Synthesis, characterization, anticancer activity, and QSAR-studies of some new tetrahydropyrimidines

Article abstract of DOI:10.1007/s00044-010-9481-4

Several new substituted 1,2,3,4 tetrahydropyrimidine derivatives have been synthesized and evaluated for their in vitro anticancer activity on various cell lines. Some of the molecules have exhibited significantly potent inhibition on several cell lines. To find out inter correlation between anticancer activity and molecular descriptors, QSAR study was carried out. Molecular descriptors used for the study were ClogP (lipophilic), CMR (steric), and polarity (electronic). Anticancer activity is expressed in the form of LogGI ₅₀⁺. Activity on different cell lines was independently correlated with molecular descriptors. On the basis of the results, significant correlation between anticancer activity on some of the cell lines and molecular descriptor was observed. Springer Science+Business Media, LLC 2010.

Full text of DOI:10.1007/s00044-010-9481-4

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2011) 20:1331–1339
DOI 10.1007/s00044-010-9481-4
ORIGINAL RESEARCH
Synthesis, characterization, anticancer activity, and QSAR-studies
of some new tetrahydropyrimidines
•
N. C. Desai M. T. Chhabaria Amit Dodiya
•
•
•
Ajit M. Bhavsar B. B. Baldaniya
Received: 5 July 2010 / Accepted: 15 October 2010 / Published online: 4 November 2010
Ó Springer Science+Business Media, LLC 2010
Abstract Several new substituted 1,2,3,4 tetrahydropyr-
imidine derivatives have been synthesized and evaluated
for their in vitro anticancer activity on various cell lines.
Some of the molecules have exhibited significantly potent
inhibition on several cell lines. To find out inter correlation
between anticancer activity and molecular descriptors,
QSAR study was carried out. Molecular descriptors used
for the study were ClogP (lipophilic), CMR (steric), and
polarity (electronic). Anticancer activity is expressed in the
form of LogGI50?. Activity on different cell lines was
independently correlated with molecular descriptors. On
the basis of the results, significant correlation between
anticancer activity on some of the cell lines and molecular
descriptor was observed.
These non planer heterocyclic compounds have emerged as
an integral backbone of calcium channel modulators
(Rovnyak et al., 1995), antihypertensive agents (Kappe,
2002), a1a-adrenergic receptor antagonists (Barrow et al.,
2000), neuropeptide Y (NPY) antagonist (Sun et al., 2009),
mitotic kinesis inhibitors (Kappe et al., 2000), hepatitis B
virus replication inhibitors (Deres et al., 2003), and several
marine derived natural products such as crambine and
betzelladine b (potent HIVgp-120 CD4 inhibitors).
Ptilomycalin alkaloids have been reported to contain
DHPMs and THPMs moiety (Snider and Shi, 1993; Patil
et al., 1995). Among tetrahydropyrimidines (THPMs) with
other types of bioactivity, Cerebrocrast (Klusa, 1995) has
been introduced as a neuroprotectant and cognition enhan-
cer. In addition, antiaggregatory activity in a number of
THPMs has also been discovered (Cooper et al., 1992). The
biological as well as medicinal importance of 1,2,3,4-THPM
prompted us for further modification in the heterocyclic
frame work for synthesis of new THPMs. While doing lit-
erature survey we have observed that not a single article is
published on the anticancer screening of title compounds.
And therefore, it is worth to undertake the synthesis and
anticancer screening of 1,2,3,4-THPMs. In the present
communication, we report herein the synthesis, anticancer
activity, and QSAR studies of the title compounds.
Keywords 1,2,3,4 Tetrahydropyrimidine ꢀ
Anticancer activity ꢀ Linear free energy relationship ꢀ
QSAR
Introduction
In the past decades, the pyrimidines and their derivatives
have attracted increasing interest in the realms of natural
and synthetic organic chemistry because of their diverse
therapeutic and pharmacological properties (Kappe, 1993).
A simple and direct method, first reported by Biginelli
1893, involves a three component, one-pot condensation of
an aldehyde, a b–ketoester, and urea or thiourea under
strongly acidic condition. This has led to the development
of multi-step strategies that produce overall higher yield,
but lack the simplicity of Biginelli synthesis. As a result,
many improved procedures for the preparation of THPMs
have been recently reported (Birgit et al., 2000; Kappe,
1998; Armido et al., 1997; Yadav et al., 2001; Zheng et al.,
2006; Reddy et al., 2004; Han et al., 2005). In this study,
N. C. Desai (&) ꢀ M. T. Chhabaria ꢀ A. Dodiya ꢀ
A. M. Bhavsar ꢀ B. B. Baldaniya
Medicinal Chemistry Division, Department of Chemistry,
Bhavnagar University, Bhavnagar, Gujarat 364 002, India
e-mail: dnisheeth@rediffmail.com
M. T. Chhabaria
Medicinal Chemistry Division, L. M. College of Pharmacy,
Navarangpura, Ahmedabad, Gujarat 380 009, India
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Med Chem Res (2011) 20:1331–1339
various derivatives of N-(3,4-dihelophenyl)-6-methyl-4-
aryl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamides
4a–l were prepared by cyclo condensation of different
N-(substituted phenyl)-3-oxo butanamides, substituted aro-
matic aldehydes and urea/thiourea in the presence of con-
centrated HCl (Scheme 1).
