Synthesis and biological evaluation of novel 6, 7-dimethoxy-3-(4-pyridyl)- 2,3,3a,4-tetrahydroindeno[1,2-c]pyrazol-2-yl-4-substituted phenylmethanone/ ethanone derivatives

Article abstract of DOI:10.3109/14756366.2011.581240

A series of 6,7-dimethoxy-3-(4-pyridyl)-2,3,3a,4-tetrahydroindeno[1,2-c] pyrazol-2-yl-4-substituted phenylmethanone/ethanone derivatives were synthesized and in vitro activity against mycobacterium tuberculosis (MTB) and INHR-MTB were carried out. Among t

Full text of DOI:10.3109/14756366.2011.581240

Journal of Enzyme Inhibition and Medicinal Chemistry, 2012; 27(1): 155–159
© 2012 Informa UK, Ltd.
ISSN 1475-6366 print/ISSN 1475-6374 online
DOI: 10.3109/14756366.2011.581240
SHORT COMMUNICATION
Synthesis and biological evaluation of novel 6, 7-dimethoxy-
3-(4-pyridyl)-2,3,3a,4-tetrahydroindeno[1,2-c]pyrazol-2-yl-4-
substituted phenylmethanone/ethanone derivatives
Mohamed Ashraf Ali1, Rusli Ismail2, Tan Soo Choon2, Manogaran Elumalai3, Suresh Kumar4,
Hasnah Osman4, Jeyabalan Govidasamy1, Rajesh Yadav1, Garima Yadav1, Ravinder Kour1, and
Swati Vyas1
1New Drug Discovery Research, Department of Medicinal Chemistry, Alwar Pharmacy College, Alwar, Rajasthan, India,
2Pharmacogenetic and Novel erapeutics Research, Institute for Research in Molecular Medicine, Universiti of Sains
Malaysia, Pennag, Malaysia, 3Department of Pharmacology, UCSI University, Kuala Lumpur Kampus, Kuala Lumpur,
Malaysia, and 4School of Chemical Sciences, Universiti Sains Malaysia, Penang, Malaysia
Abstract
Aseriesof6,7-dimethoxy-3-(4-pyridyl)-2,3,3a,4-tetrahydroindeno[1,2-c]pyrazol-2-yl-4-substitutedphenylmethanone/
ethanone derivatives were synthesized and in vitro activity against mycobacterium tuberculosis (MTB) and INHR-
MTB were carried out. Among the synthesized compounds, compound (4h) 6,7-dimethoxy-3-(4-pyridyl)-2,3,3a,4-
tetrahydroindeno[1,2-c]pyrazol-2-yl-4-pyridyl methanone was found to be the most active agent against MTB and
INHR-MTB with a minimum inhibitory concentration of 0.22 μM.
Keywords: Mycobacterial agents, pyrazoline, indanone, mycobacterium tuberculosis
Introduction
because of the worldwide population growth. Countries
Tuberculosis (TB) is a major disease in the world esti-
mated to kill over 2 million people annually. e major-
ity of cases occur in developing countries among which
the sub-Sahara Africa has the highest incidence rate per
capita and the Southeast Asian regions have the largest
number of cases. It is estimated that there were 8.3 mil-
lion new cases of TB worldwide in 2000 and that TB was
the cause of 11% of all adult acquired immune deficiency
syndrome (AIDS) deaths in 2000. In South Africa alone,
there were 2 million people co-infected with mycobacte-
rium tuberculosis (MTB) and HIV1.
One-third of the world’s population is infected with
MTB or has active TB, making it the second leading cause
of infectious death globally. In 2006, 9.2 million incident
cases were reported and 1.2 million people died as a result
of TB2,3. Although the global incidence rate appears to be
slowing, the absolute number of new cases is increasing
in Southeast Asia, Africa, and the former Soviet Union
are regions of particular concern as the surge of cases in
these regions threatens global TB control. e breakdown
of the health care infrastructure after the dissolution of
the Soviet Union has resulted in poorly functioning TB
control programs, and there is evidence of increasing
HIV infection contributing to the TB epidemic4. In Asia
and Africa, the increase in TB directly corresponds to the
worsening of the HIV epidemic over the past 2 decades5.
