An Efficient Access to Pyrimidine-based Polyfunctional Heterocycles with Anticipated Antibacterial Activity

Article abstract of DOI:10.1002/jhet.3621

6-Amino-2-thioxotetrahydropyrimidine-5-carbonitrile derivative 2 was synthesized in a good yield via refluxing a mixture of arylidene 1 and thiourea in a highly basic sodium ethoxide solution. Subsequently, the synthesized pyrimidine-2-thione derivative 2 was allowed to interact with diversified nucleophiles and electrophiles under various reaction conditions in order to have a feasible access to further new and assorted fused heterocycles. Finally, the biological activity of the newly synthesized fused pyrimidines was screened in vitro against four different Gram-positive and Gram-negative bacterial strains. All the developed heterocycles were adequately characterized utilizing ¹H-NMR, ¹³C-NMR, Fourier transform infrared, elemental analysis, and electrospray ionization–mass spectrum and tested for their antibacterial activity.

Full text of DOI:10.1002/jhet.3621

Month 2019 An Efficient Access to Pyrimidine-based Polyfunctional Heterocycles with
Anticipated Antibacterial Activity
Asmaa Kamal Mourad,*
Fatehia K. Mohammed, Gamal Hassan Tammam, and Shimaa Rabie Mohammed
Department of Chemistry, Faculty of Science, Fayoum University, 63514, Fayoum, Egypt
*
E-mail: akk00@fayoum.edu.eg
Received March 30, 2019
DOI 10.1002/jhet.3621
Published online 00 Month 2019 in Wiley Online Library (wileyonlinelibrary.com).
6
-Amino-2-thioxotetrahydropyrimidine-5-carbonitrile derivative 2 was synthesized in a good yield via
refluxing a mixture of arylidene 1 and thiourea in a highly basic sodium ethoxide solution. Subsequently,
the synthesized pyrimidine-2-thione derivative 2 was allowed to interact with diversified nucleophiles and
electrophiles under various reaction conditions in order to have a feasible access to further new and
assorted fused heterocycles. Finally, the biological activity of the newly synthesized fused pyrimidines
was screened in vitro against four different Gram-positive and Gram-negative bacterial strains. All the
1
13
developed heterocycles were adequately characterized utilizing H-NMR, C-NMR, Fourier transform
infrared, elemental analysis, and electrospray ionization–mass spectrum and tested for their antibacterial
activity.
J. Heterocyclic Chem., 00, 00 (2019).
INTRODUCTION
Fused pyrimidine heterocycles have attracted
RESULTS AND DISCUSSION
a
In continuation of our ongoing endeavors to develop
novel heterocyclic fused pyrimidine derivatives [25],
arylidene 1 was obtained via Knoevenagel condensation
reaction according to the reported procedure [26].
Subsequently, a cyclization reaction took place, and 6-
amino-4-(benzo[d][1,3]dioxol-5-yl)-2-thioxo-1,2,3,4-tetra
hydropyrimidine-5-carbonitrile (2) was produced, when a
mixture of arylidene 1 and thiourea was refluxed in
presence of strongly alkaline sodium ethoxide solution
(Scheme 1).
sizeable attention over the last decades because of their
versatile pharmacological and therapeutic merits [1,2].
Accordingly, pyrimidine and their sulfur analogues have
been recognized to act as analgesics [3,4] and to have
an immense array of biological activities [5,6] like
antifungal [7], antiviral [8], antibacterial [9–12], anti-
inflammatory [13,14], antioxidant [15], anticancer [16],
and antihypertensive [17]. Interestingly, pyrimidines are
not only revealing a profound antitumor activity [18]
but also acting as unique HIV reverse transcriptase
inhibitors [19,20]. Moreover, many pyrimidine
The structure of tetrahydropyrimidine derivative 2 was
asserted from the obtained spectral and analytical data,
which were compatible with the expected structure 2 in
derivatives
are
considered
to
be
antibiotics,
1
anticonvulsant, and calcium channel blockers [21–24].
Clearly, pyrimidines owe their therapeutic applications
to the fact that pyrimidine base is existing in uracil,
thymine, and cytosine, which are crucial building units
of the two essential nucleic acids, deoxyribonucleic
acid, and ribonucleic acid.
which H-NMR spectrum of 2 revealed single signals
at δ 4.92 corresponding to pyrimidinethione-4H proton,
6.10 due to the resonance of NH2 protons, and 9.48
and 9.70 ppm proving the existence of 2NH groups. In
addition, the molecular ion peak of 2 was detected at
m/z = 274.
©
2019 Wiley Periodicals, Inc.

A. K. Mourad, F. K. Mohammed, G. H. Tammam, and S. R. Mohammed
Vol 000
Scheme 1. Synthesis of pyrimidinethione derivative 2.
Driven by the high functionality of compound 2, the
effect of nitrogen nucleophiles, acidic medium, and other
electrophiles was studied. For instance, refluxing a
derivative 2 with acetaldehyde and malononitrile in
absolute ethanol contains few drops of piperidine gave an
access to isoquinoline derivative 5 (Scheme 2). Infrared
(IR) spectrum of 5 displayed a new absorption band at
mixture of tetrahydropyrimidine derivative
2
and
À1
formamide for 18 h furnished 5-amino-4-(benzo[d][1,3]
dioxol-5-yl)-3,4-dihydropyrimido[4,5-d]pyrimidine-
1680 cm indicating the introduction of a new carbonyl
group. Also, mass spectrum showed an ion peak at m/
+
2(1H)-thione (3) (Scheme 2).
z = 416 equivalent to (M ). Alternatively, quinoline
Interestingly, 7-thioxo-tetrahydropyrimido[4,5-d]pyrimi
derivative 6 was attainable through the condensation of
pyrimidine-2-thione derivative 2 with cyclohexanone in
the presence of Lewis acid (Scheme 2). However,
refluxing compound 2 with phenylisothiocyanate in
pyridine for 12 h gave rise to 1-(6-(benzo[d][1,3]dioxol-5-
yl)-5-cyano-2-thioxo-1,2,3,6-tetrahydropyrimidin-4-yl)-3-
phenylthiourea (7) (Scheme 2). IR spectrum of 7 revealed
dinone derivative 4a was expected to be the sole product
of refluxing tetrahydropyrimidine derivative 2 with formic
acid, but in a stark contrast to the proposed structure,
-(benzo[d][1,3]dioxol-5-yl)-2-thioxotetrahydropyrimidin-
(1H)-one (4) was obtained instead of 4a, which was in a
6
4
total agreement with the product reported by Madkour
À1
et al (Scheme 2) [27]. Also, examination of the reaction
a strong absorption at 2207 cm implying that 7 still has
1
product spectral data excluded compound 4a as H-NMR
the nitrile moiety and no cyclization reaction took place.
Subsequent cyclization was successfully achieved,
and compound 8 was furnished when the isolated
spectrum exhibited the disappearance of amino group
signal and the appearance of doublet of doublet signals
at δ 2.69 and 2.90 ppm attributed to methylene protons
of 2-thioxotetrahydropyrimidin-4(1H)-one derivative 4.
Furthermore, condensation of tetrahydropyrimidine
intermediate
extra 12 h in pyridine (Scheme 2). IR spectrum of
pyrimidopyrimidinone derivative showed
7
was heated under reflux for
8
a
Scheme 2. Reactions of tetrahydropyrimidine derivative 2.
Journal of Heterocyclic Chemistry
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Month 2019
Heterocycles based on Pyrimidine Moiety: Synthesis and Antimicrobial Evaluation
characteristic band of a new cyclic amide carbonyl group at
Noteworthy, a cyclization reaction took place, and 1,3-
diacetyl-2-thioxo-tetrahydropyrido[2,3-d]pyrimidin-7-yl a
cetate derivative 15 was furnished when tetrahydro
pyrimidine derivative 2 was refluxed with a mixture of
acetic anhydride and concentrated phosphoric acid
(Scheme 3). Later, compound 15 was fused with an
aromatic aldehyde, namely, vanillin, in presence of drops
of piperidine to afford the corresponding Schiff’s base 16
(Scheme 3). Spectroscopic data confirmed the formation
of 15 and 16 as IR spectrum of 15 displayed the absence
of the nitrile absorption frequency and the appearance of
À1
1664 cm while no absorption was observed for the nitrile
group.
with malononitrile in dimethylformamide and few drops
of piperidine for 12 furnished 2-thioxo-tetrahy
Furthermore,
refluxing
compound
2
h
dropyrido[2,3-d]pyrimidine derivative 9 (Scheme 2).
1
Inspection of H-NMR spectrum indicated the existence of
two amino groups at δ 6.22 and 4.65 ppm while mass
spectrum of pyridopyrimidine derivative 9 exhibited a
+
molecular ion peak at m/z = 340 equivalent to (M ).
In the same context, more fused pyrimidine
heterocyclic systems were accessible through the reaction
of 2 with an equimolar amount of urea or thiourea in
sodium ethoxide solution, and 4-amino-5-(benzo[d][1,3]
dioxol-5-yl)-7-thioxo-5,6,7,8-tetrahydropyrimido[4,5-d]py
rimidin-2(1H)-one (10a) or 5-amino-4-(benzo[d][1,3]dio
xol-5-yl)-3,4-dihydropyrimido[4,5-d]pyrimidine-2,7(1H,
À1
two new absorptions at 1713 and 1659 cm indicating
the introduction of new ester and amide carbonyl groups,
respectively, whereas IR spectrum of 16 showed no
absorption frequency in amino group region but a broad
À1
absorption band at 3435 cm
hydroxyl group was detected.
corresponding to new
8
H)-dithione (10b) was produced, respectively (Scheme 2).