Results and discussion
Best fitting equations obtained from simple and multiple
regression analysis are represented in Table 1. In all the
cases, best correlation was observed when all the three
descriptors are correlated. Poor correlation was observed
between physicochemical parameters and anticancer
activity on leukemia, lung, and colon cancer cell lines,
Eqs. 1, 2, and 6 with correlation coefficient (r) 0.38, 0.38,
and 0.48, respectively. Significantly good correlation
between anticancer activity on breast cancer cell line and
descriptor was observed r = 0.87, Eqs. 3. Study suggests
less lipophilic, less bulky, and electron withdrawing sub-
stituent may increase the potency. Positive influence of
lipophilic and electronic parameters and negative influence
of steric parameter was observed, when descriptors are
correlated with anticancer activity on prostate cancer cell
line (r = 0.92). Identical correlation between molecular
R2
H
H2N
Cl
R1
N
CH3
X
+
+
H2N
O
O
(3)
(1)
O
H
(2)
(i)
(ii)
R2
Cl
O
R1
N
NH
H
N
H
X
H3C
(4a-l)
-R2
Comp. -R1
-X
S
(a) 2-Cl, (b) 3-OC6H5
(c) 3-OCH3, (d) 3-OH
Cl
4a to 4d
(e) 2-OH, (f) 3-Cl
Cl
F
O
S
4e to 4f
4g to 4k
(g) 2-Cl, (h) 3-Cl
(i) 3-OC6H5 (j) 3-OCH3, (k) 3-OH
(l) 3-OC6H5
4l
F
O
Scheme 1 Synthetic route of the title compounds. i Con. HCl and
ethanol, ii reflux
123

Med Chem Res (2011) 20:1331–1339
1333
descriptor and anticancer activity on renal, ovarian, and
melanoma cell lines were observed, Eqs. 5, 7, and 8 with
correlation coefficient (r) 0.91, 0.93, and 0.89, respectively.
Study suggests that the incorporation of less lipophilic, less
bulky electron donating group enhances the potency
(Table 2).
Table 2 Correlation matrices of anticancer activity
Sr. no.
1
A.c.a
ClogP
CMR
D
Leukemia cancer cell line
A.c.a.
ClogP
CMR
D
1.000
0.083
1.000
0.852
0.33
0.261
1.000
Correlation between activity on CNS cancer cell line
and molecular descriptors suggest that by decreasing the
lipophilicity and electron density with increase in bulk of
substituent will increase potency, Eqs. 9.
-0.124
-0.210
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
2
3
4
5
6
7
8
9
Lung cancer cell line
A.c.a.
ClogP
CMR
D
1.000
-0.273
0.301
Significance of correlation between anticancer activity
and physicochemical parameters was checked by F
(Fischer’s) test. Significance of correlation coefficients of
parameters was checked by Student’s t test. Correlations
between observed values (Eq. 1) and calculated values
(Table 3) are represented by Figs. 1, 2, 3, 4, 5, 6, 7, 8, 9 in
the form of graphical representation.
1.000
0.852
0.033
1.000
-0.257
-0.210
Breast cancer cell line
A.c.a.
ClogP
CMR
D
1.000
-0.552
-0.658
0.628
1.000
0.852
0.033
1.000
-0.210
Prostate cancer cell line
Experimental
A.c.a.
ClogP
CMR
D
1.000
-0.424
-0.780
0.581
1.000
0.852
QSAR study
1.000
-0.189
-0.414
To obtain relationship between physicochemical parame-
ters and anticancer activity for the present series, we have
carried out QSAR study by Hansch’s LFER method (Ti-
wari et al., 2006; Hansch and Leo, 1995). LogGI50? is used
as dependent variable. Molecular descriptors representing
lipophilicity (ClogP), steric (CMR), and electronic (dipole)
were correlated with anticancer activity. Activities on dif-
ferent cancer cell line were correlated separately. Simple
and multiple regression analysis were carried out. Equa-
tions representing best correlation are represented in
(Table 1). Regression analysis was carried out by PC based
QSAR software (Coburn, 1976). ClogP and CMR of all the
compounds were calculated by using Bio-Loom software
(http://www.biobyte.com) and dipole of all the compounds
were calculated by using Chem Draw Ultra (http://www.
cambridgesoft.com).
Renal cancer cell line
A.c.a.
ClogP
CMR
D
1.000
-0.851
-0.743
-0.295
1.000
0.852
0.033
1.000
-0.210
Colon cancer cell line
A.c.a.
ClogP
CMR
D
1.000
-0.389
-0.209
-0.040
1.000
0.852
0.033
1.000
-0.210
Ovarian cancer cell line
A.c.a.
ClogP
CMR
D
1.000
-0.904
-0.731
-0.234
1.000
0.852
0.033
1.000
-0.210
Melanoma cancer cell line
A.c.a.