Modern chemotherapy has played a major role in the
control of TB. Yet TB still remains a leading infectious dis-
ease worldwide, largely owing to persistence of tubercle
bacillus and inadequacy of the current chemotherapy.
e increasing emergence of drug-resistant TB along
with the HIV pandemic threatens the disease control
and highlights the necessity for the understanding of the
mechanism of the current drugs and the importance to
Address for Correspondence: Prof. Mohamed Ashraf Ali, M. Pharm, PhD, Alwar, New Drug Discovery Research, New Drug Discovery
Research, Department of Medicinal Chemistry, Alwar Pharmacy College, Alwar, Rajasthan-301030, India, Alwar, 301030 India.
Tel.: 91–9911128001. Fax: 91–11-26059666. E-mail: asraf80med@rediffmail.com
(Received 12 January 2011; revised 17 March 2011; accepted 12 April 2011)
155

156 M. Ashraf Ali et al.
develop more effective drugs. e next threat for TB is the
emergence of drug-resistant strains of MTB5,6. e anti-TB
drugs that are currently utilized in the treatment are asso-
ciated with severe toxicity and adverse effects. In spite of
toxicity on repeated dosing of isoniazid (INH), it still con-
sidered to be a first line drug in the chemotherapy of TB7.
e statistics of the disease rate, drug-resistant strains of
the tubercle bacilli and the adverse effects of the current
chemotherapeutic agents clearly indicate the necessity of
new drugs with effective mechanism of actions. However,
highly effective new anti-TB drugs have not been devel-
oped in the last 40 years. Literature survey of novel chemo-
therapeutic agents reveals that the substituted pyrazoline
derivatives are proved to be active against many mycobac-
terial species8–14. Based on these literatures, the current
work was designed to synthesize novel indane substituted
pyrazoline derivatives. e present investigation of the
new compounds shows encouraging antimycobacterial
activity against MTB and INHR-MTB.
room temperature. e product 5,6-dimethoxy-2-[(E)-1-
phenylmethylidene]-1-indanone was then treated with
appropriate acid hydrazide in the presence of glacial acetic
acid to get titled compounds in 62–84% yield after recrys-
tallization with ethanol. e purity of the compounds was
checked by thin layer chromatography (TLC) and elemen-
tal analyses. Both analytical and spectral data (1H-NMR,
IR) of all the synthesized compounds were in full agree-
ment with the proposed structures. e elemental analysis
results were within 0.4% of the theoretical values.
Antimycobacterial activity
Among the 12 compounds synthesized, most of the
compounds were found to be most active with mini-
mum inhibitory concentration of less than 7 μΜ. In
addition, the in vitro test results indicated that the new
compounds were active against MTB and INH resistant
MTB. Compounds with electron rich groups substituted
on the phenyl ring were shown to have higher activity
potentials.Amongthe12newlysynthesizedcompounds,
compound 1-[6,7-dimethoxy-3-(4-pyridyl)-2,3,3a,4-
tetrahydroindeno[1,2-c]pyrazol-2-yl-4-pyridylmetha-
none (4h) was found to have maximum activity against
MTB and INHR-MTB. e minimum inhibitory con-
centration of this compound (4h) was found to be <0.30
μM. When compared to INH, the compound (4h) was
found to be 3.12-fold and 15.7-fold more active against
MTB and INHR-MTB, respectively. Following this com-
pound, 4-chlorophenyl (4f), 2,-chlorophenyl (4e) sub-
stituents show good activity with a MIC of 0.96, 2.56 and
1.28, 2.48 μM for MTB and INHR-MTB, respectively.