Also, N-acetylation reaction was observed, and the
imidate derivative 17 was formed when pyrimidinethione
The structure of 10a was substantiated on the basis of its
spectroscopic data; for example, the IR spectrum was
devoid of any absorption bands for the nitrile but exhibited
an intense absorption at 1697 cm corresponding to a
new cyclic amide carbonyl group. Also, the molecular ion
derivative
2 was allowed to react with triethyl
orthoformate in acetic anhydride (Scheme 3).
Interestingly, conducting the aforementioned reaction of 2
with triethyl orthoformate in refluxing ethanol instead of
acetic anhydride submitted 2-thioxotetrahydropyrimidin-
À1
+
peak (M ) of 10a was observed at m/z = 317. Likewise, IR
spectrum of 10b showed the disappearance of the nitrile
1
4-ylformimidate derivative 18 (Scheme 3). H-NMR data
absorption, and the mass spectrum revealed the molecular
ion peak (M ) at m/z = 333.
Acid catalyzed hydrolysis of the nitrile group in
of 18 showed the characteristic triplet–quartet splitting
pattern of the ethoxy group at δ 1.19 and 3.33 ppm; it
also showed a characteristic band at δ 7.08 ppm for
imidate (–N═CHOR) group. Furthermore, the structure of
the later compound 18 was established chemically when
a subsequent cyclization reaction took place via refluxing
it with hydrazine hydrate in ethanol to furnish
tetrahydropyrimido[4,5-d]pyrimidine-2-thione derivative
19 (Scheme 3).
+
pyrimidine-2-thione
2
into amide group afforded
compound 11, which was subjected to subsequent
cyclization to produce 2,7-dithioxo-hexahydropyrimido
[4,5-d]pyrimidin-4(1H)-one derivative 12 (Scheme 3). IR
spectrum of 11 showed no absorption for the nitrile, but a
À1
characteristic absorption band at 1674 cm
was
observed indicating the formation of a new amide
carbonyl. Also, the structure of compound 11 was proven
chemically via its cyclization in basic medium to
pyrimidopyrimidine derivative 12 (Scheme 3).
A different approach for substituted pyrazolopyrimidine
derivative 20 formation was adopted through refluxing of
pyrimidinethione derivative
2
with hydroxylamine
hydrochloride in acetic acid containing catalytic amount
of anhydrous sodium acetate (Scheme 4).
In addition, N-acetylation of NH and NH groups took
2
place when pyrimidine-2-thione derivative 2 was treated
with acetyl chloride in dry dioxane and N-(1,3-diacetyl-6-
An additional pathway for building up polyfunctionally
fused pyrimidine was achieved via the treatment of
2 with an equimolar amount of diethyl malonate or
ethyl cyanoacetate in refluxing glacial acetic acid
to afford ethyl 5-amino-4-(benzo[d][1,3]dioxol-5-yl)-7-
oxo-2-thioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidi
ne-6-carboxylate (21a) or 5-amino-4-(benzo[d][1,3]dioxol-
5-yl)-7-oxo-2-thioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]
pyrimidine-6-carbonitrile (21b), respectively (Scheme 4).
IR spectrum of 21a revealed the disappearance of the
nitrile group absorption frequency and the appearance of
(
benzo[d][1,3]dioxol-5-yl)-5-cyano-2-thioxo-1,2,3,6-tetra
hydropyrimidin-4-yl)acetamide (13) was formed
Scheme 3). IR spectrum of compound 13 exhibited a
(
À1
characteristic peak at 1692 cm corresponding to amide
carbonyl group. Another piece of evidence for the
proposed structure 13 was gained from H-NMR data,
1
which exhibited three singlet signals at δ 2.33, 2.46, and
2.50 ppm, all were integrated for three protons implying
the existence of three methyl groups. Similarly, treatment
of compound 2 with chloroacetyl chloride in dry dioxane
afforded N-(6-(benzo[d][1,3]dioxol-5-yl)-1,3-bis(2-chloro
acetyl)-5-cyano-2-thioxo-1,2,3,6-tetrahydropyrimidin-4-
yl)-2-chloroacetamide (14) (Scheme 3).
À1
two new absorptions at 1733 and 1669 cm indicating
the presence of ester and cyclic amide carbonyl groups,
respectively. An additional evidence for the suggested
1
structure of 21a was acquired from H-NMR data, which
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

A. K. Mourad, F. K. Mohammed, G. H. Tammam, and S. R. Mohammed
Vol 000
Scheme 3. Reactions of tetrahydropyrimidine derivative 2.
Scheme 4. Reactions of tetrahydropyrimidine derivative 2.
showed the distinctive triplet–quartet splitting pattern of
the ethyl group at δ 1.87 and 4.35 ppm, it also showed
characteristic peaks at δ 6.10, 9.96, 10.11, and 10.43 ppm
of compound 21b. Schiff’s bases 22a and 22b
were attainable through the fusion of compound
2 with an aromatic aldehyde, namely, vanillin or p-
nitrobenzaldehyde, and few drops of piperidine
(Scheme 4). Mass spectrum of 22a revealed the
molecular ion peak at m/z = 408; however, the molecular
confirming the existence of NH and three NH groups,
2
respectively. Similarly, spectral data and elemental
analysis were agreeable with the proposed structure
Journal of Heterocyclic Chemistry
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Month 2019
Heterocycles based on Pyrimidine Moiety: Synthesis and Antimicrobial Evaluation
ion peak of 22b was detected at m/z = 407, and it was
m/z = 400. Interestingly, reaction of pyrimidine-2-thione
derivative 2 with dimethyl acetylenedicarboxylate in
refluxing ethanol furnished 4,6-dihydropyrimido[2,1-b]
[1,3]thiazine-2-carboxylate derivative 24 rather than 4,8-
dihydropyrimido[2,1-b][1,3]thiazine-2-carboxylate
equivalent to molecular formula C H N O S.
1
9 13 5 4
In our attempts to synthesize more fused heterocyclic
systems, a new approach to construct a pyrrole ring fused
to pyrimidine moiety of pyrimidine-2-thione derivative 2
was embrace on the basis of the alkylation of 2 with α-
halo acetic acid derivative, namely, ethyl bromoacetate,
followed by the cyclization of the alkylated product in
basic medium. As pyrimidine-2-thione derivative 2
derivative 24a (Scheme 4). In addition to IR spectrum of
24 that showed new ester and cyclic amide carbonyl
absorption bands, another piece of evidence for the
1
proposed structure of 24 was acquired from H-NMR
contains NH and SH groups, they were both liable to
data, which exhibited a singlet signal at δ 3.74 ppm
equivalent to the three protons of methyl group and
revealed another peak at δ 6.82 ppm characteristic of
thiazine moiety proton. Finally, mass spectrum of 24
2
alkylation using the utilized conditions. The isolated
product revealed that both S- and N-alkylation took place
and ethyl-3-oxo-tetrahydropyrrolo[2,3-d]thiazolo[3,2-a]
pyrimidine-7-carboxylate derivative 23 was furnished
+
showed the molecular ion peak (M ) at m/z = 384.
(Scheme 4). IR spectrum of 23 revealed no absorption
frequency for the nitrile group, but two new absorption
À1
frequencies at 1733 and 1678 cm
corresponding to
ANTIMICROBIAL ACTIVITIES
ester and cyclic amide carbonyl groups were observed.
An additional proof for the proposed structure of 23 was
obtained from H-NMR data, which showed a triplet–
Antibiotics bearing pyrimidine moiety are of utmost
importance because of their potent inhibition effect of
dihydrofolate reductase enzyme, a crucial enzyme for
bacterial deoxyribonucleic acid assembly [28]. The in
vitro antimicrobial properties of the investigated
compounds were assessed against Bacillus subtilis
1
quartet splitting pattern for the ethoxy group at δ 1.46
and 4.88 ppm. Also, it showed a new peak at δ 3.78 ppm
confirming the existence of methylene group while mass
+
spectrum of 23 exhibited the molecular ion peak (M ) at
Table 1
In vitro antimicrobial activity of the synthesized compounds.
Gram-positive bacteria
Gram-negative bacteria
Pseudomonas aeruginosa Escherichia coli
IZ %Activity index
Bacillus subtilis
IZ %Activity index
Staphylococcus enteritis
Entry
Compound
IZ
%Activity index
IZ
%Activity index
1
2
3
4
5
6
7
8
9
2
3
4
5
6
8
9
10a
10b
11
12
13
14
15
16
17
18
19
20
21a
21b
22a
22b
23
7
6
5
NA
12
NA
5
5
6
NA
5
7
11
NA
NA
6
6
6
5
7
116.6
100
83.3
—
200
—
83.3
83.3
100
—
83.3
116.6
183.3
—
8
NA
5
7
3
NA
5
4
12
NA
NA
4
8
NA
8
8
10
4
NA
NA
4
NA
NA
12
11
7.5
106.6
—
66.6
93.3
40.0
—
66.6
53.3
160
—
9
9
9
3
4
8
112.5
112.5
112.5
37.5
50
100
—
—
50
—
—
112.5
50
—
100
—
—
100
—
37.5
—
112.5
—
50
—
6
6
6
6
6
7
NA
3
NA
NA
NA
3
100
100
100
100
100
116.6
—
50
—
—
—
NA
NA
4
NA
NA
9
4
NA
8
NA
NA
8
NA
3
NA
9
NA
4
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
—
53.3
106.6
—
106.6
106.6
133.3
53.3
—
50
50
3
7
116.6
200
200
116.6
—
—
—
83.3
—
—
—
12
12
7
NA
NA
NA
5
NA
NA
6
100
100
100
83.3
116.6
116.6
183.3
—
—
53.3
—
7
11
NA
6
6
6
—
100
100
100
160
146.6
100
100
83.3
100
24
NA
8
5
6
Norfloxacin
100
IZ, inhibition diameter zones expressed in millimeters (mm); NA, no observed antimicrobial activity.
