg, asparagines, potatoes, serum and

meat extracts. Colonies appear in 2-6 weeks. Two media are used to grow MTB

Middlebrook's medium which is an agar based medium and Lowenstein-Jensen

medium which is an egg based medium. MTB colonies are small and buff colored

when grown on either medium. Both types of media contain inhibitors to keep

contaminants from out-growing MT. It takes 4-6 weeks to get visual colonies on

either type of media.

Colonies of Mycobacterium tuberculosis on Lowenstein-Jensen medium

The drug susceptibility test may be performed by either the direct or the

indirect method.

The direct drug susceptibility test is performed by using a subculture from a

primary culture as the inoculum.


44444444

1.4.2 Antimycobactrial Susceptibility Testing:

EVALUTION TECHNIQUES:-

Three well-known measures of sensitivity test are available:

(1) The minimal inhibitor concentration or the MIC,

(2) The resistance ratio or the RR, and

(3) The proportion method.

These tests are set up on solid media.

(1) The minimal inhibitor concentration:

MIC is defined as the minimal concentration of the drug required to inhibit the

growth of the organisms, where growth is defined as 20 colonies or more .This

definition of growth is chosen so that only a small proportion (e.g. 1%) of wild strains

would be classified as resistant by its use. This method is simple and be carried out

with a single drug containing slope although it is preferable to use more than one

slope.

(2) Resistance ratio:

This consists of expression the resistance as a ratio of the MIC of a test strain

to that of control strain. This procedure calls for a rigid standardization since the

inherent technical errors usually make it less efficient than the MIC method in

distinguishing sensitive and resistant strains. A further disadvantage of the use of RR

is that there may be more variation in sensitivity of the control strain than in wild

strain resulting in increase in the error. However, the RRs’ are more than one slope.

(3) Proportion method:

This method of testing sensitivity has a high degree of precision. The

inoculum suspension is standardized by weight of the bacilli and serial ten-fold

dilution of the suspension are made for seeding onto drug free and drug containing

slopes.

We have used the minimal inhibition concentration to evaluate the anti-

tuberculosis activity.


45454545

It is one of the non automated in vitro bacterial susceptibility tests. This classic

method yields a quantitative result for the amount of antimicrobial agents that is

needed to inhibit growth of specific microorganisms. It is carried out in bottle.

Determination of minimal inhibition concentrations by L.J slope method:

Methods used for primary and secondary screening:

Each synthesized drug was diluted obtaining 2000 µgmL-1 concentration, as a stock

solution.

Primary screen: In primary screening 250 µgmL-1 concentration of the synthesized

drugs were taken. The active synthesized drugs found in this primary screening were

further tested in a second set of dilution against all microorganisms.

Secondary screen: The drugs found active in primary screening were similarly

diluted to obtain 500 µgmL-1, 250 µgmL-1, 200 µgmL-1, 125 µgmL-1, 100 µgmL-1, 50

µgmL-1, 25 µgmL-1, 12.5 µgmL-1, 6.25 µgmL-1, 3.125 µgmL-1 and 1.5625 µgmL-1

concentrations.

A primary screen was conducted at 250 µg/mL against M. tuberculosis H37Rv

by Lowenstein-Jensen (LJ) MIC method141 where primary 250 µg/mL dilution of each

test compound were added to liquid Lowenstein-Jensen Medium and then media were

sterilized by inspissation method. A culture of M. tuberculosis H37Rv growing on

Lowenstein-Jensen Medium was harvested in 0.85% saline in bijou bottles. DMSO

was used as vehicle to get desired concentration. These tubes were then incubated at

37°C for 24 h followed by streaking of M. tuberculosis H37Rv (5 × 104 bacilli per

tube). These tubes were then incubated at 37°C. Growth of bacilli was seen after 12,

22, and finally 28 days of incubation. Tubes having the compounds were compared

with control tubes where medium alone was incubated with M. tuberculosis H37Rv.

The concentration at which complete inhibition of colonies occurred was taken as

active concentration of test compound. The standard strain M. tuberculosis H37Rv

was tested with known drug Isoniazide and Rifampicin. The screening results are

summarized as % inhibition relative to standard drug Isoniazide and Rifampicin.

Compounds effecting < 90% inhibition in the primary screen were not evaluated

further. Compounds demonstrating at least 90% inhibition in the primary screen were

re-tested at lower concentration (MIC) in a Lowenstein-Jensen medium.


