Synthesis and antimicrobial evaluation of new series of quinazolin-5-one derivatives

Article abstract of DOI:10.1007/s13738-020-01896-0

A new series of quinazolinone derivatives were synthesized starting with anthranilic acid and cinnamoylisothiocyanate in high yields 55–99%. Their structures were elucidated by ¹H/¹³C NMR, FTIR spectroscopy, MS and elemental analysis. The study of the biological activity of all the novel compounds is reported. The minimal inhibitory concentration of some quinazolin-5-one derivatives showed potential activity against both Gram (+ve) and Gram (?ve) microorganisms more than the reference cefotaxime. In addition, some derivatives of quinazolin-5-one can be considered as antifungal agents comparing with the standard drug nystatin.

Full text of DOI:10.1007/s13738-020-01896-0

Journal of the Iranian Chemical Society
https://doi.org/10.1007/s13738-020-01896-0
ORIGINAL PAPER
Synthesis and antimicrobial evaluation of new series
of quinazolin‑5‑one derivatives
Reda A. Haggam1,2 · Essam. A. Soylem2 · Mohamed. G. Assy2 · Marium. F. Arastiedy2
Received: 31 August 2019 / Accepted: 29 February 2020
© Iranian Chemical Society 2020
Abstract
A new series of quinazolinone derivatives were synthesized starting with anthranilic acid and cinnamoylisothiocyanate
in high yields 55–99%. Their structures were elucidated by 1H/13C NMR, FTIR spectroscopy, MS and elemental analysis.
The study of the biological activity of all the novel compounds is reported. The minimal inhibitory concentration of some
quinazolin-5-one derivatives showed potential activity against both Gram (+ve) and Gram (−ve) microorganisms more than
the reference cefotaxime. In addition, some derivatives of quinazolin-5-one can be considered as antifungal agents compar-
ing with the standard drug nystatin.
Keywords Anthranilic acid · Cinnamoylthiourea · Mercaptopyrimidine · Thiadiazoloquinazolin-5-one · Antimicrobial
activity
Introduction
[7]. Moreover, quinazolinone heterocycles possess diverse
pharmacological activities including antiviral [8] and anti-
histaminic [9, 10]. Among other pharmacological activities,
quinazoline derivatives show remarkable antimicrobial prop-
erties [11]. Quinazoline derivatives displayed outstanding
biological properties involving anticonvulsant, diuretic and
antihypertensive activities as well [12–14]. Quinazoline
and quinazolinone are also used in preparation of various
functional materials for synthetic chemistry and also present
in several drug molecules such as albaconazole that have
been used as antifungal and nolatrexed as antisolid tumours
(Fig. 1) [15–17].
Nitrogen-rich heterocycles, particularly quinazolines and
quinazolinones, are useful bioactive scafolds in medicinal
chemistry and synthetic applications [1]. Quinazolinone
derivatives showed inhibitory activities on α-glucosidase
in a non-competitive manner [2]. Also, 2-(4-Fluorophenyl)-
quinazolin-4(3H)-one acts as a novel tyrosinase inhibitor
[3]. Recent developments in the green protocols were pre-
sented for the construction of highly bioactive quinazoline
and quinazolinone compounds aiming at the treatment of
diferent disorders [4]. The simple and condensed quina-
zoline derivatives have drawn much attention owing to
their applications particularly in a wide range of antitumor
activities [5]. Interest in quinazolinones as anticancer agents
has further increased since the discovery of raltitrexed and
thymitaq and their activity as thymidylate enzyme inhibi-
tors [6]. Compounds containing 2(1H)-quinazolinone ring
structure have also shown prominent anticancer activities
Owing to the importance of quinazolinone derivatives,
some synthetic procedures have been reported, for example
synthesis of 2-substituted-2,3-dihydro-4(1H)-quinazolinone
derivatives by one-pot condensation of anthranilamide with
aldehydes or ketones in the presence of boric acid under
solvent-free conditions [18]. 2,3-Dihydroquinazolin-4(1H)-
ones was prepared via Ferrite/Chitosan as a green and reus-
able nanocatalyst [19]. In addition, several organic reactions
based on green chemistry concerned with synthesis of sub-
stituted quinazolinones derivatives were reported [20–23]. It
is notable that most of these methods have drawbacks such
as using expensive reagents, non-recyclable and excess
amount of catalysts, long reaction times and toxic solvents.
In this regard, our interest has been recently directed towards
the synthesis of some novel azoles and azines of expected
* Reda A. Haggam
rhaggan99@hotmail.com
1
Department of Chemistry, Faculty of Science, Islamic
University in Almadinah Almonawara, Medina 42351,
Saudi Arabia
2
Department of Chemistry, Faculty of Science, Zagazig
University, Zagazig 44511, Egypt
Vol.:(0123456789)
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Journal of the Iranian Chemical Society
N
N
nucleophilic addition on the carboxylic carbonyl group
(Scheme 1). It is notable that compound 5 is a functionally
suitable starting material for further construction of a novel
class of fused heterocycles such as thiadiazoloquinazoline of
type 6 and thiazoloquinazoline 10. Stirring of 5 with sodium
hypochlorite at r.t for 6 h aforded thiadiazoloquinazolin-
5-one 6 in 75% yield via the amination of sulphenyl inter-
mediate A, as outlined in (Scheme 1).