ClogP
CMR
D
1.000
-0.741
-0.658
-0.115
Anticancer activity
1.000
0.852
0.033
1.000
All the synthesized compounds were screened for their
anticancer activity at National Institute of Health, National
Cancer Institute, Maryland, USA (Anne et al., 1991;
Weislow et al., 1989). Each compound was tested at five
different concentrations against 60 cell lines of nine types
of human cancer, namely leukemia, lung, colon, CNS,
melanoma, ovarian, renal, prostate, and breast cancer. A
48 h continuous drug exposure protocol was used, and a
-0.210
CNS cancer cell line
A.c.a.
ClogP
CMR
D
1.000
-0.902
-0.787
0.172
1.000
0.852
0.033
1.000
-0.210
A.c.a anticancer activity
123

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Med Chem Res (2011) 20:1331–1339
Table 3 Calculated anticancer activity of compound 4a–l
Sr. no.
Leukemia
HL-60 (TB)
Lung
HOP-92
Breast
NCI/ADP-RES
Prostate
PC-3
Renal
CKCI-1
Colon
COLO-205
Ovarian
IGRO-V1
Melanoma
SK-MEL-5
CNS
SF-268
4a
4b
4c
4d
4e
4f
-4.706
-4.492
-4.563
-4.57
-4.728
-5.001
-4.598
-4.547
-4.308
-4.503
-4.666
-4.747
-4.828
-4.691
-4.485
-4.469
-4.797
-4.823
-4.789
-4.785
-4.762
-4.776
-4.792
-4.799
-4.808
-4.797
-4.78
-4.626
-5.021
-4.769
-4.743
-4.482
-4.365
-4.569
-4.594
-4.927
-4.756
-4.683
-4.72
-4.678
-5.016
-4.612
-4.467
-4.521
-4.735
-4.571
-4.506
-4.999
-4–382
-4.36
-5.032
-5.055
-4.822
-4.758
-4.795
-5.08
-4.865
-5.07
-4.975
-5.089
-4.992
-4.954
-4.963
-4.983
-4.944
-4.919
-5.093
-4.914
-4.923
-5.112
-4.995
-5.222
-4.836
-4.749
-4.665
-4.922
-4.924
-4.952
-5.112
-4.819
-4.678
-5.028
-4.757
-4.654
-4.687
-4.904
-4.793
-4.766
-5.034
-4.634
-4.582
-5.084
-4.689
-4.831
-4.734
-4.743
-4.508
-4.608
-4.598
-4.629
4g
4h
4i
-4.998
-5.017
-4.994
-4.823
-4.36
4j
4k
4l
-4.783
-5.083
-5.083
?
Calculated anticancer activity on different cell lines is expressed in the form of Log GI50?, where GI50 = molar concentration of the compound
that inhibits 50% net cell growth
Fig. 1 Correlation between observed and calculated values is repre-
sented for leukemia cancer cell line. Line represents ratio of observed
and calculated result
Fig. 3 Correlation between observed and calculated values is repre-
sented for breast cancer cell line. Line represents ratio of observed
and calculated result
Fig. 4 Correlation between observed and calculated values is repre-
sented for prostate cancer cell line. Line represents ratio of observed
and calculated result
Fig. 2 Correlation between observed and calculated values is repre-
sented for lung cancer cell line. Line represents ratio of observed and
calculated result
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Med Chem Res (2011) 20:1331–1339
1335
Fig. 5 Correlation between observed and calculated values is repre-
sented for renal cancer cell line. Line represents ratio of observed and
calculated result
Fig. 8 Correlation between observed and calculated values is repre-
sented for melanoma cancer cell line. Line represents ratio of
observed and calculated result
Fig. 6 Correlation between observed and calculated values is repre-
sented for colon cancer cell line. Line represents ratio of observed and
calculated result
Fig. 9 Correlation between observed and calculated values is repre-
sented for CNS cancer cell line. Line represents ratio of observed and
calculated result
microtiter well, and the culture is incubated for 10 min at
room temperature. Unbound SRB is removed by washing
five times with 1% acetic acid. Then the plates are air-
dried. Bound stain is solubilized with tris buffer, and the
optical densities are read on an automated spectrophoto-
metric plate reader at a single wavelength of 515 nm.
For suspensions of cell cultures (e.g., leukemia), the
method is the same, except that at the end of the drug-
incubation period, the settled cells are fixed to the bottom
of the microtiter well by gently adding 50 ll of 80% cold
TCA (final concentration, 16% TCA).
Fig. 7 Correlation between observed and calculated values is repre-
sented for ovarian cancer cell line. Line represents ratio of observed
and calculated result
With the SRB assay, a measure is also made of the cell
population density at time zero (the time at which drugs are
added) from two extra reference plates of inoculated cells
fixed with TCA just before drug addition to the test plates.