46464646

1.5 PRESENT STUDY

The present work involves synthesis of new heterocyclic compounds bearing

2-chloroquinoline, 2-aryloxyquinoline and 2-phenyl indole as a parent moiety.

Literature survey reveals that quinoline and indole derivatives possess a tremendous

therapeutic activity. The aim of the present investigation is to synthesize some new

quinoline and indole derivatives with a hope to have fascinating antimicrobial activity

along with better antituberculosis activity. With this aim and objective, various new

biquinoline, pyranoquinoline, benzimidazole, benzothiazole and benzoxazole

derivatives of 2-chloroquinoline and 2-aryloxyquinoline as well as chromene,

pyranopyarazole and pyridobenzimidazole derivatives of 2-phenyl indole have been

synthesized. The various synthesized intermediates, the newly synthesized

compounds, their characterization and biological studies have described

systematically in different chapters.

CHAPTER 2:

Part I: Synthesis, characterization and in vitro antimicrobial and

antituberculosis evaluation of new β-aryloxyquinolines and their N-aryl

biquinoline derivatives


47474747

Part II: Synthesis, characterization and in vitro antimicrobial and

antitubercular activity of new N-cyclopropyl biquinoline derivatives

CHAPTER 3:

Part I: Conventional and microwave-assisted synthesis, characterization

and in vitro antimicrobial evaluation of new pyrano[2,3-c]pyrazole derivatives

bearing indole nucleus

Part II: Microwave-assisted synthesis, characterization and in vitro

antimicrobial evaluation of 3'-indolyl substituted 4H-chromenes catalyzed by an

organocatalyst DMAP


48484848

Part III: An efficient one-pot synthesis, characterization and in vitro

antimicrobial activity of new pyrido[1,2-a]benzimidazole derivatives bearing the

indole nucleus

CHAPTER 4

Synthesis, characterization and in vitro antimicrobial and antitubercular

activity of new quinoline based pyrano[3,2-c]quinoline derivatives catalyzed by

L-proline under aqueous media


49494949

CHAPTER 5:

An efficient synthesis, characterization and in vitro antimicrobial and

antitubercular activity of new benzimidazole, benzothiazole and benzoxazole

derivatives incorporated with quinoline nucleus via thioether linkage

REFERENCES:

1. Runge Ann Physik and Chem 31 (1834) 265.

2. Gerhardt Ann Chim et Phys 7 (1842) 251.

3. R E McGrew Encyclopedia of Medical History McGraw-Hill NewYork (1985)

166.

4. I T Raheem, S N Goodman, E N Jacobsen J Am Chem Soc 126 (2004) 706.

5. G Stork, D Niu, A Fujimoto, E R Koft, J M Balkovec, J R Tata, G R Dake J Am

Chem Soc 123 (2001) 3239.

6. K V Rao, W P Cullen Antibiot Annu (1959) 950.

7. M A Chirigos, J W Pearson, T S Papas, W A Woods, H B Wood, G Spahn Cancer

Chemother Rep 57 (1973) 305; T J McBride, J J Oleson, D R Woolf Cancer Res

26 (1966) 727.

8. M G Brazhbikova, I N Ponomarenko, E B Kovsharova, E B Kruglyak, V V

Proshlyakova Antibiotiki 13 (1968) 99.

9. H Wang, S L Yeo, J Xu, X Xu, H He, F Ronca, A E Ting, Y Wang, V C Yu, M M

Sim J Nat Prod 65 (2002) 721.

10. A J Herlt, R W Rickards J P Wu J Antibiot 38 (1985) 516; M N

Preobrazhenskaya, N V Holpne-Kozlova, E I Lazhko, J Antibiot 45 (1992) 227.

11. S Hibino Heterocycles 6 (1977) 1485; W A Remers The chemistry of antitumor

antibiotics 2 (1998) 229.


50505050

12. Z Z Ma, Y Hano, T Nomura, Y J Chen Heterocycles 46 (1997) 541 ; W J Stichenmyer,

E K Winsky, R C Donehower, S H Kaufmann J Nat Cancer Inst 85 (1993) 271; I

Pendrak, S Barney, R Wittrock, D M Lambert, W D Kingsbury J Org Chem 59 (1994)

2623; I Pendrak, R Wittrock, W D Kingsbury J Org Chem 60 (1995) 3249.

