Synthesis of Novel Substituted Tetrahydropyrimidine Derivatives and Evaluation of Their Pharmacological and Antimicrobial Activities

Article abstract of DOI:10.1002/jhet.3374

Tetrahydropyrimidine derivative 1 was employed as intermediate compound, which in turn was allowed to react with different electrophilic and nucleophilic reagents to synthesize new polyfunctionalized series of substituted pyrimidine-2-thione derivatives. Structures of the newly synthesized compounds have been elucidated by spectroscopic data and elemental analyses. The pharmacological and antimicrobial activities of synthesized products have been evaluated as drug candidates.

Full text of DOI:10.1002/jhet.3374

Month 2018
Synthesis of Novel Substituted Tetrahydropyrimidine Derivatives and
Evaluation of Their Pharmacological and Antimicrobial Activities
*
Naglaa F. H. Mahmoud
and Eman A. Ghareeb
Chemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt
*E-mail: naglaa.fawzy@yahoo.com
Received July 2, 2018
DOI 10.1002/jhet.3374
Published online 00 Month 2018 in Wiley Online Library (wileyonlinelibrary.com).
Tetrahydropyrimidine derivative 1 was employed as intermediate compound, which in turn was allowed
to react with different electrophilic and nucleophilic reagents to synthesize new polyfunctionalized series of
substituted pyrimidine-2-thione derivatives. Structures of the newly synthesized compounds have been elu-
cidated by spectroscopic data and elemental analyses. The pharmacological and antimicrobial activities of
synthesized products have been evaluated as drug candidates.
J. Heterocyclic Chem., 00, 00 (2018).
INTRODUCTION
inhibitors-[17]. Moreover, 6-aryl-5-cyano-2-thiouracil
derivatives and their condensed heterocycles exerted
promising chemotherapeutic activities as antimicrobial
and anticancer agents [18–21]. Because of all
aforementioned facts, pyrimidine and thiouracil
derivatives served as promising starting material to
synthesize polyfunctionally pyrimidine derivatives. The
antimicrobial, antioxidant, and cyctotoxic activities of
newly synthesized compounds were evaluated.
Heterocyclic compounds have been widely utilized in
synthesis of pharmacologically active-compounds [1–4].
In particular, pyrimidines and fused pyrimidines as key
building units of DNA and RNA revealed the fact that
their derivatives exhibit diverse pharmacological activities
such as anticancer [5], antiviral [6], anti-inflammatory
[7], antioxidant [8], antibacterial,-and antifungal-agents
[9]. Recently, it was reported that some series of
5-cyano-2-thiouracil derivatives showed antimicrobial
activities against Staphylococcus aureus, Bacillus subtilis,
and Escherichia coli besides their remarkable antifungal
activity against Candida albicans and Aspergillus niger
[10,11]. Furthermore, thiouracils exhibited potential
therapeutics as antiviral, anticancer, and antimicrobial
agents [12–14]. For example, S-alkylation and
N-alkylation products of pyrimidine-2-thione have been
recently reported as novel antibacterial, cytotoxic agents
[15,16], and unique HIV reverse transcriptase
RESULTS AND DISCUSSION
Chemistry. As stated vide supra and in continuation of
our previous work on the synthesis of the biologically
active compounds [22,23], herein, we investigated
6-(4-methoxyphenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydro-
pyrimidine-5-carbonitrile 1 as a key starting material to
design-and synthesize
a
library of biologically
active series of polyfunctionalized pyrimidine-2-thione
© 2018 Wiley Periodicals, Inc.

N. F. H. Mahmoud and E. A. Ghareeb
Vol 000
derivatives. Therefore, compound 1 upon alkylation with
different reagents such as ethyl iodide in the presence of
sodium acetate using (1:1) molar ratio afforded S-
alkylated product 2. H NMR of compound 2 showed
signals at δ = 3.23 and 1.34 ppm due to CH2 and CH3
protons that ascertained its proposed feature.
Next, 4-aryl-2-hydrazinyl-6-oxo-1,6-dihydropyrimidine-
5-carbonitrile 3 was afforded either via the treatment of 1
with an excess amount of hydrazine hydrate and refluxed in
ethanolic solution or treatment of S-alkylated product 2
with hydrazine hydrate. The IR spectrum exhibited strong
absorption bands at υ = 3326, 3276 cmꢀ1 (NH2), 3186,
3111 cmꢀ1 (NH), 2208 cmꢀ1 (C═N), 1686 cmꢀ1 (C═O).
On the other hand, reaction of 1 with ethyl chloroacetate in
the presence of anhydrous potassium carbonate afforded
the ethyl ester derivative 4, which in turn was subjected to
react with hydrazine hydrate to give 3.
The structure of 8 was confirmed by the spectral data
such as the IR that lacked a band corresponding to
carbonyl group (Scheme 1).
The chloropyrimidine 8 was used as a building block to
synthesize new heterocyclic compounds. Thus, it
underwent variant substitution and cyclization reactions
when it was treated with primary amines such as
anthranilic acid and/or p-aminoacetophenone to afford the
1
corresponding pyrimidoquinazoline derivative
9 and
aniline pyrimidine-2-thione derivative 10, respectively
(Scheme 2).
The structure of 9 and 10 were elucidated from their
spectral data, where the IR spectrum of compound 9
exhibited a strong absorption band at υ = 1673 cmꢀ1
corresponding to (C═O) group, while the mass spectrum
revealed the molecular ion peak at m/z 360. On the other
hand, the IR of compound 10 showed absorption band of
carbonyl group (C═O) at υ = 1677 cmꢀ1, and mass
spectrum exhibited the molecular ion peak at m/z 376.
Alkaline hydrolysis of tetrahydropyrimidine 1 using
hydrogen peroxide in ammonium hydroxide gave dioxo
tetrahydropyrimidine derivative 5. Thus, IR spectrum of 5
showed two carbonyl groups signals at υ = 1684 and
Furthermore, when chloropyrimidine derivative
underwent thiation using thiourea and/or phosphorus
pentasulfide, it afforded the dithioxo-1,2,3,4-
8
1659 cmꢀ1
.
Meanwhile, acid hydrolyses of 1 using concentrated
sulfuric acid (70%) afforded the carboxylic acid derivative
6. The structure of 6 was confirmed by the disappearance
of a characteristic absorption band for cyano group in IR
spectrum as well as appearance of an absorption band of a
tetrahydropyrimidine derivative 11. The IR spectrum of
compound 11 showed bands characteristic for NH and
C═S groups at υ = 3127, 1256, and 1232 cmꢀ1. While
the 1H NMR exhibits two exchangeable broad singlet
signals at δ = 14.13 and 8.05 ppm due to NH protons.
Further evidence was gained from mass spectrum as it
revealed the molecular ion peak at m/z 275.
Treatment of chloropyrimidine derivative 8 with sodium
azide and hydrazine hydrate gave tetrazolopyrimidine
derivative 12 and 4-hydrazinyl pyrimidine derivative 13,
respectively (Scheme 2).
carbonyl of acidic group at υ = 1709 cmꢀ1
.
Dimerization of compound 1 through disulphide linkage
was achieved upon by oxidation when it was treated with
iodine in an alkaline medium to give the corresponding
disulphide derivative 7. Mass spectrum of compound 7
showed its molecular ion peak at m/z 516.