Cl
N
O
N
N
S
O
OH
N
Me
N
Me
F
F
N
H
NH2
Albaconazole
Nolatrexed
Antifungal
Antisolid tumours
The suggested mechanism for building of quinazoline
5 started with the addition of the nucleophilic nitrogen of
anthranilic acid (1) to cinnamoylisothiocyanate (2) [32] to
aford thiourea derivative 3 which underwent an intramolec-
ular nucleophilic cyclization followed by dehydration form-
ing the target molecule mercaptoquinazoline 5, as shown in
(Scheme 2).
Fig. 1 Structure of albaconazole and nolatrexed
antitumor activity [24–29]. Inspired by these fndings, we
attempted to synthesize new quinazolinone derivatives using
commercially available reagents through a novel, easy, high-
yielding, and clean synthetic route to evaluate their biologi-
cal activities as antibacterial and antifungal agents.
The structure of compound 5 was elucidated by the spec-
tral analysis. The IR spectrum of mercaptoquinazoline deriv-
ative 5 displayed distinguishable absorption bands at 2260,
1693, 1686, 1629, 1588 cm−1 for (SH), (2C=O), (C=N) and
(C=C), respectively. In addition, the absence of carbonyl
stretching peak at 1705 cm−1 that was attributed to acidic
carbonyl supported that the (COOH) group was involved
in the cyclization. The 1H NMR of 5 showed a broad sin-
glet at δ = 12.49 ppm for (SH) group. There is multiplet
in between δ = 7.93–7.28 ppm for eight aromatic protons.
Moreover, there are two doublets at δ=6.53 and 7.56 ppm
with J = 14.9 Hz for the two vinylic protons (–CH=CH–)
(Fig. 1). Disappearance the peak at δ =12.49 ppm in D2O
spectrum emphasized that the SH proton was exchangeable
with D2O. This is an evidence for the correct suggested
structure of mercaptoquinazoline 5. Also, the mass spec-
trometry of compound 5 is in agreement with its structure
as well as its molecular weight. The IR spectrum of thi-
adiazoloquinazolin-5-one 6 revealed absorption bands at
1683 and 1627 cm−1 for (amidic C=O) and (C=N) groups,
Results and discussion
The present work is aiming at utilization of cinnamoyl thio-
urea via isothiocyanates for synthesis of new quinazolinone
derivatives by using simple available laboratory reagents.
Isothiocyanates are versatile reagents that have been used
as synthetic moiety to synthesize biologically active hetero-
cycles [30, 31]. At the beginning, the nucleophilic nitrogen
of anthranilic acid (1) was added to cinnamoylisothiocy-
anate (2) [32] in acetone under refux for 2 h to build the
cinnamoyl thiourea derivative 3 in 99% yield (Scheme 1).
Upon heating of 3 with sodium carbonate for 8 h produced
thiazine ring system 4 in 55% yield via deprotonation the
acidic hydrogen NH fanked between CO and CS groups.
On the other hand, performing the reaction in strong base
as ethanolic sodium ethoxide for 8 h resulted in mercapto-
quinazoline 5 in 87% yield throughout an intramolecular
COOH
O
S
C
Ar
N
Ar
NH2
COOH
O
2
1
2 h reflux/acetone
99%
NH
8 h/ reflux
Na2CO3
N
S
N
55%
N
Ar
S
N
6
Ar
O
- H2O
75%
4
Ar = p-ClC6H4
HOOC
NH
S
H
N
O
N
O
O
O
S
O
stirring/r.t/ 6 h
NaOCl
8h/ reflux
3
N
Ar
N
Ar
NaOEt/EtOH
NH4OH/NaOH
87%
NH2
Ar = p-ClC6H4
SH
N
5
A
Scheme 1 Basic cyclizations of cinnamoyl thiourea 3 under diferent conditions
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Journal of the Iranian Chemical Society
O
N
O
O
O
S
OH
COOH
S
O
N
Ar
HN
Ar
C
- H2O
Ar
N
NH2
SH
N
H
1
2
3
5
Scheme 2 Proposed mechanism for formation of mercaptoquinazoline 5
respectively. In the 1H NMR of 6, it was observed multiplet
in between δ = 7.73–7.45 ppm for eight aromatic protons.
In addition, there are two doublets with coupling constant
J = 14.9 Hz at δ = 6.52 and 7.57 ppm for the two vinylic
protons –CH=CH–. The high value of the coupling constant
supports that the two olefnic protons exist in trans confgu-
ration. Basic alkylation of 2-mercapto-3-cinnamoylquina-
zolinone 5 with appropriate halogenated activated methylene
reagents such as N-phenylchloroacetamide, ethyl chloroac-
etate and chloroacetamide under refux for 9–14 h resulted
in the synthesis of thiazoloquinazolineone derivatives 8 and
9 (Scheme 2). Reaction of 5 with N-phenylchloroacetamide
gave the S-alkylated quinazolinone 7 that could be isolated
in 65% yield. Upon heating compound 7 in xylene for 10 h
delivered thiazoloquinazolinone 8 in 85% yield. Refuxing of
5 with ethyl chloroacetate or chloroacetamide for 14 h gave
thiazoloquinazolinone derivatives 9a and 9b directly in 65%
yield via the S-alkylated intermediate B that could not be
isolated. An intramolecular basic cyclization of compound
5 in xylene provided thiazinoquiazolinone derivative 10 in
79% yield. Also, [2 + 4] intramolecular cycloaddition of
2-mercaptoquinazolinone 5 and maleic anhydride aforded
thiazine intermediate C that underwent hydrolysis and sub-
sequently decarboxylation forming the fnal product 11 in
69% yield (Scheme 3).
