Synthesis and evaluation of some novel tetrahydropyrimidine derivatives as antimicrobial and cytotoxic agents

Article abstract of DOI:10.1007/s11164-012-0879-0

Starting from the reaction of ethyl cyanoacetate with thiourea and the appropriate aldehydes, a series of new thiopyrimidine derivatives were prepared. Antibacterial evaluation results revealed that compounds 12b, 4c and 11b gave the highest antibacterial activity against all tested bacterial strains. Also, some of the novel compounds were evaluated as cytotoxic agents against liver cancer (HEPG2) cell line. It was noticed that some of the derivatives induced significant growth inhibition with IC₅₀ values (ranged from 6.35 to 9.38 μg/mL) in comparison to 5-Fluorouracil after treatment (IC₅₀: 5 μg/mL).

Full text of DOI:10.1007/s11164-012-0879-0

Res Chem Intermed
DOI 10.1007/s11164-012-0879-0
Synthesis and evaluation of some novel
tetrahydropyrimidine derivatives as antimicrobial
and cytotoxic agents
•
Mogedda E. Haiba Omar A. Fathalla
•
•
Ibrahim F. Zeid Abdel-mohsen M. Soliman
•
•
Sherein I. Abd El-Moez Walaa S. El-serwy
Received: 29 August 2012 / Accepted: 19 October 2012
Ó Springer Science+Business Media Dordrecht 2012
Abstract Starting from the reaction of ethyl cyanoacetate with thiourea and the
appropriate aldehydes, a series of new thiopyrimidine derivatives were prepared.
Antibacterial evaluation results revealed that compounds 12b, 4c and 11b gave the
highest antibacterial activity against all tested bacterial strains. Also, some of the
novel compounds were evaluated as cytotoxic agents against liver cancer (HEPG2)
cell line. It was noticed that some of the derivatives induced significant growth
inhibition with IC50 values (ranged from 6.35 to 9.38 lg/mL) in comparison to
5-Fluorouracil after treatment (IC50: 5 lg/mL).
Keywords Cytotoxic activity Á Antibacterial testing Á Pyrimidine Á Uracil Á
Thiazolidine
Introduction
It was reported that the anticancer activity of some 5-substituted-2-thiouracil
inhibits DNA synthesis [1, 2]. Several 5-substituted thiouracil possess chemother-
apeutic importance especially against cancer, bacteria, and parasites [3–7]. It has
M. E. Haiba Á O. A. Fathalla (&) Á A. M. Soliman Á W. S. El-serwy
Therapeutical Chemistry Department, National Research Center, Dokki, Cairo, Egypt
e-mail: omarfathalla@yahoo.com
M. E. Haiba
Pharmacetical Chemistry Department, College of Pharmacy, King Saudi University,
Riyadh 11451, Saudi Arabia
I. F. Zeid
Organic Chemistry Department, Faculty of Science, Minufiya University, Shebin El-Kom, Egypt
S. I. Abd El-Moez
Microbiology and Immunology Department, National Research Center, Dokki, Cairo, Egypt
123