Thus, we have three measurements: control optical density
(C), test optical density (T), and optical density at time zero
(T0).
sulforhodamine B (SRB) protein assay was used to esti-
mate cell viability or growth. The methodology for the
SRB assay is described in this article briefly. Adherent cell
cultures are fixed in situ by adding 50 ll of cold 50% (wt/
vol) trichloroacetic acid (TCA) (final concentration, 10%
TCA) and incubating for 60 min at 4°C. The supernatant is
then discarded, and the plates are washed five times with
deionized water and dried. One hundred microliters of SRB
solution (0.4% wt/vol in 1% acetic acid) is added to each
Using these measurements, cellular responses can be
calculated for growth stimulation, for no drug effect, and
for growth inhibition. If T is greater than or equal to T0, the
calculation is 100 9 [(T-T0)/(C-T0)]. If T is less than T0,
cell killing has occurred and can be calculated from
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Med Chem Res (2011) 20:1331–1339
Table 4 Anticancer activity of the compound 4a–l
Sr. no.
Leukemia
HL-60 (TB)
Lung
HOP-92
Breast
NCI/ADP-RES
Prostate
PC-3
Renal
CKCI-1
Colon
COLO-205
Ovarian
IGRO-V1
Melanoma
SK-MEL-5
CNS
SF-268
4a
4b
4c
4d
4e
4f
-4.81
-4.08
-4.31
-4.95
-4.30
-4.87
-4.59
-4.79
-4.76
-4.76
-4.59
-4.86
-5.92
-4.88
-4.90
-4.87
-4.30
-4.34
-4.30
-4.49
-4.68
-4.30
-4.30
-4.39
-4.80
-4.81
-4.78
-4.80
-4.75
-4.78
-4.78
-4.80
-4.81
-4.81
-4.77
-4.79
-4.70
-5.01
-4.84
-4.85
-4.47
-4.30
-4.69
-4.60
-4.92
-4.63
-4.60
-4.65
-4.75
-5.07
-4.75
-4.65
-4.40
-4.90
-4.50
-4.40
-4.90
-4.31
-4.30
-5.00
-5.10
-5.03
-5.03
-5.15
-4.55
-5.10
-4.62
-5.38
-4.75
-4.57
-4.65
-5.20
-4.80
-5.11
-4.80
-4.72
-4.60
-4.98
-4.75
-4.85
-4.97
-4.56
-4.64
-5.10
-5.00
-5.10
-5.02
-5.00
-4.90
-5.02
-4.91
-5.08
-5.05
-4.88
-4.95
-5.12
-5.05
-5.21
-4.90
-4.80
-4.55
-4.95
-4.83
-5.00
-5.05
-4.74
-4.75
-5.07
4g
4h
4i
4j
4k
4l
100 9 [(T-T0)/T0]. Growth inhibition of 50% (GI50) is
calculated from 100 9 [(T-T0)/(C-T0)] = 50, which is
the drug concentration causing a 50% reduction in the net
protein increase in control cells during the drug incubation.
Results were expressed as logGI50?, which indicates molar
concentration of compound that inhibits 50% net cell
growth. Test compounds have exhibited inhibition at sig-
nificantly low concentration (Table 4).
ethanol and 0.8 ml of HCl was added to it and the reaction
mixture was refluxed for 6 h. The reaction mixture was
poured onto crushed ice. The solid obtained was filtered,
dried, and then recrystallized from ethanol (99%). m.p.
242–243°C, yield is 65%. IR (KBr): 3383 cm-1 ([NH
medium, pyrimidine ring), 3263 and 1640 cm-1 (–CO–NH
medium, amide), 3097 cm-1 (–C–H str., aromatic),
2973 cm-1 (–CH3 str.), 1508 cm-1 ([NH weak),
1438 cm-1 ([CH medium, aromatic ring), 1020 cm-1
(–C–Cl str., aromatic), 1130 cm-1 ([C=S, str.), 640,
610 cm-1 (str., trisubstituted aromatic), 1H NMR (CDCl3):
d ppm 2.20 (s, 3H, –C–CH3), 5.59 (s, 1H, –CH), 7.0–7.93
(m, 7H, Ar–H), 9.73 (s, 1H, –NH), 9.84 (s, 1H, –NH), 10.4
(s, 1H, –CONH). LC–MS: m/z 428.99 with 36% relative
intensity [M?]. Anal. Calcd. for C18H14Cl3N3OS: C, 50.66;
H, 3.31; N, 9.85; Found C, 50.47; H, 3.26; N, 9.74%. 13C
NMR: d ppm 15.1, 50.1, 106.4, 123.0, 126.7, 128.2, 128.3,
128.6, 129.0, 29.9, 132.2, 133.9, 142.8, 159.1, 163.1,
180.3. ClogP (5.40), CMR (11.36), Polar (2.24).
Chemistry
Melting points were taken in open capillaries using paraffin
bath and are uncorrected. IR spectra were recorded on
FTIR-SIMADZU-8201pc (tmax in cm-1); 1H NMR spectra
were recorded on BRUKER AVANCE 300 FT–NMR
spectrometer using CDCl3 as a solvent and Mass spectra
carried out on Applied Bio system QTrap LC-Mass Spec-
trometer. Elemental analysis of all the compounds was
performed on Heracus CHN-Rapid Analyzer and the
results were within 0.4% of theoretical values. Purity was
checked by TLC using TLC aluminum sheet coated with
silica gel G 60, supplied by E. Merck. The spots were
located by exposing the plates to iodine vapor. All the
chemicals were supplied by S D Fine chemicals (India)
Ltd., National Chemicals (India), and E. Merck Inc. and
were used without any further purification. Physicochemi-
cal parameters are expressed in the form of ClogP, CMR,
and Polar along with their values as mentioned below.