The IR spectrum of 12 displayed absorption bands at
1694, 1686 cm−1 for (2C=O). Moreover, disappearance of
the band for SH indicated that desulphurization occured.
In its 1H NMR, there are no signals at δ value greater than
7.90 ppm. This is a clue the SH proton disappeared. The
mass spectrometry of compound 12 is in agreement with
its molecular weight M+ = 310.
Pharmacological studies
Antimicrobial evaluation
We studied the invitro antimicrobial activities for the
synthesized compounds 4, 5, 6, 7, 8, 9a, 10, 11, 12, 14
and 15 against Staphylococcus epidermidis ATCC 12228,
Staphylococcus aureus ATCC 6538, as (Gram +ve), Pseu-
domonas aeruginosa ATCC 9027, Escherichia coli ATCC
10536, as (Gram −ve) (Table 1) and fungi, namely (Can-
dida albicans ATCC 10231 and Aspergillus niger ATCC
16404) (Table 3). It is clearly observed that, from the
obtained results in Table 1, approximately all the tested
compounds exhibited signifcant antibacterial activity
against both Gram (+ve) and Gram (−ve) microorganisms,
especially compounds 6, 7 and 12 that exhibited activ-
ity against Gram (+ve) bacteria more than the standard
drug activity (cefotaxime) using the agar well difusion
method [33]. The efect of concentration gradient of the
most active compound, 6, on Gram +ve bacteria (percent-
age of inhibition) showed the maximum antibacterial at
70 µg (Table 2).
The IR spectrum of quinazolinone 7 showed disappear-
ance of the characteristic band for (SH) at 2250 cm−1, indi-
cating that S-alkylated product 7 was formed. Other bands
are present at 3345, 1693, 1686, 1665 cm−1 for (NH) and
1
(3C=O amide), respectively. The H NMR of 7 revealed
singlet at δ = 4.17 ppm for (SCH2) group. In addition, a
broad singlet at δ=12.51 ppm for (NH). The broad singlet
was exchangeable with D2O. The mass spectrometry of
quinazolinone 7 is in agreement with its molecular weight
and structure. Stirring of 5 with hydrogen peroxide in
acidic medium led to desulphurization producing quinazo-
line derivative 12 in 88% yield, but the structure 13 is not
observed (Scheme 3). On the other hand, reaction of 5 with
hydrogenperoxide in alkaline medium at r.t for 4 h gave the
oxidative product 14 in 75% yield. Finally, the disulphide
of type 15 was formed in 87% yield due to oxidative dehy-
drogenation of cinnamoylquinazolinone 5 with iodine in the
presence of acetic acid as in (Scheme 4).
The results showed that compounds 8, 12 and 14 have
exhibited antifungal activity more than the standard drug
(nystatin), as shown in Table 3. Compound 8 is the most
active one on fungi (Candida albicans ATCC 10231 and
Aspergillus niger ATCC 16404) with optimum concentra-
tion (70 µg), as shown in Table 4. By studying the efect of
time on the antifungal activity for compound 8, we found
that after 8 days, we obtain the highest percentage of get-
ting rid of fungi (Table 5).
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Journal of the Iranian Chemical Society
Ar
O
N
O
S
O
10 h/ reflux
TEA/xylene
Cl
CONHPh
N
Ar
N
CONHPh
9 h/ reflux
85%
TEA/EtOH
65%
S
CONHPh
N
O
N
O
7
8
N
Ar
Cl
Cl
CONHPh
8
SH
20 h/ reflux
TEA/EtOH
83%
Ar
5
O
O
O
S
X
Ar = p-ClC6H4
N
N
Ar
O
COX
65%
14 h/ reflux
TEA/EtOH
S
N
N
COX
9
B
9a: X = OEt
9b: X = NH2
O
O
12 h/ reflux
TEA/xylene
N
Ar = p-ClC6H4
79%
N
S
Ar
10
O
O
O
Ar
Ar
O
O
N
N
COOH
COOH
- CO2
69%
N
8 h/ reflux
xylene
N
S
COOH
S
11
C
Scheme 3 Cyclizations of 2-mercapto-3-cinnamoylquinazolinone 5
2‑({[3‑(E)‑(4‑Chlorophenyl)prop‑2‑enoyl]carba‑
mothioyl}amino)benzoic acid (3)
Experimental
Chemistry
A mixture of anthranilic acid (1) (0.137 g, 1 mol) and
p-chlorocinnamoylisothiocyanate (MP. 44–45 °C; Lit.