M. E. Haiba et al.
also been found that unsaturated ketones and chalcones have chemotherapeutic
activity [8, 9]. In addition, it has been reported that thiosemi-carbazones possess
strong biological activity against microorganisms [8]. Synthesis and biological
evaluation of certain substituted thiazoles were also studied [10]. The chemistry of
pyridons and aminopyridines has been of increasing interest [11], Many thiouracil
derivatives have been synthesized in order to evaluate their cytotoxic activity as a
trial to get more effective and less toxic agents. The cytotoxic activity results
indicated that the selected tetrahydropyrimidine derivatives showed the activity
against the liver cancer (HEPG2) tumor cell lines tested, but with varying intensities
in comparison to the known anticancer drugs: 5-Fluorouracil and Doxorubicin [12–
16]. Based on these facts, it was of interest to synthesize some new Schiff bases of
2,4-dioxo-1,2,3,4-tetrahydropyrimidines incorporated into thiazolidines, thiazoles,
and triazoles with different substitutions at the 5-position of 2-thiouracil and to
evaluate the chemotherapeutic activity of a number of them as antimicrobial and
anticancer agents.
Experimental
Chemistry
All melting points are uncorrected and were taken on electro-thermal capillary
melting point apparatus. Infrared spectra were performed on JASCO FT/IR-6100
1
using KBr discs. H NMR spectra were obtained on Jeol 270 MHz and on Jeol SX
500 MHz spectrometer using TMS as an internal standard. The mass spectra were
recorded on Jeol JMS-AX 500. All reactions were followed and checked by TLC
using chloroform–methanol.
General procedure for the preparation of compound 1c
A mixture of thiourea (10 mmol), ethyl cyanoacetate (10 mmol), and 2-bromo-
benzaldehyde was stirred in sodium ethoxide solution for 48 h and then the reaction
mixture was poured onto ice-water, and then acidified with dil HCl. The obtained
precipitate was filtered off, dried under vacuum, then crystallized from the proper
solvent to give compound 1c.
6-(2-Bromophenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile
(1c)
Crystallized from dimethylformamide, gray crystals, m.p. 270–272 °C, yield 85 %.
Analysis: for C11H6BrN3OS, M.Wt. 308.15, calcd: C, 42.87; H, 1.96; N, 13.64.
Found: C, 42.67; H, 1.70; N, 13.34. IR (KBr, cm-1): 1,692 (C=O), 2,226 (–C:N),
1
and 3,173 (NH). H NMR (DMSO-d6, d ppm): 7.12–7.90 (4H, m, aromatic) and
8.22, 11.35 (2H, s, NH, NH, exchangeable with D2O). MS: (m/z) & 308 (5 %).
123

Synthesis and evaluation of antimicrobial and cytotoxic agents
General procedure for the preparation of compound 2a
A solution of 1a [17] (10 mmol) and hydrazine hydrate (10 mmol) in methanol
(20 mL) was heated under refluxed for 5 h. Upon cooling, the formed precipitate
was filtered off, dried, then crystallized from the proper solvent to give 2a.
2-Hydrazinyl-4-(2-methylphenyl)-6-oxo-1,6-dihydropyrimidine-5-carbonitrile (2a)
Crystallized from benzene, yellow crystals, m.p. 288–290 °C, yield 90 %. Analysis:
for C12H11N5O, M.Wt. 241.24, calcd: C, 59.74; H, 4.60; N, 29.03. Found: C, 59.62;
H, 4.48; N, 28.80. IR (KBr, cm-1): 1,677 (C=O), 2,236 (–C:N), 3,150 (NH), and
1
3,444–3,300 (NH). H NMR (DMSO-d6, d ppm): 2.45 (3H, s, CH3), 3.79 (2H, s,
NH2, exchangeable with D2O), 7.31–7.42 (4H, m, aromatic), 7.87, 8.49 (2H, 2s,
2NH, exchangeable with D2O); MS: (m/z) & 242 (100 %).
General procedure for the preparation of compound 3b
A mixture of 1b [18] (10 mmol), monochloro acetic acid (10 mmol) in glacial
acetic acid (20 mL) was heated under reflux for 5 h. The reaction mixture was
cooled and the precipitate was filtered off, dried, then crystallized from the proper
solvent to give 3b.
7-(2-Hydroxyphenyl)-3,5-dioxo-2,3-dihydro-5H-[1, 3]thiazolo[3,2-a]-pyrimidine-6-
carbonitrile (3b)
Crystallized from benzene, yellow crystals, m.p. 275–278 °C, yield 83 %. Analysis
for C13H7N3O3S, M.Wt. 285.27, calcd: C, 54.73; H, 2.47; N, 14.73. Found: C,
54.59; H, 2.32; N, 14.53. IR (KBr, cm-1): 1,739 (2C=O), 2,220 (–C:N), and 3,446
(OH). 1H NMR (DMSO-d6, d ppm): 4.13 (2H, s, CH2), 7.11–7.74 (4H, m, aromatic)
and 12.83 (1H, s, OH, exchangeable with D2O); MS: (m/z) & 285 (12 %).
General procedure for the preparation of compounds 4a, 4c
A mixture of 1a, 1c (10 mmol) and sulfuric acid (15 mL) was heated in a water bath
for 3 h then cooled and poured onto ice. The precipitate was filtered off, dried, then
crystallized from the proper solvent to give 6-(substituted phenyl)-4-oxo-2-thioxo-
1,2,3,4-tetrahydropyrimidine-5-carboxylic acid 4a, 4c.
6-(2-Methylphenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid
(4a)
Crystallized from benzene, yellow crystals, m.p. 240–242 °C, yield 79 %. Analysis for
C12H10N2O3S, M.Wt. 262.28, calcd: C, 54.95; H, 3.84; N, 10.68. Found: C, 54.70; H,
1
3.65; N, 10.40. IR (KBr, cm-1): 1,619 (C=C, cis, vinyl) and 1,680 (C=O). H NMR
(DMSO-d6, d ppm): 2.31 (3H, s, CH3), 7.32-8.01 (4H, m, aromatic), 8.32, 10.32, 11.36
(3H, 3s, NH, NH, OH exchangeable with D2O); MS: (m/z) & 262 (5 %).
123