13. J P Michael Nat Prod Rep 17 (2000) 603.

14. M F Grundon, N J McCorkindale J Chem Soc (1957) 2177.

15. B Wolter, V Eilert Planta Med 13 (1981) 166.

16. J B Hudson, E A Graham, G C Chan G H N Towers Photochem Photobiol 42

(1985) 523.

17. M Mizuta, H Kannamori Mutat Res 144 (1985) 221.

18. A Fournet, A A Barrios, V Munoz, R Hocquemiller, A Cavo, J Bruneton,

Antimicrobi Agents Chemother (1993) 859.

19. A Rahman, A Khalid, N Sultana, M N Ghayur, M A Mesaik, M R Khan, A H

Gilani, M I Choudary J Enzy Med Chem 21 (2006) 703.

20. M A Yoon, T S Jeong, D S Park, M Z Xu, H W Oh, K B Song, W S Lee, H Y

Park Biol Pharm Bull 29 (2006) 735.

21. J L McCormick, T C McKee, J H Cardellina, M R Boyd, J Nat Prod 59 (1996)

469.

22. B Cuia, H Chaia, Y Donga, F D Horgena, B Hansenb, D A Madulidc, D D

Soejartoa, N R Farnswortha, G A Cordella, J M Pezzutoa, A D Kinghorna

Phytochemistry 52 (1999) 95.

23. I S Chen, H F Chen, M J Cheng, Y L Chang, C M Teng, I Tsutomu, J J Chen, I L

Tsai, J Nat Prod 64 (2001) 1143.

24. C W Wright, J A Kyereme, A G Breen, J E Brown, M F Cox, S L Croft, Y

Gokcek, H Kendrick, R M Philips, P L Pollet J Med Chem 44 (2001) 3187.

25. Skraup Chem Ber 13 (1880) 2086.

26. Dobner, V Miller Chem Ber 14 (1881) 2812; Campbell, Schaffner J Am Chem Soc

67 (1945) 86.

27. Beyer J Parkt Chem 33 (1886) 393.

28. R H Reitsema Chem Rev 47 (1948) 47.

29. Houser, Reynolds J Am Chem Soc 70 (1948) 2402.

30. A Combes Bull Soc Chim France 49 (1888) 89.

31. P Friedlaender Chem Ber 15 (1882) 2572.

32. O Fischer, C Rudolph Chem Ber 15 (1882) 1500; E Besthom, O Fischer Chem Ber

16 (1883) 68.

33. Pfitzinger J Prakt Chem 33 (1886) 100.


51515151

34. R Gordon Gould, W A Jacobs J Am Chem Soc 61 (1939) 2890.

35. O Doebner Chem Ber 20 (1887) 277.

36. W Cieslik, R Musiol, J Nycz, J Jampilek, M Vejsova, M Wolff, B Machura, J

Polanski Bioorg Med Chem 20 (2012) 6960.

37. H K Peng, C K Lin, S Y Yang, C K Tseng, C C Tzeng, J C Lee, S C Yang, Bioorg

Med Chem Lett 22 (2012) 1107.

38. H Hussain, S Specht, S R Sarite, A Hoerauf, K Krohn, Eur J Med Chem 54 (2012)

936.

39. Z Q Liu, K Han, Y J Lin, X Y Luo Biochimica et Biophysica Acta 97 (2002) 1570.

40. Y L Chen, J Zacharias, R Vince, R J Geraghty, Z Wang, Bioorg Med Chem Lett

20 (2012) 4790.

41. Y Bai, Lijuan W, Y Chen, L Yuan, W Xu, T Sun, J Mol Structure 1005 (2011)

113.

42. J D C Herenknecht, G Panchal, N Garbi, E Prina, A Fournet, C Bories, B Figadere, R

Hoequemmiller, P M Loiseau Biomedicine & Pharmacotherapy 61 (2007) 441.

43. F E Goda, A M Alaa, A Aziz, H A Ghoneim Biorg Med Chem 13 (2005) 3175.

44. C H Tseng, Y L Chen, C L Yang, C M Cheng, C H Han, C C Tzeng, Bioorg Med

Chem, 20 (2012) 4397.