Journal of Heterocyclic Chemistry
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A. K. Mourad, F. K. Mohammed, G. H. Tammam, and S. R. Mohammed
Vol 000
and Staphylococcus enteritis as representative examples
of Gram-positive bacteria and Pseudomonas aeruginosa
and Escherichia coli as representative examples
of Gram-negative bacteria. Antibiotic norfloxacin was
utilized as control criterion. Antimicrobial activity was
recorded as inhibition diameter zones in millimeters
Cairo University). IR (KBr) spectra were recorded on a
Pye-Unicam IR spectrophotometer sp 2000 (Faculty of
Science, Fayoum University), the mass spectra were run
by a Shimadzu-GC-MS-GP 1000 EX using the direct
inlet system, and nuclear magnetic resonance spectra
were recorded on Varian Mercury 300 MHz spectrometer
using tetramethylsilane as internal standard; chemical
shifts are recorded in δ units (National Center Researcher).
(mm) of investigated compounds against the patholo
gical strains (Table 1).
The compounds under investigation exhibited variation
in their antibacterial activities (Table 1). Among the
synthesized heterocycles, only pyrimidine-2-thione
derivative 2 showed robust activity against all tested
Gram-positive and Gram-negative bacteria (Table 1;
entry 1). Contrarily, 11 and 22b were biologically
inactive against the four tested bacterial strains (Table 1;
entries 10 and 23, respectively). Compounds 10a, 17, 18,
Synthesis of 2-(benzo[d][1,3]dioxol-5-ylmethylene)malono
nitrile (1).
A mixture of piperonal (0.01 mol) and malononitrile
(0.01 mol) in absolute ethanol with few drops of
piperidine was refluxed for 2 h then allowed to cool
down at room temperature; the product was filtered off,
dried, and recrystallized from ethanol as yellow crystals
À1
[
26]. Yield (1.86 g, 94%), mp 188°C; IR (KBr, cm ):
21b, and 24 exhibited moderate to excellent activities
3
097 (CH aromatic), 2926 (CH aliphatic), 2224 (C≡N).
against both Gram-positive and Gram-negative bacteria
except for P. aeruginosa (Table 1; entries 8, 16, 17, 21,
Anal. Calcd for C H N O : C: 66.66, H: 3.03, N: 14.14.
11 6 2 2
Found C: 66.83, H: 3.12, N: 14.01.
and 25, respectively). Furthermore, compound
9
displayed no antibacterial activity against Gram-negative
bacteria while compound 15 exhibited no effect against
Gram-positive bacteria (Table 1; entries 7 and 14,
respectively). However, compound 8 expressed excellent
effect against Gram-negative bacteria only (Table 1;
entry 6). Finally, compounds 12 and 20 were found to be
active only against B. subtilis with the exact activity
index percentage (Table 1; entries 11 and 19, respectively).
Synthesis of 6-amino-4-(benzo[d][1,3]dioxol-5-yl)-2-thioxo-
,2,3,4-tetrahydropyrimidine-5-carbonitrile (2).
A mixture of equimolar amounts of compound 1
1.98 g, 0.01 mol) and thiourea (0.76 g, 0.01 mol) in
sodium ethoxide solution, 0.23 g of sodium metal in
5 mL absolute ethanol, was refluxed for 4 h; the
reaction mixture was cooled down then poured
into crushed ice and neutralized with hydrochloric acid
1
(
2
(2N, 3 mL); the product was filtered off, dried, and
recrystallized from ethanol as yellow crystals. Yield
CONCLUSION
À1
(2.44 g, 89%), mp 209–210°C; IR (KBr, cm ): 3444,
3
303, 3104 (NH , 2NH), 3032 (CH aromatic), 2920
2
In conclusion, arylidene 1 was exploited as a precursor
to synthesize pyrimidine-2-thione derivative 2.
Subsequently, compound 2 was utilized as a valuable
building scaffold to construct novel and diverse
heterocycles bearing pyrimidinethione moiety. Fused
pyrimidine, pyridine, isoquinoline, quinoline, pyrazole,
and thiazine rings were accessible through simple and
straightforward reactions. Finally, the preliminary in vitro
antimicrobial activity of synthesized compounds was
screened.
(
CH aliphatic), 2211 (C≡N), 1627 (C═N), 1257 (C═S);
1
H-NMR (DMSO-d , 300 MHz, ppm) δ: 4.92 (s, 1H,
6
pyrimidinethione-4H), 5.98 (s, 2H, 1,3-dioxole-
CH ), 6.10 (s, 2H, NH ), 6.66–6.89 (m, 3H, Ar–H),
9
2
2
13
.48 (s, 1H, NH), 9.70 (s, 1H, NH);
C NMR
(DMSO-d , 100 MHz, ppm) δ: 50.4, 58.7, 103.1,
6
1
1
2
5
06.6, 108.2, 113.5, 119.4, 132.3, 136.5, 143.2,
+
46.1, 175.3; MS (70 eV) m/z (%): 274 (M , 6.65),
+
72 (M -2, 100). Anal. Calcd for C H N O S: C:
1
2 10 4 2
2.55, H: 3.64, N: 20.43, S: 11.67. Found: C: 52.03,
H: 3.22, N: 20.60, S: 12.04.
EXPERIMENTAL
Synthesis of 5-amino-4-(benzo[d][1,3]dioxol-5-yl)-3,4-dihy
dropyrimido[4,5-d] pyrimidine-2(1H)-thione (3).
Melting points were determined by an electrothermal
melting point apparatus (GALLENKAMP) and are
uncorrected. All the reactions were followed up by the
thin-layer chromatography technique with fluorescent
silica gel plates HF245 (Merck), and plates were viewed
with iodine. Silica gel (230–400 mesh) was used for flash
chromatography separations. Elemental analysis was
carried out by microanalytical unit (Faculty of Science,
A mixture of compound 2 (2.74 g, 0.01 mol) and
formamide (30 mL) was heated under reflux for 18 h,
cooled down, and poured into crushed ice, and then the
product was filtered off, dried, and recrystallized from
benzene as yellow crystals. Yield (1.76 g, 58%),
À1
mp 197–198°C; IR (KBr, cm ): 3293, 3213, 3132
(NH , 2NH), 3068 (CH aromatic), 2961 (CH aliphatic),
2
1
1601 (C═N), 1206 (C═S);
H NMR (DMSO-d6,
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Month 2019
Heterocycles based on Pyrimidine Moiety: Synthesis and Antimicrobial Evaluation
3
5
7
00 MHz, ppm) δ: 5.25 (s, 1H, pyrimidinethione-4H),
Synthesis of 5-amino-4-(benzo[d][1,3]dioxol-5-yl)-3,4,6,7,8,
-hexahydropyrimido[4,5-b]quinoline-2(1H)-thione (6).
A mixture of compound 2 (2.74 g, 0.01 mol),
cyclohexanone (5 mL, excess), and anhydrous zinc
chloride (1.0 g, 0.005 mol) was fused together under dry
conditions for 10 h. The reaction was left to cool down,
triturated with ethanol, and diluted with water; the
precipitated product was collected by filtration, dried, and
9
.93 (s, 2H, 1,3-dioxole-CH ), 6.32 (s, 2H, NH ), 6.72–
2
2
.11 (m, 3H, Ar–H), 7.86 (s, 1H, CH═N), 9.34 (s, 1H,
1
3
NH), 9.56 (s, 1H, NH); C NMR (DMSO-d , 100 MHz,
ppm) δ: 49.6, 90.1, 102.9, 107.7, 109.3, 120.4, 131.8,
6
143.2, 146.1, 149.6, 151.3, 158.3, 175.1; MS (70 eV) m/z
+
+
(%): 302 (M +1, 0.35), 301 (M , 0.08), 284 (100). Anal.
Calcd for C H N O S: C: 51.82, H: 3.65, N: 23.25, S:
13 11 5 2
recrystallized from benzene as brown crystals. Yield
1
0.63. Found C: 51.31, H: 3.47, N: 23.51, S: 10.71.
À1
(2.05 g, 58%), mp 231–232°C; IR (KBr, cm ): 3436,
Synthesis of 6-(benzo[d][1,3]dioxol-5-yl)-2-thioxotetrahy
3
369, 3260 (NH , 2NH), 3045 (CH aromatic), 2920 (CH
2
dropyrimidin-4(1H)-one (4).
1
aliphatic), 1616 (C═N), 1221 (C═S); H NMR (DMSO-
d , 300 MHz, ppm) δ: 1.78 (m, 4H, CH CH CH CH ),
A mixture of compound 2 (2.74 g, 0.01 mol) and formic
acid (40 mL) was refluxed for 24 h, left to cool, and then
the crude precipitated product was collected by filtration,
dried, and recrystallized from ethanol as white crystals.
6
2
2
2
2
2
.67 (m, 2H, hydroquinoline-CH ), 3.04 (m, 2H,
2
hydroquinoline-CH ), 5.34 (s, 1H, pyrimidinethione-4H),
2
5
6
.92 (s, 2H, 1,3-dioxole-CH ), 6.25 (s, 2H, NH ), 6.75–
2 2
À1
Yield (1.73 g, 69%), mp 270°C; IR (KBr, cm ): 3161,
.88 (m, 3H, ArH), 9.31 (s, 1H, NH), 9.59 (s, 1H, NH);
3
1
3
113 (2NH), 3050 (CH aromatic), 2958 (CH aliphatic),
696 (C═O), 1241 (C═S); H-NMR (DMSO-d6,
00 MHz, ppm) δ: 2.69 (dd, 1H, J = 7.0 and 7.9 Hz,
13
C NMR (DMSO-d , 100 MHz, ppm) δ: 23.3, 24.5,
6
1
2
1
8.9, 32.1, 49.2, 90.1, 102.0, 107.8, 108.4, 109.3, 120.3,
35.4, 145.1, 146.8, 147.1, 150.2, 155.1, 174.6; MS
pyrimidinethione-5H), 2.90 (dd, 1H, J = 7.9 and 8.1 Hz,
pyrimidinethione-5H), 4.68 (m, 1H, pyrimidinethione-
+
(70 eV) m/z (%): 355 (M +1, 6.59), 207 (100). Anal.
Calcd for C H N O S: C: 61.01, H: 5.08, N: 15.81, S:
18 18 4 2
4H), 5.98 (s, 2H, 1,3-dioxole-CH ), 6.82–6.88 (m, 3H,
2
9
.03. Found C: 61.43, H: 5.28, N: 15.62, S: 9.12.
1
3
Ar–H), 9.96 (s, 1H, NH), 11.09 (s, 1H, NH); C NMR
DMSO-d , 100 MHz, ppm) δ: 40.1, 56.5, 102.2, 107.5,
(
Synthesis of 1-(6-(benzo[d][1,3]dioxol-5-yl)-5-cyano-2-thio
6
1
09.4, 119.8, 136.5, 144.9, 146.8, 165.7, 174.5; MS
xo-1,2,3,6-tetrahydropyrimidin-4-yl)-3-phenylthiourea (7).
A mixture of compound 2 (2.74 g, 0.01 mol) and
phenylisothiocyanate (1.2 mL, 0.01 mol) in pyridine
(10 mL) was fused together for 12 h. The reaction
mixture was cooled down and triturated with ethanol; the
product was filtered off, dried, and recrystallized from
+
(70 eV) m/z (%): 250 (M , 100). Anal. Calcd for
C H N O S: C: 52.81, H: 4.07, N: 11.25, S: 12.80.
Found C: 52.41, H: 4.32, N: 11.08, S: 12.53.
1
1 10 2 3
Synthesis of 9-amino-1-(benzo[d][1,3]dioxol-5-yl)-7-oxo-3-
thioxo-1,2,3,4,6a,7-hexahydropyrimido[4,5-c]isoquinoline-8,
ethanol as brown crystals. Yield (1.88 g, 46%), mp
1
0-dicarbonitrile (5).
À1
>
360°C; IR (KBr, cm ): 3319, 3214 (4NH), 3065 (CH
A solution of acetaldehyde (0.01 mol) and malononitrile
aromatic), 2918 (CH aliphatic), 2207 (C≡N), 1622
(0.02 mol) in absolute ethanol (20 mL) was added to a
1
(
C═N), 1243 (C═S); H NMR (DMSO-d , 300 MHz,
6
suspension of compound 2 (2.74 g, 0.01 mol) in absolute
ethanol and drops of piperidine; the reaction mixture was
heated under reflux for 4 h, left to cool, and then the
solid product that precipitated was filtered off, dried, and
ppm) δ: 5.39 (s, 1H, pyrimidinethione-6H), 5.90 (s, 2H,
,3-dioxole-CH ), 6.98–7.39 (m, 3H, ArH), 7.14 (m, 1H,
1
2
ArH), 7.26 (m, 2H, ArH), 7.34 (m, 2H, ArH), 7.87 (s,
1
1
7
1
1
H, NH), 8.03 (s, 1H, NH), 8.76 (s, 1H, NH), 9.80 (s,
recrystallized from dioxane as pale brown crystals. Yield
13
H, NH); C NMR (DMSO-d , 100 MHz, ppm) δ: 58.6,
À1
6
(2.30 g, 55%), mp 292°C; IR (KBr, cm ): 3447, 3340,
2.1, 102.3, 108.7, 109.3, 118.4, 120.3, 121.4, 124.6,
28.1, 128.4, 135.2, 139.1, 144.8, 146.2, 147.5, 174.1,
75.0. Anal. Calcd for C H N O S : C: 55.74, H: 3.66,
3
236 (NH , 2NH), 3030 (CH aromatic), 2943 (CH
2
aliphatic), 2213 (C≡N), 1680 (C═O, cyclic amide), 1644
1
19 15 5 2 2
(C═N), 1250 (C═S); H NMR (DMSO-d , 300 MHz,
6
N: 17.11, S: 15.64. Found C: 55.38, H: 3.57, N: 17.28,
S: 15.86.
ppm) δ: 4.89 (d, 1H, J = 7.0 Hz, isoquinoline-CH), 5.32
s, 1H, pyrimidinethione-1H), 5.90 (s, 2H, 1,3-dioxole-
CH ), 6.22 (s, 2H, NH ), 6.72–6.89 (m, 3H, ArH), 7.85
(
2
2
Synthesis of 5-(benzo[d][1,3]dioxol-5-yl)-3-phenyl-2,7-
dithioxo-2,3,5,6,7,8-hexahydropyrimido[4,5-d]pyrimidin-4
(1H)-one (8).
(d, J = 7.0 Hz, 1H, isoquinoline-CH), 9.48 (s, 1H, NH),
1
3
9.65 (s, 1H, NH); C NMR (DMSO-d , 100 MHz, ppm)
6
δ: 58.2, 71.7, 82.6, 102.3, 108.0, 109.2, 111.8, 112.7,
A solution of 7 (4.09 g, 0.01 mol) in absolute pyridine
was refluxed for 12 h, and then the reaction mixture was
cooled down and poured on ice-cold water acidified with
hydrochloric acid. The solid precipitate was filtered off,
dried, and recrystallized from dioxane as brown crystals.
1
1
4
19.6, 120.3, 135.4, 139.8, 140.3, 145.0, 146.6, 150.6,
70.3, 175.2, 181.1; MS (70 eV) m/z (%):
+
16 (M , 5.92), 271 (100). Anal. Calcd for
C H N O S: C: 57.69, H: 2.88, N: 20.19, S: 7.69.
2
0 12 6 3
À1
Found C: 57.81, H: 2.93, N: 20.02, S: 7.52.
Yield (2.45 g, 60%), mp 285°C; IR (KBr, cm ): 3245,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

A. K. Mourad, F. K. Mohammed, G. H. Tammam, and S. R. Mohammed
Vol 000
3
1
129 (3NH), 3030 (CH aromatic), 2961 (CH aliphatic),
664 (C═O, cyclic amide), 1266 (C═S); H NMR
146.8, 151.3, 157.4, 162.1, 176.3; MS (70 eV) m/z (%):
317 (M , 1.15), 315 (M -2, 2.63), 207 (100). Anal. Calcd
1
+
+
(
DMSO-d6, 300 MHz, ppm) δ: 5.34 (s, 1H,
pyrimidinethione-5H), 5.96 (s, 2H, 1,3-dioxole-CH2),
.78–6.97 (m, 3H, ArH), 7.12 (m, 1H, ArH), 7.24
m, 2H, ArH), 7.38 (m, 2H, ArH), 8.22 (s, 1H, NH), 8.56
for C H N O S: C: 49.21, H: 3.47, N: 22.08, S: 10.09.
Found C: 49.62, H: 3.38, N: 22.16, S: 10.13.
13
11 5 3
6
Synthesis of 5-amino-4-(benzo[d][1,3]dioxol-5-yl)-3,4-
dihydropyrimido[4,5-d] pyrimidine-2,7(1H,8H)dithione (10b).
(
(
1
3
s, 1H, NH), 9.08 (s, 1H, NH); C NMR (DMSO-d6,
A mixture of equimolar amounts of compound 2 (2.74 g,
0.01 mol) and thiourea (0.76 g, 0.01 mol) in sodium
ethoxide solution, 0.23 g of sodium metal in 20 mL
absolute ethanol, was refluxed for 12 h. The reaction
mixture was poured into crushed ice and neutralized with
hydrochloric acid (10 mL, 6N). The formed precipitate
was collected by filtration, dried, and recrystallized from
1
1
1
00 MHz, ppm) δ: 57.6, 92.2, 102.7, 108.1, 109.5, 120.4,
27.5, 128.1, 128.4, 129.1, 135.0, 138.5, 145.3, 146.1,
50.7, 155.1, 170.9, 174.6; MS (70 eV) m/z (%): 410
+
(M , 6.70), 85 (100). Anal. Calcd for C H N O S :
1
9 14 4 3 2
C: 55.60, H: 3.41, N: 13.65, S: 15.60. Found C: 55.31,
H: 3.63, N: 13.82, S: 15.42.
ethanol as yellow crystals. Yield (1.74 g, 52%), mp
Synthesis of 5,7-diamino-4-(benzo[d][1,3]dioxol-5-yl)-2-thio
xo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidine-6-carbonitrile
À1
2
63°C; IR (KBr, cm ): 3300, 3198 (NH , 3NH), 3043
2
(
(
(
CH aromatic), 2949 (CH aliphatic), 1645 (C═N), 1251
(9).
1
C═S); H NMR (DMSO-d , 300 MHz, ppm) δ: 5.53
6
A mixture of compound 2 (2.74 g, 0.01 mol),
s, 1H, pyrimidinethione-5H), 5.88 (s, 2H, 1,3-dioxole-
malononitrile (0.66 g, 0.01 mol) in DMF (40 mL), and
few drops of piperidine was refluxed for 12 h, and the
reaction mixture was allowed to cool to room temperature
and then poured over crushed ice. The precipitate was
collected by filtration, dried, and recrystallized from
CH ), 6.20 (s, 2H, NH ), 6.88–7.03 (m, 3H, ArH), 8.55
2
2
13
(
s, 1H, NH), 9.13(s, 1H, NH), 9.49 (s, 1H, NH);
C
NMR (DMSO-d , 100 MHz, ppm) δ: 58.5, 102.5, 108.7,
6
1
1
09.6, 108.3, 120.6, 134.8, 145.2, 146.4, 156.9, 161.7,
74.2, 176.4; MS (70 eV) m/z (%): 333 (M , 0.34), 216
+
toluene as dark red crystals. Yield (2.30 g, 68%), mp
À1
(100). Anal. Calcd for C13H N O S : C: 46.84, H: 3.30,
11 5 2 2
2
3
1
3
5
52°C; IR (KBr, cm ): 3444, 3353, 3214 (2NH , 2NH),
2
N: 21.02, S: 19.21. Found C: 46.71, H: 3.62, N: 21.37,
S: 19.11.