Chlorination of 1 with a mixture of phosphorus
The mass spectrum of derivative 12 showed the
molecular ion peak at m/z 285. Meanwhile, IR of
4-hydrazinyl pyrimidine 13 showed absorption bands at
pentachloride and phosphorus oxychloride as
a
chlorinating reagent gave chloropyrimidine derivative 8.
Scheme 1 [Color figure can be viewed at wileyonlinelibrary.com]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Synthesis of Novel Substituted Tetrahydropyrimidine Derivatives and Evaluation
of Their Pharmacological and Antimicrobial Activities
Scheme 2 [Color figure can be viewed at wileyonlinelibrary.com]
υ = 3333, 3314, 3289, and 3170 cmꢀ1 corresponding to
NH2 and NH. While H NMR of compound 13 showed
structures and mass spectra showed the molecular ion
peaks of 17a–d derivatives at 390, 384, 389, and 445,
respectively (Scheme 3).-.
1
D2O-exchangeable singlet signals at δ = 13.15, 8.29, and
4.74 ppm due to NH and NH2 protons, hydrazinyl-6-oxo-
1,6-dihydropyrimidine derivative 3 has been utilized as a
versatile material for the synthesis of numbers of fused
heterocyclic compounds. So the hydrazine derivative 3
was reacted with electrophilic reagents such as ethyl
chloroacetate or chloroacetyl chloride, ethyl chloroformate,
and/or acetylacetone to give the corresponding pyramido
triazine derivative 14, ethyl pyrimidine hydrazine
carboxylate derivative 15, and dimethyl pyrazol
pyrimidine derivative 16, respectively. The structure of
compound 14 was confirmed by the IR spectrum that
exhibited absorption bands at υ = 3261, 3087 cmꢀ1
Oxothiazolidine derivative 18a and oxoazetidine
derivative 19a were formed when Schiff base 17a was
allowed to react with thioglycolic acid and/or
chloroacetyl chloride, respectively. The IR spectrum of
18a exhibited strong absorption bands at υ = 1693 and
1650 cmꢀ1 for two carbonyl groups. 1H NMR of
compound 18a showed singlet signals at δ = 5.24 and
3.58 ppm due to C─H and ─CH2 thiazolidinyl. Also, the
IR of compound 19a showed absorption bands at
υ = 1691 and 1650 cmꢀ1 of two carbonyl, oxoazetidine
ring was unstable so easily broken and return to Schiff
base so the mass spectrum showed the parent peak at m/z
390 (Scheme 3).
1
(NH), 1695, 1665 cmꢀ1 (C═O). In addition, H NMR of
compound 14 showed D2O-exchangeable singlet signals
at δ = 12.20 and 9.97 ppm due to NH protons. Next, the
reaction with ethyl chloroformate gave the product 15
that showed absorption band of carbonyl group (C═O) at
On the other hand, the synthesis of the novel compounds
thiazolo pyrimidine derivatives 20 and 21 were achieved
by reacting compound 1 with chloro acetic acid and/or
chloroacetyl chloride. The structures of compounds 20
and 21 were confirmed by IR that showed the complete
absence of NH absorption band and the appearance of the
carbonyl absorption bands of oxo-thiazolo ring at
υ = 1736 and 1730 cmꢀ1, respectively, as well as
1
υ = 1727 cmꢀ1, and H NMR showed bands at δ = 4.10
and 1.25 ppm, corresponding to protons of ethyl group
and molecular ion peak at m/z 329. The 1H NMR of
compound 16 showed singlet signals at δ = 11.42 ppm of
(NH) exchangeable with D2O and two singlet signals at
δ = 2.64 and 2.24 ppm corresponding to six protons of
two CH3 groups.
A series of 4-(4-methoxyphenyl)-6-oxo-2-(2-(substituted
benzylidene)hydrazinyl)-1,6-dihydropyrimidine-5-carbonitrile
17a–d derivatives were prepared from the reaction of 3
with different aromatic aldehydes in glacial acetic acid.
The IR spectra of 17a–d derivatives showed the
disappearance of NH2 band and appearance of a singlet
signal corresponding to N═CH at δ = 9.41–8.01 ppm,
respectively, in 1H NMR is an indication about the
1
appearance of the singlet signal of (COCH2) in H NMR
spectrum.
Moreover, 3-imino-thiazolo pyrimidine derivative 22
and 4-imino-pyrimido thiazine derivative 23 were
prepared by refluxing 1 with chloroacetonitrile and/or
acrylonitrile in ethanol and few drops of triethylamine.
The proposed structures of compounds 22 and 23 were in
accordance with the 1H NMR spectra that showed a
singlet signal at δ = 3.66 ppm of SCH2 in compound 22,
also two triplet signals at δ = 3.51 and 3.03 ppm for
CH2─CH2 protons in compound 23.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

N. F. H. Mahmoud and E. A. Ghareeb
Vol 000
Scheme 3 [Color figure can be viewed at wileyonlinelibrary.com]
Finally, treatment of compound 1 with oxalyl chloride in
tetrahydrofurane afforded trioxo thiazolo pyrimidine
derivative 24 via nucleophilic attacks upon the carbonyl
carbon atom of oxalyl chloride. Compound 24 was
confirmed via the appearance of two bands at υ = 1754
and 1739 cmꢀ1 of the two carbonyl groups of the
thiazolidinone ring (Scheme 4).
Antimicrobial Activity. Antibacterial activity evaluation.
The antimicrobial activities of the novel compounds have
been screened using agar diffusion method [24,25]. The
synthesized compounds have been tested for their
antibacterial activities against S. aureus (G+ve),
Pseudomonas aeruginosa (G-ve), C. albicans (yeast), and
A. niger (fungus). The obtained results are compiled in
Scheme 4 [Color figure can be viewed at wileyonlinelibrary.com]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Synthesis of Novel Substituted Tetrahydropyrimidine Derivatives and Evaluation
of Their Pharmacological and Antimicrobial Activities
Table 1
Antimicrobial activity of synthesized compounds.
Clear zone (ϕmm)
Sample name
Staphylococcus aureus
Pseudomonas aeruginosa
Candida albicans
Aspergillus niger
2
5
6
7
8
9
10
11
12
13
14
15
16
17a
17b
17c
17d
18a
19a
20
22
23
24
20
28
14
16
14
14
15
17
14
25
13
21
29
13
18
15
22
13
14
18
22
14
10
30
00
19
30
18
14
18
16
18
14
21
23
0
22
31
13
16
19
23
13
15
20
24
16
15
28
00
18
16
18
14
18
15
14
17
15
26
15
16
31
0
0
0
23
0
14
16
15
17
15
25
22
15
14
0
0
0
0
0
0
14
0
13
16
13
0
0
15
10
0
16
14
14
14
0
Streptomcin
Cyclohexamide
15
37
Table 1. It is obvious that most of the compounds show
moderate to high antimicrobial activities. In particular,
compounds 5, 13, 16, 17d, and 22 showed remarkable
antimicrobial activity, which could consider that those
compound are having the chance to be candidates as
antimicrobial agents.
Cytotoxic activity of some compounds against human tumor
cells. The prepared compounds were tested for cytotoxic
activities against three human tumor cells. The best results
Table 2
Total antioxidant capacity values of the synthesized compounds.