42–44 °C) (2) [32] (0.239 g, 1 mol) in dry acetone (50 ml)
was refuxed for 2 h. After concentration and cooling the
reaction mixture, the formed product was fltered of, dried
and recrystallized from methanol to give yellow crystals in
99% Yield. Mp. 230–231 °C. IR (KBr, cm−1): 3424 (OH),
3363, 3321 (2 NH), 1710, 1686 (2 C=O), 1628 (C=N),
1506 (C=C). Elem. Anal. Calcd. for C17H13ClN2O3S
(360.81): C, 56.59; H, 3.63; N, 7.76%. Found: C, 56.42; H,
3.51; N, 7.65%. 1H-NMR (DMSO-d6, 400 MHz) δ: 6.51,
7.55 (2H, 2d, J = 14.9 Hz, –CH=CH–), 7.35–8.48 m (8H,
m, 2Ar–H), 10.78, 11.55 (2H, 2 s, exch. with D2O, 2NH),
13.09 (1H, s, exch. with D2O, OH). m/z (EI, 70 eV) 363
(8), 361 (25), 342 (70), 238 (90), 165 (100).
All starting materials, reagents and solvents were pur-
chased from Aldrich Chemical Co., Merck Chemical Co.
All melting points were measured using an Electrothermal
IA 9100 apparatus and are uncorrected. The experiments
were done using dry solvents. The obtained products have
been purifed by recrystallization. IR spectra (KBr discs)
were recorded on a Shimadzu FTIR, 8300 PC infrared
spectrophotometer. The 1H/13C NMR was measured with
a JEOL-JNM-LA 400 MHz spectrometer using DMSO-d6
as a solvent. The coupling constants (J) are given in Hz.
The chemical shifts are expressed on the δ (ppm) scale
using TMS as the standard reference. Mass spectra were
recorded with a Shimadzu QP-2010 plus instrument at
70 eV. TLC was performed on Merck Silica Gel 60F254
with detection by way of UV light. Elemental analyses
were determined on a PerkinElmer 240 (Microanalysis
Center, Cairo University, Cairo; Egypt).
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Journal of the Iranian Chemical Society
O
N
O
N
Ar
O
O
30% H2O2
AcOH
stirr 4 h/r.t
N
Ar
12
88%
N
SH
O
O
5
Ar = p-ClC6H4
N
Ar
N
OH
13
O
O
30% H2O2
10% NaOH
stirr 4 h/r.t
N
Ar
75%
Ar = p-ClC6H4
N
H
O
O
14
O
N
I2/AcOH
stirr 4 h/r.t
N
Ar
87%
S
2
15
Scheme 4 Oxidation of 2-mercapto-3-cinnamoylquinazolinone 5 under diferent reaction conditions
Table 1 The minimal inhibitory
Comp. no.
Gram (+ve) S. epider-
midis ATCC 12228
S. aureus
Gram (-ve) P. aerugi- E. coli
concentration (MIC) of 4, 5, 6,
7, 8, 9a, 10, 11, 12, 14 and 15
ATCC 6538
nosa ATCC 9027
ATCC
10536
4
4.0
10.0
12.0
18.0
17.0
14.0
12.0
8.0
3.0
4.0
6.0
6.0
4.0
2.0
3.0
6.0
7.0
6.0
3.0
5.0
–
5.0
9.0
11.0
10.0
10.0
4.0
5.0
8.0
12.0
11.0
6.0
10.0
–
5
10.0
12.0
11.0
8.0
6.0
7.0
5.0
12.0
9.0
7.0
10.0
–
6
7
8
9a
10
11
12
14
15
9.0
17.0
14.0
13.0
16.0
–
Cefotaxime (5 mg/mL)
(control) DMF (control)
(MIC), concentration of compound inhibiting the microbial growth (µg/ml)
formed product was fltered of, washed with cold water, dried
and then recrystallized from ethanol to give yellowish crys-
tals in 55% Yield. Mp. 206–207 °C. IR (KBr, cm−1): 3340
(OH), 3143 (NH), 1705, 1685 (2 C=O), 1628 (C=N). Elem.
Anal. Calcd. for C18H16ClN2O3S (375.85): C, 57.52; H, 4.29;
2‑(6‑(4‑Chlorophenyl)‑5,6‑dihydro‑4‑oxo‑4H‑1,3‑thi‑
azin‑2‑ylamino)benzoic acid (4)
A mixture of cinnamoyl thiourea 3 (0.361 g, 1 mol) in 10%
sodium carbonate (50 ml) was refuxed for 8 h and followed
by TLC. The alkaline residue was acidifed with dil. HCl. The
1
N, 7.45%. Found: C, 57.39; H, 4.20; N, 7.38%. H-NMR
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Journal of the Iranian Chemical Society
Table 2 Efect of concentration gradient for the most active com-
Table 5 Efect of time on the antifungal activity of optimum concen-
tration (70 µg) for compound 8
pound on Gram +ve bacteria (percentage of inhibition)
Comp. no.
Concentra-
tion (µg)
S. epidermidis (%)
P. S. aureus
(%) ATCC
6538
Comp. no.