007 (CH aromatic), 2918 (CH aliphatic), 2200 (C≡N),
630 (C═N), 1246 (C═S); H NMR (DMSO-d6,
00 MHz, ppm) δ: 5.42 (s, 1H, pyrimidinethione-4H),
.98 (s, 2H, 1,3-dioxole-CH ), 6.22 (s, 2H, NH ), 4.65
1
Synthesis of 6-amino-4-(benzo[d][1,3]dioxol-5-yl)-2-thioxo-
1
,2,3,4-tetrahydropyrimidine-5-carboxamide (11).
2
2
Concentrated sulfuric acid (30 mL) was cooled down to
(
9
s, 2H, NH ), 6.78–6.87 (m, 3H, ArH), 9.11 (s, 1H, NH),
2
1
3
20°C, and then compound 2 (2.74 g, 0.01 mol) was added
with contentious stirring to keep the reaction temperature
below 30°C. The addition of 2 was completed after 0.5 h,
and the reaction was stirred at room temperature for 4 h
and then poured with stirring into 200 mL of ice-cold
water and neutralized with solid sodium carbonate till
PH = 7. The resulted solution was left overnight in the
refrigerator, and the product was precipitated, collected
by filtration, and washed many times with water, dried,
and recrystallized from dioxane as brown crystals. Yield
.40 (s, 1H, NH); C NMR (DMSO-d , 100 MHz, ppm)
6
δ: 49.6, 58.7, 73.2, 102.5, 108.1, 109.2, 113.1, 120.5,
35.3, 145.4, 146.6, 150.7, 158.1, 162.4, 174.7; MS
1
+
(70 eV) m/z (%): 340 (M , 0.23), 307 (100). Anal. Calcd
for C H N O S: C: 52.94, H: 3.52, N: 24.70, S: 9.41.
15 12 6 2
Found C: 52.76, H: 3.71, N: 24.56, S: 9.50.
Synthesis of 4-amino-5-(benzo[d][1,3]dioxol-5-yl)-7-thioxo-
5
,6,7,8-tetrahydropyrimido[4,5-d]pyrimidin-2(1H)-one (10a).
A mixture of equimolar amounts of compound 2 (2.74 g,
À1
0.01 mol) and urea (0.6 g, 0.01 mol) in sodium ethoxide
(1.78 g, 61%), mp >360°C; IR (KBr, cm ): 3328, 3195
solution, 0.23 g of sodium metal in 20 mL absolute
ethanol, was refluxed for 12 h. The reaction mixture was
poured into crushed ice and neutralized with hydrochloric
acid (10 mL, 6N). The formed precipitate was collected
by filtration, dried, and recrystallized from toluene as
(2NH , 2NH), 2923 (CH aliphatic), 1674 (C═O), 1210
2
1
(C═S); H NMR (DMSO-d , 300 MHz, ppm) δ: 5.13
6
(s, CH, pyrimidinethione-4H), 5.89 (s, 2H, 1,3-dioxole-
CH ), 6.45 (s, 2H, NH ), 6.70–6.86 (m, 3H, ArH), 7.22
2
2
13
(s, 2H, NH ), 8.87 (s, 1H, NH), 9.42 (s, H, NH);
C
2
yellow crystals. Yield (1.90 g, 60%), mp 237–238°C; IR
NMR (DMSO-d , 100 MHz, ppm) δ: 54.7, 79.8, 102.4,
108.7, 109.2, 120.2, 135.7, 138.8, 145.2, 146.7, 162.7,
6
À1
(
(
KBr, cm ): 3423, 3314, 3167 (NH , 3NH), 3090
2
CH aromatic), 2953 (CH aliphatic), 1697 (C═O, cyclic
175.5. Anal. Calcd for C H N O S: C: 49.31, H: 4.10,
12 12 4 3
1
amide), 1634 (C═N), 1245 (C═S); H NMR (DMSO-d ,
N: 19.17, S: 10.95. Found C: 49.03, H: 3.78, N: 19.42,
6
3
5
6
9
00 MHz, ppm) δ: 5.38 (s, 1H, pyrimidinethione-5H),
S: 11.12.
.87 (s, 2H, 1,3-dioxole-CH ), 6.31 (s, 2H, NH ), 6.71–
2
2
Synthesis of 5-(benzo[d][1,3]dioxol-5-yl)-2,7-dithioxo-2,3,5,
6,7,8-hexahydropyrimido-[4,5-d]pyrimidin-4(1H)-one (12).
A mixture of equimolar amounts of compound 11
.86 (m, 3H, ArH), 8.74 (s, 1H, NH), 9.24 (s, 1H, NH),
1
3
.59 (s, 1H, NH); C NMR (DMSO-d , 100 MHz, ppm)
6
δ: 58.3, 102.3, 103.5, 108.7, 109.2, 120.4, 134.9, 145.2,
(2.93 g, 0.01 mol) and thiourea (0.76 g, 0.01 mol) in
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2019
Heterocycles based on Pyrimidine Moiety: Synthesis and Antimicrobial Evaluation
sodium ethoxide solution, 0.23 g of sodium metal in 20 mL
absolute ethanol, was refluxed for 8 h; the reaction mixture
was poured into crushed ice and neutralized with
hydrochloric acid; the precipitate formed was collected
by filtration, dried, and recrystallized from dioxane as
5.65 (s, 1H, pyrimidinethione-6H), 5.94 (s, 2H, 1,3-
dioxole-CH ), 6.82–7.25 (m, 3H, ArH), 8.45 (s, 1H,
2
13
NH); C NMR (DMSO-d , 100 MHz, ppm) δ: 41.3,
6
44.0, 45.1, 58.2, 60.7, 102.8, 108.4, 110.3, 119.5, 121.0,
129.9, 130.3, 148.0, 150.2, 158.1, 160.8, 172.2, 174.6;
+
brown crystals. Yield (2.20 g, 66%), mp 146–148°C; IR
MS (70 eV) m/z (%): 503 (M , 3.43), 365 (100). Anal.
À1
(
KBr, cm ): 3246, 3171 (4NH), 3076 (CH aromatic),
Calcd for C H N O SCl : C: 42.89, H: 2.58, N: 11.12,
18
13
4
5
3
2
981(CH aliphatic), 1723 (C═O, cyclic amide), 1240
S: 6.35, Cl: 21.15. Found C: 42.63, H: 2.41, N: 11.09,
S: 6.22, Cl: 21.30.
1
(C═S); H NMR (DMSO-d , 300 MHz, ppm) δ: 5.24
6
(
s, 1H, pyrimidinethione-5H), 5.78 (s, 2H, 1,3-dioxole-
Synthesis of 1,3-diacetyl-5-amino-4-(benzo[d][1,3]dioxol-5-
yl)-2-thioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidin-7-yl
acetate (15).
CH ), 6.57–7.02 (m, 3H, ArH), 8.22 (s, 1H, NH), 8.42
(
NMR (DMSO-d , 100 MHz, ppm) δ: 56.4, 98.7, 102.3,
1
1
2
2
13
s, 1H, NH), 9.51 (s, 1H, NH), 10.18 (s, 1H, NH);
C
6
To a solution of compound 2 (2.74 g, 0.01 mol) in acetic
anhydride (15 mL), 15 mL of concentrated phosphoric acid
was added. After addition completion, the reaction mixture
became very hot, and on reflux, it turned to dark brown; the
reflux was continued for extra 10 h and then poured into
ice-cold water and neutralized with solid sodium
carbonate till PH = 7. The solid precipitate that separated
out was filtered off and recrystallized from acetic acid as
08.7, 109.6, 120.4, 135.1, 145.2, 146.6, 150.2, 158.5,
+
74.3, 178.4; MS (70 eV) m/z (%): 332 (M -2, 0.05),
16 (100). Anal. Calcd for C H N O S : C: 46.70,
1
3 10 4 3 2
H: 2.99, N: 16.76, S: 19.16. Found C: 46.95, H: 3.24,
N: 16.82, S: 19.01.