However, the compounds substituted with electron
Results and discussion
Chemistry
6 , 7 - d i m e t h o x y - 3 - ( 4 - p y r i d y l ) - 2 , 3 , 3 a , 4 -
tetrahydroindeno[1,2-c]pyrazol-2-yl-4-substituted phe-
nyl methanone/ethanone derivatives 4a–l described in
this study are shown in Table 1 and a reaction sequence
for the preparation is outlined in Scheme 1. In the initial
step, 5, 6-dimethoxy-2-[(E)-1-(4-pyridyl)methylidene]-
1-indanone analogs were synthesized by condensing
5,6-dimethoxy-1-indanone with isonicotinaldehyde in
diluted methanolic sodium hydroxide (30%) solution at
Table 1. Physical constant and antimycobacterial activity of the synthesized compounds.
O
N
R
N
O
O
H3C
H3C
N
4a-l
(MIC) µM
INHR-MTBb
Compound
R
Yield (%)
84
M.P. (°C)
144
162
143
141
128
103
176
145
164
184
198
168
—
MTBa
2.86
2.60
2.94
3.12
1.28
0.96
3.08
0.22
4.28
6.16
4.59
5.68
0.73
Cytotoxicity
>62.5
>62.5
>62.5
>62.5
>62.5
>62.5
>62.5
>62.5
>62.5
>62.5
>62.5
>62.5
>62.5
4a
4b
4c
4d
4e
4f
Phenyl-
4.12
4.32
4.94
6.12
2.48
2.56
3.08
0.72
7.28
9.46
10.59
11.22
11.37
4-bromo phenyl-
4-fluoro phenyl-
4-nitro phenyl-
2-chloro phenyl-
4-chloro phenyl-
4-methyl phenyl
Pyridyl-
60
82
70
62
75
4g
4h
4i
82
65
2-methyl phenyl-
Phenyl methyl
Phenoxy methyl-
4-methoxy phenyl
—
67
4j
72
4k
4l
80
62
INH
—
aMycobacterium tuberculosis H37Rv; bINH resistant Mycobacterium tuberculosis.
Journal of Enzyme Inhibition and Medicinal Chemistry

Synthesis and biological evaluation 157
CHO
N
O
O
O
O
O
O
H3C
H3C
CH3OH-NaOH
H3C
H3C
+
3
2
1
N
RCONHNH2
O
N
R
N
O
O
H3C
H3C
N
4a-l
Scheme 1. Protocol for synthesis of titled compounds.
rich groups such as, 4-chlorophenyl, 2-chlorophenyl,
4-flurophenyl, 4-bromophenyl and 4-nitrophenyl pro-
duced good to excellent inhibitory activity against both
the species of MTB and INHR-MTB. On the other hand,
the compounds like 4-methoxy phenyl (4l), 4-methyl
phenyl (4f), 2-methyl phenyl (4i), phenyl methyl (4j)
and phenoxy methyl (4k) showed relatively moderate
to good antitubercular activity. Out of all the substitu-
tions of the phenyl ring, the results indicate that the
pyridyl substitution causes remarkable improvement
in antimycobacterial activity. Among the newly synthe-
sized compounds, two compounds were found to be
most active compounds with minimum inhibitory con-
centration of less than 1 μM. Among them, compound
(4h) pyridyl substituent was found to be the most
active against INH and INHR-MTB. Among the newer
derivatives, it is conceivable that derivatives showing
antimycobacterial activity can be further modified to
exhibit better potency than the standard drugs. Further
studies to acquire more information about target and
quantitative structure-activity relationships (QSAR)
are in progress in our laboratory.
and are uncorrected. Purity of the compounds was
checked on TLC plates (silica gel G) with the solvent
system toluene-ethyl formate-formic acid (5:4:1) and
benzene-methanol (8:2), the spots were located under
iodine vapors or UV light. IR spectrums were obtained
on a Perkin-Elmer 1720 FT-IR spectrometer (KBr
Pellets). 1H-NMR spectra were recorded on a Bruker AC
300 MHz spectrometer using TMS as internal standard
in DMSO-d6/CDCl3.