N-(3,4-Dichlorophenyl)-6-methyl-4-(3-phenoxyphenyl)-2-
thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide (4b)
A mixture of N-(3,4-dichlorophenyl)-3-oxobutanamide
(0.01 mol), 3-phenoxybenzaldehyde (0.01 mol) and thio-
urea (0.01 mol) was treated as in the synthesis of (4a), m.p.
230–232°C, yield is 56%. IR (KBr): 3382 cm-1 ([NH
medium, pyrimidine ring), 3260 cm-1 (–CO–NH medium,
amide), 3099 cm-1 (–C–H str., aromatic), 2972 cm-1
(–CH3 str.), 1508 cm-1 ([NH weak), 1438 cm-1 ([CH
medium, aromatic ring), 1201 cm-1 (C–O–C str., aromatic),
1037 cm-1 (–C–Cl str., aromatic),1130 cm-1 ([C=S, str.).
1H NMR (CDCl3): d ppm 2.18 (s, 3H, –C–CH3), 5.54 (s, 1H,
–CH), 6.73–7.93 (m, 12H, Ar–H), 9.71 (s, 1H, –NH), 9.82
(s, 1H, –NH), 10.35 (s, 1H, –CONH). LC–MS: m/z 484.09
4-(2-Chlorophenyl)-N-(3,4-dichlorophenyl)-6-methyl-2-
thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide (4a)
A mixture of N-(3,4-dichlorophenyl)-3-oxobutanamide
(0.01 mol), 2-chlorobenzaldehyde (0.01 mol) and thiourea
(0.01 mol) was placed in the round bottom flask, 20 ml of
123

Med Chem Res (2011) 20:1331–1339
1337
with 27% relative intensity [M?]. Anal. Calcd. For
C24H19Cl2N3O2S: C, 59.51; H, 3.95; N, 8.67; Found C,
59.40; H, 3.86; N, 8.58%. 13C NMR: d ppm 15.1, 55.5, 106.4,
114.1, 115.5, 117.5, 120.0, 121.9, 123.0, 128.3, 128.5, 129.0,
129.9, 133.9, 142.9, 156.8, 157.0, 159.1, 163.1, 180.3. ClogP
(6.79), CMR (13.54), Polar (1.49).
N-(3,4-Dichlorophenyl)-4-(2-hydroxyphenyl)-6-methyl-2-
oxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide (4e)
A mixture of N-(3,4-dichlorophenyl)-3-oxobutanamide
(0.01 mol), 2-hydroxybenzaldehyde (0.01 mol) and urea
(0.01 mol) was treated as in the synthesis of (4a), m.p.
235–236°C, yield is 58%. IR (KBr): 3386 cm-1 (–OH
variable, aromatic ring), 3381 cm-1 ([NH medium,
pyrimidine ring), 3244 cm-1 (–CO–NH medium, amide),
3102 cm-1 (–C–H str., aromatic),2935 cm-1 (–CH3 str.),
1710 ([C=0 str.), 1503 cm-1 ([NH weak), 1458 cm-1
([CH medium, aromatic ring), 1028 cm-1 (–C–Cl str.,
aromatic). 1H NMR (CDCl3): d ppm 2.20 (s, 3H, –C–CH3),
5.49 (s, 1H, –CH), 6.63–7.85 (m, 7H, Ar–H), 9.77 (s, 1H,
–NH), 9.83 (s,1H, –OH), 9.86 (s, 1H, –NH), 10.42 (s, 1H,
–CONH). LC–MS: m/z 393.19 with 43% relative intensity
[M?]. Anal. Calcd. for C18H15Cl2N3O3: C, 55.12; H, 3.85;
N, 10.71; Found C, 55.03; H, 3.71; N, 10.59%. 13C NMR: d
ppm 14.4, 43.9, 108.6, 115.7, 121.2, 122.8, 123.0, 128.2,
128.3, 129.0, 129.9, 133.9, 146.1, 150.2, 154.0, 163.1.
ClogP (3.84), CMR (10.17), Polar (4.22).
N-(3,4-Dichlorophenyl)-4-(3-methoxyphenyl)-6-methyl-2-
thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide (4c)
A mixture of N-(3,4-dichlorophenyl)-3-oxobutanamide
(0.01 mol), 3-methoxybenzaldehyde (0.01 mol) and thio-
urea (0.01 mol) was treated as in the synthesis of (4a), m.p.