Synthesis of N-(1,3-diacetyl-6-(benzo[d][1,3]dioxol-5-yl)-5-
cyano-2-thioxo-1,2,3,6-tetrahydropyrimidin-4-yl)acetamide
(
13).
brown crystals. Yield (3.40 g, 77%), mp >360°C; IR
À1
A mixture of compound 2 (2.74 g, 0.01 mol) and acetyl
chloride (0.03 mol) in dioxane (30 mL) was refluxed for
h. The reaction mixture was cooled down and poured
(KBr, cm ): 3379, 3211 (NH
2
), 3089 (CH aromatic),
2918 (CH aliphatic), 1713 (C═O, ester carbonyl gp),
1
4
1659 (C═O, amide carbonyl gp), 1294 (C═S); H NMR
over crushed ice. The product was collected by filtration,
washed with water, dried, and recrystallized from ethanol
(DMSO-d
(s, 3H, CH
5.40 (s, 1H, pyrimidinethione-4H), 5.92 (s, 2H, 1,3-
dioxole-CH ), 6.32 (s, NH ), 6.89–7.40 (m, 3H, ArH);
C NMR (DMSO-d , 100 MHz, ppm) δ: 21.1, 23.6,
6
, 300 MHz, ppm) δ: 2.21 (s, 3H, CH
3
), 2.43
), 2.54 (s, 3H, CH ), 5.12 (s, 1H, pyridine-H),
3
3
as brown crystals. Yield (2.70 g, 68%), mp 260°C
À1
(
(
(
decomposition); IR (KBr, cm ): 3111 (NH), 3032
2
2
13
CH aromatic), 2960 (CH aliphatic), 2213 (C≡N), 1692
C═O), 1249 (C═S); H-NMR (DMSO-d , 300 MHz,
6
1
25.7, 58.6, 96.1, 102.3, 107.1, 108.9, 110.8, 120.8,
6
ppm) δ: 2.33 (s, 3H, CH ), 2.46 (s, 3H, CH ), 2.50
131.9, 145.0, 146.2, 149.6, 152.1, 154.7, 165.9, 170.3,
171.4, 175.0; MS (70 eV) m/z (%): 444 (M +2, 22.61),
3
3
+
(
s, 3H, CH ), 5.63 (s, 1H, pyrimidine-4H), 5.84 (s, 1H,
3
NH), 5.98 (s, 2H, 1,3-dioxole-CH ), 7.20–7.41 (m, 3H,
417 (100). Anal. Calcd for C20H N O S: C: 54.29,
H: 4.07, N: 12.66, S: 7.23. Found C: 54.32, H: 3.89,
N: 12.47, S: 7.61.
18 4 6
2
13
Ar–H); C NMR (DMSO-d , 100 MHz, ppm) δ: 23.2,
6
23.5, 24.3, 55.3, 60.3, 102.2, 108.1, 109.0, 119.5, 120.8,
1
31.0, 131.3, 146.1, 150.8, 168.3, 170.7, 172.3, 173.9;
+
Synthesis of 1,3-diacetyl-4-(benzo[d][1,3]dioxol-5-yl)-5-(4-
hydroxy-3-methoxybenzylideneamino)-2-thioxo-1,2,3,4-tetra
hydropyrido[2,3-d]pyrimidin-7-yl acetate (16).
MS (70 eV) m/z (%): 400 (M , 2.45), 275 (100). Anal.
Calcd for C H N O S: C: 54.00, H: 4.00, N: 14.00,
S: 8.00. Found C: 54.36, H: 3.91, N: 14.17, S: 8.09.
18 16 4 5
A mixture of compound 15 (4.42 g, 0.01 mol) and
vanillin (1.52 g, 0.01 mol) was fused in oil bath in
presence of few drops of piperidine for 0.5 h, and then
the reaction was left to cool down, and the resulting
precipitate was dissolved in ethanol. The resulting
solution was diluted with ice-cold water, and the formed
precipitate was filtered off, dried, and recrystallized from
ethanol as brown crystals. Yield (3.62 g, 63%), mp 261–
Synthesis
of
N-(6-(benzo[d][1,3]dioxol-5-yl)-1,3-bis(2-
chloroacetyl)-5-cyano-2-thioxo-1,2,3,6-tetrahydropyrimidin-
4
-yl)-2-chloroacetamide (14).
A mixture of compound 2 (2.74 g, 0.01 mol) and
chloroacetyl chloride (0.03 mol) in dioxane (30 mL) was
heated under reflux for 4 h. The reaction mixture was
cooled and poured over crushed ice; the product was
collected by filtration, washed with water, dried, and
recrystallized from ethanol as dark brown crystals. Yield
À1
262°C; IR (KBr, cm ): 3435 (OH), 3045 (CH
aromatic), 2922 (CH aliphatic), 1733 (C═O, ester
(
4.10 g, 82%), mp 274°C (decomposition); IR (KBr,
carbonyl gp), 1669 (C═O, amide carbonyl gp), 1617
À1
1
cm ): 3138 (NH), 3038 (CH aromatic), 2918 (CH
aliphatic), 2214 (C≡N), 1680 (C═O), 1242 (C═S); H
NMR (DMSO-d , 300 MHz, ppm) δ: 4.30 (s, 2H,
(C═N), 1255 (C═S); H NMR (DMSO-d
6
, 300 MHz,
), 2.39 (s, 3H, CH ), 2.51 (s,
), 3.70 (s, 3H, OCH ), 5.43 (s, CH,
pyrimidinethione), 5.60 (s, 1H, OH), 5.89 (s, 2H, 1,3-
1
ppm) δ: 2.26 (s, 3H, CH
3H, CH
3
3
6
3
3
COCH ), 4.52 (s, 2H, COCH ), 4.68 (s, 2H, COCH ),
2
2
2
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

A. K. Mourad, F. K. Mohammed, G. H. Tammam, and S. R. Mohammed
Vol 000
dioxole-CH ), 6.86–7.78 (m, 6H, ArH), 7.83 (s, 1H,
Pyridine 6-H), 8.56 (s, 1H, CH═N); C NMR (DMSO-
d6, 100 MHz, ppm) δ: 20.9, 23.4, 25.6, 55.8, 58.3,
Synthesis of 6-amino-4-(benzo[d][1,3]dioxol-5-yl)-5-imino-
,4,5,6-tetrahydropyrimido [4,5-d]pyrimidine-2(1H)-thione
19).
2
1
3
3
(
To a solution of compound 18 (3.3 g, 0.01 mol) in
1
1
1
02.6, 104.3, 108.1, 109.5, 111.8, 113.2, 115.0, 121.9,
25.5, 126.1, 131.3, 145.6, 146.7, 148.0, 150.2, 151.9,
ethanol (30 mL), hydrazine hydrate (0.5 mL, 0.01 mol)
was added, and the reaction mixture was refluxed for
17 h and then poured into ice-cold water. The product
was filtered off, dried, and recrystallized from ethanol as
brown crystals. Yield (1.67 g, 53%), mp 219°C; IR (KBr,
54.6, 158.1, 165.2, 168.6, 170.6, 175.0, 182.4; MS
+
(70 eV) m/z (%): 576 (M , 74.88), 213 (100). Anal.
Calcd for C H N O S: C: 58.33, H: 4.16, N: 9.72, S:
28 24 4 8
5.55. Found C: 58.62, H: 4.03, N: 9.81, S: 5.50.
À1
cm ): 3469, 3399, 3247 (NH2, 3NH), 3055
1
Synthesis of ethyl N-1,3-diacetyl-6-(benzo[d][1,3]dioxol-5-
(CH aromatic), 1619 (C═N), 1227 (C═S); H NMR
yl)-5-cyano-2-thioxo-1,2,3,6-tetrahydropyrimidin-4-ylformi
midate (17).
To a solution of compound 2 (2.74 g, 0.01 mol) in acetic
anhydride (30 mL), triethyl orthoformate (1.4 mL,
(DMSO-d6, 300 MHz, ppm) δ: 4.97 (s, 1H,
pyrimidinethione-4H), 5.89 (s, 2H, 1,3-dioxole-CH2),
6
.20 (s, 1H, imine-H), 6.97–7.41 (m, 3H, ArH), 7.96
(
(
s, 2H, NH ), 7.96 (s, 1H, NH), 8.55 (s, 1H, NH), 8.87
2
13
0.01 mol) was added, and then the reaction mixture was
s, 1H, pyrimidine-H); C NMR (DMSO-d , 100 MHz,
6
heated under reflux for 5 h; the solvent was left to
evaporate, and the solid product was filtered off, dried,
and recrystallized from toluene as reddish brown crystals.
ppm) δ: 57.5, 96.8, 102.2, 108.8, 109.3, 121.0, 133.6,
38.3, 140.7, 145.4, 146.8, 157.3, 175.5; MS (70 eV) m/z
1
+
(%): 316 (M , 38.13), 180 (100). Anal. Calcd for
À1
Yield (2.45 g, 59%), mp 228°C; IR (KBr, cm ): 3115
C H N O S: C: 49.36, H: 3.79, N: 26.58, S: 10.12.
13 12 6 2
(
(
CH aromatic), 2976 (CH aliphatic), 2208 (C≡N), 1680
Found C: 49.77, H: 3.42, N: 26.41, S: 10.53.
1
C═O), 1628 (C═N), 1250 (C═S); H NMR (DMSO-d ,
6
Synthesis of 3-amino-4-(benzo[d][1,3]dioxol-5-yl)-4,5-
dihydro-1H-pyrazolo[3,4-d]-pyrimidine-6(7H)-thione (20).
3
00 MHz, ppm) δ: 1.21 (t, 3H, J = 6.0 Hz, CH ), 2.17
3
(
s, 3H, CH ), 2.28 (s, 3H, CH ), 3.42 (q, 2H, J = 6.0 Hz,
3 3
A mixture of compound 2 (2.74 g, 0.01 mol) and
hydroxylamine hydrochloride (0.695 g, 0.01 mol) in
glacial acetic acid (30 mL) containing anhydrous sodium
acetate (0.2 g) was refluxed for 7 h. The reaction mixture
was left to stand overnight at room temperature and then
poured into crushed ice. The separated product was
collected by filtration, washed with water, dried, and
CH ), 5.25 (s, 1H, pyrimidinethione-6H), 5.88 (s, 2H,
2
1
,3-dioxole-CH ), 6.82 (s, 1H, N═CH), 7.15–7.52
2
1
3
(m, 3H, ArH); C NMR (DMSO-d , 100 MHz, ppm) δ:
6
1
1
1
5.6, 22.7, 24.9, 59.3, 63.2, 64.7, 102.2, 108.3, 109.1,
18.6, 121.0, 131.6, 145.3, 146.4, 150.4, 168.1, 170.1,
74.4, 178.5; MS (70 eV) m/z (%): 414 (M , 99.69), 268
+
(
100). Anal. Calcd for C H N O S: C: 55.07, H: 4.34,
19 18 4 5
recrystallized from ethanol as white crystals. Yield
À1
N: 13.52, S: 7.72. Found C: 55.28, H: 4.51, N: 13.32,
S: 7.81.
