New Quinoline-2-one/thiazolium bromide Derivatives; Synthesis, Characterization and Mechanism of Formation

Article abstract of DOI:10.1016/j.molstruc.2021.130501

We report on the formation of new quinoline-2-one derived by thiazolium bromides from the reaction of 3-thiosemicarbazides derived by 2-quinolones with 2-bromoacetophenones. The structure of products was elucidated by mass, IR and NMR spectra together with elemental analysis. The mechanism of products formation was discussed.

Full text of DOI:10.1016/j.molstruc.2021.130501

Journal of Molecular Structure 1239 (2021) 130501
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstr
New Quinoline-2-one/thiazolium bromide Derivatives; Synthesis,
Characterization and Mechanism of Formation
Sara M. Mostafaa, Ashraf A. Alya,∗, Samia M. Sayedb, Mohamed A. Raslanb,
Amira E. Ahmedb, Ayman Nafadyc, Esam A. Ishakd, Ahmed M. Shawkye,
El-Shimaa M.N. Abdelhafezf
a Department of Organic Chemistry, Faculty of Science, Minia University, 61519-El-Minia, Egypt
b Aswan University, Faculty of Science, Chemistry Department, 81529 Aswan, Egypt
c Chemistry department, college of science, King Saud University, Riyadh, KSA
d Department of Chemistry, Faculty of Science, Al-Azhar University, Assiut, Egypt
e Science and Technology Unit (STU), Umm Al Qura University, Makah, KSA
f Department of Medicinal Chemistry, Faculty of Pharmacy, Minia University, 61519 Minia, Egypt
a r t i c l e i n f o
a b s t r a c t
Article history:
We report on the formation of new quinoline-2-one derived by thiazolium bromides from the reaction
of 3-thiosemicarbazides derived by 2-quinolones with 2-bromoacetophenones. The structure of products
was elucidated by mass, IR and NMR spectra together with elemental analysis. The mechanism of prod-
ucts formation was discussed.
Received 26 December 2020
Revised 15 March 2021
Accepted 6 April 2021
Available online 21 April 2021
© 2021 Elsevier B.V. All rights reserved.
Keywords:
3-Thiosemicarbazides
2-quinolone
nucleophilic addition
thiazolium bromides
1. Introduction
zoles [7], phenolic thiazoles [8] and benzothiazoles [9] are well
also studied as neuroprotective agents. Furthermore, ethynyl thi-
Thiazole molecule is one of the interesting class present in
many natural and synthetic products with a broad range of biolog-
ical activities with wide spectrum pharmacological activities such
as antioxidant, antibacterial, antifungal, antitubercular, diuretic,
anti-inflammatory and anticancer activities [1]. Phosphoinositide 3
(PI 3) kinase modulators thiazolo[4,5-g]dihydroindazoles [2], HIV-
azole [10] and pyrimidyl thiazole derivatives [11] displayed good
glutamate receptors antagonist activity for the management of
anxiety disorders. Derivatives of butylthiazole [12], imidazothiazole
[13], 2-aminothiazole [14], and triazole linked thiazole [15] showed
potent anti-Alzheimer activity. Riluzole analogues [16], thiazole-
semicarbazides [17], thiazolepyridons [18], as well as thiazolo-
carboxamide [19] derivatives exhibited promising anticonvulsant
properties.