45. A Vilsmeier, A Haack Berichte 60 (1927) 119.

46. C M Marson Tetrahedron 48 (1992) 3659.

47. C Jutz Advance in org chem (1976) 225.

48. S S Eshadri J Sci Ind Res 32 (1973) 128.

49. O M Cohn Heterocycles 35 (1993) 539.

50. O M Cohn, D L Taylor J Chem Soc Chem Commun (1995) 1463.

51. O M Cohn, B Narine, B J Tamowski J Chem Soc Perkin Trans I (1981) 1520.

52. R R Amaresh, P T Perumal Indian J Chem 36B (1997) 541.

53. M Kidwai, S Jindal, S Kohli Indian J Chem 39B (2002) 462.

54. P A Pawar, P B Bajare, S B Munande J Ind Chem Soc 87 (1990) 685.

55. M M Ali, Tasneem, K C Rajana, P K Saiprakash Synlett (2001) 251.

56. M M Ali, Tasneem, K C Rajana, P K Saiprakash Synth Commun 32 (2002) 1351.

57. S Paul, M Gupta, R Gupta Synlett (2000) 1115.

58. A Srivastava ,R M Singh Indian J Chem 44B (2005) 1868.

59. B Kalluraya, J Nayak, A Adhikari, K V Sujith, N S Shetty, M Winter Phosphorus

Sulfur and Silicon 183 (2008) 1870.


52525252

60. P K Kalita, B Baruah, P J Bhuyan Tetrahedron Lett 47 (2006) 7779.

61. O M Cohn, B Narine, B Tarnowski, R Hayes, A Keyzad, S Rhouati, A Robinson,

J Chem Soc Perkin Trans 1 (1981) 2509.

62. R P Shrivastava, Neelima, A P Bhaduri Indian J Chem 26B (1987) 418.

63. K R Rao, N Bhanumathi, P B Sattur Asian J Chem 16(2) (2004) 848.

64. B Bhat, A P Bhaduri Indian J Chem 21B (1982) 729.

65. B Singh, A Chandra, M Asthana, R M Singh, Tetrahedron Lett 53 (2012) 3242.

66. B Singh, A Chandra, S Singh, R M Singh, Tetrahadron 67 (2011) 505.

67. I Cikotiene, Tetrahedron Lett 50 (2009) 2570.

68. A Chandra, S Upadhyay, B Singh, N Sharma, R M Singh, Tetrahedron 67 (2011)

9219.

69. B P Nandeshwarappa, D B Arunakumar, H S Bhojyanaik, K M Mahadevan J

Sulfur Chem 26(4) (2005) 373.

70. M Kidwai, P Saprer, K Bhushan Indian J Chem 38B (1999) 114.

71. H R Prakash Naik, H S Bhojya Naik, T Aravinda African J Pure and Appl Chem

3(9) (2009) 202.

72. D S Lamania, K R V Reddya, H S B Naika, H R P Naika, L R Naik J Sulfur Chem

31(1) (2010) 49.

73. M Abdel-aziz, M H Abdel-Rahman Eur J Med Chem 45 (2010) 3384.

74. R Abonia, J Castillo, P Cuervo, B Insuasty, J Quiroga, A Ortíz, M Nogueras, J

Cobo Eur J Org Chem 2 (2010) 317.

75. S Kumar, S Bawa, D Kaushik, B P Panda Arch Pharma Chem Life Sci 344 (2011)

474.

76. A H Kategaonkar, P V Shinde, A H Kategaonkar, S K Pasale, B B Shingate, M S

Shingare Eur J Med Chem 45 (2010) 3142.

77. El-Sayed, A Ola, El-Samary, Mona, Khillil, A Mounier Alexandria J Pharm Sci

10 (1996) 43.

78. S M Roopan, F N Khan, J S Jin, R S Kumar Res Chem Intermed 37 (2011) 919.

79. R U Pokalwar, R V Hangarge, P V Maskeb, M S Shingare ARKIVOC (xi) (2006) 196.

80. P G Mandhane, R S Joshi, P S Mahajan, M D Nikam, D R Nagargoje, C H Gill

Arabian J Chem (2011) DOI:10.1016/j.arabjc.2011.01.025.

81. D C Mungra, M P Patel, D P Rajani, R G Patel Eur J Med Chem 46 (2011) 4192.

82. S T Hazeldine, L Polin, J Kushner, K White, T H Corbett, J Biehl, J P Horwitz

Bioorg Med Chem 13 (2005) 1069.