Time
Candida albicans
Aspergillus niger
ATCC 12228
(%) ATCC 10231
(%) ATCC 16404
8
12 h
1 day
18.0
33.0
44.0
52.0
59.0
66.0
73.0
79.0
84.0
84.0
84.0
83.0
21.0
35.0
42.0
54.0
61.0
68.0
76.0
83.0
89.0
89.0
88.0
89.0
6
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
12.0
22.0
35.0
49.0
58.0
72.0
85.0
85.0
84.0
16.0
31.0
45.0
58.0
67.0
81.0
90.0
90.0
89.0
2 days
3 days
4 days
5 days
6 days
7 days
8 days
9 days
10 days
11 days
Table 3 The minimal inhibitory concentration (MIC) of 4, 5, 6, 7, 8,
9a, 10, 11, 12, 14 and 15
Comp. no.
Fungi Candida albi-
cans ATCC 10231
Aspergillus
niger ATCC
16404
(DMSO-d6, 400 MHz) δ: 2.75 (2H, d, J=2.6 Hz, CH2CO),
3.25 t (1H, t, J=2.6 Hz, CHAr), 6.59–7.93 m (8H, m, 2Ar-
H), 12.62 (1H, s, exch. with D2O, NH), 13.39 s (1H, s, exch.
with D2O, OH). 13C-NMR (DMSO-d6, 100 MHz) δ: 35.4
(CH2CO), 110.2, 115.3, 118.5, 128.4, 129.3, 130.4, 133.1,
135.7, 139.8, 142.0, 149.4, 162.2, 168.7 (CO amide), 171.1
(CO acid). m/z (EI, 70 eV) 376 (100), 348 (40), 273 (50),
160 (10).
4
10.0
8.0
7
5.0
7.0
9.0
8.0
10.0
7.0
4.0
3.0
10.0
11.0
6.0
8.5
–
5
6
7
8.0
14.0
7.0
5.0
7.0
12.0
13.0
9.0
8
9a
10
11
12
14
15
3‑[(E)‑3‑(4‑Chlorophenyl)acryloyl]‑2‑mercapto‑
quinazolin‑4(3H)‑one (5)
A mixture of cinnamoyl thiourea derivative 3 (0.361 g, 1 mol)
in sodium ethoxide solution (50 ml) was refuxed for 8 h and
followed by TLC. The solvent was removed under reduced
pressure. The alkaline residue was acidifed with dil. HCl. The
formed product was fltered of, washed with water, dried and
recrystallized from ethanol to give pale yellow crystals in 87%
Yield. Mp. 160–161 °C. IR (KBr, cm−1): 2260 (SH), 1693,
1686 (2C=O), 1629 (C=N), 1588 (C=C). Elem. Anal. Calcd.
for C17H11ClN2O2S (342.80):C, 59.56; H, 3.23; N, 8.17%.
Found: C, 59.53; H, 3.20; N, 8.13%. 1H-NMR (DMSO-d6,
400 MHz) δ: 6.53, 7.56 (2H, 2d, J=14.9 Hz, –CH=CH–),
7.28–7.93 (8H, m, Ar-H), 12.49 (1H, br s, exch. with D2O,
SH). 13C-NMR (DMSO-d6, 100 MHz) δ: 121.2, 122.1, 123.6,
125.1, 126.5, 127.8, 128.6, 129.2, 133.3, 134.6, 137.4, 144.5,
165.8 (NCS), 166.2 and 169.4 (2C=O). m/z (EI, 70 eV) 342
(20), 301 (100), 282 (80), 178 (69), 165 (55).
Nystatin (5 mg/mL) (con- 12.5
trol) DMF (control)
–
(MIC), concentration of compound inhibiting the microbial growth
(µg/ml)
Table 4 Efect of concentration gradient for the most active com-
pound on fungi (percentage of inhibition)
Comp. no.
Concentra- Candida albicans
Aspergillus niger
(%) ATCC 16404
tion (µg)
(%) ATCC 10231
8
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
18.0
29.0
41.0
53.0
63.0
75.0
83.0
82.0
82.0
21.0
35.0
49.0
61.0
70.0
81.0
87.0
87.0
87.0
3‑[2‑(4‑Chlorophenyl)ethenyl]‑7,8‑dihydro‑5H‑[1, 2,
4] thiadiazolo[5,4‑b]quinazolin‑5‑one (6)
A mixture of mercaptoquinazoline derivative 5 (0.343 g,
1 mol), sodium hypochlorite (1 mol), 30% ammonium
1 3

Journal of the Iranian Chemical Society
hydroxide solution (10 ml) and 10% sodium hydroxide
(15 ml) was stirred at r.t for 6 h. The alkaline reaction mix-
ture was then acidifed with dil. HCl. The formed product
was fltered of, washed with cold water, dried and recrys-
tallized from acetic acid to give yellowish crystals in 75%
Yield. Mp. 340–341 °C. IR (KBr, cm−1): 1683 (C=O), 1627
(C=N), 1588 (C=C). Elem. Anal. Calcd. for C17H10ClN3OS
(339.80): C, 60.09; H, 2.97; N, 12.37%. Found: C, 59.99; H,
2.84; N, 12.31%. 1H-NMR (DMSO-d6, 400 MHz) δ: 6.52,
7.57 (2H, 2d, J=14.9 Hz, –CH=CH–), 7.45–7.73 (8H, m,
2Ar-H). 13C-NMR (DMSO-d6, 100 MHz) δ: 118.3, 121.9,
122.6, 125.5, 126.3, 127.6, 129.6, 130.2, 134.5, 135.3,
138.6, 139.2, 163.3 (NCN), 164.3 (NCS), 170.8 (C=O).