integrase inhibitor thiazolo[5,4-b] pyrimidine-5(4H)-ones and
a
serine/threonine protein kinase-3 (GSK-3) inhibitors thiazole[5,4-
f]quinazolin-9-ones [3] revealed their therapeutic potential in var-
ious diseases. Pramipexole possessing 2-amino-thiazole fused with
cyclohexane ring, where aminothiazole moiety is an isostere to the
catechol ring of dopamine, demonstrated dopamine D2 agonist ac-
tivity [4]. Riluzole containing aminothiazole moiety is a new neu-
roprotective drug that was approved for the treatment of amy-
otrophic lateral sclerosis (ALS) [5]. Moreover, Hofmann Le Roche
has developed a benzothiazole derivative ASN115 (tozadent) as a
potent adenosine A2AR antagonist for treatment of Parkinson’s dis-
ease which is in phase II clinical trials [6]. Tetrahydrobenzothia-
Researchers have reviewed that 2-quinolone (carbostyril) skele-
ton is an important structural moiety present in a large number of
alkaloids [20,21] and in numerous biologically active compounds
[2,20-27]. Some of them exhibited for example, antioxidative activ-
ity [21], nitric oxide production inhibitory activity [27], and cyto-
toxicity against human tumor cell lines [22]. Others revealed an-
giotensin II receptor antagonist [21], glycine NMDA receptor antag-
onists [23], endothelin receptor antagonist [24], antiplatelet agents
[26], and antitumor agents [25]. Therefore, 2-quinolones are taken
into consideration as valuable intermediates in organic synthesis
[28-33].
Recently, Aly et al. prepared ethyl pyranoquinoline-
∗
4-carboxylates
and
dialkyl
2(4-oxo-1,4-dihydroquinolin-3-
Corresponding authors.
yl)fumarates [34] as well as 4-hydroxy-2-quinolones with 2-(2-
E-mail addresses: ashrafaly63@yahoo.com, ashraf.shehata@mu.edu.eg (A.A. Aly).
https://doi.org/10.1016/j.molstruc.2021.130501
0022-2860/© 2021 Elsevier B.V. All rights reserved.

S.M. Mostafa, A.A. Aly, S.M. Sayed et al.
Journal of Molecular Structure 1239 (2021) 130501
Fig. 1. Design of the target quinoline-2-one/thiazolium bromide derivatives 9a-i
oxo-1,2-dihydroindol-3-ylidene)malononitrile and spiro(indoline-
3,4’-pyranoquinoline)-3’-carbonitriles [35]. Moreover, Aly and his
co-workers synthesized bis(1,2-dihydroquinolin-3-yl)succinic acid
derivatives by one-pot reaction of one equivalent aromatic amines
with two equivalents diethyl malonate [36]. Reaction of four
equivalents of 4-hydroxyquinolin-2(1H)-ones with one equivalent
mediates hydrazine quinolone 5a-c were prepared by react-
ing compounds 4a-c with hydrazine hydrate [39]. Whereas the
corresponding quinoline-2-one/thiosemicarbazide derivatives 7a-
d
were obtained during reaction of hydrazine quinolones 5a-
c with the appropriate isothiocyanates 6a-c [47]. Thus, reaction
of quinoline-2-one/ thiosemicarbazide derivatives 7a-d with 2-
bromoacetophenones 8a-c gave the newly prepared quinoline-2-
one/thiazolium bromide derivatives 9a-i (Scheme 1). The struc-
tures of thiazol-2(3H)-ylidene)-2-oxo-quinolin-4-yl) hydrazinium
bromide 9a-i were elucidated by IR, NMR, mass spectra and ele-
mental analyses.
acenaphthoquinone
gave
1,2-dihydroacenaphthylene)-1,1,2,2-
tetrayl-tetrakis(4-hydroxyquinolin-2(1H)-ones) in good to excellent
yields [37]. In the view of the biological and pharmaceutical
activities, we also reported the design and synthesis of a series
of fused naphthofuroquinoline-6,7,12-triones and pyrano[3,2-
c]quinoline-6,7,8,13-tetraones as potential ERK inhibitors [38].
The synthesized compounds were targeted as candidates to ex-
tracellular signal-regulated kinases ERK1/2 with considerable
As an example, quinoline-2-one/thiazolium bromide derivative
9a, its molecular formula was proved from elemental analysis
as C26H22BrN4OS (Experimental section). Since, mass spectroscopy
unlikely showed the base peak of the salt to be assigned at
m/z = 439. The IR spectrum of quinoline-2-one/thiazolium bromide
derivative 9a showed absorption band at ν = 3330-3320 cm−1 as-
signed for the NH group. No absorption was noted for free car-
bonyl of quinolone in the IR spectrum. The 1H NMR spectrum of
9a showed one broad singlet for one proton at δ = 12.20 ppm
assigned to the quinolone NH-proton. The 1H NMR spectrum of
9a showed a broad singlet at δ = 10.25 ppm assigned to the
deshielded exo-hydrazonium NH-proton. Three singlets were ap-
peared at δ = 2.15, 2.30 and 6.00 ppm for thiazole-CH3, quinolone-
CH3 and quinolone-CH-3, respectively. In 13C NMR spectrum of 9a,
it was observed carbon signals at δ = 162.0 ppm (quinolone-C-2),
and 156.4 ppm (C=N) (Experimental Section). The quinolone-CH3
appears at δ = 20.8 ppm, whereas the thiazole-CH3 appeared at
δ = 22.0 ppm. Both of the thiazole-C-5 and quinolone-CH-3 res-
onated in the 13C NMR spectrum at δ = 115.0 and 95.4 ppm, re-
spectively (see the experimental section).
antineoplastic activity along with
a molecular docking study
using ATP-binding site of ERK2 [38]. Two series of diethyl 2-[2-
(substituted-2-oxo-1,2-dihydroquinolin-4-yl)hydrazono]succinates
and 1-(2-oxo-1,2-dihydro-quinolin-4-yl)-1H-pyrazoles have been
designed and synthesized [39]. Seven compounds were further ex-
amined against the most sensitive cell lines, leukemia CCRF-CEM,
and MOLT-4 [39]. Another two series of N-2,3-bis(6-substituted
quinolin-3-yl)naphthalene-1,4-diones and bisquinolinone triethyl-
ammonium salts were successfully synthesized [40]. We have
also recently reported review dealt with the interesting synthetic
approaches and biological applications of quinolones [41].
Recently, it has been reported on the synthetic routes of differ-
ent thiazolidinones from several thiosemicarbazides and thiocarbo-
hydrazides by using different reagents, and their biological evalu-
ation was also discussed [42,43]. Thiosemicarbazones were used
as a starting material for the synthesis of different heterocyclic
compounds, i.e., naphthothiazole and naphtho-thiadiazepines [44],
4-thiazolidinone derivatives [45,46], 1,3,4-thiadiazoles [47] which
possessed potential biological activities such as anticancer [48],
antioxidants [49], antifungal [50], and antibacterial [51]. Recently,
Another example was shown in case of the quinoline-2-
one/thiazolium bromide derivative 9h, whereas the mass spectrum
showed the molecular peak at m/z = 468/466 (37/100). The 1H
NMR showed a multiplet integrated with two protons at δ = 5.25-
5.15 ppm (allyl=CH2) in addition to a multiplet at δ = 4.06-4.02
ppm (allyl-CH2). The allyl=CH appeared as a multiplet at δ = 6.22-
6.11 ppm. The remarkable proton signal of the CH-4-thiazole res-
onated at δ = 7.15 ppm. In 13C NMR spectrum of 9h, it was ob-
served carbon signals at δ = 161.4 ppm (for C=O), and 154.9
ppm (for C=N) (Experimental Section). The allyl=CH, allyl=CH2,
quinolone-CH-3, and quinolone-CH3 resonated at δ =134.0, 118.2,
95.8 and 21.0 ppm, respectively.
Aly et al, synthesized also
a series of 6-substituted quinolin-
2-one thiosemicarbazides [52] whereas the designed final com-
pounds were evaluated for their in vitro activity against the urease-
producing R. mucilaginosa and Proteus mirabilis bacteria as fun-
gal and bacterial pathogens, respectively [52]. Based on the previ-
ously mentioned aspects, we encouraged to design and synthesize
new thiazolium derived by 2-quinolone derivatives via reaction of
thiosemicarbazides with 2-bromoacetophenones. The designed tar-
get quinoline-2-one/thiazolium bromide derivatives of assumed bi-
ological activity is as illustrated in Fig. 1.
The mechanism described the formation of quinoline-2-
one/thiazolium bromide derivatives 9a-i can be based upon an
initial proton abstract by triethylamine (Et3N) led to increase the
nucleophilicity of sulphur as shown in Scheme 2. Thereafter, sul-
phur anion would attack to the electrophilic-CH in 8 to form
the intermediate 11 accompanied by elimination of a bromide
anion to form 12. Subsequently, cyclization process would then
2. Results and Discussion
Compounds 2-5 were synthesized according to reported
method and their structures were confirmed by matching their
spectral data with the reported ones [53-55]. The key inter-
2

S.M. Mostafa, A.A. Aly, S.M. Sayed et al.
Journal of Molecular Structure 1239 (2021) 130501
Scheme 1. Synthesis of quinoline-2-one/thiazolium bromide derivatives 9a-i
Scheme 2. Mechanism describes the formation of quinoline-2-one/thiazolium bromide derivatives 9a-i
occurs by the attack of the lone pair of the hydrazinyl-NH to
borough, UK), and are uncorrected. The IR spectra were recorded
from potassium bromide disks with a FT device, Minia Univer-
sity NMR spectra were measured in DMSO-d6 on a Bruker AV-
400 spectrometer (400 MHz for 1H, 100 MHz for 13C, and 40.55
MHz for 15N); chemical shifts are expressed in δ (ppm), versus
internal tetramethylsilane (TMS) = 0 ppm for 1H and 13C, and
external liquid ammonia = 0 ppm for 15N. Coupling constants
are stated in Hz. Mass spectra were recorded on a Finnigan Fab
70 eV, Institute of Organic Chemistry, Karlsruhe University, Karl-
sruhe, Germany. TLC was performed on analytical Merck 9385 sil-
ica aluminum sheets (Kieselgel 60) with Pf254 indicator; TLC’s were
the β-electrophilic vinyl would give the salt 13. Neutralization of
13 via proton transfer would give intermediate 14. Finally, elim-
ination of water molecule from 14 followed by addition of the
extrusion hydrogen bromide would finally give compounds 9a-i
(Scheme 2).
3. Experimental
Melting points were determined using open glass capillaries on
a Gallenkamp melting point apparatus (Weiss-Gallenkamp, Lough-
3

S.M. Mostafa, A.A. Aly, S.M. Sayed et al.
Journal of Molecular Structure 1239 (2021) 130501
viewed at λmax = 254 nm. Elemental analyses were carried out at
the Microanalytical Center, Cairo University, Egypt.
General preparation of quinoline-2-one/ thiosemicarbazide
derivatives 7a-d
CH), 120.0 (Ar-C), 114.8 (allyl-CH2=), 105.2 (thiazole-CH-4), 95.4
(quinolone-CH-3), 56.5 (OCH3), 45.7 (allyl-CH2-N) ppm; IR (KBr):
υ´ = 3320-3308 (NH,s), 3052 (Ar-CH), 2933-2820 (Aliph-CH), 1643
(C=O), 1612 cm−1 (C=N). MS (70 eV, %): m/z = 405 (54), 375
(98), 365 (63), 329 (72), 282 (17), 136 (67), 107 (19). Anal. Calcd
for C22H21BrN4O2S (485.40): C, 54.44; H, 4.36; N, 11.54; S, 6.61;
Found: C, 54.60; H, 4.22; N, 11.60; S, 6.44.
To
a suspension of hydrazinoquinolones 5a-c (1 mmol) in
dioxan (25 mL), the appropriate isothiocyanate derivatives 6a-c (1
mmol) were added and the mixture was heated at reflux on a boil-
ing water-bath for 3-4 h. The mixture was then left to cool and
the precipitate so formed was filtered off, washed with hot ethanol
and recrystallized to give the target compounds [47].
6-Chloro-4(2-(3,5-diphenylthiazol-2(3H)-ylidene)-2-oxo-
quinolin-4-yl)hydrazinium bromide (9d). Yellow crystals
(DMF/H2O), yield: 0.431 g (82%), mp = 314-316 °C; 1H NMR
(400 MHz, DMSO-d6): δ = 12.30 (s, 1H, quinolone-NH), 10.00 (s,
1H, hydrazine-NH), 7.60-7.49 (m, 6H, Ar-H + NH), 7.40-7.32 (m,
8H, Ar-H), 6.85 (s, 1H, thiazole-CH-4), 6.10 ppm (s, 1H, quinolone-
CH-3); 13C NMR (100 MHz, DMSO-d6): δ = 162.4 (quinolone-C-2),
156.0 (C=N), 139.4, 139.0 (Ar-C), 138.5 ppm (thiazole-C-5), 135.0
(Ar-C), 128.9, 127.8, 127.0, 126.6, 126.2 (Ar-CH), 125.4, 125.0, 124.6
(Ar-C), 122.0, 121.8, 121.0, 119.0 (Ar-CH), 105.3 ppm (thiazole-
CH-4), 95.8 (quinolone-CH-3); IR (KBr): υ´ = 3320-3310 (NH,s),
3016 (Ar-CH), 2982-2870 (Aliph-CH), 1654 (C=O), 1610 cm−1
(C=N). MS (70 eV, %): m/z = 446/445 (100/33), 411 (33), 368
(22), 291 (19), 270 (11), 175 (12), 124 (40), 110 (21). Anal. Calcd
for C24H18 BrClN4OS (525.85): C, 54.82; H, 3.45; N, 10.65; S, 6.10;
Found: C, 55.90, H, 3.30; N, 10.80; S, 6.22.
General procedure for the synthesis of quinoline-2-
one/thiazolium bromide derivatives 9a–i
To a suspension of quinoline-2-one/ thiosemicarbazide deriva-
tives 7a-d (1 mmol) in absolute EtOH (50 mL) containing 0.5
mL of Et3N, the appropriate bromoacetophenones 8a-c derivatives
(1 mmol) were added and the mixture was heated at reflux on a
boiling water bath for 12–16 h. The mixture was then left to cool,
and the precipitate of quinoline-2-one/thiazolium bromide deriva-
tives 9a-h was collected by filtration, then washed by 100 mL cy-
clohexane and recrystallized from the stated solvents.
6-Methyl-4-(2-(5-methyl-3,4-diphenylthiazol-2(3H)-ylidene)-
2-(2-oxo-quinolin-4-yl)hydrazinium bromide (9a). Yellow crys-
tals (DMF/EtOH), yield: 0.415.2 g (80%), mp = 340-342 °C; 1H
NMR (400 MHz, DMSO-d6): δ = 12.20 (s, 1H, quinolone-NH),
10.25 (s, 1H, hydrazine-NH), 8.00 (s, 1H, Ar-H), 7.51-7.39 (m, 4H,
Ar-H, NH), 7.35-7.22 (m, 5H, Ar-H), 7.20-7.04 (m, 4H, Ar-H), 6.00
(s, 1H, quinolone-CH-3), 2.30 (s, 3H, quinolone-CH3), 2.15 ppm
(s, 3H, thiazole-CH3); 13C NMR (100 MHz, DMSO-d6): δ = 162.0
(quinolone-C-2), 156.4 (C=N), 149.0 (thiazole-C-4), 139.5, 138.5,
135.0 (Ar-C), 130.4, 128.8, 128.4, 127.3, 126.9, 125.1 (Ar-CH), 124.6,
123.4, 122.0 (Ar-C), 121.8, 121.0, 120.1 (Ar-CH), 115.0 (thiazole-C-5),
95.4 (quinolone-CH-3), 22.0 (thiazole-CH3), 20.8 (quinolone-CH3)
4-(2-(2-5(4-Bromophenyl)-3-phenylthiazol-2(3H)-ylidene)-2-
(6-chloro-2-oxo-quinolin-4-yl hydrazinium bromide (9e).
Yellow crystals (DMF/EtOH), yield: 0.568 g (94%), mp = 283-285
°C; 1H NMR (400 MHz, DMSO-d6): δ = 12.25 (s, 1H, quinolone-
NH), 10.10 (s, 1H, hydrazine-NH), 8.40-8.25 (m, 4H, Ar-H +NH),
7.90-7.75 (m, 4H, Ar-H), 7.35-7.25 (m, 5H, Ar-H), 7.00 (s, 1H,
thiazole-CH-4), 6.10 ppm (s, 1H, quinolone-CH-3); 13C NMR (100
MHz, DMSO-d6): δ = 161.8 (quinolone-C-2), 156.8 (C=N), 139.8,
139.4, 135.0 (Ar-C), 133.0 (thiazole-C-5), 129.5, 128.9, 128.0, 127.4,
125.4 (Ar-CH), 125.0, 124.6, 123.8, 122.7 (Ar-C), 122.0, 121.8, 121.0
(Ar-CH), 109.0 ( thiazole-CH-4), 96.0 ppm (quinolone-CH-3); IR
(KBr): υ´ = 3342-3305 (NH,s), 3021 (Ar-CH), 2980-2848 (Aliph-CH),
1653 (C=O), 1605 cm−1 (C=N). MS (70 eV, %): m/z = 524/522
(36/66), 489 (25), 438 (17), 391 (47), 313 (4), 199 (13), 154 (61),
149 (100). Anal. Calcd for C24H17 Br2ClN4OS (604.74): C, 47.67; H,
2.83; N, 9.26; S, 5.30. Found: C, 47.52; H, 2.70; N, 9.37; S, 5.44.
4-(2-(3-Allyl-5(4-bromophenyl)thiazol-2(3H)-ylidene)-2-(6-
chloro-2-oxoquinolin-4-yl) hydrazinium bromide (9f). Yellow
crystals (DMF), yield: 0.523 g (90%), mp = 250-252 °C; 1H NMR
(400 MHz, DMSO-d6): δ = 12.33 (s, 1H, quinolone-NH), 10.20 (s,
1H, hydrazine-NH), 7.70-7.52 (m, 5H, Ar-H +NH), 7.45-7.20 (m, 3H,
Ar-H), 7.00 (s, 1H, Thiazole-CH-4), 6.00 (m, 1H, allyl-CH=), 5.98
(s, 1H, quinolone-CH-3), 5.28 (m, 2H, allyl-CH2=), 4.15 (m, 2H,
CH2-N); 13C NMR (100 MHz, DMSO-d6): δ = 161.1 (quinolone-C-2),
154.9 (C=N), ); 139.0, (Ar-C), 138.2 (Thiazole-C-5), 136.5, 135.0
(Ar-C), 134.0 (allyl-CH=), 128.6, 127.6 (Ar-CH), 127.0, 126.8 (Ar-C),
122.0, 121.8, 121.0 (Ar-CH), 120.0 (Ar-C), 114.9 (allyl-CH2=), 105.3
(thiazole-CH-4), 95.4 (quinolone-CH-3), 45.8 (allyl-CH2-N) ppm; IR
(KBr): ν = 3340-3322 (NH,s), 3025 (Ar-CH), 2980-2850 (Aliph-CH),
1608 (C=O), 1600 cm−1 (C=N). MS (70 eV, %): m/z = 488/486
(17/100), 414 (4), 398 (5), 307 (15), 289 (12), 183 (15), 136 (83), 91
(38). Anal. Calcd for C21H17 Br2ClN4OS (568.71): C, 44.35; H, 3.01;
N, 9.85; S, 5.64; Found: C, 44.44; H, 2.90; N, 9.90; S, 5.70.
ppm; IR (KBr): υ´
=
3330-3320 (NH,s), 3010 (Ar-CH), 2980-
2860 (Aliph-CH), 1640 (C=O), 1613 cm−1 (C=N). MS (70 eV, %):
m/z = 439 (100), 424 (27), 409 (32), 391 (5), 376 (17), 343 (3), 267
(7), 102 (50%). Anal. Calcd for C26H23BrN4OS (519.46): C, 60.12; H,
4.46; N, 10.79; S, 6.17. Found: C, 60.16, H, 4.33; N, 10.70; S, 6.25.