Pharmacological Activity. Determination of total antioxidant
Total antioxidant capacity
(mg AAE/g compound)
capacity.
The total antioxidant capacity of the tested
Compound No.
compounds was estimated via phosphomolybdenum
antioxidant technique. The total antioxidant capacity
values equivalent to ascorbic acid in mg ascorbic acid
equivalent (AAE)/g compound are presented in Table 2.
The obtained values were varied and ranged from 121.65
to 824.0 mg AAE/g compound. Moreover, the results
revealed that compounds 7, 5, 6, and 9 showed the most
potent activity followed by compounds 24, 22, 17d, 19a,
15, 14, 16, 17a, 18a, 17b, and 17c having moderate
activity, respectively. On the other hand, compounds 20,
2, 23, and 8 showed the lowest activity, respectively.
From the aforementioned results, we can conclude that
the tested compounds have different abilities on the
reduction of Mo (VI) to Mo (V) and subsequent
formation of a green phosphate/Mo (V) complex at acid
pH, which may be due to the variation in the chemical
structures of tested compounds and to the presence or
absence of certain substituents like carbonyl, hydroxyl,
methoxy, and carboxylic.
2
5
6
7
8
9
218.64 2.01
560.47 2.95
547.78 3.40
824.0 4.04
121.65 3.25
510.32 5.10
317.47 3.49
303.00 4.03
281.81 3.25
421.82 2.95
431.65 4.50
409.03 3.40
381.57 2.02
373.42 2.35
446.61 2.02
397.24 3.40
432.63 1.23
238.45 3.49
452.30 4.50
134.96 2.02
481.51 4.89
11
12
13
14
15
17a
17b
17c
17d
18a
19a
20
22
23
24
Results are (means SD) (n = 3). AAE, ascorbic acid equivalent.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

N. F. H. Mahmoud and E. A. Ghareeb
Vol 000
were observed for compounds 13, 14, 15, and 17b, which
were found very strong cytotoxic compounds. Compounds
11, 16, 17a, and 17d were also considered strongly
cytotoxic. Finaly, compounds 2, 9, 10, 12, 20, 22, and 23
were moderate in their cytotoxic activity, and compounds
5, 6, 7, 8, 17c, and 18a showed weak cytotoxicity (Table 3).
2-(Ethylthio)-4-(4-methoxyphenyl)-6-oxo-1,6-dihydropyrimidine-
5-carbonitrile (2). An equimolar mixture of pyrimidine 1
(0.01 mol, 2.59 g) and ethyl iodide (0.01 mol, 1.56 mL)
in ethanol containing sodium acetate was heated under
reflux for 10 h. The reaction mixture was cooled and
poured onto ice. The formed precipitate was filtered,
dried, and crystallized from benzene to give 2.
Yield (71%), mp 244–246°C. Anal. Calcd for
C14H13N3O2S (287): C, 58.53; H, 4.52; N, 14.63.
Found: C, 58.26; H, 4.32; N, 14.83. FTIR (KBr)
(cmꢀ1): 3134 (NH), 2941, 2849 (C─H aliphatic), 2224
(CN), 1673 (C═O), 1602 (C═C). 1H NMR (DMSO-
d6): δH (ppm) 13.60 (s, 1H, NH, D2O exchangeable),
EXPERIMENTAL
All melting points were measured on a Gallenkamp
electric melting point apparatus (Germany) uncorrected.-
The infrared spectra were recorded in potassium bromide
disks on a pyeUnicam SP-3-300 (Cambridge, England)
and Shimadzu FTIR 8101 PC infrared spectrophotometers
(Shimadzu Corp., Kyoto, Japan).
8.01 (d,
J = 6.82 Hz, 2H, Ar─H), 7.13 (d,
J = 6.82 Hz, 2H, Ar─H), 3.86 (s, 3H, OCH3), 3.23 (q,
2H, CH2), 1.34 (t, J = 6.82 Hz, 3H, CH3). MS, m/z
(%): 287 (M.+, 100%).
The H NMR and 13C NMR were recorded at a Varian
1
Mercury VX-300 MHz and 75 MHz (Varian, Inc., Palo
Alto, CA), respectively, using TMS as internal standard
2-Hydrazinyl-4-(4-methoxyphenyl)-6-oxo-1,6-dihydropyri-
midine-5-carbonitrile (3).
A mixture of pyrimidine 1
(0.01 mol, 2.59 g) and hydrazine hydrate (0.04 mol,
2 mL) in ethanol was heated under reflux for 8 h. The
formed precipitate was filtered, dried, and crystallized
from dioxan to give 3.
in
deuterated
chloroform
(CDCl3)
or
deuterateddimethylsulphoxide (DMSO-d6). Chemical
shifts are measured in ppm. The mass spectra were
recorded on
a Shimadzu GCMS-QP-1000EX mass
Yield (52%), mp 236–240°C. Anal. Calcd for
C12H11N5O2 (257): C, 56.03; H, 4.28; N, 27.23. Found:
C, 56.47; H, 4.45; N, 26.83. FTIR (KBr) (cmꢀ1): 3326,
3276 (NH2), 3186, 3111 (NH), 2208 (CN), 1686 (C═O).
1H NMR (DMSO-d6): δH (ppm) 10.15 (s, 1H, NH, D2O
exchangeable), 8.2 (s, 1H, NH, D2O exchangeable),
7.83–6.99 (m, 4H, Ar─H), 6.8 (s, 2H, NH2, D2O
exchangeable), 3.86 (s, 3H, OCH3). MS, m/z (%): 257
(M.+, 100%).
spectrometer at 70 eV. Elemental analyses were carried
out at the microanalytical center of Cairo University. All
the reactions and the purity of the new compounds were
followed and checked by TLC using TLC aluminum
sheets silica gel F254
.
Table 3
Cytotoxic activity of some compounds against human tumor cells.
In vitro cytotoxicity IC50 (μM)
Ethyl 2-((5-cyano-4-(4-methoxyphenyl)-6-oxo-1,6-dihydro-
pyrimidine-2-yl)thio)acetate (4). A mixture of pyrimidine
Compounds
HePG2
HCT-116
MCF-7
1 (0.01 mol, 2.59 g) and ethyl chloroacetate (0.01 mol,
1.22 mL) in acetone containing potassium carbonate
anhydrous was heated under water steam for 7 h. The
reaction mixture was allowed to cool and then acidified
by HCl after pouring into water/ice. The formed
precipitate was filtered, dried, and crystallized from
benzene to give 4.
DOX
2
5
6
7
4.50 0.2
21.31 1.8
68.81 4.1
93.35 5.3
78.56 4.5
61.34 3.6
49.27 2.9
24.75 2.1
13.62 1.2
32.69 2.5
3.48 0.2
11.35 1.0
5.49 0.3
19.12 1.6
9.80 0.8
7.74 0.5
85.92 4.7
15.07 1.4
73.55 4.3
28.13 2.4
46.20 2.8
54.01 3.1
5.23 0.3
23.90 2.0
65.16 3.9
>100
4.17 0.2
27.43 2.5
58.12 4.2
84.25 5.1
71.36 4.4
48.71 3.9
33.54 3.1
28.67 2.7
17.09 1.6
42.28 3.6
7.28 0.6
81.14 4.7
44.06 3.2
41.62 3.0
31.48 2.4
14.28 1.5
38.55 2.8
6.45 0.4
9.14 0.8
8.23 0.7
22.41 1.8
12.72 1.3
10.53 1.1
89.26 4.8
18.79 1.6
69.24 4.1
35.07 2.7
52.39 3.5
62.48 3.9
8
9
10
11
12
13
14
15
16
17a
17b
17c
17d
18a
20
22
23
Yield (86%), mp 220–222°C. Anal. Calcd for
C16H15N3O4S (345): C, 55.65; H, 4.38; N, 12.17. Found:
C, 55.33; H, 3.98; N, 11.95. FTIR (KBr) (cmꢀ1): 3079
(NH), 2219 (CN), 1726, 1667 (C═O). 1H NMR
(DMSO-d6): δH (ppm) 13.7 (s, 1H, NH, D2O
exchangeable), 7.96 (d, J = 6.82 Hz, 2H, Ar─H), 7.08
(d, J = 6.82 Hz, 2H, Ar─H), 4.11(q, 2H, CH2), 4.01 (s,
2H, CH2), 3.84 (s, 3H, OCH3), 1.12 (t, J = 6.82 Hz, 3H,
CH3). MS, m/z (%): 344 (M+ ꢀ1, 100%).
7.91 0.7
9.34 0.9
25.11 2.2
14.50 1.4
11.87 1.2
76.80 4.6
20.58 1.8
63.84 4.2
30.59 2.8
55.36 4.0
36.03 3.3
6-(4-Methoxyphenyl)-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-
carbonitrile (5).
A mixture of pyrimidine 1 (0.01 mol,
2.59 g), ammonia solution (12.5 mL), and hydrogen peroxide
(3.5 mL) was stirred at room temperature for 4 h. The
IC50 (μM): 1–10 (very strong); 11–20 (strong); 21–50 (moderate); 51–100
(weak), and above 100 (non-cytotoxic). DOX, doxorubicin.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Synthesis of Novel Substituted Tetrahydropyrimidine Derivatives and Evaluation
of Their Pharmacological and Antimicrobial Activities
reaction mixture was left overnight; the formed precipitate was
filtered, dried, and crystallized from ethanol to give 5.
3-(4-Methoxyphenyl)-10-oxo-1-thioxo-2,10-dihydro-1H-
pyrimido[6,1-b]quinazoline-4-carbonitrile (9).
A mixture
of 8 (0.01 mol, 2.77 g) and anthranilic acid (0.01 mol,
1.37 g) in ethanol was heated under reflux for 6 h. The
formed precipitate was filtered, dried, and crystallized
from ethanol to give 9.
Yield (42%), mp over 300°C. Anal. Calcd for
C12H9N3O3 (243): C, 59.25; H, 3.70; N, 17.28. Found:
C, 59.48; H, 4.09; N, 16.85. FTIR (KBr) (cmꢀ1): 3138
1
(NH), 2221 (CN), 1684, 1659 (C═O). H NMR (DMSO-
Yield (25%), mp 249–250°C. Anal. Calcd for
C19H12N4O2S (360): C, 63.33; H, 3.33; N, 15.55. Found:
C, 62.92; H, 3.64; N, 15.85. FTIR (KBr) (cmꢀ1): 3180
(NH), 2209 (CN), 1673 (C═O), 1605 (C═C), 1256
(C═S). 1H NMR (DMSO-d6): δH (ppm) 11.93 (s, 1H,
1NH, D2O exchangeable), 8.65–7.11 (m, 8H, Ar─H),
3.86 (s, 3H, OCH3). 13C NMR (DMSO-d6), δ ppm
169.53, 162.18, 161.59, 160.36, 158.33, 140.85, 133.47,
133.26, 131.12, 130.99, 130.54, 128.37, 122.35, 122.02,
120.75, 120.53, 120.48, 113.88, 55.45. MS, m/z (%): 360
(M.+, 100%).
d6): δH (ppm) 12.52 (s, 1H, NH, D2O exchangeable),
10.5 (s, 1H, NH, D2O exchangeable), 7.34–6.88 (m, 4H,
Ar─H), 3.86 (s, 3H, OCH3). MS, m/z (%): 243 (M.+,
16%), 242 (100%).
6-(4-Methoxyphenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropy-
rimine-5-carboxylic acid (6). A solution of pyrimidine 1
(0.01 mol, 2.59 g) in sulfuric acid 70% (30 mL) was
heated under reflux for 3 h. The reaction mixture was
allowed to cool and then neutralized by NH4OH after
pouring onto ice. The formed precipitate was filtered,
dried, and crystallized from ethanol to give 6.
Yield (50%), mp 146–148°C. Anal. Calcd for
C12H10N2O4S (278): C, 51.79; H, 3.59; N, 10.07. Found:
C, 51.39; H, 3.19; N, 10.47. FTIR (KBr) (cmꢀ1): broad
4-((4-Acetylphenyl)amino)-6-(4-methoxyphenyl)-2-thioxo-
1,2-dihydropyrimidine-5-carbonitrile (10). A mixture of 8
(0.01 mol, 2.77 g) and p-amino acetophenone (0.01 mol,
1.35 g) in ethanol containing drops of Conc HCl was
heated under reflux for 7 h. The formed precipitate was
filtered, dried, and crystallized from ethanol to give 10.
Yield (60%), mp 284–286°C. Anal. Calcd for
C20H16N4O2S (376): C, 63.82; H, 4.25; N, 14.89. Found:
C, 63.59; H, 4.05; N, 15.29. FTIR (KBr) (cmꢀ1): 3307,
1
band at 3394 (OH, NH), 1709, 1651 (C═O). H NMR
(DMSO-d6): δH (ppm) 12.52 (s, 1H, OH), 11.82 (s, 1H,
NH, D2O exchangeable), 10.15 (s, 1H, NH, D2O
exchangeable), 7.98–7.15 (m, 4H, Ar─H), 3.81(s, 3H,
OCH3). MS, m/z (%): 278 (M.+, 20%).
2,20-Disulfanediylbis(4-(4-methoxyphenyl)-6-oxo-1,6-
1
3127 (NH), 2212 (CN), 1677 (C═O), 1602 (C═C). H
dihydropyrimidine-5-carbonitrile) (7).
A solution of
NMR (DMSO-d6): δH (ppm) 14.14 (s, 1H, NH, D2O
exchangeable), 11.20 (s, 1H, NH, D2O exchangeable),
7.87–6.81 (m, 8H, Ar─H), 3.86 (s, 3H, OCH3), 1.07 (s,
3H, CH3). MS, m/z (%): 376 (M.+, 100%).
6-(4-Methoxyphenyl)-2,4-dithioxo-1,2,3,4-tetrahydropyrimidine-
5-carbonitrile (11). A mixture of 8 (0.01 mol, 2.77 g) and
iodine (0.01 mol, 2.34 g) in potassium iodide solution
(0.01 mol, 1.66 g) was added to compound 1 (0.01 mol,
2.59 g) in 10% sodium hydroxide solution (20 mL) and
was stirred at room temperature for 4 h. The formed
precipitate was collected and crystallized from ethanol
to give 7.
thiourea (0.01 mol, 0.76 g) in ethanol containing drops of
glacial acetic acid (five drops) was heated under reflux for
15 h. The formed precipitate was filtered, dried, and
crystallized from butanol to give 11. Yield (73%).
Yield (12%), mp 286–289°C. Anal. Calcd for
C24H16N6O4S2 (516): C, 55.81; H, 3.10; N, 16.27.
Found: C, 56.11; H, 3.34; N, 15.97. FTIR (KBr) (cmꢀ1):
1
3148 (NH), 2205 (CN), 1673 (C═O). H NMR (DMSO-
A mixture of 8 (0.01 mol, 2.77 g) and phosphorus
pentasulphide (0.01 mol, 2.22 g) in dry toluene was
heated under reflux for 2 h. The formed precipitate was
filtered, dried, and crystallized from ethanol to give 11.
Yield (60%), mp 291–293°C. Anal. Calcd for
C12H9ON3S2 (275): C, 52.36; H, 3.27; N, 15.27. Found:
C, 52.68; H, 2.87; N, 14.87. FTIR (KBr) (cmꢀ1): 3127
d6): δH (ppm) 12.52 (s, 2H, 2NH, D2O exchangeable),
8.18–7.08 (m, 8H, Ar─H), 3.86 (s, 6H, OCH3). MS, m/z
(%): 516 (M.+, 6), 257 (14).
4-Chloro-6-(4-methoxyphenyl)-2-thioxo-1,2-dihydropyrimidine-
5-carbonitrile (8). A mixture of pyrimidine 1 (0.01 mol,
2.59 g), phosphorous oxychloride (10 mL), and
phosphorous pentachloride (1.5 g) was heated under
water steam for 8 h. The reaction mixture was allowed
to cool and then poured onto ice. The formed precipitate
was filtered, dried, and crystallized from ethanol to give 8.
Yield (92%), mp 172–174°C. Anal. Calcd for
C12H8N3OSCl (277): C, 51.98; H, 2.88; N, 15.16. Found:
C, 51.64; H, 3.09; N, 14.93. FTIR (KBr) (cmꢀ1): 3127
1
(NH), 2224 (CN), 1606 (C═C), 1256, 1232 (C═S). H
NMR (DMSO-d6): δH (ppm) 14.13 (s, 1H, NH, D2O
exchangeable), 8.05 (s, 1H, NH, D2O exchangeable),
7.69 (d, J = 6.82 Hz, 2H, Ar─H), 7.12 (d, J = 6.82 Hz,
2H, Ar─H), 3.87 (s, 3H, OCH3). MS, m/z (%): 275 (M.+,
100%).
1
(NH), 2222 (CN), 1624 (C═N), 1262 (C═S). H NMR
7-(4-Methoxyphenyl)-5-thioxo-5,6-dihydrotetrazolo[1, 5-c]
pyrimidine-8-carbonitrile (12).
(0.01 mol, 2.77 g) and sodium azide (0.01 mol, 0.65 g)
in glacial acetic acid was heated under reflux for 5 h. The
A
mixture of
8
(DMSO-d6): δH (ppm) 12.52 (s, 1H, 1NH, D2O
exchangeable), 8.2–7.7 (m, 4H, Ar─H), 3.86 (s, 3H,
OCH3). MS, m/z (%): 245 (M.+ꢀS, 100%).
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

N. F. H. Mahmoud and E. A. Ghareeb
Vol 000
reaction mixture was allowed to cool and then poured into
ice/water. The formed precipitate was filtered, dried, and
crystallized from ethanol to give 12.
Yield (50%), mp 154–156°C. Anal. Calcd for
C15H15N5O4 (329): C, 54.71; H, 4.55; N, 21.27. Found:
C, 54.98; H, 4.32; N, 21.53. FTIR (KBr) (cmꢀ1): broad
band centered at 3232 (3NH), 2223 (CN), 1727, 1651
(C═O), 1605 (C═C). 1H NMR (DMSO-d6): δH (ppm)
12.36 (s, 1H, NH, D2O exchangeable), 10.25 (s, 1H, NH,
D2O exchangeable), 9.50 (s, 1H, NH, D2O
exchangeable), 7.89 (d, J = 6.82 Hz, 2H, Ar─H), 7.09 (d,
J = 6.82 Hz, 2H, Ar─H), 4.10 (q, 2H, CH2), 3.86 (s, 3H,
OCH3), 1.25 (t, J = 6.82 Hz, 3H, CH3). MS, m/z (%):
329 (M.+, 100%).
Yield (51%), mp over 300°C. Anal. Calcd for
C12H8N6OS (284): C, 50.70; H, 2.81; N, 29.57. Found:
C, 52.09; H, 2.40; N, 29.29. FTIR (KBr) (cmꢀ1): 3166
1
(NH), 2220 (CN), 1604 (C═C), 1258 (C═S). H NMR
(DMSO-d6): δH (ppm) 13.02 (s, 1H, NH, D2O
exchangeable), 7.99 (d, J = 6.82 Hz, 2H, Ar─H), 7.32 (d,
J = 6.82 Hz, 2H, Ar─H), 3.86 (s, 3H, OCH3). MS, m/z
(%): 285 (M.++1, 100%).
4-Hydrazinyl-6-(4-methoxy phenyl)-2-thioxo-1,2-dihydro-
2-(3,5-dimethyl-1H-pyrazol-1-yl)-4-(4-methoxyphenyl)-6-
oxo-1,6-dihydropyrimidine-5-carbonitrile (16). A mixture
pyrimidine-5-carbonitrile (13).
A
mixture of
8
(0.01 mol, 2.77 g) and hydrazine hydrate (0.04 mol,
2 mL) in ethanol was heated under reflux for 7 h. The
reaction mixture was allowed to cool. The formed
precipitate was filtered, dried, and crystallized from
ethanol to give 13.
of hydrazino 3 (0.01 mol, 2.57 g) and acetyl acetone
(0.01 mol, 0.98 mL) in absolute ethanol was heated
under reflux for 12 h. The formed precipitate was filtered,
dried, and crystallized from dioxan to give 16.
Yield (72%), mp 230–232°C. Anal. Calcd for
C17H15N5O2 (321): C, 63.55; H, 4.67; N, 21.80. Found:
C, 63.83; H, 4.76; N, 21.65. FTIR (KBr) (cmꢀ1): 3339
Yield (55%), mp 224–226°C. Anal. Calcd for
C12H11N5OS (273): C, 52.74; H, 4.02; N, 25.64. Found:
C, 53.25; H, 3.85; N, 26.96. FTIR (KBr) (cmꢀ1): 3333,
3314, 3289, 3170 (NH2, NH), 2194 (CN), 1609 (C═C),
1
(NH), 2218 (CN) 1669 (C═O), 1593 (C═C). H NMR
(DMSO-d6): δH (ppm) 11.42 (s, 1H, NH, D2O
exchangeable), 8.03 (d, J = 6.82 Hz, 2H, Ar─H), 7.13 (d,
J = 6.82 Hz, 2H, Ar─H), 6.30 (s, 1H, CH═C pyrazol),
3.88 (s, 3H, OCH3), 2.64 (s, 3H, CH3), 2.24 (s, 3H,
CH3). 13C NMR (DMSO-d6), δ ppm 167.73, 162.25,
161.65, 152.46, 148.54, 143.81, 130.57, 127.13, 116.02,
114.01, 112.15, 91.31, 55.43, 40.33, 40.06, 14.88, 13.29.
MS, m/z (%): 321 (M.+, 100%).
1
1265 (C═S). H NMR (DMSO-d6): δH (ppm) 13.15 (s,
1H, NH, D2O exchangeable), 8.29 (s, 1H, NH, D2O
exchangeable), 7.69 (d, J = 6.82 Hz, 2H, Ar─H), 7.12 (d,
J = 6.82 Hz, 2H, Ar─H), 4.74 (s, 2H, NH2, D2O
exchangeable), 3.86 (s, 3H, OCH3). MS, m/z (%): 273
(M.+, 18%), (271, 100%).
8-(4-Methoxyphenyl)-4,6-dioxo-1,3,4,6-tetrahydro-2H-
pyrimido[2,1-c][1,2,4]triazine-7-carbonitrile (14). A mixture
4-(4-Methoxyphenyl)-6-oxo-2-(2-(4-nitrobenzylidene)
of 3 (0.01 mol, 2.57 g) and ethylchloroacetate or
chloroacetyl chloride (0.01 mol) in glacial acetic acid
was heated under reflux for 6 h. The formed precipitate
was filtered, dried, and crystallized from ethanol to
give 14.
hydrazinyl)-1,6-dihydropyrimidine-5-carbonitrile (17a).
A
mixture of 3 (0.01 mol, 2.57 g) and p-nitrobenzaldehyde
(0.01 mol, 1.51 mL) in glacial acetic acid was heated
under reflux for 6 h. The formed precipitate was filtered,
dried, and crystallized from ethanol to give 17a.
Yield (28%), mp 270–272°C. Anal. Calcd for
C14H11N5O3 (297): C, 56.56; H, 3.70; N, 23.56. Found:
C, 56.81; H, 3.35; N, 23.26. FTIR (KBr) (cmꢀ1): 3261,
3087 (NH), 2218 (CN), 1695, 1665 (C═O), 1605 (C═C).
1H NMR (DMSO-d6): δH (ppm) 12.20 (s, 1H, 1NH, D2O
exchangeable), 9.97 (s, 1H, 1NH, D2O exchangeable),
7.90 (d, J = 6.82 Hz, 2H, Ar─H), 7.05 (d, J = 6.82 Hz,
2H, Ar─H), 3.83 (s, 3H, OCH3), 1.91 (s, 2H, CH2). 13C
NMR (DMSO-d6), δ ppm 169.67, 162.21, 161.67,
156.88, 148.54, 130.14, 128.11, 117.22, 113.63, 91.3,
55.34, 40.28, 40.00, 20.89. MS, m/z (%): 299 (M.+ +2,
51.7), (257, 100%).
Yield (85%), mp over 300°C. Anal. Calcd for
C19H14N6O4 (390): C, 58.46; H, 3.58; N, 21.53. Found:
C, 58.67; H, 3.31; N, 21.73. FTIR (KBr) (cmꢀ1): 3353,
1
3264 (NH), 2214 (CN), 1655 (C═O), 1606 (C═C). H
NMR (DMSO-d6): δH (ppm) 12.48 (s, 1H, 1NH, D2O
exchangeable), 11.26 (s, 1H, 1NH, D2O exchangeable),
8.38 (s, 1H, CH═N), 8.27–8.21 (m, 4H, Ar─H), 7.92 (d,
J = 6.82 Hz, 2H, Ar─H), 7.08 (d, J = 6.82 Hz, 2H,
Ar─H), 3.85 (s, 3H, OCH3). 13C NMR (DMSO-d6), δ
ppm 169.67, 162.21, 161.71, 158.13, 147.85, 144.21,
139.91, 130.20, 128.78, 123.4 (2), 123.1 (2), 117.15,
113.63 (2), 91.3, 55.36, 40.05. MS, m/z (%): 390 (M.+,
93), (268, 100%).
Ethyl 2-(5-cyano-4-(4-methoxyphenyl)-6-oxo-1,6-dihydro-
pyrimidine-2-yl)hydrazine-1-carboxylate (15).
A mixture
2-(2-((1H-indol-3yl)methylene)hydrazinyl)-4-(4-
of 3 (0.01 mol, 2.57 g) and ethylchloroformate (0.02 mol,
2.16 mL) in glacial acetic acid was heated under reflux
for 10 h. The reaction mixture was allowed to cool and
then poured onto ice/water. The formed precipitate was
filtered, dried, and crystallized from ethanol to give 15.
methoxyphenyl)-6-oxo-1,6-dihydropyrimidine-5-carbonitrile
(17b). A mixture of 3 (0.01 mol, 2.57 g) and indol-3-
aldehyde (0.01 mol, 1.44 g) in glacial acetic acid was
heated under reflux for 6 h. The formed precipitate was
filtered, dried, and crystallized from ethanol to give 17b.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Synthesis of Novel Substituted Tetrahydropyrimidine Derivatives and Evaluation
of Their Pharmacological and Antimicrobial Activities
Yield (79%), mp over 300°C. Anal. Calcd for
C21H16N6O2 (384): C, 65.62; H, 4.16; N, 21.87. Found: C,
66.91; H, 4.47; N, 21.66. FTIR (KBr) (cmꢀ1): 3378, 3269,
3142 (NH), 2217 (CN), 1667 (C═O), 1633 (C═N), 1603
(C═C). 1H NMR (DMSO-d6): δH (ppm) 12.20 (s, 1H,
NH, D2O exchangeable), 11.72 (s, 1H, 1NH, D2O
exchangeable), 11.42 (s, 1H, NH, D2O exchangeable),
8.44 (s, 1H, CH═N), 8.37–7.07 (m, 9H, 8Ar─H + CH
indolyl), 3.85 (s, 3H, OCH3). MS, m/z (%): 384 (M.+, 72),
(142, 100%).
thiazolidinyl), 3.84 (s, 3H, OCH3), 3.58 (s, 2H, CH2
thiazolidinyl). MS, m/z (%): 466 (M.++2, 60).
2-((3-Chloro-2-(4-nitrophenyl)-4-oxoazetidine-1yl)amino)-
4-(4-methoxyphenyl)-6-oxo-1,6-dihydropyrimidine-5-
carbonitrile (19a). A mixture of 17a (0.01 mol, 4.61 g)
and chloroacetyl chloride (0.01 mol, 11.2 mL) in
dimethylformamide was stirred for 8 h, and the reaction
mixture was left overnight. The reaction mixture was
poured onto cold water. The formed precipitate was
filtered, dried, and crystallized from ethanol to give 19a.
Yield (30%), mp over 300°C. Anal. Calcd for
C21H15N6O5Cl (466): C, 54.07; H, 3.21; N, 18.02.
Found: C, 54.31; H, 3.39; N, 17.68. FTIR (KBr) (cmꢀ1):
3228, 3109 (NH), 2219 (CN), 1691, 1650 (C═O), 1604
(C═C). 1H NMR (DMSO-d6): δH (ppm) 11.52 (s, 1H,
NH, D2O exchangeable), 10.25 (s, 1H, NH, D2O
exchangeable), 8.26–6.88 (m, 8H, Ar─H), 5.64 (s, 1H,
CHCl), 5.02 (s, 1H, NCH), 3.84 (s, 3H, OCH3). MS, m/z
(%): 390 (M.+, 100%).
2-(2-(Benzo[d][1,3]dioxol-5-yl)methylene)hydrazinyl)-4-(4-
methoxyphenyl)-1,6-dihydropyrimidine-5-carbonitrile
(17c). A mixture of 3 (0.01 mol, 2.57 g) and piperonal
(0.01 mol, 1.5 g) in glacial acetic acid was heated under
reflux for 6 h. The formed precipitate was filtered, dried,
and crystallized from ethanol to give 17c.
Yield (43%), mp over 300°C. Anal. Calcd for
C20H15N5O4 (389): C, 61.69; H, 3.85; N, 17.99. Found:
C, 62.25; H, 3.51; N, 18.30. FTIR (KBr) (cmꢀ1): 3213,
3142 (NH), 2207 (CN), 1662 (C═O), 1630 (C═N), 1601
(C═C). 1H NMR (DMSO-d6): δH (ppm) 12.28 (s, 2H,
2NH, D2O exchangeable), 8.07 (s, 1H, CH═N), 8.02–
6.92 (m, 7H, Ar─H), 6.07 (s, 2H, OCH2O), 3.83 (s, 3H,
OCH3). MS, m/z (%): 389 (M.+, 100%).
7-(4-Methoxyphenyl)-3,5-dioxo-2,3-dihydro-5H-thiazolo[3,2-
a]pyrimidine-6-carbonitrile (20). A mixture of pyrimidine 1
(0.01 mol, 2.59 g) and chloroacetic acid (0.01 mol, 0.95 mL)
in DMF (30 mL) was heated under reflux for 12 h. The
reaction mixture was concentrated, was allowed to cool,
and was poured onto ice. The formed precipitate was
filtered, dried, and crystallized from ethanol to give 20.
Yield (50%), mp over 300°C. Anal. Calcd for
C14H9N3O3S (299): C, 56.18; H, 3.01; N, 14.04. Found:
C, 56.40; H, 3.41; N, 14.34. FTIR (KBr) (cmꢀ1): 2230
(CN), 1736, 1672 (C═O), 1605 (C═C). 1H NMR
(DMSO-d6): δH (ppm) 8.02–7.34 (m, 4H, Ar─H), 4.20
(s, 2H, SCH2), 3.86 (s, 3H, OCH3). MS, m/z (%): 299
(M.+, 7), (134, 100%).
2-(2-(Anthracen-1-ylmethylene)hydrazinyl)-4-(4-
methoxyphenyl)-6-oxo-1,6-dihydropyrimidine-5-carbonitrile
(17d).
A mixture of 3 (0.01 mol, 2.57 g) and
anthraldehyde (0.01 mol, 2.06 g) in butanol (3 mL) was
fused at temperature not more than 200°C. The formed
precipitate was filtered, dried, and crystallized from
ethanol to give 17d.
Yield (59%), mp 282–284°C. Anal. Calcd for
C27H19N5O2 (445): C, 72.80; H, 4.26; N, 15.73. Found:
C, 73.11; H, 4.46; N, 15.45. FTIR (KBr) (cmꢀ1): 3342,
3285 (NH), 2212 (CN), 1655 (C═O), 1633 (C═N), 1603
(C═C). 1H NMR (DMSO-d6): δH (ppm) 11.25 (s, 1H,
NH, D2O exchangeable), 10.62 (s, 1H, NH, D2O
exchangeable), 9.41 (s, 1H, CH═N), 8.71–7.04 (m, 13H,
Ar─H), 3.85 (s, 3H, OCH3). MS, m/z (%): 445 (M.+, 40).
7-(4-Methoxyphenyl)-2,5-dioxo-2,3-dihydro-5H-thiazolo[3,2-
a]pyrimidine-6-carbonitrile (21). A mixture of pyrimidine 1
(0.01 mol, 2.59 g), chloroacetyl chloride (0.01 mol,
11.2 mL) in ethanol (30 mL), and triethylamine were
heated under reflux for 12 h. The reaction mixture was
concentrated, was allowed to cool, and was poured onto
ice/HCl. The formed precipitate was filtered, dried, and
crystallized from ethanol to give 21.
4-(4-Methoxyphenyl)-2-((2-(4-nitrophenyl)-4-
oxothiazolidin-3yl)amino)-6-oxo-1,6-dihydropyrimidine-5-
carbonitrile (18a).
A
mixture of hydrazinyl 17a
Yield (43%), mp over 300°C. Anal. Calcd for
C14H9N3O3S (299): C, 56.18; H, 3.01; N, 14.04. Found:
C, 56.32; H, 3.21; N, 14.27. FTIR (KBr) (cmꢀ1): 2219
(CN), 1730, 1673 (C═O), 1604 (C═C). 1H NMR
(DMSO-d6): δH (ppm) 8.02–7.34 (m, 4H, Ar─H), 5.11
(s, 2H, CH2C═O), 3.86 (s, 3H, OCH3). MS, m/z (%): 299
(M.+, 25).
(0.01 mol, 4.61 g) and thioglycolic acid (0.01 mol,
0.92 mL) in dry toluene was heated under reflux for 20 h.
The reaction mixture was concentrated and was allowed
to cool. The formed precipitate was filtered, dried, and
crystallized from ethanol to give 18a.
Yield (69%), mp over 300°C. Anal. Calcd for
C21H16N6O5S (464): C, 54.31; H, 3.44; N, 18.10. Found:
C, 54.70; H, 3.34; N, 17.86. FTIR (KBr) (cmꢀ1): 3142,
3105 (NH), 2223 (CN), 1693, 1650 (C═O), 1619 (C═C).
1H NMR (DMSO-d6): δH (ppm) 11.32 (s, 1H, NH, D2O
exchangeable), 10.52 (s, 1H, NH, D2O exchangeable),
8.26–7.07 (m, 8H, Ar─H), 5.24 (s, 1H, CH
3-Imino-7-(4-methoxyphenyl)-5-oxo-2,5-dihydro-5H-
thiazolo[3,2-a]pyrimidine-6-carbonitrile
(22).
To-a
solution of pyrimidine 1 (0.01 mol, 2.59 g) in ethanol
(30 mL), chloroacetonitrile (0.01 mol, 0.75 mL) was
added dropwise with continuous stirring during 30 min in
the presence of drops of triethylamine, and then the
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

N. F. H. Mahmoud and E. A. Ghareeb
Vol 000
mixture was heated under reflux for 14 h. The reaction
mixture was neutralized by HCl after pouring onto
ice/water. The formed precipitate was filtered, dried, and
crystallized from ethanol to give 22.
(G-ve), C. albicans (yeast), and A. niger (fungus), were
used. Nutrient agar plates were heavily seeded uniformly
with 1 mL of 105–106 cells/mL in case of bacteria and
yeast. A Czapek–Dox agar plate seeded by the fungus
was used to evaluate the antifungal activities. Then, a
hole was made in media by gel cutter (Cork borer no.4)
in sterile condition. Then, one drop of melted agar was
poured into the hole and allowed to solidify to make a
base layer. After that, specific amount of culture filtrate
(0.1 mL) was poured into the hole. Then, plates were
kept at low temperature (4°C) for 2–4 h to allow
maximum diffusion. The plates were then incubated at
37°C for 24 h for bacteria and at 30°C for 48 h in upright
position to allow maximum growth of the organisms. The
antimicrobial activity of the test agent was determined by
measuring the diameter of zone of inhibition expressed in
millimeter (mm). The experiment was carried out more
than once, and mean of reading was recorded [24,25].
Yield (53%), mp 154–156°C. Anal. Calcd for
C14H10N4O2S (298): C, 56.37; H, 3.35; N, 18.79. Found:
C, 56.60; H, 3.15; N, 19.11. FTIR (KBr) (cmꢀ1): 3437
1
(NH), 2218 (CN), 1678 (C═O), 1601 (C═C). H NMR
(DMSO-d6): δH (ppm) 10.25 (s, 1H, NH, D2O
exchangeable), 8.02–7.34 (m, 4H, Ar─H), 3.86 (s, 3H,
OCH3), 3.66 (s, 2H, SCH2). MS, m/z (%): 298 (M.+,
100%).
4-Imino-8-(4-methoxyphenyl)-6-oxo-3,4-dihydro-2H,6H-
pyrimido[2,1-b][1,3]thiazine-7-carbonitrile (23). A mixture
of pyrimidine 1 (0.01 mol, 2.59 g) and acrylonitrile
(0.02 mol, 1.06 mL) in the presence of triethylamine was
heated under reflux in absolute ethanol. The reaction
mixture was poured onto diluted HCl. The formed
precipitate was filtered, dried, and crystallized from
ethanol to give 23.
Experimental for Antioxidant Activity. Determination of
total antioxidant capacity.
The antioxidant activity of
Yield (86%), mp 232–234°C. Anal. Calcd for
C15H12N4O2S (312): C, 57.69; H, 3.84; N, 17.94. Found:
C, 58.05; H, 3.99; N, 17.78. FTIR (KBr) (cmꢀ1): 3187
each compound was determined according to
phosphomolybdenum method using ascorbic acid as
standard. This assay is based on the reduction of Mo (VI)
to Mo (V) by the sample analyte and subsequent
formation of a green colored [phosphate = Mo (V)]
complex at acidic pH with a maximal absorption at
695 nm. In this method, 0.5 mL of each compound
(100 μg/mL) in methanol was combined in dried vials
with 5 mL of reagent solution (0.6 M sulfuric acid,
28 mM sodium phosphate, and 4 mM ammonium
molybdate). The vials containing the reaction mixture
were capped and incubated in a thermal block at 95°C for
90 min. After the samples had cooled at room
temperature, the absorbance was measured at 695 nm
against a blank. The blank consisted of all reagents and
solvents without the sample, and it was incubated under
the same conditions. All experiments were carried out in
triplicate. The antioxidant activity of the sample was
expressed as the number of AAE [26].
1
(NH), 2216 (CN), 1652 (C═O), 1601 (C═C). H NMR
(DMSO-d6): δH (ppm) 9.52 (s, 1H, NH, D2O
exchangeable), 8.00 (d, J = 6.82 Hz, 2H, Ar─H), 7.11 (d,
J = 6.82 Hz, 2H, Ar─H), 3.85 (s, 3H, OCH3), 3.51 (t,
J = 6.82 Hz, 2H, SCH2CH2), 3.03 (t, J = 6.82 Hz, 2H,
SCH2CH2). 13C NMR (DMSO-d6), δ ppm 166.30,
164.31, 162.22, 161.41, 130.70, 127.11, 120.44, 120.41,
118.92, 116.03, 113.99, 91.3, 55.47, 25.96, 17.55. MS,
m/z (%): 312 (M.+, 31), (259, 100%).
7-(4-Methoxyphenyl)-2,3,5-trioxo-2,3-dihydro-5H-thiazolo[3,2-
a]pyrimidine-6-carbonitrile (24). A solution of pyrimidine 1
(0.01 mol, 2.59 g) in (15 mL) tetrahydrofuran was stirred at
room temperature for 10 min. The solution of oxalyl chloride
(0.01 mol, 1.27 mL) in dry tetrahydrofuran (15 mL) was
added dropwise in the presence of triethylamine during
30 min with continuous stirring. After this, the mixture was
stirred for 8 h and was left overnight. The solid obtained was
filtered, dried, and crystallized from THF to give 24.
Cytotoxicity Assay. Materials and methods. Cell line
hepatocellular carcinoma (HEPG-2), mammary gland
(MCF-7), and colorectal carcinoma (HCT-116). The cell
lines were obtained from ATCC via holding company for
biological products and vaccines (VACSERA), Cairo,
Egypt.
Yield (60%), mp 251–252°C. Anal. Calcd for C14H7
N3O4S (313): C, 53.67; H, 2.23; N, 13.41. Found: C,
53.86; H, 2.43; N, 13.01. FTIR (KBr) (cmꢀ1): 2237
1
(CN), 1754, 1714, 1657 (C═O), 1604 (C═C). H NMR
Doxorubicin was used as a standard anticancer drug for
comparison. Chemical reagents: The reagents RPMI-1640
medium, MTT, and DMSO (Sigma Co., St. Louis, USA),
fetal bovine serum (GIBCO, UK).
MTT Assay. The aforementioned cell lines were used
to determine the inhibitory effects of compounds on cell
growth using the MTT assay. This colorimetric assay is
based on the conversion of the yellow tetrazolium
bromide (MTT) to a purple formazan derivative by
(DMSO-d6): δH (ppm) 7.61 (d, J = 6.82 Hz, 2H, Ar─H),
7.06 (d, J = 6.82 Hz, 2H, Ar─H), 3.80 (s, 3H, OCH3).
MS, m/z (%): 313 (M.+, 100%).
Experimental for Antimicrobial Activity. The samples
were prepared by dissolving 2 mg in 2 mL of DMSO,
and 100 μL (containing 100 μg) was used in this test.
The antimicrobial activity of different samples was
investigated by the agar cup plate method. Four different
test microbes, namely S. aureus (G+ve), P. aeruginosa
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Synthesis of Novel Substituted Tetrahydropyrimidine Derivatives and Evaluation
of Their Pharmacological and Antimicrobial Activities
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mitochondrial succinate dehydrogenase in viable cells.
Cell lines were cultured in RPMI-1640 medium with
10% fetal bovine serum. Antibiotics added were
100 units/mL penicillin and 100 μg/mL streptomycin at
37°C in a 5% Co2 incubator. The cell lines were seedes
in a 96-well plate at a density of 1.0 × 104 cells/well. at
37 C for 48 h under 5% Co2. After incubation the cells
were treated with different concentration of compounds
and incubated for 24 h. After 24 h of drug treatment,
20 μl of MTT solution at 5 mg/mL was added and
incubated for 4 h. Dimethyl sulfoxide (DMSO) in a
volume of 100 μL is added into each well to dissolve the
purple formazan formed. The colorimetric assay is
measured and recorded at absorbance of 570 nm using a
plate reader (EXL 800, USA). The relative cell viability
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CONCLUSION
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6-(4-methoxyphenyl)-4-oxo-2-thioxo-1,2,3,4-
tetrahydropyrimidine-5-carbonitrile was utilized as
building blocks to construct new polyfunctionally
substituted pyrimidine-2-thione derivatives. Some of the
products exhibited promising antimicrobial and
pharmacological activities.
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Acknowledgment. The authors would like to express their
appreciation for Ain Shams University.
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet