HETEROCYCLIC CHEMISTRY: SYNTHESIS AND

BIOLOGICAL EVALUATION OF SOME AZOLE

DERIVATIVES

SUMMARY SUBMITTED TO MAHARISHI MARKANDESHWAR UNIVERSITY, MULLANA

FOR THE AWARD OF THE DEGREE OF

DOCTOR OF PHILOSOPHY IN

CHEMISTRY BY

KAMALNEET KAUR (Regn. No. 07-ECM-1158)

DEPARTMENT OF CHEMISTRY

MAHARISHI MARKANDESHWAR UNIVERSITY

MULLANA, AMBALA (HARYANA)

APRIL, 2015

i

SUMMARY

Heterocyclic compounds are an important class of organic compounds that exhibited a

wide range of biological properties. Furthermore, a large number of natural products

possess a variety of heterocyclic systems. Azoles are the five-membered heterocyclic

compounds containing two heteroatoms and atleast one of them is nitrogen. Many

azoles derivatives have been used as antibacterial, antifungal, anti-inflammatory and

anti-diabetic, antiviral, anticonvulsant and antitubercular agents. Owing to their

immense biological importance it was thought worthwhile to undertake the synthesis

of some azole derivatives, specifically pyrazoles, thiazoles and isoxazolines.

The work reported in this investigation has been presented in the form of three

Chapters (1-3), which are independent of each other.

CHAPTER-1 SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL

EVALUATION OF SOME NOVEL 3,5-DIMETHYLPYRAZOLE

DERIVATIVES

Azole derivatives have gained much more attention in the field of synthetic and

medicinal chemistry owing to their diverse biological properties. Among them,

pyrazole is a five-membered heterocyclic compound containing three carbon and two

adjacent nitrogen atoms. The general structure of pyrazole is shown in Figure 1.

N NR'

R''

R'''

R12

3 4

5

R, R', R'', R''' = H or alkyl or aryl or heteroaryl

Pyrazole

Fig.1

Pyrazole core is found in several natural products. It has been reported in literature

that substitution on pyrazole nucleus resulted in development of many medicinally

potent compounds. Pyrazole derivatives displayed broad spectrum of biological

properties such as antimicrobial, antitubercular, anticonvulsant, anti-inflammatory,

antiobesity, agricultural germicidal, insecticidal and acaricidal activities. They also act

as GABA receptor antagonists, inhibitors against DNA gyrase and topoisomerase IV

at their respective ATP binding sites, antiproliferative and anticancer agents. It has

been reported in literature that pyrazole derivatives having methyl group at position-3

ii

and/or -5 have gained much medicinal importance. A brief review regarding various

synthetic procedures and biological developments of pyrazole derivatives having

methyl group at position-3 and/or -5 is outlined in the beginning of this Chapter

(Section 1.1)

In a view of these observations it was envisaged in the present investigation to

undertake the synthesis of three series of some new 3,5-dimethyl substituted pyrazole

derivatives with an expectation to find biologically potent agents (Section 1.2A, 1.2B

and 1.2C). The structures of synthesized compounds were established with the help of

combined application of IR, NMR (1H, 13C) spectroscopy, mass spectrometry and

elemental analyses. The 2D NMR spectral techniques such as COSY, ROSEY, HSQC

and HMBC wherever required were also used in structural elucidation of some of the

synthesized compounds.

1.2A Synthesis, Characterization and Biological Evaluation of Some Novel 2-(3,5-

Dimethyl-1H-pyrazol-1-yl)-1-arylethanones

It has been found that some pyrazole derivatives having methyl group at position-3

and -5 act as potent antibacterial, antioxidant and anticancer agents I. Literature

survey also revealed that some phenacyl and napthacyl substituted pyrazole,

imidazole and triazoles exhibit a wide range of important pharmacological properties.

Keeping in view of the great biological potential and importance of 3,5-

dimethylpyrazole, phenacyl and napthacylazole, and in continuation of our ongoing

research work on the synthesis of novel pyrazole derivatives as potential biological

active agents, we planned to synthesize a series of 11 hybrid compounds having

phenacyl or napthacyl moiety at position-1 and methyl group at positions-3 and -5 of

the pyrazole nucleus.

In literature, Santhosh et al. have reported a one pot solvent mediated multicomponent

approach for the synthesis of some 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-arylethanone

derivatives (Scheme-23).

O O+ NH2NH2.H2O ArCOCH2Br

reflux271

NN

ArO

94a-d

95a-d

1' 2'

3'

4'

5'

1

2ethanol+

Scheme-23 One pot multicomponent synthesis of 2-(3,5-dimethyl-1H-pyrazol-1-yl)-

1-arylethanones by Santhosh et al.

iii

To achieve the target compounds 95a-k, we decided to perform one-pot

multicomponent approach under similar conditions as reported by Santhosh et al. with

an expectation to achieve the product in a very short period of time in a highly

regioselective manner, by the reaction of acetylacetone 71, hydrazine hydrate 2 and

differently substituted phenacyl bromides 94a-d in ethanol under reflux.

Unfortunately, in actual practice this method generated four compounds as evidenced

by appearance of four spots in TLC of the crude reaction mixture. The 1H NMR

spectrum of crude reaction mass showed a number of sharp signals at δ 2.17 (s, 3H),

2.29 (s, 3H), 2.44 (s, 9H), 5.65 (s, 2H), 5.98 (s, 1H), 6.04 (s, 1H) and many distinct

multiplets in range of δ 7.37-7.99 corresponding to 15 protons which confirmed the

formation of 95a albeit along with significant amount of side products. In view of

multicomponent reaction based results, and behavior of the reaction of different types

of 1,3-β-diketones with various hydrazines or of phenacyl bromides, it was planned to

reinvestigate and further explore this approach. To enunciate the facts,

multicomponent reaction was again carried out under similar conditions which led to

a mixture of different compounds. Thus, there was a great need to find a novel

synthetic route which not only provides the target compounds regioselectively with

excellent yields but also avoids the use of toxic solvents and prolonged reaction time.

In view of an extension of these observations, we developed a greener and

regioselective protocol to synthesize 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-

arylethanone derivatives 95a-k using one pot grind stone methodology has been

developed (Scheme-25).

In order to synthesize 95a, acetylacetone 71 (1 mole eq.) was treated with hydrazine

hydrate 2 (1.1 mole eq.) at 0 ºC and the resultant reaction mixture was ground with

phenacyl bromide 94a (0.9 mole eq.) in the presence of sodium carbonate (0.5 mole

eq.) under solvent free conditions. The desired product 95a was formed

regioselectively within 10-15 minutes in excellent yield with high purity. The

structure of crude 95a was established on the basis of a combined use of IR, 1H NMR, 13C NMR spectroscopy and mass spectrometry.