4-(2-(3-Benzyl-5(4-bromophenyl)thiazol-2(3H)-ylidene)-2-(6-
methoxy-2-oxo-quinolin-4-yl) hydrazinium bromide (9b). Yellow
crystals (DMF/EtOH), yield: 0.491 g (84%), mp = 320-322 °C; 1H
NMR (400 MHz, DMSO-d6): δ = 12.25 (s, 1H, quinolone-NH),
10.20 (s, 1H, hydrazine-NH), 8.20 (s, 1H, Ar-H), 7.77-7.58 (m, 4H,
Ar-H + NH), 7.57-7.44 (m, 4H, Ar-H), 7.25-7.19 (m, 4H, Ar-H),
6.95 (s, 1H, thiazole-CH-4), 5.94 (s, 1H, quinolone-CH-3), 4.00 (s,
2H, CH2-benzyl), 3.95 ppm (s, 3H, OCH3); 13C NMR (100 MHz,
DMSO-d6): δ = 162.4 (quinolone-C-2), 155.8 (C=N), 143.0, 140.0,
(Ar-C), 138.1 (thiazole-C-5), 135.0, 129.8, 129.0, 127.6, 127.4 (Ar-
CH), 127.0, 126.8, 126.7 (Ar-C), 122.0, 121.8, 121.0 (Ar-CH), 119.2
(Ar-C), 105.1 (thiazole-CH-4), 95.0 (quinolone-CH-3), 56.0 (OCH3),
40.4 (CH2-Ph) ppm; IR (KBr): υ´ = 3340-3330 (NH,s), 3030 (Ar-CH),
2988-2810 (Aliph-CH), 1650 (C=O), 1611 cm−1 (C=N). MS (70 eV,
%): m/z = 534/532 (22/100), 501/499 (8/12), 468/466 (89/39), 453
(30), 410/408 (24/44), 390 (41), 375 (11), 349 (30). Anal. Calcd for
C26H22Br2N4O2S (614.35): C, 50.83; H, 3.61, N, 9.21; S, 5.22. Found:
C, 50.99; H, 3.55; N, 9.33; S, 5.18.
4-(2(3-Allyl-4-phenylthiazol-2(3H)-ylidene))-2-(6-methoxy-
2-oxo-quinolin-4-yl)hydrazinium bromide (9c). Yellow crystals
(DMF/MeOH), yield: 0.418 (86%), mp = 270-272 °C; 1H NMR (400
MHz, DMSO-d6): δ = 12.33 (s, 1H, quinolone-NH), 10.22 (s, 1H,
hydrazine-NH), 8.00 (s, 1H, Ar-H), 7.80-7.60 (m, 4H, Ar-H + NH),
7.5-7.29 (m, 4H, Ar-H), 6.97 (s, 1H, thiazole-CH4), 6.00 (m, 1H,
allyl-CH=), 5.98 (s, 1H, quinolone-CH-3), 5.28 (m, 2H, allyl-
CH2=), 4.15 (m, 2H, CH2-N), 3.95 ppm (s, 3H, OCH3); 13C NMR
(100 MHz, DMSO-d6): δ = 161.0 (quinolone-C-2), 155.0 (C=N),
143.0, 140.0, 135.0 (Ar-C), 138.2(thiazole-C-5), 134.0 (allyl-CH=),
128.6, 127.6, 127.0 (Ar-CH), 126.8 (Ar-C), 122.0, 121.8, 121.0 (Ar-
4-(2(4-(4-Bromophenyl)-3-phenylthiazol-2(3H)-ylidene)-6-
chloro-2-oxoquinolin-4-yl)- hydrazinium bromide (9g). Yellow
crystals (DMF/MeOH), yield: 0.581 g (96%), mp = 260-262 °C;
1H NMR (400 MHz, DMSO-d6): δ = 12.25 (s, 1H, quinolone-NH),
10.10 (s, 1H, hydrazine-NH), 8.40-8.25 (m, 4H, Ar-H + NH), 7.90-
7.79 (m, 4H, Ar-H), 7.75 (s, 1H, thiazole-CH-5), 7.35-7.25 (m, 5H,
Ar-H), 6.10 ppm (s, 1H, quinolone-CH-3); 13C NMR (100 MHz,
DMSO-d6): δ = 161.8 (quinolone-C-2), 156.8 (C=N), 139.8, 139.4
(Ar-C), 137.0 (thiazole-C-4), 135.0 (Ar-C), 129.5, 128.9, 128.0, 127.4,
125.4 (Ar-CH), 125.0, 124.6, 123.8, 122.7 (Ar-C), 122.0, 121.8, 121.0
4

S.M. Mostafa, A.A. Aly, S.M. Sayed et al.