General procedure
Synthesis of 5,6-dimethoxy-2-[(E)-1-(4-pyridyl)methylidene]-
1-indanone (3)
5,6-dimethoxy-1-indanone (1.92 g, 0.01 mol) were dis-
solved in methanol. en, a solution of sodium hydrox-
ide (30%, 5 mL) and isonicotinaldehyde (1.02 g, 0.01 mol)
in 10 mL of pet. ether was added to the resulting solution
with continuous stirring. After 4 h of stirring, the resulting
solution was allowed to stand overnight. It was poured
into ice-cold water and then neutralized with hydrochlo-
ric acid. e solid separate was filtered off, dried and
purified from ethanol.
IR: (KBr, cm−1): 3042 (CH), 1642 (C=O), 1439
(C=C). 1HNMR (DMSO-d6, ppm): δ3.1–3.23 (2H, m,
CH2), 3.6 (6H, s, OCH3), 7.20 (1H, s, CH), 6.70–6.96
(2H, m, Aromatic); 7.5–8.80 (4H, m, pyridine); Mass
(m/z) 282 M+1); Cal/Ana [C(72.58) 72.56, H(5.37) 5.35,
N(4.98) 4.96].
All the compounds were tested for cytotoxicity (1C50)
in VERO cells at concentrations 62.5 μg/mL or 10 times.
After 72 h exposure, viability was assessed on the basis
of cellular conversion of MTT into a formazan product
using the Promega CellTiter 96 Non-radioactive cell pro-
liferation method. Most of the active compounds were
found to be nontoxic below 62.5 μg/mL.
General procedure
Synthesis of compound (4a–l)
Materials and methods
To the compound 5,6-dimethoxy-2-[(E)-1-(4-pyridyl)
methylindene]-1-indanone (3) (0.001 mol) in 15 mL of
glacial acetic acid, 0.001 mol of appropriate acid hydraz-
ide was added and the reaction mixture was refluxed for
e entire chemicals were supplied by E. Merck
(Germany) and S.D fine chemicals (India). Melting
points were determined by open tube capillary method
© 2012 Informa UK, Ltd.

158 M. Ashraf Ali et al.
12 h and cooled. e progress of the reaction was moni-
tored by TLC and after completion of the reaction, the
solvent was evaporated by vacuo and the reaction mix-
ture was poured on to crushed ice (20 gm). e product
obtained was filtered and washed with water and then
recrystallized from methanol.
Aromatic); 7.4–8.50 (4H, m, pyridine); Mass (m/z) 434
(M+1); Cal/Ana [C(66.44) 66.42, H(4.65) 4.63, N(9.688)
9.66].
1 - [ 6 , 7 - d i m e t h o x y - 3 - ( 4 -p y r i d y l ) - 2 , 3 , 3 a , 4 -
tetrahydroindeno[1,2-c]pyrazol-2-yl-4-methylphenyl
methanone(4g) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O),
1
6,
7-dimethoxy-3-(4-pyridyl)-2,3,3a,4-
metha-
1439 (C=C), 766 (C-F). HNMR(DMSO-d6, ppm): δ1.72
tetrahydroindeno[1,2-c]pyrazol-2-yl-phenyl
(3H, s, CH3) 2.1–2.4 (2H, m, CH2), 2.5–2.6 (1H, m,
CH-Indane), 3.6 (6H, s, OCH3), 5.5 (1H, d, pyrazoline-CH),
6.60–7.10 (6H, m, Aromatic); 7.4–8.50 (4H, m, pyridine);
Mass (m/z) 414 (M+1); Cal/Ana [C(72.62) 72.60, H(5.61)
5.60, N(10.16) 10.14].