(
1.67 g, 58%), mp >360°C; IR (KBr, cm ): 3435, 3383,
3
190 (NH2, 3NH), 3030 (CH aromatic), 2921
1
(CH aliphatic), 1613 (C═N), 1258 (C═S); H NMR
Synthesis of ethyl N-6-(benzo[d][1,3]dioxol-5-yl)-5-cyano-2-
thioxo-1,2,3,6-tetrahydropyrimidin-4-ylformimidate (18).
(DMSO-d6, 300 MHz, ppm) δ: 5.01 (s, 1H,
pyrimidinethione-4H), 5.90 (s, 2H, 1,3-dioxole-CH2),
A mixture of compound 2 (2.74 g, 0.01 mol) and
triethyl orthoformate (10 mL) in ethanol (30 mL) was
stirred under reflux for 8 h. After cooling to room
temperature, the separated precipitate was filtered off,
dried, and recrystallized from methanol as brown
6
.72 (s, 2H, NH ), 6.91–7.36 (m, 3H, ArH), 8.56 (s, 1H,
2
13
NH), 9.42 (s, 1H, NH), 9.82 (s, 1H, NH); C NMR
DMSO-d , 100 MHz, ppm) δ: 55.1, 102.6, 103.5, 108.7,
(
6
1
09.6, 120.5, 133.7, 144.8, 146.1, 147.6, 158.4, 174.6;
+
+
MS (70 eV) m/z (%): 293 (M +4, 15.42), 291 (M +2,
.03), 274 (100). Anal. Calcd for C H N O S:
crystals. Yield (2.15 g, 65%), mp >360°C; IR
À1
3
(
KBr, cm ): 3218, 3129 (2NH), 3045 (CH aromatic),
12 11 5 2
C: 49.82, H: 3.80, N: 24.22, S: 11.07. Found C: 50.12,
H: 3.54, N: 24.67, S: 11.31.
2
919 (CH aliphatic), 2220 (C≡N), 1612 (C═N), 1256
1
(
(
C═S); H-NMR (DMSO-d , 300 MHz, ppm) δ: 1.19
t, 3H, J = 4.2 Hz, CH ), 3.33 (q, 2H, J = 5.9 Hz,
6
3
Synthesis of ethyl 5-amino-4-(benzo[d][1,3]dioxol-5-yl)-7-
oxo-2-thioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidine-
6-carboxylate (21a).
CH ), 5.02 (s, 1H, pyrimidinethione-6H), 6.12 (s, 2H,
2
1
,3-dioxole-CH ), 7.08 (s, 1H, N═CH), 7.14–7.48
2
(
m, 3H, Ar–H), 7.65 (s, 1H, NH), 8.64 (s, 1H, NH);
A mixture of compound 2 (2.74 g, 0.01 mol), diethyl
malonate (1.52 mL, 0.01 mol), and glacial acetic acid
(20 mL) was refluxed for 12 h. The reaction mixture was
left to cool down to room temperature, and the formed
product was collected by filtration, dried, and
recrystallized from ethanol as yellow crystals. Yield
1
3
C NMR (DMSO-d , 100 MHz, ppm) δ: 15.5, 68.8,
6
6
1
2.2, 64.5, 102.3, 108.2, 109.5, 117.6, 120.8, 132.2,
45.3, 146.6, 150.6, 168.6, 175.0; MS (70 eV) m/z
+
(%): 332 (M +2, 2.23), 300 (100). Anal. Calcd for
C H N O S: C: 54.54, H: 4.24, N: 16.96, S: 9.69.
Found C: 54.21, H: 4.38, N: 17.23, S: 9.51.
1
5 14 4 3
À1
(2.32 g, 60%), mp 242°C; IR (KBr, cm ): 3245, 3214,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2019
Heterocycles based on Pyrimidine Moiety: Synthesis and Antimicrobial Evaluation
3
118 (NH2, 3NH), 3095 (CH aromatic), 2923
60.2, 72.8, 102.3, 108.4, 109.3, 113.2, 115.0, 118.6,
120.9, 125.7, 126.9, 134.6, 142.2, 146.6, 148.4, 150.1,
151.8, 161.2, 174.6; MS (70 eV) m/z (%): 408
(
(
CH aliphatic), 1733 (C═O, ester carbonyl gp), 1669
C═O, cyclic amide), 1256 (C═S); H-NMR (DMSO-d ,
1
6
+
+
300 MHz, ppm) δ: 1.87 (t, 3H, J = 5.3 Hz, CH ), 4.35
(M , 2.02), 406 (M -2, 19.24), 323 (100). Anal. Calcd
3
(
q, 2H, J = 6.0 Hz, CH ), 5.10 (s, 1H, pyrimidinethione-
for C H N O S: C: 58.82, H: 3.92, N: 13.72, S: 7.84.
2
20 16 4 4
4
6
H), 6.02 (s, 2H, 1,3-dioxole), 6.10 (s, 2H, NH ), 6.86–
Found C: 59.12, H: 3.88, N: 13.81, S: 7.51.
2
.93 (m, 3H, Ar–H), 9.96 (s, 1H, NH), 10.11
1
3
Synthesis
of
4-(benzo[d][1,3]dioxol-5-yl)-6-(4-
(s, 1H, NH), 10.43 (s, 1H, NH); C NMR (DMSO-d6,
nitrobenzylideneamino)-2-thioxo-1,2,3,4-
tetrahydropyrimidine-5-carbonitrile (22b).
A mixture of compound 2 (2.74 g, 0.01 mol) and p-
nitrobenzaldehyde (1.51 g, 0.01 mol) in presence of few
drops of piperidine was subjected to fusion in oil bath for
1
1
1
0
00 MHz, ppm) δ: 15.8, 60.5, 61.3, 94.3, 96.5, 102.6,
08.0, 109.7, 120.3, 134.1, 145.4, 146.5, 150.6, 158.1,
58.9, 162.6, 174.3; MS (70 eV) m/z (%): 387 (M -1,
.75), 275 (100). Anal. Calcd for C H N O S:
+
1
7 16 4 5
C: 52.57, H: 4.12, N: 14.43, S: 8.24. Found C: 52.14,
H: 4.37, N: 14.81, S: 8.01.
0
.5 h, and then the reaction mixture was left to cool
down, and the resulting product was dissolved in ethanol
and diluted with ice-cold water. The separated solid was
filtered off, dried, and recrystallized from toluene as
brown crystals. Yield (3.10 g, 76%), mp 167°C; IR (KBr,
Synthesis of 5-amino-4-(benzo[d][1,3]dioxol-5-yl)-7-oxo-2-
thioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidine-6-carbo
nitrile (21b).
A mixture of compound 2 (2.74 g, 0.01 mol), ethyl
À1
cm ): 3358, 3219 (2NH), 3005 (CH aromatic), 2929
cyanoacetate (1.06 mL, 0.01 mol), and glacial acetic acid
(
CH aliphatic), 2195 (C≡N), 1604 (C═N), 1243 (C═S);
(20 mL) was refluxed for 12 h. The reaction mixture was
1
H NMR (DMSO-d , 300 MHz, ppm) δ: 5.35 (s, CH,
6
left to cool down to room temperature, and then the
separated solid was collected by filtration, dried, and
recrystallized from ethanol as yellow crystals. Yield
pyrimidinethione-4H), 5.90 (s, 2H, 1,3-dioxole-CH2),
.81–7.20 (m, 3H, ArH), 7.58 (d, 2H, J = 7.5 Hz, ArH),
8.23 (s, 1H, NH), 8.32 (d, 2H, J = 7.5 Hz, ArH), 8.75
6
À1
(
(
2.50 g, 73%), mp 258°C; IR (KBr, cm ): 3323, 3187
NH , 3NH), 3026 (CH aromatic), 2899 (CH aliphatic),
13
(
s, 1H, CH═N), 9.83 (s, 1H, NH); C NMR (DMSO-d6,
2
1
100 MHz, ppm) δ: 58.2, 72.8, 102.5, 108.9, 109.6, 117.0,
2
185 (C≡N), 1725 (C═O, cyclic amide), 1246 (C═S); H
1
1
20.3, 124.6, 131.5, 134.6, 140.2, 145.1, 146.5, 150.7,
NMR (DMSO-d , 300 MHz, ppm) δ: 5.18 (s, 1H,
pyrimidinethione-4H), 5.98 (s, 1H, 1,3-dioxole-CH2),
6
51.8, 162.1, 175.6; MS (70 eV) m/z (%): 407
+
(M , 1.16), 323 (100). Anal. Calcd for C H N O S:
19 13 5 4
6.40 (s, 2H, NH ), 6.68–6.89 (m, 3H, ArH), 7.98 (s, 1H,
2
1
3
C: 56.01, H: 3.19, N: 17.19, S: 7.86. Found C: 56.43,
H: 3.38, N: 17.01, S: 7.53.
NH), 8.88 (s, 1H, NH), 9.21 (s, 1H, NH); C NMR
DMSO-d , 100 MHz, ppm) δ: 61.0, 93.7, 101.8, 108.7,
(
6
1
1
09.4, 115.6, 117.3, 120.6, 134.7, 145.2, 146.3, 148.8,
Synthesis of ethyl 6-amino-5-(benzo[d][1,3]dioxol-5-yl)-3-
oxo-2,3,5,8-tetrahydropyrrolo-[2,3-d]thiazolo[3,2-a]pyrimi
dine-7-carboxylate (23).