The 1H NMR spectrum of 95a displayed two sharp singlets due to six protons at δ

2.17 and 2.24 which affirm the presence of two methyl groups at positions- 3' and -5'

of the pyrazole nucleus, respectively. The CH2 protons resonated downfield as a

singlet at δ 5.46 due to its attachment with carbonyl carbon and nitrogen at position-1'

of the pyrazole ring. Another sharp singlet corresponding to one proton at δ 5.91 was

iv

observed due to 4'-H pyrazole ring, besides a multiplet centered around at δ 7.49-7.98

due to five aromatic protons. Further evidence in support of an exclusive formation of

95a came by recording its 13C NMR spectrum which showed the three characteristic

signals of pyrazole system at δ 148.29, 105.91, and 140.73 due to C-3', C-4' and C-5',

respectively. The formation of pyrazole was further supported on the basis of its mass

spectrum which showed a molecular ion peak at m/z = 214.1 (M+) in conformity with

molecular formula C13H14N2O of 95a.

Cl Br NO2 F FCH3

F FCl

a b c d e f g h i j k

Ar

For compds (94, 97)

O O

i) NH2NH2 .H2O 2, 0 oCii) ArCOCH2Br, Na2CO3, grind, 80 oC

71

NN

ArO

94a-k

95a-k

1' 2'

3'

4'

5'

1

2

One pot

Scheme-25 A highly regioselective one pot solvent free synthesis of 2-(3,5-dimethyl-

1H-pyrazol-1-yl)-1-arylethanones 95a-k

In order to assess their potential the compounds were screened for antibacterial,

anticancer potential besides study the effects of compounds on plasmid DNA under

UV irradiation. Among all, 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-(naphth-2-

yl)ethanone 95j displayed good inhibitory profile against E. coli and S. aureus which

was about 50% and 25% of the Ampicillin (standard drug), respectively. The

compounds, 95a and 95f showed relatively moderate inhibition against P. aeruginosa

and E. coli. The compounds 95c and 95d were found to be highly active and

completely degraded both forms of DNA (SC and OC), even at a very low

concentration of 1 µg (95c) under irradiation of UV light. However, 95h and 95f

resulted in complete DNA degradation at 30 µg concentration. Moreover, 95h showed

fluorescence at 15 µg concentration and increased the intensity of both bands of DNA

(SC and OC) as compared to control. On the other hand, to valorize the biological

potential, the compounds were screened for their cytotoxic activity on colon (HCT116

and HT29), prostate (DU145), ovarian (SKOV3) and lung (A549) cancer cell lines.

The compound 95j was found to be cytotoxic to all the cancer cell lines, except

SKOV3, with more selectivity towards the colon cancer cell lines (HCT116, HT29)

v

and A549 lung cancer cell line. On A549 lung cancer cell line, 95j and 95k exhibited

similar potency as carboplatin in inhibiting cell viability.

1.2B Synthesis, Characterization and Biological Evaluation of Some Novel 2-(3,5-

Dimethyl-1H-pyrazol-1-yl)-1-arylethanols

Literature revealed that alkanol derivatives bearing (1H-triazol-1-yl) group at β-

position have gained significance importance especially in the field of antifungal

research. Some potent antifungal drugs like Fluconazole, Voriconazole and

Albaconazole are alkanol derivatives having (1H-triazol-1-yl) group at β-position.

Recently, pyrazole derivatives have been reported as an excellent class of DNA-

photocleaving agents. It has been reported that pyrazole derivatives are known to

possess excellent antioxidant activity.

Keeping in view of the high antifungal potential associated with alkanol derivatives

bearing (1H-triazol-1-yl) group at β-position as well as excellent antimicrobial, DNA

photocleaving and antioxidant profile associated with pyrazole containing compounds

and in continuation to our previous work related to the synthesis of biologically

potent 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-arylethanones, it was planned to

synthesize some novel alkanol derivative having (1H-pyrazol-1-yl) group at β-

position with an expectation to find new class of antimicrobial, DNA photocleaving

and antioxidant agents.

The synthetic route adopted to synthesize 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-

arylethanols 97a-k is depicted in Scheme-27. The starting precursors 95a-k were

prepared report by performing one-pot solvent free reaction of acetyl acetone with

hydrazine hydrate and differently substituted bromides in presence of sodium

carbonate (Scheme-25). To achieve the target compounds, 2-(3,5-dimethyl-1H-

pyrazol-1-yl)-1-arylethanones 95a-k (1 mole eq.) were treated with sodium

borohydride (0.25 mole eq.) using methanol as a solvent at 5 ºC temperature. The

desired products 97a-k were formed within 10-12 minutes with high purity.

vi

NN

O

95a-k

1' 2'

3'

4'

5'

1

2

Cl Br NO2 F FCH3

F FCl

NN

OHb

97a-k

1' 2'

3'

4'

5'

1

2

Ha

Hc

Hd

Ar Ar

NaBH4, MeOH

5 oC, stir

a b c d e f g h i j k

Ar

For compds (95, 97)

Scheme-27 Synthesis of 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-arylethanols 97a-k

In IR spectral data, disappearance of carbonyl (C=O) and an appearance of hydroxyl

(OH) stretching vibrational bands at 1690 cm-1 and 3216 cm-1, respectively indicated

the formation of compound 97a. In 1H NMR spectrum, appearance of three sharp

singlets at δ 2.01, 2.24 and 5.80 due to 3'-CH3, 5'-CH3 and 4'-H protons, respectively

attached to pyrazole nucleus further provided a firm evidence in support of the

formation of 97a. A broad singlet at δ 4.80 was observed due to the presence of OHb

proton. The three doublet of doublet patterns at δ 4.01 (2JHc-Hd = 13.92 Hz and 3JHc-Ha

= 7.92 Hz), δ 4.15 (2JHd-Hc = 13.94 Hz and 3JHd-Ha = 2.76 Hz) and at δ 5.08 (3JHa-Hc =

7.72 Hz and 3JHa-Hd = 2.48 Hz) were assigned to Hc, Hd and Ha protons, respectively.

The assignment of these protons was fully supported via 1H NMR study reported by

Prakash and Claramunt et al. A multiplet center around at δ 7.27-7.56 was attributed

to five aromatic protons. Both the geminal protons (Hc and Hd) resonated at different

chemical shifts to give doublet of doublet pattern due to their diastereotopic nature.

Further evidence in support of the structure of 97a came from its recorded 13C NMR

spectrum which showed the disappearance of carbonyl carbon signal at δ 192.66 and

an appearance of a signal at δ 73.49 for C-1 carbon at more upfield value due to its

attachment with hydroxyl group.

All synthesized compounds were evaluated to assess their antimicrobial and

antioxidant potential. In addition the effect of compounds on plasmid DNA was also

studied. Among the series, compounds 97j and 97k were found to exhibit significant

inhibitory potential against C. albicans using Amphotericin-B as a standard drug.