53535353

83. U J Ries, H W M Priepke, N H Hauel, E E J Haaksma, J M Stassen, W Wienen, H

Nar Bioorg Med Chem Lett 13 (2003) 2291.

84. R S Upadhayaya, G M Kulkarni, N R Vasireddy, J K Vandavasi, S S Dixit, V

Sharma, J Chattopadhyaya Bioorg Med Chem 17 (2009) 4681.

85. Y Liu, Y Feng, R Wang, Y Gao, L Lai Bioorg Med Chem Lett 11 (2001) 1639.

86. R J Sundberg, Indoles, Academic Press Limited, New York, 1996, 1.

87. A Baeyer, C A Knop Ann. 140 (1866) 1.

88. F G Hopkienns, S W Cole J. Physiol. (Lond.) 27 (1901) 4.

89. P K Pallaghy, A P Melnikova, E C Jimenez, B M Olivera, R S Norton

Biochemistry 38(35) (1999) 11553.

90. R S Jones Progress in Neurobiology 19(1-2) (1982) 117.

91. S N Young Rev. Psychiatr. Neuroscience 32(6) (2007) 394.

92. S D Paredes, A Korkmaz, L C Manchester, D X Tan, R J Reiter J Exp Bot 60(1) (2009)

57.

93. A Altun, B Ugur-Altun Int J Clin Pract 61(5) (2007) 835.

94. J A Boutin, V Audinot, G Ferry, P Delagrange Trends Pharmacol Sci 26(8) (2005) 412.

95. R Hardeland Endocrine 27(2) (2005) 119.

96. R J Reiter, D Acuña-Castroviejo, D X Tan, S Burkhardt Ann N Y Acad Sci 939 (2001)

200.

97. P Venault, G Chapouthier Scientific World Journal 7 (2007) 204.

98. B G Katzung, S Masters, A Trever Basic and Clinical Pharmacol McGraw Hill. 2009,

p. 110. ISBN 978-0-07-160405-5.

99. P L Schiff Am J Pharm Educ 70(5) (2006) 98.

100. E Fischer, F Jourdan Berichte der Deutschen Chemischen Gesellschaft 16(2) (1883)

2241.

101. S Wagaw, B H Yang, S L Buchwald J Am Chem Soci 120(26) (1998) 6621.

102. P G Gasman, T J van Bergen, D P Gilbert, B W Cue J Am Chem Soc 96 (1974) 5495.

103. G Bartoli, G Palmieri, M Bosco, R Dalpozzo Tet Lett 30 (1989) 2129.

104. W Madelung Ber. Dtsch. Chem. Ges. 45 (1912) 1128.

105. R Puri, V Palit, P M Loadman, M Flannigan, T Shah, G A Choudry, S Basu, J

A Double, G Lenaz, S Chawla, M Beer, C V Kalken, R d Boer, J H Beijnen, C

J Twelves, R M Phillips The J. Urology 176(4) (2006) 1344.

106. H M Prince, M Bishton, Hematology Meeting Reports (Parkville, Australia: Peter

MacCallum Cancer Centre and University of Melbourne) 3(1) (2009) 33.


54545454

107. P Cook, I James N Engl J Med 305(26) (1981) 1560.

108. Faltus, F Geerling Neuropsychobiology 12(1) (1984) 34.

109. Hall, Chapman, P H Rhodes, Dictionary of organic compounds. London: Chapman &

Hall. 1996.

110. G Gründer, H Wetzel, E Hammes, O Benkert Psychopharmacology 111(1) (1993)

123.

111. M R Bell, T E D'Ambra, V Kumar, M A Eissenstat, J L Herrmann, J R Wetzel, D

Rosi, R E Philion, S J Daum J Med Chem 34(3) (1991) 1099.

112. I A Leneva, R J Russell, Y S Boriskin, A J Hay Antiviral Res 81(2) (2009) 132.

113. H Wieland, W Konz, H Mittasch, Justus Liebigs Annalen der Chemie 513 (1934) 1.

114. J Qu, N Kumar, M Alamgir, D S Black Tet Lett 50 (2009) 5628.

115. R S Chavan, A P Khadke Asian J Chem 24(6) (2012) 2711.

116. S Paul, M Gupta, R Gupta Synlett, 8 (2000) 1115.

117. V N Pathak, M Jain, A Tiwari The New J Org Synth 40(5) (2008) 493.

118. W Wang, M Cai, C Xiong, J Zhang, D Trivedi, V J Hruby Tetrahadron 58

(2002) 7365.