190–191°C, yield is 54%. IR (KBr): 3386 cm-1 ([NH
medium, pyrimidine ring), 3266 cm-1 (–CO–NH medium,
amide), 3094 cm-1 (–C–H str., aromatic), 2977 cm-1
(–CH3 str.), 1503 cm-1 ([NH weak), 1436 cm-1
([CH medium, aromatic ring), 1210 cm-1 (C–O–C str.,
aromatic), 1035 cm-1 (–C–Cl str., aromatic),1120 cm-1
([C=S, str.). 1H NMR (CDCl3): d ppm 2.19 (s, 3H,
–C–CH3), 3.71 (s, 3H, –O–CH3), 5.57 (s, 1H, –CH),
6.58–7.90 (m, 7H, Ar–H), 9.75 (s, 1H, –NH), 9.84 (s, 1H,
–NH), 10.38 (s, 1H, –CONH). LC–MS: m/z 422.05 with
21% relative intensity [M?]. Anal. Calcd. for C19H17
Cl2N3O2S: C, 54.03; H, 4.06; N, 9.95; Found C, 53.94; H,
4.01; N, 9.87%. 13C NMR: d ppm 15.1, 55.5, 55.8, 106.4,
110.9, 112.3, 119.2, 123.0, 129.0, 129.6, 129.9, 133.9,
144.2, 159.1, 160.4, 163.1, 180.3. ClogP (4.6), CMR
(11.49), Polar (2.59).
4-(3-Chlorophenyl)-N-(3,4-dichlorophenyl)-6-methyl-2-
oxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide (4f)
A mixture of N-(3,4-dichlorophenyl)-3-oxobutanamide
(0.01 mol), 3-chlorobenzaldehyde (0.01 mol) and urea
(0.01 mol) was treated as in the synthesis of (4a), m.p.
231–232°C, yield is 58%. IR (KBr): 3382 cm-1 ([NH
medium, pyrimidine ring), 3246 cm-1 (–CO–NH medium,
amide), 3101 cm-1 (–C–H str., aromatic), 2933 cm-1
(–CH3 str.), 1701 cm-1 ([C=0 str.), 1500 cm-1 ([NH
weak), 1458 cm-1 ([CH medium, aromatic ring),
N-(3,4-Dichlorophenyl)-4-(3-hydroxyphenyl)-6-methyl-2-
thioxo-1,2,3,4-tetrahydro pyrimidine-5-carboxamide (4d)
1
1028 cm-1 (–C–Cl str., aromatic). H NMR (CDCl3): d
ppm 2.15 (s, 3H, C–CH3), 5.51 (s, 1H, –CH), 7.27–7.89(m,
7H, Ar–H,), 7.61 (s, 1H, –NH), 9.46 (s, 1H, –NH), 10.42 (s,
1H, –CONH). LC–MS: m/z 411.03 with 79% relative
intensity [M?]. Anal. Calcd. for C18H14Cl3N3O2: C, 52.64;
A mixture of N-(3,4-dichlorophenyl)-3-oxobutanamide
(0.01 mol), 3-hydroxybenzaldehyde (0.01 mol) and thio-
urea (0.01 mol) was treated as in the synthesis of (4a), m.p.
239–241°C, yield is 58% IR (KBr): 3388 cm-1 (–OH
variable, aromatic ring), 3385 cm-1 ([NH medium,
pyrimidine ring), 3263 cm-1 (–CO–NH medium, amide),
3095 cm-1 (–C–H str., aromatic), 2972 cm-1 (–CH3 str.),
1501 cm-1 ([NH weak), 1438 cm-1 ([CH medium, aro-
matic ring), 1021 cm-1 (–C–Cl str., aromatic),1125 cm-1
([C=S, str.). 1H NMR (CDCl3): d ppm 2.17 (s, 3H,
–C–CH3), 5.55 (s, 1H, –CH), 6.53–7.85 (m, 7H, Ar–H),
9.75 (s, 1H, –NH), 9.81 (s, 1H, –OH), 9.84 (s, 1H, –NH),
10.38 (s, 1H, –CONH). LC–MS: m/z 409.02 with 68%
relative intensity [M?]. Anal. Calcd. for C18H15Cl2N3O2S:
C, 52.95; H, 3.70; N, 10.29; Found C, 52.76; H, 3.59; N,
10.15%. 13C NMR: d ppm 15.1, 55.5, 106.4, 112.5, 113.9,
119.5, 123.0, 129.0, 129.9, 130.0, 133.9, 144.6, 158.3,
159.1, 163.1, 180.3. ClogP (4.02), CMR (11.03), Polar
(2.38).
H, 3.44; N, 10.23; Found C, 52.50; H, 3.32; N, 10.11%. 13
C
NMR: d ppm 14.4, 49.6, 108.6, 123.0, 125.0, 126.7, 126.8,
129.0, 129.9, 130.0, 133.9, 134.1, 144.6, 146.1, 150.2,
163.1. ClogP (5.27), CMR (10.51), Polar (4.03).
N-(3-Chloro-4-fluorophenyl)-4-(2-chlorophenyl)-6-methyl-
2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide (4g)
A mixture of N-(3-chloro-4-fluorophenyl)-3-oxobutana-
mide (0.01 mol), 2-chlorobenzaldehyde (0.01 mol) and
thiourea (0.01 mol) was treated as in the synthesis of (4a),
m.p. 215–217°C, yield is 55%. IR (KBr): 3336 cm-1 ([NH
medium, pyrimidine ring), 3207 cm-1 (–CO–NH medium,
amide), 3097 cm-1 (–C–H str., aromatic), 2975 cm-1
(–CH3 str.), 1506 cm-1 ([NH weak), 1437 cm-1 ([CH
123

1338
Med Chem Res (2011) 20:1331–1339
medium, aromatic ring), 1033 cm-1 (–C–Cl str., aromatic),
NMR: d ppm 15.1, 55.5, 106.4, 114.1, 115.5, 117.5, 120.0,
121.9, 123.0, 128.3, 128.5, 129.0, 129.9, 133.9, 142.9,
156.8., 157.0, 159.1, 163.1, 180.3. ClogP (6.34), CMR
(13.06), Polar (2.52).