They also exhibited moderate inhibitory potential against S. cerevisiae, which was

about 25% of standard drug. On the other hand, 97g-i were found four times less

active against both the fungal strains. The compound 97i exhibited four-fold lesser

vii

inhibitory profile against P. aeruginosa in comparison to Ciprofloxacin as a standard

drug. In the DNA photocleavage study, the compounds 97e and 97h were found to act

as potent DNA photocleaving agents at 60 µg concentration while compounds 97g,

97i and 97j exhibited moderate DNA photocleaving potential. In addition, compounds

97d and 97f protected the DNA from the effect of UV-irradiation. In the present

study, it has also been observed from DPPH method, the compounds 97d and 97e

were found to act as antioxidant agents.

1.2C Synthesis, Characterization and Biological Evaluation of Some Novel (E)-1-

Aryl-2-(3,5-dimethyl-4-(aryldiazenyl)-1H-pyrazol-1-yl)ethanones

As already discussed, pyrazole derivatives are known to possess diverse biological

properties. More specifically, 4-arylazopyrazole derivatives have gained much

importance due to a broad spectrum of their biological potential as anti-

staphylococcal, analgesic, antioxidant, cytotoxic and CDK2-cyclin E inhibiting

agents. It has already been reported that 4-arylazopyrazoles bearing 3,5-dimethyl

substituents were found to be associated with potential antibacterial and antimicrobial

activities.

Prompted from the above facts and in continuation to our ongoing interest in the

synthesis of new biologically active compounds, it was planned to synthesize some

novel arylazopyrazoles under solvent free conditions and to explore their

antimicrobial, antioxidant and UV-mediated DNA damage protecting potential with

an expectation to find new class of bioactive agents.

The synthesis of twenty-one novel (E)-1-aryl-2-(3,5-dimethyl-4-(aryldiazenyl)-1H-

pyrazol-1-yl)ethanones 101a-u has been accomplished according to Scheme-30.

viii

N N

NN

H

grind stone, 100 oC

N N

NN

R

OAr

R

CH3 Cl Br F NO2

1

2 1' 2'

3'

4'

5'

1''2''

3''4''

5''

6''

100a-c 101a-u

For compds (101) a b cR = CH3, H, F

a b c d e f g

h i j k l m n

o p q r s t u

For compds

(101)

Ar

For compds (101a-g), R = CH3(10h-n), R = H(101o-u), R = F

Na2CO3

94a-f, 94 j

Scheme-30 Solvent free synthesis of (E)-1-aryl-2-(3,5-dimethyl-4-(aryldiazenyl)-1H-

pyrazol-1-yl)ethanones 101a-u

The present methodology provides a milder and greener synthetic route to give the

products 101a-u of high purity within 10-15 minutes. In this protocol, initially 4-

methylphenylazo-3,5-dimethylpyrazole 100a was ground with phenacyl bromide 94a

in the presence of sodium carbonate at 100ºC under solvent free conditions to yield

101a. An appearance of carbonyl (C = O) stretching vibrational band at 1690 cm-1

indicated the formation of 101a. In the 1H NMR spectrum, compound 101a displayed

a singlet at δ 5.52 due to methylene (CH2) protons besides a multiplet centered

around at δ 7.50-8.00 due to five aromatic protons (H-2''' to H-6'''). The structure of

101a was further supported by its 13C NMR spectrum in which signals were appeared

at δ 191.76 and 55.57 due to carbonyl and CH2 carbon, respectively. Other signals in

the range of 128.17-134.37 were indicating the presence of aromatic carbons (C-1''' to

C-6'''). Further confirmation of 101a was supported by the mass spectral data which

showed a molecular ion peak at 332 (m/z) in conformity with molecular formula

C20H20N4O.

The present methodology provides a milder and greener synthetic route to give the

products 101a-u of high purity within 10-15 minutes. In this protocol, initially 4-

methylphenylazo-3,5-dimethylpyrazole 100a was ground with phenacyl bromide 94a

in the presence of sodium carbonate at 100ºC under solvent free conditions to yield

101a. An appearance of carbonyl (C=O) stretching vibrational band at 1690 cm-1

ix

indicated the formation of 101a. In the 1H NMR spectrum, compound 101a displayed

a singlet at δ 5.52 due to methylene (CH2) protons besides a multiplet centered

around at δ 7.50-8.00 due to five aromatic protons (H-2''' to H-6'''). The structure of

101a was further supported by its 13C NMR spectrum in which signals were appeared

at δ 191.76 and 55.57 due to carbonyl and CH2 carbon, respectively. Other signals in

the range of 128.17-134.37 were indicating the presence of aromatic carbons (C-1''' to

C-6''').

To explore biological potential, the compounds were evaluated for their antimicrobial,

antioxidant and UV mediated DNA damage protective activity. Among the series, six

compounds 101b, 101i, 101k, 101l, 101m and 101t were found to exhibit a very good

level of antibacterial activity, four compounds 101g, 101o, 101p and 101t were

emerged as an efficient class of antifungal agents in reference to the standard drugs

viz. Ciprofloxacin and Amphotericin-B, respectively. In the UV mediated DNA

damage protecting study, all compounds 101a-u (except 101d) protected the plasmid

DNA from the UV damaging effect and 101e was found to be the most potent DNA

protecting agent which avoids the transformation of the native supercoiled form into

an opencircular and linear form. In addition, the compounds 101f, 101m and 101t

were found active in antioxidant screening using DPPH assay.

CHAPTER-2 SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL

EVALUATION OF SOME NOVEL THIAZOLE DERIVATIVES

Thiazoles are the five-membered heterocyclic compounds which contain sulphur and

nitrogen at the position-1 and position-3, respectively. The general structure of

thiazole ring is shown in Figure 1.

SN

R

R'

R''

1 23

4

5

R, R', R'' =H or alkyl or aryl or heteroaryl

Thiazole

Fig. 1

Thiazole ring is found in a large number of natural products. Thiazole and its

derivatives were known to possess a wide range of biological properties. Some potent

drugs bearing thiazole nucleus include Fanetizole (anti-inflammatory agent),

Tiazofurin (antineoplastic agent), Penicillin (potent antibiotic), Sulfatiazol

x

(antimicrobial) and Abafungin (antifungal). It has been reported that substitution at

position-2 and -4 of thiazole ring leads to the development of many bioactive agents.

2,4-Disubstituted thiazoles displayed antimicrobial, anti-inflammatory, anticancer,

antimalarial, antimycobacterial, chemopreventive and antioxidant properties.

Moreover, they act as inhibitor of metastatic cancer cell migration and invasion,

ovarian cancer cell growth inhibitor, P-glycoprotein inhibitor besides corticotropin-

releasing factor 1 receptor antagonists. The most common approach used to construct

thiazole system is Hantzsch thiazole synthesis which involves the reaction of

thioureas or thioamides with α-haloketones. An update review regarding various

synthetic procedures and biological developments of 2,4-disubstituted thiazole

derivatives is outlined in the beginning of this Chapter (Section 2.1).