M. E. Haiba et al.
6-(2-Bromophenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid
(4c)
Crystallized from dimethylformamide, yellow crystals, m.p. 260–262 °C, yield
72 %. Analysis for C11H7BrN2O3S, M.Wt. 327.15, calcd: C, 40.38; H, 2.16; N,
8.56. Found: C, 40.18; H, 2.00; N, 8.32. IR (KBr, cm-1): 1,570 (C=C, cis, vinyl) and
1
1,701 (C=O). H NMR (DMSO-d6, d ppm): 7.10–7.90 (4H, m, aromatic), 8.11,
10.22, 11.20 (3H, 3s, NH, OH, NH exchangeable with D2O); MS: (m/z) & 327
(5 %).
General procedure for the preparation of compound 5
A mixture of 2a (10 mmol) and acetic anhydride (30 mL) was heated under reflux
for 2 h. Then the mixture was cooled, and the solid obtained was crystallized from
the proper solvent to give 5.
3-Methyl-7-(2-methylphenyl)-5-oxo-5,8-dihydro[1, 2, 4]triazolo[4,3-a]pyrimidine-
6-carbonitrile (5)
Crystallized from acetic acid, yellow crystals, m.p. 230–232 °C, yield 70 %.
Analysis for C14H11N5O, M.Wt. 265.27, calcd: C, 63.39; H, 4.18; N, 26.40. Found:
C, 63.22; H, 4.01; N, 26.24. IR (KBr, cm-1): 1,690 (C=O), 2,228 (–C:N), and
3,310 (NH). 1H NMR (DMSO-d6, d ppm): 2.41, 2.61 (6H, 2s, 2CH3), 6.91-7.70 (4H, m,
aromatic), and 9.92 (1H, s, NH, exchangeable with D2O).
General procedure for the preparation of compound 6
A mixture of 2a (10 mmol) and trimetylorthoformate (30 mL) was heated under
reflux for 2 h. Upon cooling, the solid obtained was filtered off and crystallized
from the proper solvent to give 6.
7-(2-Methylphenyl)-5-oxo-5,8-dihydro[1, 2, 4]triazolo[4,3-a]pyrimidine-6-
carbonitrile (6)
Crystallized from acetic acid, yellow crystals, m.p. 280–282 °C, yield 75 %.
Analysis for C13H9N5O, M.Wt. 251.24, calcd: C, 62.15; H, 3.61; N, 27.87. Found:
C, 62.03; H, 3.52; N, 27.74. IR (KBr, cm-1): 1,684 (C=O), 2,215 (–C:N) and
3,228 (Sec NH). 1H NMR (DMSO-d6, d ppm): 2.42 (3H, s, CH3), 7.14–7.87 (4H, m,
aromatic), 8.31 (1H, s, CH) and 12.30 (1H, s, NH, exchangeable with D2O).
General procedure for the preparation of compound 7
A mixture of 2a (10 mmol) and p-anisaldehyde (10 mmol) in absolute ethanol
(30 mL) was heated under reflux for 6 h. The reaction mixture was cooled and the
solid obtained was filtered off and crystallized from the proper solvent to give 7.
123

Synthesis and evaluation of antimicrobial and cytotoxic agents
4-[2-(4-Methoxybenzylidene)hydrazino]-6-(2-methylphenyl)-2-thioxo-1,2,3,4-
tetrahydropyrimidine-5-carbonitrile (7)
Crystallized from dimethylformamide, yellow crystals, m.p. \ 300 °C, yield 80 %.
Analysis for C20H17N5O2, M.Wt. 359.38, calcd : C, 66.84; H, 4.77; N, 19.49. Found:
C, 66.78; H, 4.64; N, 19.22. IR (KBr, cm-1): 1,695 (C=O), 2,218 (–C:N), and
3,161 (NH). 1H NMR (DMSO-d6, d ppm) : 2.31 (3H, s, CH3), 3.82 (3H, s, –OCH3),
6.54 (1H, s, –CH=N–), 7.31-8.10 (8H, m, aromatic) and 9.61, 11.41 (2H, s, 2NH,
exchangeable with D2O); MS : [M?2]? m/z & 361 (0.20 %).
General procedure for the preparation of compound 8
A solution of 2a (10 mmol) and diethyl oxalate (10 mmol) in absolute ethanol
(40 mL) was heated under reflux for 12 h. The reaction mixture was cooled and the
solid obtained was filtered off and crystallized from the proper solvent to give 8.
8-(2-Methylphenyl)-3,4,6-trioxo-3,4,6,9-tetrahydro-2H-pyrimido[2,1-c][1, 2, 4]
triazine-7-carbonitrile (8)
Crystallized from benzene, yellow crystals, m.p. 180–182 °C, yield 85 %. Analysis for
C14H9N5O3, M.Wt. 295.25, calcd: C, 56.95; H, 3.07; N, 23.72, found: C, 56.87; H, 2.85;
1
N, 23.65. IR (KBr, cm-1), 1,671 (C=O), 2,218 (–C:N), and 3,338 (NH); H NMR
(DMSO-d6, d ppm): 2.41 (3H, s, CH3), 7.42–8.32 (4H, m, aromatic) and 10.21, 12.32
(2H, s, 2NH, exchangeable with D2O); MS: [M-1]? m/z & 294 (2.5 %).
General procedure for the preparation of compound 9
A mixture of 2a (10 mmol) and ethylchloroformate (20 mmol) in pyridine (30 mL)
was heated under reflux for 16 h, cooled, and then poured on HCl. The solid
obtained was filtered off and crystallized from the proper solvent to give 9.
7-(2-Methylphenyl)-3,5-dioxo-2,3,5,8-tetrahydro[1, 2, 4]triazolo[4,3-a]pyrimidine-
6-carbonitrile (9)
Crystallized from benzene, yellow crystals, m.p. 260-262 °C, yield 65 %. Analysis
for C13H9N5O2, M.Wt. 267.24, calcd: C, 58.43; H, 3.39; N, 26.21. Found: C, 58.23;
H, 3.11; N, 26.05. IR (KBr, cm-1): 1,666 (C=O), 2,216 (–C:N), and 3,443 (Sec
NH). 1H NMR (DMSO-d6, d ppm): 2.34 (3H, s, CH3), 7.12–8.00 (4H, m, aromatic)
and 10.01, 12.21 (2H, 2s, 2NH, exchangeable with D2O); MS: [M?1]? m/z & 268
(7.41 %).
General procedure for the preparation of compounds 11a, 11b
A mixture of 10 [4] (5 mmol), and the proper aldehydes, namely, 2,5-dimethoxy-
benzaldehyde and 3,5-dimethoxy-benzaldehyde in ethanol (50 mL) was heated
under reflux for 7–10 h. The solid obtained was filtered off and crystallized from the
123

M. E. Haiba et al.
proper solvent to give N-[substituted]-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-
sulfonohydrazides 11a, 11b.
N’-[(1Z)-(2,5-dimethoxyphenyl)methylene]-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-
5-sulfonohydrazide (11a)
Crystallized from acetic acid, white crystals, m.p. 265–267 °C, yield 70 %. Analysis for
C13H14N4O6S, M.Wt. 354.34, calcd: C, 44.06; H, 3.98; N, 15.81. Found: C, 43.87; H,
3.83; N, 15.76. IR (KBr, cm-1): 1,334–1,300 (S=O), 1,497, 1,617 (C=C, aromatic),
1
1,670 (C=O), and 3,432 (NH). H NMR (DMSO-d6, d ppm) : 3.61 (1H, s, NH,
exchangeable with D2O), 3.82 (6H, s, 2OCH3), 6.9-7.2 (3H, m, aromatic), 7.42 (1H, s,
CH=N), 8.92 (1H, s, CH of uracil), 11.01 (1H, s, NH imide, exchangeable with D2O),
11.81 (1H, s, NH uera, exchangeable with D2O). MS: m/z & 354 (1 %).
N’-[(1Z)-(3,5-dimethoxyphenyl)methylene]-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-
5-sulfonohydrazide (11b)
Crystallized from benzene, white crystals, m.p. 270–272 °C, yield 65 %. Analysis for
C13H14N4O6S, M.Wt. 354.34, calcd: C, 44.06; H, 3.98; N, 15.81. Found: C, 43.85; H,
3.80; N, 15.69. IR (KBr, cm-1): 1,338–1,300 (S=O), 1,497, 1,610 (C=C, aromatic),
1
1,675 (C=O), and 3,332 cm-1(NH). H NMR (DMSO-d6, d ppm): 3.73 (1H, s, NH,
exchangeable with D2O), 3.82 (6H, s, 2OCH3), 6.6,6.91 (3H, m, aromatic), 7.00 (1H, s,
CH=N), 8.62 (1H, s, CH of uracil), 11.11 (1H, s, NH imide, exchangeable with D2O),
11.9 (1H, s, NH urea, exchangeable with D2O); MS: m/z = 354 (1 %).
General procedure for the preparation of compounds 12a, 12b
A mixture of11a, 11b (5 mmol)andthioglycolic acid(5 mmol) indrybenzene (10 mL)
was heated under reflux for 6 h. The volatile solvent was evaporated and the reaction
mixture was neutralized with cold dilute sodium bicarbonate solution. The solid
obtained was crystallized from the proper solvent to give N-[2-(substituted)-4-oxo-1,3-
thiazolidin-3-yl]-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-sulfonamides 12a, 12b.
N-[2-(2,5-dimethoxyphenyl)-4-oxo-1,3-thiazolidin-3-yl]-2,4-dioxo-1,2,3,4-
tetrahydropyrimidine-5-sulfonamide (12a)
Crystallized from benzene, white crystals, m.p. 285–287 °C, yield 75 %. Analysis for
C15H16N4O7S2, M.Wt. 428.44, calcd: C, 42.05; H, 3.76; N, 13.08. Found: C, 41.86; H,
3.65; N, 12.90. IR (KBr, cm-1): 1,408–1,202 (S=O), 1,460, 1,546 (C=C, aromatic), 1,680
(C=O of uracil), 1,726 (C=O of thiazolidine), and 3,450 (NH); MS: m/z & 428 (1 %).
N-[2-(3,5-dimethoxyphenyl)-4-oxo-1,3-thiazolidin-3-yl]-2,4-dioxo-1,2,3,4-
tetrahydropyrimidine-5-sulfonamide (12b)
Crystallized from benzene, white crystals, m.p. 270–272 °C, yield 75 %. Analysis
for C15H16N4O7S2, M.Wt. 428.44, calcd : C, 42.05; H, 3.76; N, 13.08. Found: C,
123

Synthesis and evaluation of antimicrobial and cytotoxic agents
41.92; H, 3.67; N, 12.93. IR (KBr, cm-1): 1,365–1,322 (S=O), 1,468, 1,603 (C=C,
aromatic), 1,684 (C=O of uracil), 1,723 (C=O of thiazolidine), and 3,400 (NH).
1H NMR (DMSO-d6, d ppm) : 2.11 (1H, s, NH, exchangeable with D2O), 3.81 (6H, s,
2OCH3), 3.92 (2H, s, CH2 of thiazolidinone ring), 5.91 (1H, s, CH of thiazolidinone
ring), 6.21 (1H, s, NH urea, exchangeable with D2O), 6.72, 6.90 (3H, m, aromatic),
8.11 (1H, s, CH of uracil) and 10.4 (1H, s, NH imide, exchangeable with D2O); MS:
m/z & 428 (5 %).
Biological evaluation
Antibacterial activity test
According to Wiart [19], 11 compounds (2a, 4a, 4c, 5, 6, 7, 8, 9, 11a, 11b and 12b)
diluted in DMSO with conc. 100 mg/mL, 6-mm-diameter filter paper Whatman no 1
was soaked in 50 lL of each diluted compound. Tobramycin (10 lg/mL) was used
as control positive broad spectrum antibiotic. DMSO was used as control negative.
Strains selected for being tested are isolated of feed by products of animal origin
including poultry (E. coli O157 and S. typhimurrium) as well as from mastitic cow
milk (L. monocytogenes, S. aureus, P. aeruginosa and B. cereus). These strains are
commonly accused of being a cause of food intoxication.
Muller Hinton agar plates were inoculated with strains prepared in conc.
equivalent with 0.5 McFerland and streaked onto the agar plates using sterile swabs,
and then discs containing the tested compound were placed onto the surface using
sterile forceps and embedded in the agar. All plates were incubated at 37 °C/24 h.
The zone of inhibition was measured in mm using a ruler.
Anticancer activity test
Measurement of potential cytotoxicity by SRB assay
The five tetrahydropyrimidine (5, 7, 8, 11b and 12b) derivatives were subjected to a
screening system for evaluation of their antitumor activity against liver cancer
(HEPG2) tumor cell lines in comparison to the known anticancer drugs,
5-Fluorouracil and Doxorubicin.
O
O
OH
OH
O
OH
O
F
HN
H
O
OH
H C O
3
O
O
N
H
OH
NH
2
Doxorubicin
5-Flurouracil
Potential cytotoxicity of the selected tetrahydropyrimidine derivatives was tested
using the method of Ref. [20]. As follows:
123

M. E. Haiba et al.
O
S
C
CN
Sodium ethoxide
HN
NC-CH2COOC2H5
+
+
RCHO
S
N
H
R
NH
H N
2
2
1 a-c
O
CN
HN
S
N
H
R
H
2
1 a-c
S
O
4
O
HN
CN
R
O
COOH
N
H N
2
N
H
HN
2a
S
N
H
R
4 a,c
O
CN
O
N
N
S
R
3b
H C
3
Br
HO
a, R=
b, R=
c, R=
Scheme 1 Preparation of a series thiopyrimidine derivatives
1- Cells were plated in 96-multiwell plates (104 cells/well) for 24 h before
treatment with the compound(s) to allow attachment of cells to the wall of the
plate.
2- Different concentrations of the compound under test (0, 1, 2.5, 5, 10 lg/mL)
were added to the cell monolayer. Triplicate wells were prepared for each
individual dose.
123

Synthesis and evaluation of antimicrobial and cytotoxic agents
O
O
N
CH
N
3
CN
O
CN
CH
N
3
O
O
C
HN
NH
CH
CN
3
CH
3
AC2O
N
OC
H
5
Cl
2
N
N
H
H
N
2
HN
N
N
H
2a
5
9
O
CN
O
O
CH
3
N
CN
CH
N
O
N
3
N
N
H
HN
N
N
H
H
C
O
3
6
O
N
CN
CH
8
3
HN
HC
N
N
H
7
Scheme 2 Preparation of a series thiopyrimidine derivatives
3- Monolayer cells were incubated with the compound(s) for 48 h at 37 °C and in
an atmosphere of 5 % CO2.
4- After 48 h, cells were fixed, washed and stained with Sulfo-Rhodamine-B stain.
5- Excess stain was washed with acetic acid and the attached stain was recovered
with Tris EDTA buffer.
6- Color intensity is measured in an ELISA reader.
7- The relation between the surviving fraction and drug concentration is plotted to
get the survival curve of each tumor cell line after the specified compound.
Results and discussion
Thiourea and ethyl cyanoacetate reacted with 2-bromobenzaldehyde to give 6-(2-
bromo
phenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile
1c
(Scheme 1). Compound 1a [17] was reacted with hydrazine hydrate to give
2-hydrazino-4-(2-methyl phenyl)-6-oxo-1,6-dihydropyrimidine-5-carbonitrile 2a
(Scheme 1). Compound 1b [18] was reacted with monochloro acetic acid to give
7-(2-hydroxyphenyl)-3,5-dioxo-3,5-dihydro-2H-thiazolo[3,2-a]pyrimidine-6-carbo-
nitrile 3b (Scheme 1). Compounds 1a, 1c were allowed to react with sulfuric acid to
give 4-oxo-2-thioxo-6-(substituted phenyl)-1,2,3,4-tetrahydropyrimidine-5-car-
boxylic acid 4a, 4c (Scheme 1).
123

M. E. Haiba et al.
R'
O
O
O
H
N
NH
NH2
O
S
R'CHO
HN
S
N
HN
O
O
O
N
H
O
N
H
10
11a, b
R'
H
N
O
O
S
N
S
HN
O
O
O
N
H
12a, b
H CO
3
OCH3
a, R'=
b, R'=
OCH
3
OCH3
Scheme 3 Preparation of a series pyrimidine derivatives
Compound 2a reacted with acetic anhydride, trimetylorthoformate, p-anisalde-
hyde, diethyloxalate and ethyl chloroformate to give compounds 5, 6, 7, 8, 9,
respectively (Scheme 2).
Compound 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-sulfonohydrazide 10 [4]
reacted with the proper aldehydes to give N-[substituted]-2,4-dioxo-1,2,3,4-
tetrahydropyrimidine-5-sulfonohydrazides 11a, 11b which then reacted with
thioglycolic acid to give N-[2-(substituted) -4-oxo-1,3-thiazolidin-3-yl]-2,4-dioxo-
1,2,3,4-tetrahydropyrimidine-5-sulfonamides 12a, 12b (Scheme 3).
123

Synthesis and evaluation of antimicrobial and cytotoxic agents
Table 1 The preliminary antimicrobial screening test for the prepared compounds using Tobramycin
and DMSO as control
Tested strains
E. coli
O157
S.
L.
S.
typhimurium monocytogenes aureus
P. B.
aeruginosa cereus
Tested chemicals
2a
4a
4c
5
–
11
13.5
–
–
12
16.5
–
–
–
17.5
–
–
–
–
–
17.5
–
20
19
–
19.5
–
15.5
14
6
–
–
–
–
–
7
–
–
–
–
–
–
8
–
–
17
–
17.5
17
–
–
9
–
–
15
11.5
17
16
15
–
11a
11b
12b
12
9
16.5
19.5
20.3
14
–
13
–
15.5
18.5
14
13.5
19
17
20
14
15.3
Tobramycin (10 lg/ 15
mL)
16
DMSO
–
–
–
–
–
–
Table 2 Effect of some
Compounds
IC50
selected tetrahydropyrimidine
derivatives on hepatic
carcinoma cell line HEPG2
Doxorubicin (Dox)
3.56 lg/mL
5.0 lg/mL
6.35
5-Fluorouracil (5-FU)
5
7
8.54
8
6.59
11b
12b
4.1
9.38
The antibacterial activity test was carried out in triplicate and the mean of the
zone of inhibition was tabulated in Table 1. Results revealed that compound 12b
gave the highest antibacterial activity against all tested strains with a mean zone of
inhibition equal (18.1 lg/mL), followed by compound 4c (17.6 lg/mL) and finally
11b (15.2 lg/mL). In contrast, compound 7 showed no antibacterial activity against
all tested strains. Table 2 shows that all compounds exhibited growth inhibition
activity on the tested tumor panel cell line between 1 and 10 lg/mL concentrations
in comparison to the known anticancer drugs: 5-Fluorouracil and Doxorubicin. It
can be seen from the results that the novel derivatives induced a significant growth
inhibition towards the liver cancer (HEPG2) cell line in comparison to 5-Fluoro-
uracil after treatment with IC50 values (ranged from 6.35 to 9.38 lg/mL) for each
compound while the IC50 value for 5-Fluorouracil was 5 lg/mL.
123

M. E. Haiba et al.
Conclusion
A novel series of some new pyrimidine derivatives were synthesized and evaluated
as antibacterial and anticancer agents against liver carcinoma cell lines. The
antibacterial activity results exhibited that compounds 12b, 4c and 11b induced the
largest zones of bacterial inhibition and were considered the best antibacterial
agents in this series. Meanwhile, five tested tetrahydropyrimidine derivatives (5, 7,
8, 11b and 12b) exhibited significant growth inhibition against liver carcinoma cell
lines comparing to 5-Fluorouracil.
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