Journal of Molecular Structure 1239 (2021) 130501
(Ar-CH), 105.3 ( thiazole-CH-5), 96.0 ppm (quinolone-CH-3); IR
(KBr): ν = 3340-3310 (NH,s), 3022 (Ar-CH), 2990-2890 (Aliph-CH),
1650 (C=O), 1606 cm−1 (C=N). MS (70 eV, %): m/z = 524/522
(50/100), 436 (54), 313 (4), 307 (48), 199 (75), 167 (23), 154 (61),
149 (73). Anal. Calcd for C24H17 Br2ClN4OS (604.74): C, 47.67; H,
2.83; N, 9.26; S, 5.30. Found: C, 47.52; H, 2.70; N, 9.37; S, 5.44.
4-(2(3-Allyl-5-(4-bromophenyl)thiazol-2(3H)-ylidene)-2-(6-
methyl-2-oxoquinolin-4-yl)-hydrazinium bromide (9h). Yellow
crystals (DMF/EtOH), yield: 0.504 g (92%), mp = 300-302 °C; 1H
NMR (400 MHz, DMSO-d6): δ = 11.70 (s, 1H, quinolone-NH), 9.88
(s, 1H, hydrazine-NH), 7.70-7.52 (m, 5H, Ar-H + NH), 7.45-7.20
(m, 3H, Ar-H), 7.15 (s, 1H, thiazole-CH-4), 6.22-6.11 (m, 1H, allyl-
CH), 5.97 (s, 1H, quinolone-CH-3), 5.25-5.15 (m, 2H, ally=CH2),
4.06-4.02 (m, 2H, allyl-CH2), 2.10 (s, 3H, CH3); 13C NMR (100
MHz, DMSO-d6): δ = 161.4 (quinolone-C-2), 154.9 (C=N), 139.0,
(Ar-C), 138.2 (Thiazole-C-5), 136.5, 135.0 (Ar-C), 134.0 (allyl-CH=),
128.5, 127.5 (Ar-CH), 127.1, 126.6 (Ar-C), 122.1, 121.9, 121.1 (Ar-
CH), 120.0 (Ar-C), 118.2 (allyl=CH), 105. 3 (thiazole-CH-4), 95.8
(quinolone-CH-3), 45.8 (allyl-CH2-N), 21.0 ppm (CH3); IR (KBr):
υ´ = 3332-3320 (NH,s), 3020 (Ar-CH), 2991-2888 (Aliph-CH), 1652
(C=O), 1602 cm−1 (C=N). MS (70 eV, %): m/z = 468/466 (37/100),
414/412 (15/50), 398 (26), 313 (9), 307 (38), 289 (11), 163 (11), 136
(65), 91 (39). Anal. Calcd for C22H20Br2N4OS (548.29): C, 48.19; H,
3.68; N, 10.22; S, 5.85. Found: C, 48.30; H, 3.81; N, 10.40; S, 5.76.
1-(5(4-Bromophenyl)-3,4-diphenylthiazol-2(3H)-ylidene)-2-
Supplementary materials
Supplementary material associated with this article can be
found, in the online version, at doi:10.1016/j.molstruc.2021.130501.
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