In a view the immense importance of 2,4-disubstitution in thiazole derivatives it was

envisaged in the present investigation to undertake the synthesis of two series of some

new 2,4-disubstituted thiazole derivatives with an expectation to find biologically

potent agents (Section 2.1A and 2.2B). The structures of synthesized compounds were

established with the help of combined application of IR, NMR (1H, 13C) spectroscopy,

mass spectrometry and elemental analyses. The 2D NMR spectral techniques such as

COSY, ROSEY, HSQC and HMBC wherever required were also used in structural

elucidation of some of the synthesized compounds.

2.2A Synthesis, Characterization and Biological Evaluation of Some Novel

Oxazolidinone-Thiazole Hybrids

Owing to diverse biological properties oxazolidinone and thiazole containing motifs

have gained a great attention of scientific community in the field of medicinal

chemistry. Oxazolidinone derivatives exhibited a wide range of applications in the

field of antimicrobial, anticancer and anti-tubercular research. Compounds bearing

oxazolidinone moiety as antimicrobial agents contributed a lot in this field. They

exhibited very high potential against Gram-positive multidrug resistant strains.

Linezolid (marketed under the trade name zyvox), a potent antimicrobial was the first

member of oxazolidinone family approved by the US Food and Drug Administration

(FDA) for the treatment of serious infection caused by Gram-positive bacteria. It

inhibits protein synthesis prior to chain initiation step by binding to the 50S ribosomal

subunit to prevent formation of 70S initiation complex. Some other biologically active

oxazolidinone pharmacores include eperezolid and posizolid, which were used as

promising antibiotics to treat bacterial infections while torezolid was used in the

xi

treatment of complicated skin infections. In addition, thiazole containing motifs have

also attracted much interest over the years due to their role in the development of

pharmacologically active compounds.

Prompted from the above facts and in continuation to our ongoing interest in the

synthesis of new biologically active compounds, it was planned to synthesize some

novel structural hybrids incorporating both the thiazole and oxazolidinone moiety.

The main objective of the study is to explore antimicrobial, antioxidant and UV-

mediated DNA damage protecting ability of the compounds with an expectation to

find new class of biologically potent agents.

The synthesis of novel oxazolidinone-thiazole hybrid compounds 87a-m has been

accomplished according to Scheme-29.

NH

O O

NH NH2

S

HaHb

ArCOCH2Br86a-m

NHO

O

NH

HaHb

S

NAr

85 87a-m

Ar =Cl BrCH3 NO2 F

FCl

O OO

O

H3C OH

1 23

54

61'

2'3'

4'

5'6'

1''2''

3''4''

5''

1'''2'''

3'''4'''

5'''6'''

2'''3'''

4'''

5'''6'''

1''' 1''' 2'''3'''

4'''

5'''6'''

1'''2'''

3'''4'''

5'''

6'''

1'''2''' 3'''

4'''

5'''6'''

1'''2'''3'''

4'''5'''6'''

1'''2'''

3'''4'''

5'''6'''

1'''2'''

3'''4'''

5'''

6'''

1''' 2'''3'''

4'''

5'''

6'''

7'''8''' 9'''

10'''

1'''2'''

3'''

4'''5'''6'''

7'''8'''

9'''

10'''

1'''2''' 3'''

4'''

5'''6'''1''''

2''''3''''

5'''' 6''''

4''''

1'''

2'''

4'''5'''6'''

3'''

1'''

2'''

3'''4'''5'''

6'''

7'''

8'''9'''

10'''

a b c d e f

g h i j k

l m

NHO

O

NH2

HaHb

84

HCl / H2O

NH4SCN, reflux1'2'

3'4'

5'

6'

1'' 2''3''

4''

5''1 2

3

45

61'

2'3'4'

5'

6'NaHCO3

EtOH, reflux

For compds (86, 87)

Scheme-29 Synthesis of oxazolidinone-thiazole hybrid compounds 87

The disappearance of two signals for NH2 protons and an appearance of a

characteristic singlet at δ 6.96 due to thiazole proton (H-5'') in the 1H NMR spectrum

confirmed the formation of 87a. In the IR spectrum, appearance of C=C, C=N and

C=O stretching vibrational bands at 1551, 1605 and 1728 cm-1, respectively further

supported the structure of 87a. In 13C NMR spectrum, observation of three

xii

characteristic signals at δ 162.92, 150.27 and 100.99 due to C-2', C-4', and C-5',

respectively provided the firm evidence in support of the formation of thiazole

nucleus.

All compounds were evaluated for their antimicrobial, antioxidant and UV mediated

DNA damage protective activity. Among the series, compound 87i was emerged as

the most potent antimicrobial agent. It exhibited equivalent inhibitory action against

one bacterial strain B. subtilis and two fungal strains namely, C. albicans and S.

cerevisiae in comparison to the respective standard drugs, Ciprofloxacin and

Amphotericin-B. The compound 87i was found to display two-fold and four-fold

lesser inhibitory potential against S. aureus as well as P. aeruginosa and E. coli,

respectively in reference to the standard drug. Other promising antimicrobial agents

include the compounds 87f-h where 87c, 87j and 87l were found to exhibit an

excellent level of antibacterial activity. In addition, all compounds 87a-m were found

to express very high DNA damage protecting ability under UV irradiation.

Furthermore, 87m was found to display a very high level of fluorescence property

among the series. The results of antioxidant study revealed that the compounds 87d

and 87j were found as the most potent antioxidants even more than ascorbic acid, a

reference compound.

2.2B Synthesis, Characterization and Biological Evaluation of Some Novel (E)-2-

(3,5-Dimethyl-4-(aryldiazenyl)-1H-pyrazol-1-yl)-4-arylthiazoles

Among azoles, thiazoles, pyrazoles and thiazole-pyrazole hybrids have attracted great

attention over the years due to their remarkable biological activities. Motifs

containing thiazole nucleus exhibited antitrypanosomal, antimicrobial, anticancer,

anti-inflammatory and antiviral properties. An extensive part of research in this field

revealed that 4-arylazo substituted pyrazole derivatives were found to act as analgesic,

cytotoxic, anti-staphylococcal, antioxidant, and CDK2-cyclin E inhibiting agents. In

literature, 3,5-dimethyl substituted 4-arylazopyrazole derivatives were also reported

to exhibit high antimicrobial and antibacterial potential. Moreover, pyrazole linked

thiazoles exhibited antibacterial, antimicrobial and ΔF508-CFTR corrector activities

besides treating cardiovascular diseases.

The literature survey revealed that compounds bearing pyrazole and thiazole nuclei

act as efficient DNA photocleaving agents.