none (4a) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O), 1439
(C=C), 766 (C-F). 1HNMR(DMSO-d6, ppm): δ2.1–2.4
(2H, m, CH2), 2.5–2.6 (1H, m, CH-Indane), 3.6 (6H, s,
OCH3), 5.5 (1H, d, pyrazoline-CH), 6.60–7.10 (7H, m,
Aromatic);7.4–8.50 (4H, m, pyridine); Mass (m/z) 400
(M+1); Cal/Ana [C(72.17) 72.10, H(5.30) 5.29, N(10.52)
10.50].
1 - [ 6 , 7 - d i m e t h o x y - 3 - ( 4 -p y r i d y l ) - 2 , 3 , 3 a , 4 -
tetrahydroindeno[1,2-c]pyrazol-2-yl-4-pyridyl
methanone(4h) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O),
1
4-bromophenyl-6,7-dimethoxy-3-(4-pyridyl)-
2, 3, 3a, 4-tetrahydroindeno[1, 2-c]pyrazol-2-yl
methanone(4b) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O),
1439 (C=C), 766 (C-F). HNMR(DMSO-d6, ppm): δ1.72
(3H, s, CH3), 2.1–2.4 (2H, m, CH2), 2.5–2.6 (1H, m,
CH-Indane), 3.6 (6H, s, OCH3), 5.5 (1H, d, pyrazoline-CH),
6.60–7.10 (2H, m, Aromatic); 7.4–8.50 (8H, m, pyridine);
Mass (m/z) 401 (M+1); Cal/Ana [C(68.99) 68.97, H(5.03)
5.01, N(13.99) 13.97].
1
1439 (C=C), 766 (C-F). HNMR(DMSO-d6, ppm): δ2.1–
2.4 (2H, m, CH2), 2.5–2.6 (1H, m, CH-Indane), 3.6 (6H,
s, OCH3), 5.5 (1H, d, pyrazoline-CH), 6.60–7.10 (6H, m,
Aromatic); 7.4–8.50 (4H, m, pyridine); Mass (m/z) 479
(M+1); Cal/Ana [C(60.26) 60.24, H(4.21) 4.20, N(8.78)
8.76].
1 - [ 6 , 7 - d i m e t h o x y - 3 - ( 4 -p y r i d y l ) - 2 , 3 , 3 a , 4 -
tetrahydroindeno[1,2-c]pyrazol-2-yl-2-methylphenyl
methanone(4i) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O),
1
4-fluorophenyl-6,7-dimethoxy-3-(4-pyridyl)-2-
, 3, 3a, 4-tetrahydroindeno[1, 2-c]pyrazol-2-yl-
methanone(4c) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O),
1439 (C=C), 766 (C-F). HNMR(DMSO-d6, ppm): δ1.72
(3H, s, CH3) 2.1–2.4 (2H, m, CH2), 2.5–2.6 (1H, m,
CH-Indane), 3.6 (6H, s, OCH3), 5.5 (1H, d, pyrazoline-CH),
6.60–7.10 (6H, m, Aromatic); 7.4–8.50 (4H, m, pyridine);
Mass (m/z) 414 (M+1); Cal/Ana [C(72.62) 72.60, H(5.61)
5.60, N(10.16) 10.14].
1 - [ 6 , 7 - d i m e t h o x y - 3 - ( 4 -p y r i d y l ) - 2 , 3 , 3 a , 4 -
tetrahydroindeno[1,2-c]pyrazol-2-yl]-2-phenyl-1-
ethanone(4j) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O), 1439
(C=C), 766 (C-F). 1H-NMR (DMSO-d6, ppm): δ2.1–2.4
(2H, m, CH2), 2.5–2.6 (1H, m, CH-Indane), 3.2 (2H, m,
benzyl-CH2),3.6(6H,s,OCH3),5.5(1H,d,pyrazoline-CH),
6.60–7.10 (6H, m, Aromatic); 7.4–8.50 (4H, m, pyridine);
Mass (m/z) 414 (M+1); Cal/Ana [C(72.62) 72.60, H(5.61)
5.60, N(10.16) 10.14].
1 - [ 6 , 7 - d i m e t h o x y - 3 - ( 4 -p y r i d y l ) - 2 , 3 , 3 a , 4 -
tetrahydroindeno[1,2-c]pyrazol-2-yl]-2-phenoxy-1-
ethanone(4k) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O), 1439
(C=C), 766 (C-F). 1HNMR(DMSO-d6, ppm): δ2.1–2.4 (2H,
m, CH2), 2.5–2.6 (1H, m, CH-Indane), 3.2 (2H, m, phe-
oxy-CH2), 3.6 (6H, s, OCH3), 5.5 (1H, d, pyrazoline-CH),
6.60–7.10 (6H, m, Aromatic); 7.4–8.50 (4H, m, pyridine);
Mass (m/z) 430M+1); Cal/Ana [C(69.92) 69.90, H(5.40)
5.38, N(9.78) 9.76].
1
1439 (C=C), 766 (C-F). HNMR(DMSO-d6, ppm): δ2.1–
2.4 (2H, m, CH2), 2.5–2.6 (1H, m, CH-Indane), 3.6 (6H,
s, OCH3), 5.5 (1H, d, pyrazoline-CH), 6.60–7.10 (6H, m,
Aromatic); 7.4–8.50 (4H, m, pyridine); Mass (m/z) 418
(M+1); Cal/Ana [C(60.06) 69.04, H(4.83) 4.81, N(10.07)
10.09].
6 , 7 - d i m e t h o x y - 3 - ( 4 - p y r i d y l ) - 2 , 3 , 3 a , 4 -
tetrahydroindeno[1,2-c]pyrazol-2-yl-4-nitrophenyl
methanone(4d) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O),
1
1439 (C=C), 766 (C-F). HNMR(DMSO-d6, ppm): δ2.1–
2.4 (2H, m, CH2), 2.5–2.6 (1H, m, CH-Indane), 3.6 (6H,
s, OCH3), 5.5 (1H, d, pyrazoline-CH), 6.60–7.10 (6H, m,
Aromatic); 7.4–8.50 (4H, m, pyridine); Mass (m/z) 445
(M+1); Cal/Ana [C(68.86) 68.88, H(4.54) 4.52, N(12.61)
12.63].
2-chlorophenyl-6,7-dimethoxy-3-(4-pyridyl)-
2, 3, 3a, 4-tetrahydroindeno[1, 2-c]pyrazol-2-yl
methanone(4e) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O),
1
1439 (C=C), 766 (C-F). HNMR(DMSO-d6, ppm): δ2.1–
2.4 (2H, m, CH2), 2.5–2.6 (1H, m, CH-Indane), 3.6 (6H,
s, OCH3), 5.5 (1H, d, pyrazoline-CH), 6.60–7.10 (6H, m,
Aromatic); 7.4–8.50 (4H, m, pyridine); Mass (m/z) 434
(M+1); Cal/Ana [C(66.44) 66.42, H(4.65) 4.63, N (9.688)
9.66].
1 - [ 6 , 7 - d i m e t h o x y - 3 - ( 4 -p y r i d y l ) - 2 , 3 , 3 a , 4 -
tetrahydroindeno[1,2-c]pyrazol-2-yl-4-methoxyphenyl
methanone(4l) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O),
1
4-chlorophenyl-6,7-dimethoxy-3-(4-pyridyl)-
2, 3, 3a, 4-tetrahydroindeno[1, 2-c]pyrazol-2-yl
methanone(4f) IR:(KBr, cm−1): 3042 (CH), 1642 (C=O),
1439 (C=C), 766 (C-F). HNMR(DMSO-d6, ppm): δ2.1–
2.4(2H, m, CH2), 2.5–2.6 (1H, m, CH-Indane), CH2), 3.6
(9H, s, OCH3), 5.5(1H, d, pyrazoline-CH), 6.60–7.10
(6H, m, Aromatic); 7.4–8.50 (4H, m, pyridine); Mass
(m/z) 430M+1); Cal/Ana [C(69.92) 69.90, H(5.40) 5.38,
N(9.78) 9.76].