119. T Janosik, A L Johnson, J Bergman Tetrahadron 58 (2002) 2813.

120. S Paul, M Gupta Synth Comm 35(2) (2005) 213.

121. B S Hansen, T K Hansen, S Tullin, M C Jorgensen, US2004/138301, (2004) (A1)

English

122. S Kumar, V Kumar, S Chimni Tet Lett 44 (2003) 2101.

123. LG Life Sciences Ltd. WO2009/25478, (2009) (A1) English

124. R M Rao, G N Reddy, J Sreeramulu Der Pharma Chemica 3(5) (2011) 301.

125. H M Patel, N Darji, J Pillai, B Patel Inter J Institutional Pharm Life Sci 2(4)

(2012) 2249.

126. M G Bursavich, N Brooijmans, L Feldberg, I Hollander, S Kim, S Lombardi, K

Park, R Mallon, A M Gilbert Bioorg Med Chem Lett 20 (2010) 2586.

127. J S Biradar, B S Sasidhar Eur J Med Chem 46 (2011) 6112.

128. J S Biradar, B S Sasidhar, R. Parveen Eur J Med Chem 45 (2010) 4074.

129. M Pojarova, D Kaufmann, R Gastpar, T Nishino, P Reszka, P J Bednarski, E V

Angerer Bioorg Med Chem 15 (2007) 7368.

130. S Vogel, D Kaufmann, M Pojarova, C Müller, T Pfaller, S Kühne, P J Bednarski,

E V Angerer Bioorg Med Chem 16 (2008) 6436.

131. R Gupta, A Jain, R Joshi, M Jain Bull Korean Chem Soc 32(3) (2011) 899.


55555555

132. URL: http://en.wikipedia.org/wiki/Streptococcus_pneumoniae

http://www.textbookofbacteriology.net/S.pneumoniae.html

133. URL: http://en.wikipedia.org/wiki/Clostridium_tetani

http://www.britannica.com/EBchecked/topic/122245/Clostridium-tetani

http://www.textbookofbacteriology.net/clostridia.html

134. URL: http://en.wikipedia.org/wiki/Bacillus_subtilis

http://www.thelabrat.com/restriction/sources/Bacillussubtilis.shtml

http://www.textbookofbacteriology.net/Bacillus.html

135. URL: http://web2.uconn.edu/mcbstaff/graf/Student%20presentations

/Salmonellatyphi/Salmonellatyphi.html

http://en.wikipedia.org/wiki/Salmonella

http://www.sanger.ac.uk/Projects/S_typhi/

http://www.textbookofbacteriology.net/salmonella.html

http://www.britannica.com/EBchecked/topic/519550/Salmonella-typhi

http://microbes.historique.net/typhi.html

136. URL: http://en.wikipedia.org/wiki/Vibrio_cholerae

http://www.textbookofbacteriology.net/cholera.html

http://microbes.historique.net/cholerae.html

137. URL: http://en.wikipedia.org/wiki/Escherichia_coli

http://emedicine.medscape.com/article/217485-overview

http://familydoctor.org/online/famdocen/home/common/digestive

/disorders/242.html

http://www.textbookofbacteriology.net/e.coli.html

138. URL: http://en.wikipedia.org/wiki/Candida_albicans

139. URL: http://en.wikipedia.org/wiki/Aspergillus_fumigatus

http://www.aspergillus.org.uk/

140. National Committee for Clinical Laboratory Standards (NCCLS), 940, West

Valley Road, Suite 1400, Wayne, Pennsylvania 19087-1898, USA. Performance

Standards for Antimicrobial Susceptibility Testing; Twelfth Informational

Supplement. NCCLS document (2002) M100-S12 (M7) [ISBN 1-56238-454-6].

141. A Rattan, Antimicrobials in Laboratory Medicine, B I Churchill, Livingstone,

New Delhi, (2000), 85.

1. Thesis Front Cover - Emboss -...

Documents

Transcript of 1. Thesis Front Cover - Emboss -...