Prompted from the above facts, it was planned to synthesize some novel 4-aryl-2-(3,5-

dimethyl-1H-pyrazol-1-yl)thiazole derivatives bearing arylazo group at position-4 of

xiii

the pyrazole moiety under solvent free conditions. The two main objectives of the

study include, to observe the influence of 4-arylazo group on the Hantzsch thiazole

approach in both the solvent free as well as solvent mediated conditions, and to

explore the biological potential of the target compound with an expectation to find a

new class of bioactive compounds.

The synthesis of novel (E)-2-(3,5-dimethyl-4-(aryldiazenyl)-1H-pyrazol-1-yl)-4-

arylthiazoles 92a-p has been accomplished via Hantzsch thiazole approach under

solvent free conditions (Scheme-31).

N N

NN

grind stone, 100 oC

N N

NN

R R

CH3ClBr F

1 2

3

4

5

1'2'

3'4'

5'

6'

NH2S

NS

Ar

1'' 2''

3''4''

5''

For compds (91) a b cR = CH3, H, F

For compds

(92)

Ar

For compds (92a-f), R = CH3(92g-l), R = H(92m-p), R = F

a b c d e f

g h i j k lm n o p

91a-c 92a-p

Na2CO3

86a, 86b, 86d-f, 86i

Scheme-31 Solvent free synthesis of (E)-2-(3,5-dimethyl-4-(aryldiazenyl)-1H-

pyrazol-1-yl)-4-arylthiazoles 92a-p

To get the product (E)-2''-(3,5-dimethyl-4-(p-tolyldiazenyl)-1H-pyrazol-1-yl)-4''-

phenylthiazole 92a, the reactant (E)-3,5-dimethyl-4-(p-tolyldiazenyl)-1H-pyrazole-1-

carbothioamide 91a was ground with phenacyl bromide 86b in the presence of

sodium carbonate at 100 ºC temperature. The product 92a of high purity was formed

within 10-15 minutes under solvent free conditions (Scheme-31). The structure of 92a

was established on the basis of a combined use of IR, NMR (1H & 13C), COSY,

ROESY, HSQC and HMBC spectroscopy.

The disappearance of N-H stretching bands at 3140 and 3387 cm-1 due to NH2 group

of carbothioamide indicated the formation of compound 92a. In the 1H NMR

xiv

spectrum, disappearance of two signals at δ 6.96 and 8.69 for NH2 protons and an

appearance of singlet at δ 7.21 due to thiazole proton (H-5'') confirmed the formation

of 92a. The structure of 92a was further supported by its 13C NMR spectrum in which

three characteristic signals of thiazole system at δ 161.67, 152.79 and 109.10 were

appeared due to C-2', C-4', and C-5', respectively.

In the present investigation, initially an attempt to perform the reaction of 91a with

86b in ethanol under reflux conditions was made which resulted in an exclusive

formation of a mixture of thiocyanatoketone 93 and cleaved pyrazole 94. The results

were supported by the appearance of a characteristic signal at δ 4.72 (s, 2H, CH2) of

93 as well as a signal at δ 2.52 (s, 6H, 3,5-CH3) and 2.34 (s, 3H, 4'-CH3) of 94 in the 1H NMR spectrum of the crude reaction mixture (Scheme-32). This observation was

consistent to the previously reported results based on the reaction of 4-unsubstituted

pyrazole-1-carbothioamide. In this study, it has been found that arylazo group present

at position-4 of the pyrazole moiety did not play any role in preventing the cleavage

of C-N bond in the reaction of differently substituted pyrazole-1-carbothioamides

with α-bromoketones.

N N N N

NH2S

NS

Ph

Z Z

+ PhCOCH2BrEtOH

reflux+ Ph

OSCN +

N NH

Z

Z = CH3NN

91a

86b

92a

93

94

Scheme-32 The reaction of (E)-3,5-dimethyl-4-(p-tolyldiazenyl)-1H-pyrazole-1-

carbothioamide 91a with phenacyl bromide 86b under solvent mediated conditions

To explore the biological potential, all the synthesized compounds were evaluated for

their antimicrobial and antioxidant potential. In addition, effect of compounds on

plasmid DNA under UV irradiation was also studied. The results of antimicrobial

study revealed that among the series, compounds 92g-l were found active selectively

against C. albicans. The compound 92l exhibited two-fold high antifungal potential in

comparison to Amphotericin-B, a standard drug against C. albicans. The compound

92k was found equipotent and 92g-j displayed half of the potential in reference to the

standard drug. In DNA based study, 92j and 92n was found as the most potent DNA

damage protecting and DNA photocleaving agent, respectively at 40 µg

xv

concentration. The compounds 92d, 92e, 92g, 92i, 92k, 92m and 92o also displayed a

significant level of DNA damage protective potential whereas 92l and 92p exhibited

appreciable DNA photocleavage activity. In the antioxidant study, all compounds

were found inactive.

CHAPTER-3 SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL

EVALUATION OF SOME NOVEL 5-HYDROXY-5-TRIFLUOROMETHYL

ISOXAZOLINE DERIVATIVES

Isoxazolines are an important class of five-membered heterocyclic compounds in

which oxygen and nitrogen heteroatoms are present at position-1 and position-2,

respectively. The general structure of isoxazoline is shown in Figure 1.

R, R', R'' = H or alkyl or aryl or heteroaryl

NO

R''

R'

R

1

2

3

4

5

Isoxazoline-2

Fig.1

Isoxazoline containing compounds were found to exhibit a wide range of bioactivities

such as anti-inflammatory, analgesic, antibacterial, anthelmimtic, anticancer and

antitubercular. Introduction of trifluoromethyl group on the isoxazoline nucleus

further resulted in development of many biologically active agents (Figure 2).

O NF3C

NR5

R6

R1

NN

N

Insecticidal

O N

F3C

Ar2

Ar1

IIAntiparasitic

O N

Ph PhSO2CF3

F3C

X

Used in Agrochemicals

NO

F3CHO

NN

R

S

Antimicrobial

IIII

IV

Fig.2

The synthetic and biological developments made in recent past of some isoxazoline

derivatives bearing trifluoromethyl group is outlined in the form of review in the

beginning of this Chapter (Section 3.1)

Also reported that halo substitution on isoxazoline moiety resulted in many potent

anticancer agents. It has been reported that azoles having arylazo group at position-4

xvi

were known as efficient antimicrobial, antibacterial, anti-staphylococcal, analgesic,

antioxidant, cytotoxic and CDK2-cyclin E inhibiting agents.

Prompted from the above facts Section 3.2 deals with the synthesis of some novel

isoxazoline derivatives having haloarylazo group at position-4 in order to explore

their biological potential with an expectation to find new class of biologically active

agents. The structures of synthesized compounds was established with the help of

combined application of IR, NMR (1H, 13C and 19F) spectroscopy, mass spectrometry

and elemental analyses.

The synthesis of some novel (E)-4-(aryldiazenyl)-3-aryl-5-(trifluoromethyl)-4,5-

dihydroisoxazol-5-ol derivatives 89 has been accomplished according to the reaction

sequence shown in Scheme-28.

Ar CF3

O O

NN

R

NH2OH.HCl / NaOAc

EtOH, reflux, 4 h

O N

N

F3CHO

N

R

Ar

87a-n, 87aa-an 89a-n, 89aa-an

For compds (87, 89) (a-g), R = I; (h-n), R = Br; (aa-ag), R = Cl; (ah-an), R = F

12

34

1''2''

3''4''

5''6''

1''2''

3''4''

5''

6''

1 2

3

45

88

OCH3Cl Br F

For compds

( 87, 89)

Ar

a b c d e f g h i j k l m n aa ab ac ad ae af agah ai aj ak al am an

��

Scheme-28 Synthesis of (E)-4-(aryldiazenyl)-3-aryl-5-(trifluoromethyl)-4,5-

dihydroisoxazol-5-ol derivatives 89 To achieve the target compound 89a, (E)-1-(4-chlorophenyl)-4,4,4-trifluoro-2-((4-

iodophenyl)diazenyl)butane-1,3-dione 87a was treated with hydroxylamine

hydrochloride 88 in the presence of sodium acetate using ethanol under reflux

conditions. The structure of 89a was established on the basis of a combined use of IR,

NMR (1H, 13C and 19F) spectroscopy and mass spectrometry. In IR spectrum, two

absorption bands due to NH and OH str. at 3292 and 3005 cm-1 were appeared. The 1H NMR spectroscopy is not a useful tool to distinguish between compounds 87 and

89. In 13C NMR spectrum of 89a, carbon-5 resonated as a quartet at δ 98.52 ppm (2JC-

xvii

F = 35.21 Hz) while C-4 and C-3 resonated as singlets at δ 131.95 and 154.60 ppm,

respectively. The carbonyl carbon peaks, C-1 at δ 189.68 and C-3 at 175.32 ppm (2JC-

F = 33.20 Hz) in the starting precursor 87a were found to be disappeared in the

product. A sharp signal in 19F NMR spectrum at δ - 78.86 ppm also provides a firm

evidence in support of the structure of isoxazoline. Further confirmation of 89a was

supported by the mass spectral data which showed a molecular ion peak at m/z =

495.9 (M+) in conformity with molecular formula C16H10ClF3IN3O2. The probable

mechanism for the formation of 89 is given in Scheme-29.

NH2OH Ar CF3

O O

R'

+Ar CF3

N

R'

OOH

N O

Ar CF3

OH

R'H87

For compound (87, 89) R' =R

NN

89

Scheme-29 The probable mechanism of formation of (87, 89)

In the study involving the effects of compounds on DNA, it has been found that some

of synthesized compounds exhibited very high DNA damage protecting effect.

EXPERIMENTAL

The Experimental part is common for all the Chapters

Chemistry

Melting points were determined by open capillary method and are uncorrected. The

FT-IR spectra of the compounds were recorded on FT-Infra-Red Spectrometer Model

RZX (Perkin Elmer) using KBr pellets. The 1H and 13C NMR spectra were recorded

on Bruker Advance II 400 NMR Spectrometer at 400 MHz and 100 MHz,

respectively; chemical shifts are expressed on δ-scale downfield from TMS as an

internal standard. Mass spectra were recorded on Waters Micromass Q-Tof Micro

Mass spectrometer equipped with electrospray ionization (ESI) and atmospheric

pressure chemical ionization sources having mass range of 4000 amu in quadruple

and 20000 amu in ToF. Thermo Scientific (FLASH 2000) CHN Elemental Analyser

was used to determine percentages of C, H and N with an accuracy of 0.3%. The

absorbance for the antioxidant activity was recorded on specord 250 analytikjena UV

spectrophotometer.

xviii

Biological Evaluation

Antibacterial Activity

Antibacterial activity of synthesized compounds 95a-k was studied by the agar well

diffusion method using N,N-dimethylformamide (DMF) solvent against various

pathogenic strains of gram positive and gram negative bacteria (Staphylococcus

aureus, Escherichia coli, Klebsiella pneumoniae, Enterococcus and Psuedomonas

aeruginosa). The tested pathogenic strains of bacteria were isolated from the patients

in Maharishi Markandeshwar Medical College, Maharishi Markandeshwar

University, Mullana, Haryana. Nutrient agar medium (25 ml) was poured into each

petri plate and agar plates were swabbed with 100 μL inocula of each test bacterium

and kept for 15 min for adsorption. Using sterile cork borer of 8 mm diameter, wells

were bored into the seeded agar plates and these were loaded with a 50 μL volume.

Solutions of the test compounds and standard were prepared in DMF at concentration

of 2000 µg/mL. From this stock solution, two-fold dilutions of the compounds (2, 4,

8….. 1024 µg/mL) were inoculated to the corresponding wells. All the plates were

incubated at 37 °C for 24 h. Antibacterial activity of each synthesized compound was

evaluated by measuring the zone of growth inhibition with zone reader (Hi Antibiotic

zone scale) and MIC was determined at the lowest concentration of the

compound tested that was able to inhibit visible growth of bacteria. DMF was used as

a negative control whereas Ampicillin was used as a reference drug.

Antimicrobial activity

Test microorganisms: On the basis of clinical importance in causing diseases in

humans, total six microbial strains were selected. These strains include two Gram-

positive bacteria viz. Staphylococcus aureus MTCC 96 and Bacillus subtilis MTCC

121, two Gram-negative bacteria viz. Escherichia coli MTCC 1652 and Pseudomonas

aeruginosa MTCC 741 and two yeasts namely Candida albicans MTCC 227 and

Saccharomyces cerevisiae MTCC 170. All the microbial cultures were purchased

from Microbial Type Culture Collection (MTCC), IMTECH, Chandigarh.

Subculturing of bacterial strains were done on Nutrient Agar (NA) while yeasts were

carried on Malt Extract Agar (MEA) plates.

Determination of zone of inhibition

The zones of inhibition of all the synthesized compounds 97a-k, 101a-u, 87a-m, 92a-

p, 89a-n and 89aa-an were measured by the agar well diffusion method. The

inoculum suspensions of the test microorganisms were prepared by using 16 h old

xix

cultures adjusted to 108 cfu/ml by referring the 0.5 McFarland standards. Total 20 ml

of agar medium (NA in case of antibacterial and MEA in case of antifungal) was

poured into each petri plate and then plates were swabbed with 100 µl inocula of the

test microorganisms and kept for 15 min for adsorption. Wells were bored into the

seeded agar plates using a sterile cork borer of diameter (8 mm) and these were

loaded with a 100 µl volume with concentration of 4.0 mg/ml of each compound

reconstituted in the dimethylsulphoxide (DMSO). The incubation of all the plates was

carried at 37 oC for 24 h. Antimicrobial activity of each compound against the

selected organisms was evaluated by measuring the zone of inhibition with zone

reader (Hi Antibiotic zone scale) Ciprofloxacin and Amphotericin-B were used as

positive control for bacterial and yeast strains, respectively. This procedure was

performed in three replicate plates for each organism.

Determination of minimum inhibitory concentration (MIC)

MIC is the lowest concentration of an antimicrobial compound that inhibits the visible

growth of the microorganisms after incubation. MIC of the various compounds

against bacterial and yeast strains was tested through a modified agar well diffusion

method. In this protocol, a two-fold serial dilution of each compound was prepared by

first reconstituting the compound in DMSO followed by dilution in sterile distilled

water to achieve a decreasing concentration range of 4 to 0.0625 mg/ml. A 100 µl

volume of each dilution was introduced into wells (in triplicate) in the agar plates

already seeded with 100µl of standardized inoculum (108 cfu/ml) of the test microbial

strain. All test plates were incubated aerobically at 37 oC for 24 h and observed for the

inhibition zones. MIC, taken as the lowest concentration of the chemical compound

that inhibited the growth of the microbes which was shown by a clear zone of

inhibition and was recorded for each test organism. Ciprofloxacin and Amphotericin-

B were used as positive controls while DMSO was used as a negative control in this

investigation.

Free radical-scavenging of the compounds using DPPH analysis

The DPPH free radical scavenging activity is based on the fact that methanolic

solution of DPPH which imparts vivid purple color and gives strong absorption band

at 515 nm, gets reduced in the presence of an antioxidant compound. Different

concentrations of the compounds 97a-k, 101a-u, 87a-m, 92a-p, 89a-n and 89aa-an

under evaluation (50-400 µg/mL) were added to 4mL of a DPPH solution (120 µM)

in methanol and incubated at 37 °C temperature for 30 min dark. The absorbance was

xx

determined at 515 nm and the percentage free radical scavenging (%) was calculated

according the following equation:

Scavenging % = [(Acontrol – Asample) / Acontrol] x 100

where, Acontrol is the absorbance of the control reaction (containing all reagents except

the test compounds), and Asample is the absorbance of the test compound. Ascorbic

acid was used as a positive control and tests were conducted in triplicate.

Effects of compounds on plasmid DNA under UV irradiation

Treatment of plasmid DNA with the samples

The stock solutions for all tested compounds were prepared by dissolving 0.005 g of

compound in 0.5 ml of DMSO. All synthesized compounds in DMSO were added

separately to volume of 2µl containing plasmid DNA in TE (Tris 10 mM, EDTA 0.01

mM, pH 8.0) buffer. The same volume of DMSO as used to make the solution of the

test compounds was added into A and control C. The reaction volumes except A were

held in caps of polyethylene microcentrifuge tubes, which were irradiated directly on

the surface of a trans-illuminator (8000 mW/cm) at 360 nm for 1 h at room

temperature. After that A, control (C) and test samples were incubated at 37 °C for

0.5 h.

Agarose gel electrophoresis

After the treatment, electrophoresis was performed according to the given procedure

mentioned.

To a 2 ml 50X tris-acetate EDTA buffer (TAE) (40 mM Tris, 20 mM acetic acid, 1

mM EDTA, pH: 8.0), added 98 ml of autoclaved water to make it 1X TAE buffer.

Agarose (0.8 g) was dissolved by boiling to the resultant mixture. When the gel

attained 55 ºC temperature, 10 mg/ml of ethidium bromide (ETBR) was added. The

treated DNA sample mixed with 6X loading dye (0.25%) bromophenol blue added

and then it was poured into gel cassette fitted with a comb. The gel was then allowed

to solidify. The comb was carefully removed and the gel was placed over

electrophoresis chamber flooded with tris-acetate EDTA buffer (40 mM Tris, 20 mM

acetic acid, 1 mM EDTA, pH: and 30% glycerol) was carefully loaded into the wells

along with control (C) and A, and electrophoresis was carried out at 5V/cm for 2.0 h

and the bands were observed under UV transilluminator.

xxi

Anticancer activity

Cell Culture

SKOV3 cell lines were grown in DMEM medium (10-013-CV, Corning), HCT116

and HT29 were maintained in McCoy’s 5A medium (166600-082, Life techonlogies),

DU145 were grown in Eagle's Minimum Essential Medium (EMEM), and A549 were

grown in RPMI medium. All the media contained 10% fetal bovine serum (FBS), 100

units/mL penicillin, and 100 mg/ml streptomycin. Cells were grown in a 37 ºC

incubator with 5% CO2.

Cell Viability assay

The effect of the compounds 95a-k on the cell viability of different cancer cell lines

was determined by performing colorimetric MTT assay as previously described, in

which the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyletetrazolium bromide) is

reduced to its insoluble crystal form formazan. Briefly, different cancer cells

(HCT116, HT29, DU145, SKOV3, and A549) were incubated in 96 well plates at

concentration of 30000 cells per mL in a 96 well plate for overnight. Further, the cells

were treated with increasing concentration of the compounds (0-50 μM) in triplicates

for 48 h and 72 h time points. MTT (M2128, Sigma) reagent (5 mg/mL) was added to

each well 3 h prior to the termination time point and plates were placed back in the

incubator at 37 ºC. After 3 h, the formazan crystals were dissolved in 100 μL DMSO.

Optical density was measured at 570 nm by using a microplate reader (Dynex

Technologies, MRX Revelation; Chantilly, VA, USA). The background reading was

measured at 630 nm, which was subtracted from 570 nm reading during the cell

viability calculation.

xxii

LIST OF PUBLICATIONS

1. Vinod Kumar, Kamalneet Kaur, Girish Kumar Gupta, Anil Kumar Sharma,

Pyrazole containing natural products: Synthetic preview and biological

significance, European Journal of Medicinal Chemistry, 2013, 69, 735-753.

2. Vinod Kumar, Kamalneet Kaur, Girish K. Gupta, Akhilesh K. Gupta, Sunil

Kumar, Developments in synthesis of the anti-inflammatory drug, celecoxib:

A review, Recent Patents on Inflammation & Allergy Drug Discovery, 2013,

7(2), 124-134.

3. Vinod Kumar, Girish Kumar Gupta, Kamalneet Kaur, Randhir Singh, 4-

Fluorophenylhydrazones as potential COX-2 inhibitors: A novel, efficient, one

solid phase synthesis, docking study and pharmacological evaluation,

Medicinal Chemistry Research, 2013, 22 (12), 5890-5900.

4. Vinod Kumar, Kamalneet Kaur, Deepkamal N. Karelia, Vikas Beniwal,

Girish Kumar Gupta, Arun K. Sharma, Akhilesh Kumar Gupta, Synthesis and

biological evaluation of some 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-

arylethanones: Antibacterial, DNA photocleavage, and anticancer activities,

European Journal of Medicinal Chemistry, 2014, 81, 267-276.

5. Kamalneet Kaur, Vinod Kumar, Anil Kumar Sharma, Girish Kumar Gupta,

Isoxazoline containing natural products as anticancer agents: A review,

European Journal of Medicinal Chemistry, 2014, 77, 121-133.

6. Girish Kumar Gupta, Kamalneet Kaur, Shikha Singh, Vinod Kumar,

Isolation of 4-hydroxythiazoline: A solid phase study in Hantzsch thiazole

reaction, Research Journal of Chemistry and Environment, 2014, 18(2), 38-34.

7. Vinod Kumar, Kamalneet Kaur, Girish Kumar Gupta, Triazole and

Oxadiazole containing Natural Products: A review, The Natural Product

Journal, 2014, 4, 115-130.

8. Girish K. Gupta, Vinod Kumar, Kamalneet Kaur, Imidazole containing

natural products as antimicrobial agents: A review, The Natural Product

Journal, 2014, 4, 73-81.

9. Kamalneet Kaur, Vinod Kumar, Vikas Beniwal, Vikas Kumar, K.R Aneja,

Vishal Sharma, Sundeep Jaglan, Synthesis, antimicrobial, antioxidant and

DNA photocleavage study of some novel 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-

arylethanols, Arabian Journal of Chemistry, 2015 (Communicated).

xxiii

10. Kamalneet Kaur, Vinod Kumar, Vikas Beniwal, Vikas Kumar, K.R Aneja,

Vishal Sharma, Sundeep Jaglan, Novel (E)-1-aryl-2-(3,5-dimethyl-4-

(aryldiazenyl)-1H-pyrazol-1-yl)ethanones: Solvent free synthesis,

antimicrobial, antioxidant and UV mediated DNA damage protective activity

studies, Medicinal Chemistry Research, 2015 (Communicated).

11. Kamalneet Kaur, Vinod Kumar, Vikas Beniwal, Vikas Kumar, K.R Aneja,

Vishal Sharma, Sundeep Jaglan, Novel (E)-1-aryl-2-(3,5-dimethyl-4-

(aryldiazenyl)-1H-pyrazol-1-yl)ethanones: Solvent free synthesis,

antimicrobial, antioxidant and UV mediated DNA damage protective activity

study, Medicinal Chemistry Research, 2015 (Communicated).

12. Vinod Kumar, Kamalneet Kaur, Fluorinated Isoxazolines and Isoxazoles:

Synthetic preview and biological significance (to be Communicated).

13. Synthesis and UV mediated DNA damage protective activity of (E)-4-

(aryldiazenyl)-3-aryl-5-(trifluoromethyl)-4,5-dihydroisoxazol-5-ols (to be

Communicated).

14. Synthesis of some novel oxazolidinone-thiazole hybrids as potential

antimicrobial, antioxidant and UV mediated DNA damage protecting agents

(to be Communicated).

PATENTS FILED

1. Process for synthesis of chalcones and uses thereof, Vinod Kumar, Kamalneet

Kaur, Duha Adnan, Girish Kumar Gupta, Vikas Beniwal, Sunil Kumar,

No.146/DEL//2014 (Application filed on dated 17/1/2014).

2. Process for Novel 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-arylethanones as DNA

photocleaving Agents, Vinod Kumar, Kamalneet Kaur, Vikas Beniwal,

Girish Kumar Gupta, Akhilesh Kumar Gupta, No.144/DEL/2014 (Application

filed on dated 17/1/2014).

3. 2-(3,5-Dimethyl-1H-pyrazol-1-yl)-1-(naphth-2-yl)ethanone as potential

anticolon cancer agent, Vinod Kumar, Kamalneet Kaur, Deepkamal N.

Karelia, Arun K. Sharma, Girish Kumar Gupta, Akhilesh Kumar Gupta,

No.145/DEL/2014 (Application filed on dated 17/1/2014).

xxiv

CONFERENCES/SEMINARS/WORKSHOPS/ SYMPOSIUM ATTENDED

1. 3rd National Conference on “Recent Advances in Chemical and Environmental

Sciences” organized by Multani Mal Modi College, Patiala on 28th Feb, 2011-

01st March, 2011.

2. National Seminar on “Recent Trends in Herbal Drug Research” organized by

Pharmaceutical Department, MMU Mullana on 20th-21st October 2011.

3. National Workshop on “Spectroscopic techniques and their applications”

organized by Chemistry Department, MMU Mullana on 12th November, 2011.

4. One day Workshop on “Analytical Techniques for Research in Pharmacy”

organized by Pharmaceutical Department, MMU Mullana on 07th December,

2012.

5. Poster presentation on the topic “A Mild Approach to 2,4-Disubstituted

Thiazoles : Solid Phase Study in Hantzsch Thiazole Synthesis” in the National

Conference on Recent Advances in Chemical and Environmental Sciences”

organized by Multani Mal Modi College, Patiala on 31st January, 2013.

6. Poster on the topic “A mild, greener and a solvent-free synthesis of 4-Aryl-2-(4-

arylazo-3,5-dimethylpyrazol-1-yl)thiazoles” to be presented in the International

Conference on the Recent Advances in Chemical Sciences (Novel Molecules for

Diagnosis and Therapeutics) organized by Arya P.G College Panipat on 24-26th

February, 2013.

7. One day seminar on “AAS instrumentation and unique patented technologies”

joinly orgainized by Perkin Elmer and M.M College of Pharmacy, Mullana on

3rd April, 2013.

8. One day seminar on “Recent Advances in Liquid Chromatography” organized

by M.M College of Pharmacy, M.M. University, Mullana-Ambala on 31st Jan,

2014.

9. Poster presentation on the topic “Greener and practical approach for synthesis of

some 2, 4-disubstituted thiazoles: A solid phase study in Hantzsch thiazole

reaction” in “Professor Ram Chand Paul National Symposium on New Visions

in Chemical Sciences” organized by Department of Chemistry & Centre of

Advanced Studies in Chemistry, Panjab University, Chandigarh on 15-16 Feb,

2014 (Won Best poster award).

xxv

10. One day Seminar, “Answering the Obesity Epidemic: Challenges and

Opportunities” organized by M.M College of Pharmacy, M.M. University,

Mullana-Ambala on 4th March, 2014.

11. 1st International Virtual Conference on “Information retrieval on scientific

literature: Emerging frontiers and challenges”, organized by M.M. University,

Mullana-Ambala on 10-11th June 2014.

12. National Seminar on “Safety in Chemistry Laboratory” organized by

Department of Chemistry, M.M. University, Mullana-Ambala on 12th Nov,

2014.

13. Poster presentation on the topic “Synthesis and antimicrobial evaluation of

some novel 2-(pyrazol-1-yl)ethanols” in the 7th National Conference on

“Recent Advances in Chemical, Biological and Environmental Sciences”

organized by Multani Mal Modi College, Patiala on 30th -31st January, 2015.