1
1439 (C=C), 766 (C-F). HNMR(DMSO-d6, ppm): δ2.1–
2.4 (2H, m, CH2), 2.5–2.6 (1H, m, CH-Indane), 3.6 (6H,
s, OCH3), 5.5 (1H, d, pyrazoline-CH), 6.60–7.10 (6H, m,
Journal of Enzyme Inhibition and Medicinal Chemistry

Synthesis and biological evaluation 159
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Biology
e primary screening was conducted at a concentra-
tion of 6.25 µg/mL (or molar equivalent of highest
molecular weight compound in a series of congeners)
against MTB H37Rv (ATCC27294) and INH resistant
MTB in BACTEC 460 radiometric system15. Compound
demonstrating at least 90% inhibition in the primary
screen was re-examined at lower concentration (MIC)
in broth microdilution assay with alamarBlue. e MIC
was defined as the lowest concentration inhibiting 99%
of the innoculum. Concurrent with the determination
of MICs, compounds were tested for cytotoxicity (IC50)
in VERO at concentration equal to and greater than the
MIC for MTB H37Rv and INH resistant MTB after 72 h
exposure. Viability was assessed on the basis of cellular
conversion of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-
diphenyltetrazolium bromide) into a formazan product
using the Promega CellTiter 96 Non-radioactive cell
proliferation assay16.
10. Ali MA, Samy JG, Manogaran E, Sellappan V, Hasan MZ,
Ahsan MJ et al. Synthesis and antimycobacterial evaluation
of novel 5,6-dimethoxy-1-oxo-2,5-dihydro-1H-2-indenyl-5,4-
substituted phenyl methanone analogues. Bioorg Med Chem Lett
2009;19:7000–7002.
Acknowledgments
11. Küçükgüzel SG, Rollas S. Synthesis, characterization of novel
coupling products and 4-arylhydrazono-2-pyrazoline-5-ones as
potential antimycobacterial agents. Farmaco 2002;57:583–587.
12. Ali MA, Shaharyar M. Oxadiazole mannich bases: Synthesis
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13. Shaharyar M, Ali MA, Bakht MA, Murugan V. Synthesis and
antimycobacterial activity of 4-[5-(substituted phenyl)-4,
5-dihydro-3-isoxazolyl]-2-methylphenols. J Enzyme Inhib Med
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e authors wish to express their thanks to Pharmaco-
genetic and Pharmacogenomic Research, Institute for
Research in Molecular Medicine, Universiti of Sains
Malaysia, Pennag, Malaysia and Alwar Pharmacy
College, Alwar, Rajasthan, India, for providing research
facilities.
Declaration of interest
14. Ragavan RV, Vijayakumar V, Kumari NS. Synthesis and
antimicrobial activities of novel 1,5-diaryl pyrazoles. Eur J Med
Chem 2010;45:1173–1180.
e authors report no conflicts of interest.
15. Heifets LB, Flory MA, Lindholm-Levy PJ. Does pyrazinoic acid as
an active moiety of pyrazinamide have specific activity against
mycobacterium tuberculosis? Antimicrob Agents Chemother
1989;33:1252–1254.
16. Gundersen LL, Nissen-Meyer J, Spilsberg B. Synthesis and
antimycobacterial activity of 6-arylpurines: e requirements for
the N-9 substituent in active antimycobacterial purines. J Med
Chem 2002;45:1383–1386.
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© 2012 Informa UK, Ltd.