60.3, 163.5, 176.0; MS (70 eV) m/z (%): 341
+
(M , 28.76), 157 (100). Anal. Calcd for C H N O S:
1
5 11 5 3
C: 52.78, H: 3.22, N: 20.52, S: 9.38. Found C: 52.59,
H: 3.67, N: 20.86, S: 9.07.
A mixture of compound 2 (2.74 g, 0.01 mol), ethyl
bromoacetate (2.22 mL, 0.02 mol), and anhydrous
potassium carbonate (1.37 g, 0.01 mol) in dry acetone
Synthesis of 4-(benzo[d][1,3]dioxol-5-yl)-6-(4-hydroxy-3-
methoxybenzylideneamino)-2-thioxo-1,2,3,4-
(40 mL) was heated under reflux with contentious stirring
tetrahydropyrimidine-5-carbonitrile (22a).
for 10 h; the reaction was left to stand overnight at room
temperature and then poured over crushed ice. The
separated solid was filtered off, washed with water, dried,
and recrystallized from dioxane as orange crystals. Yield
A mixture of compound 2 (2.74 g, 0.01 mol) and
vanillin (1.52 g, 0.01 mol) in presence of few drops of
piperidine was subjected to fusion in oil bath for 0.5 h,
and then the reaction mixture was left to cool down, and
the resulting product was dissolved in ethanol and diluted
with ice-cold water. The separated solid was filtered off,
dried, and recrystallized from benzene as orange crystals.
À1
(3.15 g, 79%), mp 156°C; IR (KBr, cm ): 3357, 3190
(NH
, NH), 3099 (CH aromatic), 2983 (CH aliphatic),
2
1733 (C═O, ester carbonyl gp), 1678 (C═O, cyclic
1
amide); H-NMR (DMSO-d
(t, 3H, J = 5.1 Hz, CH ), 3.78 (s, 2H, thiazole-CH
(q, 2H, J = 5.3 Hz, CH ), 5.98 (s, 2H, 1,3-dioxole-CH
6.13 (s, 1H, pyrimidine-H), 6.66 (s, 2H, NH ), 6.70–7.01
(m, 3H, Ar–H), 9.70 (s, 1H, NH); C NMR (DMSO-d ,
6
, 300 MHz, ppm) δ: 1.46
), 4.88
),
6
À1
Yield (2.70 g, 66%), mp 221°C; IR (KBr, cm ): 3327,
3
2
3180 (2NH, OH), 3011 (CH aromatic), 2918 (CH
2
2
1
aliphatic), 2186 (C≡N), 1623 (C═N), 1242 (C═S); H
2
13
NMR (DMSO-d , 300 MHz, ppm) δ: 3.78 (s, 3H,
6
OCH ), 5.52 (s, 1H, pyrimidinethione-4H), 5.58 (s, 1H,
100 MHz, ppm) δ: 15.3, 31.7, 58.3, 61.2, 102.0, 107.6,
3
OH), 6.04 (s, 2H, 1,3-dioxole-CH ), 6.70–7.20 (m, 6H,
108.5, 109.2, 110.6, 120.9, 124.0, 131.3, 141.1, 145.5,
2
ArH), 8.25 (s, 1H, NH), 8.60 (s, 1H, CH═N), 9.32 (s,
146.6, 150.1, 164.1, 168.8; MS (70 eV) m/z (%): 400
13
+
1
H, NH); C NMR (DMSO-d , 100 MHz, ppm) δ: 56.1,
(M , 19.57), 271 (100). Anal. Calcd for C18
H
16
N
O
4
S:
5
6
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

A. K. Mourad, F. K. Mohammed, G. H. Tammam, and S. R. Mohammed
Vol 000
C: 54.00, H: 4.00, N: 14.00, S: 8.00. Found C: 54.37,
H: 4.13, N: 14.31, S: 7.84.
Acknowledgment. We would like to extend our profound
gratitude to Fayoum University for financing this work.
Synthesis of methyl 8-amino-6-(benzo[d][1,3]dioxol-5-yl)-7-
cyano-4-oxo-4,6-dihydropyrimido[2,1-b][1,3]thiazine-2-carbo
xylate (24).
REFERENCES AND NOTES
[
1] Jubeen, F.; Iqbal, S. Z.; Shafiq, N.; Khan, M.; Parveen, S.;
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A mixture of compound 2 (2.74 g, 0.01 mol) and
dimethyl acetylene dicarboxylate (1.22 mL, 0.01 mol) in
ethanol (30 mL) was refluxed for 15 h. The crude solid
product that precipitated out was collected by filtration,
dried, and recrystallized from ethanol as red crystals.
[
[
4] Chikhale, R. V.; Bhole, R. P.; Khedekar, P. B.; Bhusari, K. P.
Eur J Med Chem 2009, 44, 3645.
À1
Yield (2.70 g, 70%), mp 268°C; IR (KBr, cm ): 3442,
3
2
337 (NH ), 3057 (CH aromatic), 2950 (CH aliphatic),
[5] Naikoo, R. A.; Mir, M. A.; Bhat, S.; Tomar, R.; Bhat, R. A.;
Malla, M. A. Curr Bioactive Compds 2016, 12, 236.
2
207 (C≡N), 1725 (C═O, ester carbonyl), 1698 (C═O,
[6] Pałasz, A.; Cież, D. Eur J Med Chem 2015, 97, 582.
1
cyclic amide), 1640 (C═N); H-NMR (DMSO-d6,
[7] Wang, S. C.; Gao, J. G.; Zhang, S.; Liu, S.; Jiang, L.
3
00 MHz, ppm) δ: 3.74 (s, 3H, OCH3), 5.60
Phosphorus Sulfur Silicon Relat Elem 2018, 193, 245.
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[
(
(
(
s, 1H, pyrimidine-H), 5.98 (s, 2H, 1,3-dioxole), 6.04
s, 2H, NH ), 6.82 (s, 1H, thiazine-CH), 6.79–6.91
m, 3H, Ar–H); C NMR (DMSO-d , 100 MHz, ppm) δ:
2
[
13
6
5
1
1
0.3, 55.1, 68.5, 102.6, 108.5, 110.5, 117.7, 120.8,
[
10] Cui, P.; Li, X.; Zhu, M.; Wang, B.; Liu, J.; Chen, H. Bioorg
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11] Verbitskiy, E. V.; Baskakova, S. A.; Gerasimova, N. A.;
21.1, 131.3, 141.3, 145.1, 146.5, 148.2, 157.8, 163.2,
+
66.8; MS (70 eV) m/z (%): 384 (M , 11.92), 207 (100).
[
Anal. Calcd for C H N O S: C: 53.12, H: 3.12, N:
Evstigneeva, N. P.; Zil’berberg, N. V.; Kungurov, N. V.; Kravchenko,
M. A.; Skornyakov, S. N.; Pervova, M. G.; Rusinov, G. L.; Chupakhin,
O. N.; Charushin, V. N. Bioorg Med Chem Lett 2017, 27, 3003.
1
7 12 4 5
14.58, S: 8.33. Found C: 53.41, H: 3.35, N: 14.18, S: 8.07.
[12] Verbitskiy, E. V.; Baskakova, S. A.; Gerasimova, N. A.;
Evstigneeva, N. P.; Zil’berberg, N. V.; Kungurov, N. V.; Kravchenko,
M. A.; Rusinov, G. L.; Chupakhin, O. N.; Charushin, V. N. Mendeleev
Commun 2018, 28, 393.
ANTIMICROBIAL ACTIVITY ASSAY
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2018, 77, 339.
Disc diffusion protocol utilizing sterile Whatman No. 5
[
filter paper discs (11 mm diameter) was used to screen
the in vitro antimicrobial properties of compounds under
investigation towards selected microbial strains [29].
Accordingly and after purification by recrystallization, the
tested compounds were dissolved in ethanol, 11 mm filter
paper discs were loaded with 10 mg/mL of compounds
under investigation (50 μL), and total dryness was
accessible through placing the discs with caution under a
stream of hot air.
[15] Khaldi-Khellafi, N.; Makhloufi-Chebli, M.; Oukacha-Hikem,
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Dumas, F. J Mol Struct 2019, 1181, 261.
[16] Prachayasittikul, S.; Pingaew, R.; Worachartcheewan, A.;
Sinthupoom, N.; Prachayasittikul, V.; Ruchirawat, S.; Prachayasittikul,
V. M. Rev Med Chem 2017, 17, 869.
[17] Alam, O.; Khan, S. A.; Siddiqui, N.; Ahsan, W.; Verma, S. P.;
Gilani, S. J. Eur J Med Chem 2010, 45, 5113.
[18] Kaur, R.; Kaur, P.; Sharma, S.; Singh, G.; Mehndiratta, S.;
Bedi, P. M.; Nepali, K. Recent Pat Anticancer Drug Discov 2015, 10, 23.
[19] Kang, D.; Fang, Z.; Li, Z.; Huang, B.; Zhang, H.; Lu, X.; Xu,
Posteriorly, 10 mL freshly prepared Muller–Hinton agar
medium seeded with the test bacterial strain was poured in
each test plate. The discs were placed on the top of agar
plates’ surfaces, which were incubated at 5°C for 1 h to
permit a good diffusion. The incubation was performed
for 24 h at 37°C. After incubation, the microorganism’s
outgrowth was observed. The average inhibition zone
diameters were recorded in millimeters and used as norm
for the antimicrobial activity. Noteworthy, the plates were
done in triplicate to obtain the average growth. The
inhibitory effect of the investigated compounds is
proportional to the observed clear zone size. In each
experiment, solvent disc control was incorporated as
negative criterion. For comparison, norfloxacin (standard
drug) was also screened for antibacterial activity using
the same conditions.
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet