Iodobenzene diacetate-mediated isomerization of pyrazolyl chalcones and their cytotoxicity and anti-microbial activity

Article abstract of DOI:10.1007/s12039-015-0791-4

Synthesis of cis (E)-1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-3-phenyl/aryl/heteroarylprop-2-en-1-ones from 1-phenyl-3-methyl-4-acetylpyrazol-5-one was achieved in good yield. s-cis (E)-1-(5-Hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-3-arylprop-2-e

Full text of DOI:10.1007/s12039-015-0791-4

c
J. Chem. Sci. Vol. 127, No. 3, March 2015, pp. 413–423. ꢀ Indian Academy of Sciences.
DOI 10.1007/s12039-015-0791-4
Iodobenzene diacetate-mediated isomerization of pyrazolyl chalcones
and their cytotoxicity and anti-microbial activity
MAHAVIR PARSHADa, VIKAS VERMAa, DEVINDER KUMARa,∗
,
BALASUBRAMANIAN NARASIMHANb, SMIT KOURc, SHASHANK SINGHc and
PAYARE LAL SANGWANc
aDepartment of Chemistry, Guru Jambheshwar University of Science & Technology,
Hisar 125001, Haryana, India
bFaculty of Pharmaceutical Sciences, M D University, Rohtak 124 001, Haryana, India
cCancer Pharmacology Division and Bioorganic Chemistry Division, CSIR-Indian
Institute of Integrative Medicine, Jammu 180 001, India
e-mail: dk_ic@yahoo.com
MS received 8 March 2014; revised 31 August 2014; accepted 16 September 2014
Abstract. Synthesis of cis (E)-1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-3-phenyl/aryl/heteroa-
rylprop-2-en-1-ones from 1-phenyl-3-methyl-4-acetylpyrazol-5-one was achieved in good yield. s-cis (E)-1-(5-
Hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-3-arylprop-2-en-1-ones were isomerized to s-trans (E)-4-(3-
(phenyl/aryl/heteroaryl)acryloyl)-5-methyl-2-phenyl-1H-pyrazol-3(2H)-ones using iodobenzene diacetate in
dichloromethane at room temperature in excellent yield. The structure and geometry of these α, β-unsaturated
ketones (pyrazolyl ketones) were established with the help of NMR, 2D NMR and HRMS techniques. The
cytotoxicity of pyrazolyl chalcones showed that s-cis (E) 1-(5-Hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-
3-(4-methylphenyl)-prop-2-en-1-one is active at very low concentrations (IC50 13.3 μM) against colon cancer
cell line (HCT-116). The in vitro anti-microbial studies of pyrazolyl chalcones were also tested against gram-
positive (B. subtilis, S. aureus) and gram-negative bacteria (E. coli) and for anti-fungal activity against C.
albicans and A. niger.
Keywords. Pyrazolyl chalcone; iodobenzene diacetate; cytotoxicity; anti-microbial.
1. Introduction
Prompted by the above observations and our own inter-
est in this field,12 we report herein an improved syn-
thesis of cis (E)-1-(5-hydroxy-3-methyl-1-phenyl-1H-
pyrazol-4-yl)-3-phenyl/aryl/heteroarylprop-2-en-1-ones
(pyrazolyl chalcones, 2) by condensation of 1-phenyl-3-
methyl-4-acetylpyrazol-5-one (1) and aromatic aldehy-
des in good yield. Further, the pyrazolyl chalcones (2)
are isomerized to s-trans (E)-4-(3-(phenyl/aryl/hetroaryl)
acryloyl)-5-methyl-2-phenyl-1H-pyrazol-3(2H)-ones
(3) using iodobenzene diacetate (commonly used hy-
pervalent iodine reagent) in dichloromethane by stirring
at room temperature in excellent yield (90–98%) within
0.5 to 1 h. To the best of our knowledge the s-cis to
s-trans isomerization is probably the first report of its
kind. The cytotoxicity of these pyrazolyl chalcones (2
and 3) is studied against five cancer cell lines. These
compounds were also tested in vitro for their anti-
bacterial activity against gram-positive (B. subtilis, S.
aureus) and gram-negative bacteria (E. coli) and for
anti-fungal activity against C. albicans and A. niger as
well.
The α, β-unsaturated ketones (chalcones) are open
chain compounds consisting of two aromatic rings
joined by a three carbon enone system and constitute
an attractive molecular scaffolds for the search of new
biologically active flavonoids and isoflavonoids.1–4 The
incorporation of pyrazole moiety in chalcones has been
considered of great interest due to their better bio-
logical activities i.e., anti-microbial,5 anti-infective,6
cytotoxic,7 anti-invasive,8 anti-oxidant and anti-inflam-
matory activity.9 Further, it has been reported that the
presence of enone functionality in chalcones having
pyrazole moiety enhance their biological activity.10
Recently, there has been much interest in the utilisation
of hypervalent iodine reagents for many useful organic
transformations and synthesis of important active
intermediates and biologically active molecules.11
∗For correspondence
413

414
Mahavir Parshad et al.
MHz, CDCl3): 178.0 (C-6), 165.2 (C-5), 147.0 (C-3),
2. Experimental
144.1 (C-8), 137.7 (C-1ꢁ), 134.4 (C-1ꢁꢁ), 131.1 (C-4ꢁ),
129.2 (C-2ꢁꢁ/C-6ꢁꢁ), 129.1 (C-3ꢁꢁ/C-5ꢁꢁ), 129.0, 128.6 (C-
3ꢁ/C-5ꢁ), 125.9 (C-4ꢁꢁ), 119.8 (C-2ꢁ/C-6ꢁ), 119.2 (C-7),
104.7 (C-4), 16.5 (C3-CH3); HRMS: m/z (M+) calcd.
for C19H16N2O2: 304.1206, found: 305.1278 (M+H).
2.1 General
Melting points were determined in open capillaries and
are uncorrected. Iodobenzene diacetate was purchased
from Aldrich. FTIR spectra were obtained in KBr on
IR Affinity-I (Shimadzu) spectrophotometer and are
2.2b s-cis (E) 1-(5-Hydroxy-3-methyl-1-phenyl-1H-
pyrazol-4-yl)-3-(4-methoxyphenyl)-prop-2-en-1-one (2b):
M.p.: 152–153◦C (lit.13 M.p. 153◦C); yield: 88%; IR
(KBr)ν: 3169, 1631, 1568, 1516 cm−1; NMR δH (400
reported in cm−1. H, 13C NMR, DEPT-135, 1D NOE
1
difference spectra and 2D-NMR, COSY (correlation
spectroscopy), HSQC (heteronuclear single-quantum
coherence), HMBC (heteronuclear multiple bond cor-
relation), TOCSY (total correlation spectroscopy) and
ROESY (rotating frame enhancement spectroscopy)
spectra were scanned on a Bruker Avance III NMR
spectrometer operating at 400 MHz in CDCl3 and are
expressed as ppm with respect to TMS. HRMS were
recorded on the 6500 series Agilent Accurate-Mass
Q-TOF LC/MS system.