1
1177 cm-1 ([C=S, str.). H NMR (CDCl3): d ppm 2.13
(s, 3H, –C–CH3), 4.59 (s, 1H, –CH), 7.01–7.85 (m, 7H,
Ar–H), 9.71 (s, 1H, –NH), 9.80 (s, 1H, –NH), 10.44 (s, 1H,
–CONH). LC–MS: m/z 411.02 with 68% relative intensity
[M?]. Anal. Calcd. for C18H14Cl2FN3OS: C, 52.69; H,
3.44; N, 10.24; Found C, 55.53; H, 3.31; N, 10.09%. 13C
NMR: d ppm 15.1, 50.1, 106.4, 123.0, 126.7, 128.2, 128.3,
128.6, 129.0, 132.2, 129.9, 133.9, 142.8, 159.1, 163.1,
180.3. ClogP (4.95), CMR (10.88), Polar (2.27).
N-(3-Chloro-4-fluorophenyl)-4-(3-methoxyphenyl)-6-
methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-
carboxamide (4j)
A mixture of N-(3-chloro-4-fluorophenyl)-3-oxobutana-
mide (0.01 mol), 3-methoxybenzaldehyde (0.01 mol) and
thiourea (0.01 mol) was treated as in the synthesis of (4a),
m.p. 226–227°C, yield is 54%. IR (KBr): 3333 cm-1 ([NH
medium, pyrimidine ring), 3202 cm-1 (–CO–NH medium,
amide), 3095 cm-1 (–C–H str., aromatic), 2977 cm-1
(–CH3 str.), 1504 cm-1 ([NH weak),1436 cm-1 ([CH
medium, aromatic ring), 1201 cm-1 (C–O–C str., aro-
matic), 1033 cm-1 (–C–Cl str., aromatic), 1175 cm-1
([C=S, str.). 1H NMR (CDCl3): d ppm 2.16 (s, 3H,
–C–CH3), 3.73 (s, 3H, –O–CH3), 5.57 (s, 1H, –CH),
6.68–7.98 (m, 7H, Ar–H), 9.73 (s, 1H, –NH), 9.84 (s, 1H,
–NH), 10.51 (s, 1H, –CONH). LC–MS: m/z 406.07 with
26% relativeintensity [M?]. Anal. Calcd. for C19H17
ClFN3O2S: C, 56.23; H, 4.22; N, 10.35; Found C, 56.10; H,
4.15; N, 10.23%. 13C NMR: d ppm 15.1, 55.5, 55.8, 106.4,
110.0, 1122.3, 119.2, 123.0, 129.0, 129.6, 129.9, 133.9,
144.2, 159.1, 160.4, 163.1, 180.3. ClogP (4.16), CMR
(11.01), Polar (1.23).
N-(3-Chloro-4-fluorophenyl)-4-(3-chlorophenyl)-6-methyl-
2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide (4h)