3437 (NH), 1696, 1684 (2 C=O amide), 1627 (C=N), 1588
(C=C). Elem. Anal. Calcd. for C25H16ClN3O2S (457.07):
C, 65.57; H, 3.52; N, 9.18%. Found: C, 65.42; H, 3.38; N,
9.10%. 1H-NMR (DMSO-d6, 400 MHz) δ: 6.51, 7.58 (2H,
2d, J=14.9 Hz, –CH=CH–), 6.89–7.94 (13H, m, 3Ar-H),
10.68 (1H, br s, exch. with D2O, NH). 13C-NMR (DMSO-d6,
100 MHz) δ: 121.8, 123.4, 123.7, 123.9, 124.3, 125.4, 126.7,
127.3, 128.6, 129.3, 129.5, 132.2, 134.8, 136.3, 138.3,
140.6, 141.5, 145.7, 156.9 (NCN), 161.8, 169.5 (2 C=O).
Ethyl‑3‑[2‑(4‑Chlorophenyl)ethenyl]‑5‑oxo‑5H‑thiaz
olo[2,3‑b]quinazoline‑2‑carboxylate (9a)
General procedure for synthesis of compounds 7, 8,
9a, b, 10 and 11
The formed product was fltered of, washed with water and
crystallized from benzene to give greenish yellow crys-
tals in 65% Yield. Mp. 201–202 °C. IR (KBr, cm−1): 1727
(C=O ester), 1693 (C=O amide), 1606 (C=N), 1589 (C=C).
Elem. Anal. Calcd. forC21H15ClN2O3S (410.87): C, 61.39;
H, 3.68; N, 6.82%. Found: C, 61.26; H, 3.50; N, 6.74%.
1H-NMR (DMSO-d6, 400 MHz) δ: 1.23 (3H, t, J=7.1 Hz,
CH3), 2.42 (2H, q, J = 7.1 Hz, CH2), 6.51, 7.57 (2H, 2d,
J=14.9 Hz,–CH=CH–), 6.64–8.61 (8H, m, 2Ar-H), 12.43
(2H, s, exch. with D2O, NH2).
A mixture of 2-mercapto-3-cinnamoylquinazolinone (5)
(0.343 g, 1 mol) in ethanol or xylene (10 ml), appropri-
ate halogenated methylene or anhydride reagents such as
N-phenylchloroacetamide, ethyl chloroacetamide, chloro-
acetamide and maleic anhydride (10 mmol) in ethanol or
xylene (15 ml), and a few drops of TEA was refuxed for
8–20 h and followed by TLC. The formed product obtained
after concentration and cooling was fltered of and recrystal-
lized from the proper solvent.
3‑[2‑(4‑Chlorophenyl)ethenyl]‑5‑oxo‑5H‑thiazolo[2,
3‑b]quinazoline‑2‑carboxamid (9b)
2‑((E)3‑(3‑(4‑Chlorophenyl)acryloyl)‑3,4‑dihy‑
dro‑4‑oxoquinazolin‑2‑ylthio)‑N‑phenylacetamide
(7)
The formed product was fltered of, washed with water and
crystallized from ethanol to give white crystals in 65% Yield.
Mp. 170–171 °C. IR (KBr, cm−1): 3438, 3412 (NH2), 1692,
1667 (2 C=O amide), 1606 (C=N), 1588 (C=C). Elem.
Anal. Calcd. C19H12ClN3O2S (381.84): C, 59.76; H, 3.17;
N, 11.00%. Found: C, 59.72; H, 3.12; N, 11.08%. 1H-NMR
(DMSO-d6, 400 MHz) δ: 6.53, 7.54 (2H, 2d, J=14.9 Hz,
–CH=CH–), 7.45–8.61 (8H, m, 2Ar-H), 5.80 (2H, br s, exch.
with D2O, NH2). m/z (EI, 70 eV) 384 (20), 382 (55), 316
(45), 165 (95), 141 (55), 137 (70).
The formed product was fltered of, washed with water
and crystallized from ethanol to give yellowish-white crys-
tals in 65% Yield. Mp. 187–188 °C. IR (KBr, cm−1): 3345
(NH), 1693, 1686, 1665 (3 C=O amide), 1606 (C=N), 1588
(C=C). Elem. Anal. Calcd. for C25H18ClN3O3S (475.95):
C, 63.09; H, 3.81; N, 8.83%. Found: C, 63.03; H, 3.76;
1
N, 8.77%. H-NMR (DMSO-d6, 400 MHz) δ: 4.17 (2H,
s, SCH2), 6.51, 7.57 (2H, 2d, J = 14.9 Hz, –CH=CH–),
6.81–7.87 (13H, m, 3Ar-H), 12.51 (1H, s, exch. with D2O,
NH). 13C-NMR (DMSO-d6, 100 MHz) δ: 32.8 (SCH2),
121.8, 122.4, 123.1, 124.0, 124.2, 125.6, 126.7, 127.9,
128.6, 129.2, 131.3, 132.1, 134.4, 137.4, 138.5, 139.8, 164.2
(NCS), 165.8, 168.8, 169.3 (3 C=O). m/z (EI, 70 eV) (100),
463 (30), 301 (40), 218 (25), 93 (26).