ꢁ
ꢁ
MHz, CDCl3): 7.94–7.92 (m, 2H, C2 -H, C6 -H), 7.91
(d, 1H, J = 15.5 Hz, C8-H), 7.59 (d, 2H, J = 8.7 Hz,
ꢁꢁ
ꢁꢁ
ꢁ
ꢁ
C2 -H, C6 -H), 7.44 (t, 2H, J = 7.6, 6.5 Hz, C3 -H, C5 -
ꢁ
H), 7.26–7.22 (m, 1H, C4 -H), 7.01 (d, 1H, J = 15.5
ꢁꢁ
ꢁꢁ
Hz, C7-H), 6.96 (d, 2H, J = 8.7 Hz, C3 -H, C5 -H),
ꢁꢁ
3.87 (s, 3H, C4 -OCH3), 2.58 (s, 3H, C3-CH3); NMR
δC (100 MHz, CDCl3): 177.6 (C-6), 165.6 (C-5), 162.2
(C-4ꢁꢁ), 147.0 (C-3), 144.0 (C-8), 137.8 (C-1ꢁ), 130.5
(C-2ꢁꢁ/C-6ꢁꢁ), 129.0 (C-3ꢁ/C-5ꢁ), 127.2 (C-1ꢁꢁ), 125.7 (C-
4ꢁ), 119.7 (C-2ꢁ/C-6ꢁ), 116.4 (C-7), 114.6 (C-3ꢁꢁ/C-5ꢁꢁ),
2.2 General procedure for the Synthesis of s-cis (E)-1-
(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-3-
phenyl/aryl/heteroarylprop-2-en-1-ones (2)
ꢁꢁ
104.3 (C-4), 55.5 (C4 -OCH3), 16.5 (C3-CH3); HRMS:
m/z (M+) calcd. for C20H18N2O3: 334.1314, found:
335.1386 (M+H).
1-Phenyl-3-methylpyrazol-5-one (4.002 g, 0.023 mol)
was dissolved by heating in sodium dried dioxane
(150 mL) in a 250 mL round bottom flask. The solu-
tion was cooled to room temperature and calcium
hydroxide (3.33 g, 0.045 mol) was added in portions
followed by acetyl chloride (2.19 g, 0.028 mol). The
reaction mixture was refluxed for 30 min followed by
removal of excess dioxane under vacuum. The residue
was treated with 10% HCl and the resulting mixture
was extracted with dichloromethane (2×30 mL). The
excess dichloromethane was distilled off to give the
solid which was recrystalized with aqueous methanol
to afford 1-phenyl-3-methyl-4-acetylpyrazol-5-one (1).
Reaction of 1 with various substituted aromatic alde-
hydes (1:1 molar ratio) in chloroform using piperidine
in catalytic amount under reflux for 5-6 h furnished cis
(E)-1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-
3-phenyl/aryl/heteroarylprop-2-en-1-ones (2) in good
yield.
2.2c s-cis (E) 1-(5-Hydroxy-3-methyl-1-phenyl-1H-
pyrazol-4-yl)-3-(4-methylphenyl)-prop-2-en-1-one (2c):
M.p.: 158–159◦C (lit.13 M.p. 158◦C); yield: 87%;
IR(KBr)ν: 1600, 1597, 1543 cm−1; NMR δH (400 MHz,
ꢁ
ꢁ
CDCl3): 7.95–7.89 (m, 2H, C2 -H, C6 -H), 7.88 (d, 1H,
ꢁꢁ
J = 14.8 Hz, C8-H), 7.53 (d, 2H, J = 7.6 Hz, C2 -
ꢁꢁ
ꢁ
ꢁ
H, C6 -H), 7.44–7.40 (m, 2H, C3 -H, C5 -H), 7.29–7.21
ꢁꢁ
ꢁꢁ
ꢁ
(m, 3H, C3 -H, C5 -H, C4 -H), 7.11 (d, 1H, J = 14.8
ꢁꢁ
Hz, C7-H), 2.61 (s, 3H, C3-CH3), 2.42 (s, 3H, C4 -CH3);
NMR δC (100 MHz, CDCl3): 177.8 (C-6), 165.5 (C-
5), 147.0 (C-3), 144.2 (C-8), 141.9 (C-4ꢁꢁ), 137.7 (C-
1ꢁ), 131.7 (C-1ꢁꢁ), 129.9 (C-2ꢁꢁ/C-6ꢁꢁ), 129.0 (C-3ꢁꢁ/C-5ꢁꢁ),
128.6 (C-3ꢁ/C-5ꢁ), 125.8 (C-4ꢁ), 119.8 (C-2ꢁ/C-6ꢁ), 118.0
ꢁꢁ
(C-7), 104.4 (C-4), 21.6 (C4 -CH3), 15.4 (C3-CH3);
HRMS: m/z (M+) calcd. for C20H18N2O2: 318.1367,
found: 319.1440 (M+H).
2.2d s-cis (E) 1-(5-Hydroxy-3-methyl-1-phenyl-1H-
2.2a s-cis (E) 1-(5-Hydroxy-3-methyl-1-phenyl-1H- pyrazol-4-yl)-3-(4-chlorophenyl)-prop-2-en-1-one (2d):
pyrazol-4-yl)-3-phenyl-prop-2-en-1-one (2a): M.p.: M.p.: 171–172◦C; yield: 83%; IR(KBr)ν: 1788, 1620,
158–159◦C (lit.13 M.p. 158◦C); yield: 84% ; IR(KBr)ν: 1579, 1570, 1560 cm−1; NMR δH (400 MHz, CDCl3):
1625, 1564, 1517, 1427 cm−1; NMR δH (400 MHz, 7.90 (d, 1H, J = 7.6 Hz, C2 -H, C6 -H), 7.87 (d, 1H,
ꢁ
ꢁ
ꢁ
ꢁ
ꢁꢁ
CDCl3): 7.96–7.91 (m, 2H, C2 -H, C6 -H), 7.94 (d, J = 15.6 Hz, C8-H), 7.55 (d, 2H, J = 8.4 Hz, C3 -H,
ꢁꢁ
ꢁꢁ
ꢁ
ꢁ
ꢁꢁ
ꢁꢁ
1H, J = 15.6 Hz, C8-H), 7.64–7.62 (m, 2H, C2 -H, C5 -H), 7.46–7.41 (m, 4H, C3 -H, C5 -H, C2 -H, C6 -H),
ꢁ
ꢁ
ꢁꢁ
ꢁꢁ
ꢁ
C6ꢁꢁ-H), 7.46–7.42 (m, 5H, C3 -H, C5 -H, C3 -H, C5 -H, 7.26 (m, 1H, C4 -H ), 7.15 (d, 1H, J = 15.6 Hz, C7-
ꢁꢁ
ꢁ
C4 -H), 7.26–7.23 (m, 1H, C4 -H), 7.16 (d, 1H, J = H), 2.58 (s, 3H, C3-CH3); NMR δC (100 MHz, CDCl3):
15.6 Hz, C7-H), 2.59 (s, 3H, C3-CH3); NMR δC (100 177.9 (C-6), 165.0 (C-5), 146.9 (C-3), 142.5 (C-8),

Iodobenzene diacetate mediated study
415
137.6 (C-1ꢁ), 137.0 (C-1ꢁꢁ), 132.9 (C-2ꢁꢁ/C-6ꢁꢁ), 129.7
(C-3ꢁꢁ/C-5ꢁꢁ), 129.4 (C-3ꢁ/C-5ꢁ), 129.0 (C-4ꢁ), 126.0 (C-
4ꢁꢁ), 119.9 (C-2ꢁ/C-6ꢁ), 119.8 (C-7), 104.7 (C-4), 16.5
(C3-CH3); HRMS: m/z (M+) calcd. for C19H15ClN2O2:
338.0826, found: 339.0899 (M+H).
the iodosobenzene followed by recrystalization with
dichloromethane and hexane to obtain s-trans (E)-4-
(3-(phenyl/aryl/hetroaryl)acryloyl)-5-methyl-2-phenyl-
1H-pyrazol-3(2H)-ones (3).