A mixture of N-(3-chloro-4-fluorophenyl)-3-oxobutana-
mide (0.01 mol), 3-chlorobenzaldehyde (0.01 mol) and
thiourea (0.01 mol) was treated as in the synthesis of (4a),
m.p. 224–225°C, yield is 56%. IR (KBr): 3335 cm-1 ([NH
medium, pyrimidine ring), 3206 cm-1 (–CO–NH medium,
amide), 3097 cm-1 (–C–H str., aromatic), 2975 cm-1
(–CH3 str.), 1506 cm-1 ([NH weak), 1437 cm-1 ([CH
medium, aromatic ring), 1038 cm-1 (–C–Cl str., aromatic),
1177 cm-1 ([C=S, str.). 1H NMR (CDCl3): d ppm 2.15 (s,
3H, –C–CH3), 4.57 (s, 1H, –CH), 7.11–7.85 (m, 7H, Ar–
H), 9.73(s, 1H, –NH), 9.81 (s, 1H, –NH), 10.41 (s, 1H,
–CONH). LC–MS: m/z 411.03 with 29% relative intensity
[M?]. Anal. Calcd. for C18H14Cl2FN3OS: C, 52.69; H,
3.44; N, 10.24; Found C, 55.59; H, 3.32; N, 10.14%. 13C
NMR: d ppm 15.1, 54.7, 106.4, 123.0, 125.0, 126.7, 126.8,
129.0, 129.9, 130.0, 133.9, 134.1, 144.6, 159.1, 163.1,
180.3. ClogP (4.95), CMR (10.88), Polar (1.54).
N-(3-Chloro-4-fluorophenyl)-4-(3-hydroxyphenyl)-
6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-
5-carboxamide (4k)
N-(3-Chloro-4-fluorophenyl)-6-methyl-4-
(3-phenoxyphenyl)-2-thioxo-1,2,3,4-tetrahydropyrimidine-
5-carboxamide (4i)
A mixture of N-(3-chloro-4-fluorophenyl)-3-oxobutana-
mide (0.01 mol), 3-hydroxybenzaldehyde (0.01 mol) and
thiourea (0.01 mol) was treated as in the synthesis of (4a),
m.p. 235–236°C, yield is 51%. IR (KBr): 3384 cm-1 (–OH
variable, aromatic ring), 3335 cm-1 ([NH medium,
pyrimidine ring), 3203 cm-1 (–CO–NH medium, amide),
3095 cm-1 (–C–H str., aromatic), 2973 cm-1 (–CH3 str.),
1508 cm-1 ([NH weak), 1435 cm-1 ([CH medium, aro-
matic ring), 1036 cm-1 (–C–Cl str., aromatic), 1173 cm-1
([C=S, str.) 1H NMR (CDCl3): d ppm 2.20 (s, 3H,
–C–CH3), 5.39 (s, 1H, –CH), 6.60–8.10 (m, 7H, Ar–H), 9.73
(s, 1H, –NH), 9.82 (s, 1H, –OH), 9.86 (s, 1H, –NH), 10.42
(s, 1H, –CONH). LC–MS: m/z 393.05 with 56% relative
intensity [M?].Anal. Calcd. for C18H15ClFN3O2S: C, 55.17;
A mixture of N-(3-chloro-4-fluorophenyl)-3-oxobutana-
mide (0.01 mol), 3-phenoxybenzaldehyde (0.01 mol) and
thiourea (0.01 mol) was treated as in the synthesis of (4a),
m.p. 220–222°C, yield is 46%. IR (KBr): 3337 cm-1 ([NH
medium, pyrimidine ring), 3207 cm-1 (–CO–NH medium,
amide), 3097 cm-1 (–C–H str., aromatic), 2976 cm-1
(–CH3 str.), 1507 cm-1 ([NH weak),1436 cm-1 ([CH
medium, aromatic ring), 1210 cm-1 (C–O–C str., aro-
matic), 1034 cm-1 (–C–Cl str., aromatic), 1175 cm-1
([C=S, str.). 1H NMR (CDCl3): d ppm 2.15 (s, 3H,
–C–CH3),4.54 (s, 1H, –CH), 6.72–7.85 (m, 12H, Ar–H),
9.68 (s, 1H, –NH), 9.83 (s, 1H, –NH), 10.42 (s, 1H,
–CONH). LC–MS: m/z 432.09 with 32% relative intensity
[M?]. Anal.Calcd. for C24H19ClFN3O2S: C, 61.60; H,
4.09; N, 8.98; Found C, 61.42; H, 4.01; N, 8.89%. 13C
H, 3.86; N, 10.72; Found C, 55.01; H, 3.75; N, 10.60%. 13
C
NMR: d ppm 15.1, 55.8, 106.4, 112.5, 113.9, 119.5, 123.0,
129.0, 129.9, 133.0, 133.9, 144.6, 158.3, 159.1, 163.1, 180.3.
ClogP (3.57), CMR (10.55), Polar (2.41).
123

Med Chem Res (2011) 20:1331–1339
1339
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A mixture of N-(3-chloro-4-fluorophenyl)-3-oxobutanamide
(0.01 mol), 3-phenoxybenzaldehyde (0.01 mol) and urea
(0.01 mol) was treated as in the synthesis of (4a), m.p.
229–230°C, yield is 45%. IR (KBr): 3448 cm-1 ([NH
medium, pyrimidine ring), 3276 cm-1 (–CO–NH medium,
amide), 3101 cm-1 (–C–Hstr., aromatic), 2965 cm-1 (–CH3
str.),1710 cm-1 ([C=0 str.),1500 cm-1 ([NH weak),
1455 cm-1 ([CH medium, aromatic ring), 1220 cm-1 (C–
1
O–C str., aromatic), 1030 cm-1 (–C–Cl str., aromatic). H
NMR (CDCl3): d ppm 1.82 (s, 3H, –C–CH3), 5.56 (s, 1H,
–CH), 6.72–8.05 (m, 12H, Ar–H), 7.61 (s, 1H, –NH), 9.43 (s,
1H, –NH), 10.45 (s, 1H, –CONH). LC–MS: m/z 452.19
with 29% relative intensity [M?]. Anal.Calcd. for
C24H19ClFN3O3: C, 63.79; H, 4.24; N, 9.30; Found C, 63.65;
H, 4.11; N, 9.12%. 13C NMR: d ppm 14.4, 50.4, 108.6, 114.1,
115.5, 117.5, 120.0, 121.9, 123.0, 128.3, 128.5, 129.0, 129.9,
130.0, 133.9, 142.9, 146.1, 150.2, 156.8, 157.0, 163.1, 180.3.
ClogP (6.21), CMR (12.21), Polar (4.61).
Acknowledgments The authors are thankful to Dr. V. L Narayanan
and Edward Sausville, National Institutes of Health, National Cancer
Institute, Maryland, USA for anticancer screening and the authors
express their sincere thanks to the Department of Chemistry,
Bhavnagar University, Bhavnagar for providing research facilities.
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