2‑(4‑Chlorophenyl)‑[1, 3] thiazino[2,3‑b]quinazo‑
line‑4,6‑dione (10)
The formed product was fltered of, washed with water and
crystallized from ethanol to give yellow crystals in 79%
Yield. Mp. 210–211 °C. IR (KBr, cm−1): 1689, 1666 (2
C=O amide), 1628 (C=N), 1589 (C=C). Elem. Anal. Calcd.
C17H9ClN2O2S (340.78): C, 59.92; H, 2.66; N, 8.22%.
Found: C, 59.87; H, 2.60; N, 8.16%. 1H-NMR (DMSO-d6,
400 MHz) δ: 6.44 (1H, s, olefnic –COCH=), 7.58–8.23 (8H,
m, 2Ar-H). m/z (EI, 70 eV) 343 (10), 341 (31), 236 (20), 146
(40), 135 (45), 91 (100).
3‑[2‑(4‑Chlorophenyl)ethenyl]‑5‑oxo‑N‑phe‑
nyl‑5H‑[1, 3] thiazolo[2,3‑b]quinazoline‑2‑carboxa‑
mide (8)
The formed product was fltered of, washed with water
and crystallized from toluene to give deep yellowish brown
crystals in 85% Yield. Mp. 209–210 °C. IR (KBr, cm−1):
1 3

Journal of the Iranian Chemical Society
1
H, 3.33; N, 8.43%. H-NMR (DMSO-d6, 400 MHz) δ:
6.52, 7.57 (2H, 2d, J = 14.9 Hz, –CH=CH–), 7.83–8.61
(8H, m, 2Ar-H), 11.60 (1H, s, exch. with D2O, NH). 13C-
NMR (DMSO-d6, 100 MHz) δ: 121.4, 122.3, 124.6, 125.5,
126.4, 127.3, 128.3, 129.6, 133.7, 134.6, 139.2, 144.8,
162.2 (NCONH), 166.8, 169.3 (2 C=O). m/z (EI, 70 eV)
329 (15), 327 (43), 182 (60), 162 (70), 92 (100), 64(60).
4‑[2‑(4‑Chlorophenyl)ethenyl]‑6‑oxo‑2H,6H‑[1, 3]
thiazino[2,3‑b]quinazoline‑2‑carboxylic acid (11)
The formed product was fltered of, washed with water and
crystallized from n-butanol to give grey crystals in 69%
Yield. Mp. 228–229 °C. IR (KBr, cm−1): 3419 (OH), 1710,
1683 (2 C=O amide), 1628 (C=N), 1589 (C=C). Elem.
Anal. Calcd. C20H13ClN2O3S (396.85): C, 60.53; H, 3.30;
1
N, 7.06%. Found: C, 60.44; H, 3.24; N, 7.01%. H-NMR
3‑[(E)‑3‑(4‑Chlorophenyl)
(DMSO-d6, 400 MHz) δ: 3.45 (1H, d, J=1.8 Hz, CH–S),
6.23 (1H, d, J=1.8 Hz, olefnic –CH=C–N), 6.50, 7.57 (2H,
2d, J = 14.9 Hz, –CH=CH–), 7.23–8.61 (8H, m, 2Ar-H),
11.46 (1H, s, exch. with D2O, OH). m/z (EI, 70 eV) 399
(55), 397 (28), 260 (15), 181 (40), 164 (70), 92 (100), 85
(28).
acryloyl]‑2‑(2‑(3‑[(E)‑3‑(4‑chlorophenyl)
acryloyl]‑3,4‑dihydro‑4‑oxoquinazolin‑2‑yl]disul‑
phanyl)quinazolin‑4(3H)‑one (15)
To a solution of 2-mercapto-3-cinnamoylquinazolinone (5)
(0.343 g, 1 mol) of in acetic acid (20 ml), iodine (1 mol)
in acetic acid (10 ml) was added dropwise with stirring at
r.t for 4 h. The reaction mixture was poured into ice-cold
water (50 ml), and the formed product was fltered of,
washed with water, dried and recrystallized from ethanol
to give purple crystals in 87% Yield. Mp. 252–253 °C. IR
(KBr, cm−1): 1694, 1688 (2 C=O amide), 1627 (C=N),
1589 (C=C). Elem. Anal. Calcd. C34H20Cl2N4O4S2
(683.58): C, 59.74; H, 2.95; N, 8.20%. Found: C, 59.70;
General procedure for synthesis of compounds 12,
14
To a solution of 2-mercapto-3-cinnamoylquinazolinone (5)
(0.343 g, 1 mol) in 10% sodium hydroxide solution and/or
acetic acid (20 ml), H2O2 (0.02 mol) was added dropwise
with stirring at r.t. The reaction mixture was stirred further-
more for 4 h and followed by TLC as well. The mixture was
worked up as usual, and the formed product was fltered of,
washed with water, dried and recrystallized from the proper
solvent.