2.3a s-trans (E) 4-Cinnamoyl-5-methyl-2-phenyl-1H-
pyrazol-3(2H)-one (3a): M.p.: 142–143◦C; yield:
90%; IR(KBr)ν: 3371, 1712, 1597 cm−1; NMR δH (400
MHz, CDCl3): 7.92 (d, 1H, J = 15.3 Hz, C8-H), 7.82–
2.2e s-cis (E) 1-(5-Hydroxy-3-methyl-1-phenyl-1H-
pyrazol-4-yl)-3-(2-furyl)-prop-2-en-1-one (2e): M.p.:
168–169◦C (lit.13 M.p. 168◦C); yield: 82%; IR(KBr)ν:
3093, 1734, 1604, 1521 cm−1; NMR δH (400 MHz,
ꢁ
ꢁ
ꢁꢁ
7.77 (m, 2H, C2 -H, C6 -H), 7.51–7.16 (m, 8H, C3 -H,
ꢁꢁ
ꢁꢁ
ꢁꢁ
ꢁ
ꢁ
ꢁ
ꢁꢁ
C5 -H, C2 -H, C6 -H, C3 -H, C5 -H, C4 -H, C4 -H), 6.65
(d, 1H, J = 15.3 Hz, C7-H), 2.59 (s, 3H, C3-CH3), 1.55
(br s, 1H, NH); NMR δC (100 MHz, CDCl3): 183.4 (C-
6), 165.4 (C-5), 158.9 (C-3), 148.1 (C-8), 137.1 (C-1ꢁ),
133.6 (C-1ꢁꢁ), 131.6 (C-4ꢁꢁ), 129.1 (C-3ꢁꢁ/C-5ꢁꢁ), 129.0
(C-2ꢁꢁ/C-6ꢁꢁ), 128.9 (C-3ꢁ/C-5ꢁ) 126.0 (C-4ꢁ), 119.4 (C-
2ꢁ/C-6ꢁ), 118.6 (C-7), 20.8 (C3-CH3); HRMS: m/z (M+)
calcd. for C19H16 N2O2: 304.1205, found: 305.1278
(M+H).
ꢁ
ꢁ
CDCl3): 7.92 (d, 2H, J = 8.0 Hz, C2 -H, C6 -H), 7.66
ꢁꢁ
(d, 1H, J = 15.2 Hz, C8-H), 7.58 (s, 1H, C5 -H), 7.43 (t,
ꢁ
ꢁ
2H, J = 8.0, 7.6 Hz, C3 -H, C5 -H), 7.23 (t, 1H, J = 7.2
ꢁ
Hz, C4 -H), 7.01 (d, 1H, J = 15.2 Hz, C7-H), 6.76 (br
ꢁꢁ
ꢁꢁ
s, 1H, C3 -H), 6.55 (br s, 1H, C4 -H), 2.56 (s, 3H, C3-
CH3); NMR δC (100 MHz, CDCl3): 177.0 (C-6), 165.5
(C-5), 158.9 (C-2ꢁꢁ), 151.3 (C-3), 145.8 (C-8), 137.8 (C-
1ꢁ), 129.7 (C-5ꢁꢁ), 129.0 (C-3ꢁ/C-5ꢁ), 125.7 (C-4ꢁ), 119.7
(C-2ꢁ/C-6ꢁ), 117.3 (C-7), 116.5 (C-3ꢁꢁ), 113.0 (C-4ꢁꢁ),
104.8 (C-4) 16.4 (C3-CH3); HRMS: m/z (M+) calcd.
for C17H14N2O3: 294.1009, found: 295.1076 (M+H).
2.3b s-trans (E) 4-(3-(4-Methoxyphenyl)acryloyl)-
5-methyl-2-phenyl-1H-pyrazol-3(2H)-one (3b): M.p.:
140–141◦C; yield: 94%; IR(KBr)ν: 3157, 1705, 1581,
1506 cm−1; NMR δH (400 MHz, CDCl3); 7.87 (d, 1H,
2.2f s-cis (E) 1-(5-Hydroxy-3-methyl-1-phenyl-1H-
pyrazol-4-yl)-3-(4-bromophenyl)-prop-2-en-1-one (2f):
M.p.: 169–170◦C; yield: 85%; IR(KBr)ν: 3059, 2927,
1631, 1573, 1504, 1419 cm−1; NMR δH (400 MHz,
ꢁ
J = 15.2 Hz, C8-H), 7.81 (d, 2H, J = 7.9 Hz, C2 -H,
ꢁ
ꢁꢁ
ꢁꢁ
C6 -H), 7.46 (d, 2H, J = 8.6 Hz, C2 -H, C6 -H), 7.34 (t,
ꢁ
ꢁ
2H, J = 8.0, 7.8 Hz, C3 -H, C5 -H), 7.17 (t, IH, J = 7.3
ꢁ
ꢁ
CDCl3):); 7.91 (d, 2H, J =7.6 Hz, C2 -H, C6 -H ), 7.85
ꢁ
ꢁ
ꢁꢁ
Hz, C4 -H), 6.87 (d, 2H, J = 8.6 Hz, C3 -H, C5 -H), 6.52
(d, 1H, J = 15.6 Hz, C8-H), 7.57 (d, 2H, J = 8.4 Hz,
ꢁꢁ
(d, 1H, J = 15.2 Hz, C7-H), 3.82 (s, 3H, C4 -OCH3),
ꢁꢁ
ꢁꢁ
ꢁꢁ
ꢁꢁ
C3 -H, C5 -H), 7.46 (d, 2H, J = 8.4 Hz, C2 -H, C6 -H),
2.62 (s, 3H, C3-CH3), 1.55 (br s, 1H, NH); NMR δC
(100 MHz, CDCl3): 183.3 (C-6), 165.7 (C-5), 162.5 (C-
4ꢁꢁ), 159.2 (C-3), 147.8 (C-8), 137.2 (C-1ꢁ), 131.0 (C-
2ꢁꢁ/C-6ꢁꢁ), 128.9 (C-3ꢁ/C-5ꢁ), 126.4 (C-1ꢁꢁ), 125.9 (C-4ꢁ),
119.4 (C-2ꢁ/C-6ꢁ), 116.1 (C-7), 114.5 (C-3ꢁꢁ/C-+5ꢁꢁ), 54.4
ꢁ
ꢁ
7.42 (d, 2H, J = 8.4 Hz, C3 -H, C5 -H), 7.24 (d, 1H,
ꢁ
J = 7.4 Hz, C4 -H), 7.13 (d, 1H, J = 15.6 Hz, C7-H),
2.58 (s, 3H, C3-CH3) ; NMR δC (100 MHz, CDCl3):
177.9 (C-6), 165.0 (C-5), 146.9 (C-3), 142.6 (C-8),
137.6 (C-1ꢁ), 133.3 (C-1ꢁꢁ), 132.4 (C-2ꢁꢁ/C-6ꢁꢁ), 129.8
(C-3ꢁꢁ/C-5ꢁꢁ), 129.0 (C-3ꢁ/C-5ꢁ), 126.0 (C-4ꢁ), 125.4
(C-4ꢁꢁ), 119.9 (C-2ꢁ/C-6ꢁ), 119.8 (C-7), 104.8 (C-4),
16.5 (C3-CH3); HRMS: m/z (M+) calcd. for C19H15
BrN2O2: 382.0315, found: 383.0389 (M+H).
ꢁꢁ
(C4 -OCH3), 20.8 (C3-CH3); HRMS: m/z (M ) calcd.
for C20H18N2O3: 334.1315, found: 335.1386 (M+H).
2.3c s-trans (E) 5-Methyl-2-phenyl-4-(3-p-tolylacryloyl)-
1H-pyrazol-3(2H)-one (3c): M.p.: 144–145◦C; yield:
90%; IR(KBr)ν: 3367, 1710, 1589 cm−1; NMR δH (400
MHz, CDCl3): 7.89 (d, 1H, J = 15.2 Hz, C8-H), 7.81
2.3 General procedure for the Synthesis of s-trans
(E)-4-(3-(phenyl/aryl/hetroaryl)acryloyl)-5-methyl-2-
phenyl-1H-pyrazol-3(2H)-ones (3)
ꢁ
ꢁ
(d, 2H, J = 8.0 Hz, C2 -H, C6 -H), 7.39 (d, 2H, J =
ꢁꢁ
ꢁꢁ
ꢁ
8.0 Hz, C2 -H, C6 -H), 7.35 (t, 2H, J = 8.0 Hz, C3 -H,
ꢁ
ꢁꢁ
ꢁꢁ
ꢁ
To the solution of cis (E)-1-(5-hydroxy-3-methyl-1- C5 -H), 7.20–7.16 (m, 3H, C3 -H, C5 -H, C4 -H), 6.60
phenyl-1H-pyrazol-4-yl)-3-phenyl/aryl/heteroarylprop- (d, 1H, J = 15.2 Hz, C7-H), 2.62 (s, 3H, C3-CH3), 2.39
ꢁꢁ
2-en-1-ones (2) (0.001 mol) in dichloromethane 15 mL, (s, 3H, C4 -CH3), 1.55 (br s, 1H, NH); NMR δC (100
iodobenzene diacetate (0.001 mol) was added in small MHz, CDCl3): 183.4 (C-6), 165.5 (C-5), 159.1 (C-3),
portions in 10 min. The reaction mixture was further 148.2 (C-8), 142.4 (C-4ꢁꢁ), 137.1 (C-1ꢁ), 130.9 (C-1ꢁꢁ),
stirred for 0.5 to 1 h at room temperature till the 129.8 (C-2ꢁꢁ/C-6ꢁꢁ), 129.0 (C-3ꢁꢁ/C-5ꢁꢁ), 128.9 (C-3ꢁ/C-
completion of reaction as monitored by TLC. The 5ꢁ), 125.9 (C-4ꢁ), 119.4 (C-2ꢁ/C-6ꢁ), 117.6+(C-7), 21.6
ꢁꢁ
excess dichloromethane was distilled off to give a (C4 -CH3), 20.8 (C3-CH3 ); HRMS: m/z (M ) calcd. for
solid mass which was triturated with hexane to remove C20H18N2O2: 318.1363, found: 319.1435 (M+H).

416
Mahavir Parshad et al.
2.3d s-trans (E) 4-(3-(4-Chlorophenyl)acryloyl)-5- 1-one (2) and s-trans (E)-4-(3-(phenyl/aryl/hetroaryl)
methyl-2-phenyl-1H-pyrazol-3(2H)-one (3d): M.p.: acryloyl)-5-methyl-2-phenyl-1H-pyrazol-3(2H)-ones
160–161◦C; yield: 93%; IR(KBr)ν: 3165, 1708, 1591 (3) were dissolved in DMSO to form stock solutions
cm−1; NMR δH (400 MHz, CDCl3): 7.85 (d, 1H, J = (10 mM/mL), which were filter sterilized before testing
ꢁ
ꢁ
15.6 Hz, C8-H), 7.80 (d, 2H, J = 8.0 Hz, C2 -H, C6 - on cell lines. Human Pancreatic cancer cell line
ꢁꢁ
ꢁꢁ
H), 7.43 (d, 2H, J = 8.4 Hz, C2 -H, C6 -H), 7.37–7.33 (PANC1), Colon (Colo-205, HCT-116), lung carci-
ꢁ
ꢁ
ꢁꢁ
ꢁꢁ
(m, 4H, C3 -H, C5 -H, C3 -H, C5 -H), 7.19 (t, 1H, J = noma cell line (A549, NCI-H322) were procured from
ꢁ
7.2 Hz, C4 -H), 6.61 (d, 1H, J = 15.6 Hz, C7-H), European Collection of cell cultures (ECACC). The
2.62 (s, 3H, C3-CH3), 1.55 (br s, 1H, NH); NMR δC human cancer cell lines were grown in tissue culture
(100 MHz, CDCl3): 183.6 (C-6), 165.3 (C-5), 153.0 flasks in complete growth medium (RPMI-1640/ MEM/
(C-3), 146.7 (C-8), 137.7 (C-1ꢁ), 137.0 (C-1ꢁꢁ) 132.0 DMEM medium supplemented with 10% fetal calf
(C-4ꢁ), , 130.1 (C-2ꢁꢁ/C-6ꢁꢁ), 128.9 (C-3ꢁ/C-5ꢁ), 126.1 serum, 100 μg/mL streptomycin and 100 units/mL pe-
(C-4ꢁ), 119.4 (C-2ꢁꢁ/C-6ꢁꢁ), 119.0 (C-7), 20.8 (C3-CH3); nicillin) in carbon dioxide incubator (New Brunswick,
HRMS: m/z (M+) calcd. for C19H15ClN2O2: 338.0821, Galaxy 170R, Eppendorf) at 37◦C, 5% CO2 and 98%
found: 339.0891 (M+H).
RH.
The sulforhodamine B (SRB) assay was performed,
in which cell suspension of optimum cell density
(7500–15000 cells/100 μL) was seeded and exposed
to 1 μM, 10 μM, 30 μM, 50 μM, concentrations of
test materials in complete growth medium (100 μL)
were added after 24 h of incubation along with known
cytotoxic agents paclitaxel, 5-Florouracil (5-FU) and
Erlotinib as positive controls. After further 48 h, incu-
bation cells were fixed with ice-cold TCA for 1h at
4◦C. After 1 h, the plates were washed five times with
distilled water and allowed to air dry followed by the
addition of 100 μL of 0.4% SRB dye for 0.5 h at
room temperature. Plates were then washed with 1%
v/v acetic acid to remove the unbound SRB. The bound
dye was solubilized by adding 100 μL of 10 mM tris
buffer (pH = 10.4) to each well. The plates were put on
the shaker for 5 min to solublize the dye completely, and
finally the reading was taken at 540 nm on microplate
reader (BioTek Synergy HT). IC50 was determined by
plotting OD against concentration.14
2.3e s-trans (E) 4-(3-(Furan-2-yl)acryloyl)-5-methyl-
2-phenyl-1H-pyrazol-3(2H)-one (3e): M.p.: 114–
115◦C; yield: 92%; IR(KBr)ν: 3126, 1707, 1678, 1598
cm−1; NMR δH (400 MHz, CDCl3): 7.92 (d, 2H, J =
ꢁ
ꢁ
8.0 Hz, C2 -H, C6 -H), 7.61 (d, 1H, J = 15.6 Hz, C8-H),
ꢁꢁ
ꢁ
7.59 (s, 1H, C3 -H), 7.33 (t, 2H, J = 8.0, 7.6 Hz, C3 -H,
ꢁ
ꢁ
C5 -H), 7.17 (t, 1H, J = 7.6, 7.2 Hz, C4 -H), 6.74 (d,
ꢁꢁ
1H, J = 3.2 Hz, C5 -H), 6.51 (d, 1H, J = 15.6 Hz, C7-
ꢁꢁ
H), 6.49 (br s, 1H, C4 -H), 2.62 (s, 3H, C3-CH3), 1.55
(br s, 1H, NH); NMR δC (100 MHz, CDCl3): 183.3 (C-
6), 165.5 (C-5), 158.9 (C-3), 150.6 (C-2ꢁꢁ), 146.1 (C-8),
137.1 (C-1ꢁ), 133.2 (C-5ꢁꢁ), 128.8 (C-3ꢁ/C-5ꢁ), 125.9
(C-4ꢁ), 119.5 (C-2ꢁ/C-6ꢁ), 118.6 (C-7), 116.1 (C-3ꢁꢁ),
113.0 (C-4ꢁꢁ), 20.8 (C3-CH3); HRMS: m/z (M+) calcd.
for C17H14N2O3: 294.1003, found: 295.107 (M+H).
2.3f s-trans (E) 4-(3-(4-Bromophenyl)acryloyl)-5-
methyl-2-phenyl-1H-pyrazol-3(2H)-one (3f): M.p.:
135–136◦C yield: 98%; IR(KBr)ν: 3068, 1708, 1597,
1489 cm−1; NMR δH (400 MHz, CDCl3): 7.83 (d, 1H,
2.5 Evaluation of anti-microbial activity
(determination of MIC)
ꢁ
J = 15.3 Hz, C8-H), 7.80 (d, 2H, J =8.6 Hz, C2 -
ꢁ
ꢁꢁ
ꢁꢁ
H, C6 -H ), 7.51 (d, 2H, J = 8.4 Hz, C3 -H, C5 -H),
ꢁ
ꢁ
ꢁꢁ
ꢁꢁ
7.37–7.33 (m, 4H, C3 -H, C5 -H, C2 -H, C6 -H), 7.19
The anti-microbial activity of all the pyrazolyl chal-
cones (2 and 3) was performed against Gram-positive
bacteria: Staphylcococcus aureus [MTCC 2901], Bacil-
lus sublitis [MTCC 2063], Gram-negative bacterium:
Escherichia coli [MTCC 1652] and fungal strains:
Candida albicans [MTCC 227] and Aspergillus niger
[MTCC 8189] using tube dilution method. Dilutions
of test and standard compounds were prepared in
double strength nutrient broth – I.P. (bacteria) or
Sabouraud dextrose broth I.P. (fungi). The samples
were incubated at 37◦C 1◦C for 24 h (bacteria),
25◦C for 7 days (A. niger) and 37◦C 1◦C for 48 h
ꢁ
(t, 1H, J = 7.4, 6.8 Hz, C4 -H), 6.62 (d, 1H, J = 15.3
Hz, C7-H), 2.59 (s, 3H, C3-CH3), 1.55 (br s, 1H, NH);
NMR δC (100 MHz, CDCl3): 183.3 (C-6), 165.2 (C-5),
158.6 (C-3), 146.7 (C-8), 137.0 (C-1ꢁ), 132.5 (C-3ꢁꢁ/C-
5ꢁꢁ), 132.4 (C-1ꢁꢁ), 130.2 (C-2ꢁꢁ/C-6ꢁꢁ), 128.9 (C-3ꢁ/C-5ꢁ),
126.2 (C-4ꢁꢁ), 126.1 (C-4ꢁ) 119.4 (C-2ꢁ/C-6ꢁ), 119.1
(C-7), 20.8 (C3-CH3); HRMS: m/z (M+) calcd. for
C19H15BrN2O2: 382.0313, found: 383.0384 (M+H).
2.4 Evaluation of cytotoxicity assay
All the pyrazolyl chalcones i.e.s-cis (E)-1-(5-hydroxy- (C. albicans) and the results were recorded in terms of
3-methyl-1-phenyl-1H-pyrazol-4-yl)-3-arylprop-2-en- MIC.

Iodobenzene diacetate mediated study
417
reaction between aldehyde and ketone.17 The 13C NMR
of 2f displayed signals due to enone moiety at δ 177.9,
119.8 and 142.6 assigned to C=O, C-7 and C-8, respec-
tively. The high resolution mass spectrum of 2f showed
the molecular ion peak at m/z 383.0389 (M+H) (calcd.
for C19H15BrN2O2: 382.0315).
3. Results and Discussion
3.1 Chemistry
The 4-acylpyrazolones are interesting class of β-
diketones containing pyrazole fused to a chelating arm
that is useful in coordination chemistry.15 In the present
study, 1-phenyl-3-methyl-4-acetylpyrazol-5-one (1)16
is used as starting material for the synthesis of
cis (E)-1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-
4-yl)-3-phenyl/aryl/heteroarylprop-2-en-1-ones (2, OH
form) in good yield (70–88%) by condensation with
aromatic aldehydes (scheme 1). It may be mentioned
that some of pyrazolyl chalcones (2) have been pre-
pared using different reaction conditions in low yield
(30–40%) without reporting any spectroscopic data and
explanation about structure.13 However, all the pyra-
zolyl chalcones have been synthesized with improved
procedure.
Further, pyrazolyl chalcones (2) may exist more as
OH and NH tautomer (figures 1 and 2) due to fast pro-
tropic exchange and may involve intramolecular hydro-
gen bonding. The OH/NH signal in NMR could not be
observed. Further, 2 is also having s-cis (E) geometry
rather than the s-trans (E) geometry based on detailed
NMR analysis. It was earlier noted that two double
bonds of enone moiety in chalcones were positioned
cis with respect to each other in several x-ray crystal
structure of chalcone and the s-cis isomer of chalcone
was more stable that the s-trans conformer by at least
3.9 kcal/mol.18 Each mutually coupled protons and their
connectivities with carbons along with identification of
different carbons and long range coupling were anal-
ysed thoroughly with the help of COSY, HSQC, DEPT-
135 and HMBC experiments for structure elucidation
of pyrazolyl chalcone (2).
The cis (E)-1-(5-hydroxy-3-methyl-1-phenyl-1H-
pyrazol-4-yl)-3-phenyl/aryl/heteroarylprop-2-en-1-ones
(2) was stirred in dichloromethane at room temperature
in presence of iodobenzene diacetate. To our surprise,
2 was isomerized to s-trans (E)-4-(3-(phenyl/aryl/
hetroaryl)acryloyl)-5-methyl-2-phenyl-1H-pyrazol-3(2H)-
ones (3, NH form) instead of the formation of pyrano-
pyrazole (4) (scheme 2). The structure of 3 was deter-
mined using IR, NMR (1H and 13C), DEPT-135, 2D-
NMR (COSY, HSQC, HMBC, TOCSY and ROESY),
NOE difference spectra and HRMS data. The IR spec-
trum of 3f showed the bands at 3068 and 1708 cm−1
due to C-H str. and C=O str., respectively. However,
O-H/N-H str. vibrational band was not observed. In
1H NMR spectrum, the two doublets of enone moiety
appeared at δ 6.62 (J = 15.3 Hz) and 7.83 (J = 15.3 Hz)
The pyrazolyl chalcones (2) were subjected to rigor-
ous study as they can adopt different conformations by
rotating around the sigma bond of enone moiety leading
to different geometries: E s-cis and s-trans, Z s-cis and
s-trans conformations along with enol (OH and keto)
and (NH) tautomerism (figures 1 and 2). The structure
of compound 2 was determined with the help of IR,
NMR (1H and 13C), 2D-NMR (COSY, HSQC, HMBC,
TOCSY and ROESY) and HRMS data. The IR spec-
trum of 2f showed the bands at 3059, 2927, 1631 cm−1
due to C-H str. and C=O str. The O-H/N-H str. vibra-
1
tional band was not observed. In H NMR spectrum,
the two doublets of enone moiety appeared at δ 7.13
(J = 15.6 Hz) and 7.85 (J = 15.6 Hz) assigned to C7-H
(Hα) and C8-H (Hβ) respectively, indicate thereby the
E configuration around the double bond of enone
moiety. The pyrazolyl chalcone (2f) having Z configu-
ration was not observed at all. This fact is also suppor-
ted by the literature study indicating that the chalcone
having E configuration is the principle product of
Scheme 1. Synthesis of cis (E)-1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-
4-yl)-3-phenyl/aryl/heteroarylprop-2-en-1-ones (2).

418
Mahavir Parshad et al.
O
H
O
O
N
N
O
N
H
O
H
O
N
H
O
N
N
N
N
O
H3C
H3C
H3C
H3C
s-cis (Z)
s-trans (Z)
s-trans (E)
s-cis (E)
O
O
N
O
H
N
O
H
N
N
H
O
H
O
N
N
N
N
O
O
H3C
H3C
H3C
H3C
s-trans (Z)
s-cis (Z)
s-cis (E)
s-trans (E)
Figure 1. OH tautomer of 2.
assigned to C7-H (Hα) and C8-H (Hβ), respectively indi- chemical shift value of the proton (C7-H) in the reactant
cating thereby again the E configuration around sigma (2). Further, it was observed that there was very small
bond of enone moiety. But the C7-H (Hα) was found to deshielding (∼0.04 ppm) of methyl proton (C3-CH3) of
be shielded in comparison to C7-H (Hα) of 2 that res- pyrazole moiety. The melting point of the products (3)
onated at δ 7.13. The NH signal was observed at δ 1.55. is also lower in comparison to the reactants (2) suggest-
The 13C NMR of 3f displayed signals due to enone ing a decrease in the extent of hydrogen bonding. The
moiety at δ 183.3, 119.1 and 146.7 assigned to C=O, role of pyrazole moiety in isomerization cannot be ruled
C-7 and C-8, respectively. The high resolution mass out because when (E)-1-(2-hydroxyphenyl)-3-arylprop-
spectrum of 3f showed the molecular ion peak at m/z 2-en-1-ones were treated with iodobenzene diacetate
383.0384 (M+H) (calcd. for C19H15BrN2O2: 382.0315). under similar condition there was no isomerization,
The isomerization of s-cis geometry to s-trans geo- rather the starting material recovered back.
metry around sigma bond was established by analysis
There was difference in the chemical shift values of
of the data presented in table 1. There was almost no carbons C-3, C-6 and C-7 in compounds 2 and 3 as indi-
change in the chemical shift value of proton (C8-H) cated in the table 2. The increase in chemical shift value
in both 2 and 3, but the proton (C7-H) is shielded by ∼12 ppm C-3 of pyrazole moiety and by ∼5 ppm in
(∼0.5 ppm) in the product (3) in comparison to the C-6 (C=O) and C-7 of enone moiety was observed on
Figure 2. NH tautomer of 2.

Iodobenzene diacetate mediated study
419
Scheme 2. Isomerization of s-trans (E)-4-(3-(phenyl/aryl/heteroaryl)acryloyl)-
5-methyl-2-phenyl-1H-pyrazol-3(2H)-ones (3).
isomerization of 2 to 3. However, there was no diffe-
The probable mechanism consists of addition of
rence in chemical shift values of carbons C-5 (C=O) iodobenzene diacetate on enone double bond of 2
and very minor difference in chemical shift of C-8. resulting in the formation of 5 that may undergo rota-
Moreover, the changes in the chemical shift value of tion around single bond thus producing 6 thereby
carbon (C-3) of pyrazole moiety form δ 146.9 to 158.6 relieving the steric strain. The intermediate 6 is then
might be expected only when OH tautomer of pyrazole attacked by the moisture to form the cyclic interme-
is transformed to NH tautomer.19 These data support diate (7) that eliminates iodosobenzene to produce 3.
the isomerization of 2 to 3. However, the C-4 chemical However, the pyranopyrazole (4) was not formed even
shift value was not observed. The s-cis (E) geometry in traces (scheme 3). In order to establish the role of
of 2 and s-trans (E) geometry of 3 was also supported moisture, the above reaction was also carried out in
by TOCSY, ROESY and 1D NOE difference spectra as dichloromethane in presence of a drop of water; the
explained for 2f and 3f (figure 3). TOCSY and ROESY result was found to be same.
experiments established the correlation of hydrogens
in space and the percentage enhancement of signals in
1D NOE difference spectrum explained the proximity
3.2 Biological studies
of hydrogens in space thereby substantiating the above
3.2a Cytotoxic activity: The cytotoxic activity of
assignment in support of the structure of 2f and 3f.
s-cis (E)-1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-
In 1D NOE difference spectra of 2f, saturating C7-H
4-yl)-3-arylprop-2-en-1-ones (2) and s-trans (E)-1-(5-
showed unexpected enhancement to C3-CH3 (37.4%) of
hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-3-arylprop-
2-en-1-ones (3) based on SRB (Sulphorhodamine B
pyrazole moiety whereas saturating C3-CH3 gave
2.39% enhancement of C7-H. Saturating C8-H showed
assay) was performed against panel of five cancer cell
ꢁꢁ ꢁꢁ
only enhancement to C2 /6 -H (0.43%). In case of
lines (PANC-1, COLO-205, HCT-116, A549 and NCI-
H322). The cytotoxicity of pyrazolyl chalcone (2c)
3f, saturating C3-CH3 of pyrazole moiety indicated
ꢁ
ꢁ
enhancement to C-2 /6 -H (0.36%), C7-H (1.27%) and
C8-H (0.29%) whereas saturating C8-H produced
enhancement of C3-CH3 (1.36%), C7-H (0.92%) and
was found to be more active at very low concentrations
with IC50 of 13.3 μM against colon cancer cell line
(HCT-116) and it is moderately active against A549
cancer cell line. However, pyrazolyl chalcones (2d and
2e) were also active against A549 with IC50 values of
25.4 and 23.0 μM, respectively whereas 2d was also
active against NCI-H322 with IC50 25.7 μM. These
ꢁꢁ ꢁꢁ
C2 /6 -H (2.39%). Further, saturating C7-H shows only
ꢁꢁ ꢁꢁ
enhancement in C2 /6 -H (0.44%). All these results are
consistent with the s-cis (E) geometry for 2f and s-trans
(E) geometry for 3f.
Table 1. Melting point and selected proton chemical shift values of 2 and 3.
Compd. M.p. (◦C) δ (Hα) δ (Hβ) Compd. M.p. (◦C) δ (Hα) δ (Hβ)
2a
2b
2c
2d
2e
2f
158–159
152–153
158–159
171–172
168–169
169–170
7.16
7.01
7.11
7.15
7.01
7.13
7.94
7.91
7.88
7.90
7.66
7.85
3a
3b
3c
3d
3e
3f
142–143
140–141
144–145
160–161
114–115
135–136
6.65
6.52
6.60
6.61
6.51
6.62
7.92
7.87
7.89
7.85
7.61
7.83

420
Mahavir Parshad et al.
Table 2. Selected carbon shift values of compounds 2 and 3.
Compound
C-3
C-4
C-5
C-6
C-7
C-8
2a
2b
2c
2d
2e
2f
3a
3b
3c
3d
3e
3f
147.0
147.0
147.0
146.9
151.3
146.9
158.9
159.2
159.1
153.0
158.9
158.6
104.7
104.3
104.4
104.7
104.8
104.8
n.o.
n.o.
n.o.
n.o.
n.o.
165.2
165.6
165.5
165.0
165.5
165.0
165.4
165.7
165.5
165.3
165.5
165.2
178.0
177.6
177.8
177.9
177.0
177.9
183.4
183.3
183.4
183.6
183.3
183.3
119.2
116.4
118.0
119.8
117.3
119.8
118.6
116.1
117.6
119.0
118.6
119.1
144.1
144.0
144.2
142.5
145.8
142.6
148.1
147.8
148.2
146.7
146.1
146.7
n.o.
n.o. not observed
result depicted that prazolyl cahlcones (2) having s-cis acryloyl)-5-methyl-2-phenyl-1H-pyrazol-3(2H)-ones
(3) were also tested in vitro for their anti-bacterial
activity against Gram-positive Bacillus subtilis [MTCC
2063], Staphylococcus aureus [MTCC 2901] and
Gram-negative Escherichia coli [MTCC 1652] and
in vitro anti-fungal activity against Candida albicans
[MTCC 227] and Aspergillus niger [MTCC 8184].
Double strength nutrient broth-I.P. and Sabouraud
dextrose broth-I.P20 were employed for bacterial
configuration are more active than the isomeric pyra-
zolyl chalcones (3) having s-trans configuration except
3a as reflected by relative IC50 values (table 3).
3.2b Anti-microbial activity: The s-cis (E)-1-(5-hydroxy-
3-methyl-1-phenyl-1H-pyrazol-4-yl)-3-arylprop-2-en-1-
ones (2) and s-trans (E)-4-(3-(phenyl/aryl/hetroaryl)-
H
H
H
H
H
H
H
O
O
N
N
H
O
H
O
N
N
37.4%
H3C
H3C
H
H
0.43%
H
H
H
H
2.39%
H
H
H
H
H
H
Br
Br
2f
H
H
H
H
H
H
O
H
O
O
N
N
N
HN
HN
HN
O
O
O
0.36%
0.92%
H3C
1.27%
H
H
H3C
H3C
H
H
H
H
H
1.36%
2.39%
0.44%
H
H
0.29%
H
H
H
H
H
H
H
H
H
Br
Br
Br
3f
Figure 3. Correlation of hydrogens using TOCSY, ROESY and 1D NOE difference spectra.

Iodobenzene diacetate mediated study
421
O
O
N
O
N
N
H
O
H
O
rotation
around
H
O
OAc
OAc
N
N
N
Ph
I
+
single
bond
H3C
H3C
Ph
H3C
AcO
Ph
OAc
I
I
OH2
O
Ar
O
Ar
Ar
O
O
2
H3C
CH3
5
6
-H
-OAc
O
O
Ar
N
O
O
N
N
H
H
O
N
N
N
O
H3C
H3C
-PhIO, AcOH
H3C
Ph
I
Ar
O
O
Ar
O
4
H3C
H
3
7
Scheme 3. Mechanism of isomerization of 2 to 3.
MICan = 0.93 × 10−2 μM/ml) and 3b (MICca = 0.93 ×
10−2 μM/ml; MICan = 0.93 × 10−2 μM/ml) emerged as
most active ones against C. albicans and A. niger.
Compound 2d having anti-microbial activity close
to the standard drug ciprofloxacin may be taken as
lead compound for the development of anti-bacterial
agents. Similarly compounds 2b and 3b can be selected
as lead compounds for the development of anti-fungal
activity as their activity is close to the standard drug
fluconazole.
and fungal growth respectively. Minimum inhibitory
concentrations [MIC] were determined by means of
standard serial dilution21 and are presented in table 4.
Results of anti-microbial activity (table 4) demon-
strated that compound 2d and 3d were the most
potent ones among the synthesized compounds against
S. aureus and B. subtilis (MIC range = 0.89–1.85
× 10−2 μM/mL). Compounds 2d (MICec = 0.92 ×
10−2 μM/ml) was found to be most active against E.
coli. Compound 2b (MICca = 1.87 × 10−2 μM/ml;
Table 3. In vitro cytotoxicity (IC50 μM) of 2 and 3 against a panel of five human
cancer lines.
Tissue →
Cell line →
Entry ↓
Pancreatic
PANC-1
Colon
COLO-205
Colon
HCT-116
IC50
Lung
A549
Lung
NCI-H322
2a
>50
>50
39.3
37.8
32.2
44.6
34.3
>50
>50
>50
>50
>50
0.06
–
>50
>50
48.6
>50
40.6
>50
26.7
>50
>50
>50
>50
>50
–
>50
44.2
13.3
30.9
33.3
>50
32.6
>50
45.1
>50
>50
na
49.4
40.8
21.9
25.4
23.0
49.9
30.0
45.3
35.1
>50
>50
na
35.9
>50
45.3
25.7
28.2
>50
48.8
>50
32.8
>50
>50
na
2b
2c
2d
2e
2f
3a
3b
3c
3d
3e
3f
Paclitaxel
5FU
–
0.2
–
3.2
18.8
–
–
–
–
0.35
Erlotinib
–
–
na = not active

422
Mahavir Parshad et al.
Table 4. In vitro anti-microbial activity of 2 and 3.
MIC (10−2 μM/mL)
B. subtilis E. coli C. albicans
Compounds
S. aureus
A. niger
2a
2b
2c
2d
2e
2f
4.11
7.48
3.93
1.84
4.25
4.46
4.11
7.48
15.70
1.85
4.25
6.77
0.94a
8.21
3.74
3.93
1.84
8.49
4.46
4.11
3.74
7.85
1.85
4.25
3.39
0.94a
4.11
7.48
3.93
0.92
4.25
8.92
16.43
7.48
3.93
3.70
4.25
6.77
0.94a
16.43
1.87
7.85
7.38
16.99
4.46
4.11
0.93
7.85
3.70
8.50
13.54
1.02b
4.11
0.93
3.93
7.38
4.25
17.84
4.11
0.93
3.93
3.70
17.00
6.77
1.02b
3a
3b
3c
3d
3e
3f
Std.
aCiprofloxacin bFluconazole
3.2c Structure activity relationship (SAR) studies: 4. Conclusions
The following structure activity relationship may be
In summary, we have synthesized s-cis (E)-1-(5-hydroxy-
3-methyl-1-phenyl-1H-pyrazol-4-yl)-3-arylprop-2-en-
1-ones (2) in good yield and then isomerized to
s-trans (E)-4-(3-(phenyl/aryl/heteroaryl)acryloyl)-5-
methyl-2-phenyl-1H-pyrazol-3(2H)-ones (3) using
iodobenzene diacetate in dichloromethane at room
temperature in excellent yield. The structures of these
α, β-unsaturated ketones (pyrazolyl ketones 2 and 3)
were established with the help of NMR, 2D NMR
and HRMS techniques. The cytotoxicity of pyrazolyl
chalcones showed that 2c is active at very low concen-
trations IC50 13.3 μM against colon cancer cell line
(HCT-116). These compounds were also tested in vitro
for their anti-bacterial activity against gram-positive
andgram-negative bacteria and as well as for anti-fungal
activity. The compounds 2d and 3d showed significant
anti-bacterial activity against E. coli and B. subtilis,
respectively and 2b and 3b showed significant anti-fungal
activity against C. albicans and A. niger respectively.
drawn from cytotoxic and anti-microbial activity resu-
lts of s-cis (E)-1-(5-hydroxy-3-methyl-1-phenyl-1H-
pyrazol-4-yl)-3-arylprop-2-en-1-ones (2) and s-trans
(E)-4-(3-(phenyl/aryl/hetroaryl)acryloyl)-5-methyl-2-
phenyl-1H-pyrazol-3(2H)-ones (3) derivatives:
1. The cytotoxicity screening results indicated that
the pyrazolyl ketones (2) are more active than the
isomeric pyrazolyl ketones (3) and the presence of
methyl group improved the cytotoxic activity of
2b to the extent that it was better than the control.
2. The presence of electron withdrawing chloro
group at p-position of the phenyl nucleus attached
to position-4 of pyrazole through enone moiety
improved the anti-bacterial activity of the pyra-
zolyl chalcones. The role of electron withdrawing
group in improving the anti-bacterial activity is
supported by the findings of Sharma et al.22
3. The presence of electron donating methoxy group
at p-position of the phenyl nucleus attached
to position-4 of pyrazole through enone moiety
improved the anti-fungal activity of the pyrazolyl
chalcones. The role of electron releasing groups in
improving the anti-fungal activity is supported by
our recent findings.12
Supplementary Information
The supplementary data i.e., NMR, 2D NMR and
graphs of cytotoxic activity, associated with this article
are available at www.ias.ac.in/chemsci.
4. The introduction of heterocyclic moiety furan
doesn’t improve the anti-microbial spectrum of
pyrazolyl chalcones. The results are similar to one
of our previous studies.23
Acknowledgements
5. From these result we may conclude that different
structural modifications are required for a com- Mahavir Parshad thanks University Grants Commis-
pound to be effective against anti-bacterial and sion, New Delhi for financial support and award of tea-
anti-fungal targets. This is in accordance with the cher fellowship to Mahavir Parshad under FIP scheme
results of Sortino et al.24
12th plan period.

Iodobenzene diacetate mediated study
423
13. Mohanty S K, Sridhar R, Padmanavan S Y, Sundar R
and Mittra A S 1977 Indian J. Chem. 15B 1146
14. Houghton P, Fang R, Techatanawat I, Steventon G,
Hylands P J and Lee C C 2007 Methods 42 377
15. Marchetti F, Pettinari C and Pettinari R 2005 Coordina-
tion Chem. Rev. 249 2909
References
1. Sahu K N, Balbhadra S S, Choudhary J and Kohli V D
2012 Curr. Med. Chem. 19 209
2. Katsori A M and Hadjipavlou-Litina D 2009 Curr. Med.
Chem. 16 1062
16. Jensen B S 1959 Acta Chem. Scand. 13 1668
17. Espinoza-Hicks J C, Rodriguez-Valdez L M, Nevarez-
Moorillon G V and Camacho-Davila A 2012 J. Mol.
Struct. 1020 88
3. Go M L, Wu X and Liu X L 2005 Curr. Med. Chem. 12
481
4. Batovska D I and Todorova I T 2010 Curr. Clin. Phar-
macol. 5 1
18. (a) Garcia J I, Mayorala J A, Salvatell L, Assfeld X
and Ruiz-Lopez M F 1996 J. Mol. Struct. (Theochem)
362 187; (b) Thirunarayanan G, Gopalakrishnan M and
Vanangamudi G 2007 Spectrochim. Acta Part A 67
1106; (c) Yong Y, Ahn S, Hwang D, Yoon H, Jo G, Kim
Y H, Kim S H, Kohb D and Lima Y 2013 Magn. Reson.
Chem. 51 364
19. (a) Kumar D, Singh S P, Martinez A, Fruchier A,
Elguero J, Martinez-Ripoll M, Carrio J S and Virgilli A
1995 Tetrahedron 51 4891; (b) Holzer W, Kautsch C,
Laggner C, Claramunt R M, Perez-Torralba M, Alkorta I
and Elguero J 2004 Tetrahedron 60 6791
20. Pharmacopoeia of India 1996 Ministry of Health
Department, Govt. of India (New Delhi) II p A-88
21. Cappucino J G and Sherman N 1999 In Microbiology–A
Laboratory Manual (California: Addison Wesley) p 263
22. Sharma P, Rane N and Gurram V K 2004 Bioorg. Med.
Chem. Lett. 14 4185
5. Siddiqui Z N, Mohammed T N, Ahmad A and Khan A
U 2011 Bioorg. Med. Chem. Lett. 21 2860
6. Shelke S N, Mhaske G R, Bonifacio V D B and
Gawande M B 2012 Bioorg. Med. Chem. Lett. 22 5727
7. Nagaraju M, Deepthi E G, Ashwini C, Vishnuvardhan
M V P S, Nayak V L, Chandra R, Ramakrishna S and
Gawali B B 2012 Bioorg. Med. Chem. Lett. 22 4314
8. Roman B I, De Ryck T, Dierickx L, Vanhoecke B W A,
Katritzky A R, Bracke M and Stevens C V 2012 Bioorg.
Med. Chem. Lett. 20 4812
9. Bandgar B P, Gawande S S, Bodade R G, Gawande N M
and Khobragade C N 2009 Bioorg. Med. Chem. Lett. 17
8168
10. Insuasty B, Tigreros A, Orozco F, Quiroga J, Abonia R,
Nogueras M, Sanchez A and Cobo J 2010 Bioorg. Med.
Chem. 18 4965
11. (a) Moriarty R M and Prakash O 2008 In Hyperva-
lent Iodine in Organic Chemistry: Chemical Transfor-
mations (UK: Wiley-Blackwell); (b) Wirth T 2003 Top.
Curr. Chem. 224 1; (c) Zhdankin V V and Stang P J 2008
Chem. Rev. 108 5299; (d) Varvoglis A 2009 ARKIVOC 1
12. Verma V, Singh K, Kumar D, Klapotke T M, Stierstorfer
J, Narasimhan B, Qazi A K, Hamid A and Jaglan S 2012
Eur. J. Med. Chem. 56 195
23. Kumar P, Narasimhan B, Sharma D, Judge V and
Narang R 2009 Eur. J. Med. Chem. 44 1853
24. Sortino M, Delgado P, Jaurez S, Quiroga J, Abonia R,
Insuasty B, Nogueras M, Rodero L, Garibotto F M,
Enriz R D and Susana S A 2007 Bioorg. Med. Chem. 15
484