1
H, 2.88; N, 8.17%. H-NMR (DMSO-d6, 400 MHz) δ:
6.52, 7.58 (4H, 2d, J = 14.9 Hz, 2–CH=CH–), 7.90–8.60
(16H, m, 4Ar-H). m/z (EI, 70 eV) 686 (60), 301 (15), 178
(10), 165 (100), 65 (35).
3‑[(E)‑3‑(4‑Chlorophenyl)acryloyl]quinazo‑
lin‑4(3H)‑one (12)
Antimicrobial evaluation
The formed product was fltered of, washed with water and
crystallized from n-butanol to give yellowish-white crys-
tals in 88% Yield. Mp. 342–343 °C. IR (KBr, cm−1): 1694,
1686 (2 C=O amide), 1629 (C=N), 1590 (C=C). Elem.
Anal. Calcd. C17H11ClN2O2 (310.73): C, 65.71; H, 3.57;
Mueller–Hinton agar plates were surface-inoculated
with the tested strains suspensions adjusted to match 0.5
McFarland standards, and the inoculated were spread over
the surfaces of plates using sterile cotton swabs. After dry-
ing of the plates, cups (10 mm diameter) were punched
in the agar. Samples were dissolved in DMF. Diferent
concentrations of each tested compound were calculated
(100–500 µg), using the MIC (Minimal Inhibitory Con-
centration). The (MIC) of each compound was calculated
from the authentic concentration. Then 100 μL from each
tested sample or the antimicrobial agents (control) was
added into the cups. The plates were incubated at 37 °C for
24 h for bacteria and at 30 °C for 5 days for fungi growth
[33]. The antibacterial activity was determined by meas-
uring the diameter of the zone of inhibition and compar-
ing to the antimicrobial agents (control). The experiment
was repeated three times, and the mean inhibition zones
were calculated. The plate cultures were incubated, and the
development of the inhibition growth zones was observed.
1
N, 9.02%. Found: C, 65.61; H, 3.49; N, 8.92%. H-NMR
(DMSO-d6, 400 MHz) δ: 6.52, 7.57 (2H, 2d, J=14.9 Hz,
–CH=CH–), 7.15–7.89 (9H, m, 2Ar-H and N=CH). 13C-
NMR (DMSO-d6, 100 MHz) δ: 122.8, 123.1, 123.8, 125.3,
126.8, 127.2, 128.6, 129.5, 133.2, 135.6, 138.2, 145.0, 153.4
(NCN), 166.4, 169.3 (2 C=O). m/z (EI, 70 eV) 310 (100),
301 (35), 282 (45), 275 (80), 137 (55), 119 (35).
3‑[(E)‑3‑(4‑Chlorophenyl)acryloyl]quinazo‑
line‑2,4(1H,3H)‑dione (14)
The formed product was fltered of, washed with water
and crystallized from benzene to give yellowish-white
crystals in 75% Yield. Mp. 240–241 °C. IR (KBr, cm−1):
3320 (NH), 1697, 1690, 1686 (3 C=O amide), 1606
(C=N), 1588 (C=C. Elem. Anal. Calcd. C17H11ClN2O3
(326.73): C, 62.49; H, 3.39; N, 8.57%. Found: C, 62.37;
1 3

Journal of the Iranian Chemical Society
9. V. Alagarsamy, R. Giridhar, M.R. Yadav, Bioorg. Med. Chem.
Lett. 15, 1877–1880 (2005)
Conclusion
10. V. Alagarsamy, R. Giridhar, M.R. Yadav, J. Pharm. Pharmacol.
58, 1249–1255 (2006)
In summary, we succeeded in preparation a novel series of
quinazolin-5-one derivatives with in high yields via com-
merciable available reagents. The molecular structures of
the new compounds were confrmed via spectroscopic data.
The minimal inhibitory concentration (MIC) for quinazolin-
5-one derivatives 6–8, 12 and 14 exhibited more potential
activity as antibacterial and antifungal agents in comparison
with the standard references.
11. T. Herget, M. Freitag, M. Morbitzer, R. Kupfer, T. Stamminger,
M. Marschall, Antimicrob. Agents Chemother. 48, 4154–4162
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12. A. Maleki, RSC Adv. 4, 64169–64173 (2014)
13. A. Maleki, Tetrahedron Lett. 54, 2055–2059 (2013)
14. A. Maleki, Tetrahedron 68(38), 7827–7833 (2012)
15. D.J. Connolly, D. Cusack, T.P. O’Sullivan, P.J. Guiry, Tetrahedron
61(43), 10153–10202 (2005)
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Acknowledgements The authors are so grateful to Dr. Zainab Fathy
Elsawah in pharmacology dept., Faculty of Science, Zagazig Univer-
sity, for performing and explaining the biological activity section in
this report. Also, the authors thank all the associated personnel in any
reference that contributed in/for the achievement of this article.
17. A. Mohammad, Int. J. Med. Chem. 8(3), 1–27 (2014)
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Compliance with ethical standards
22. A. Maleki, T. Kari, M. Aghaei, J. Porous Mater. 24, 1481 (2017)
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3751–3759 (2008)
Conflict of interest This research holds no confict of interest and is
not funded through any source.
24. M.H. Sherif, M.G. Assy, N. Yousif, M.M. Galahom, J. Iran.
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