Design, Synthesis, and Pharmacological Assay of Novel Compounds Based on Pyridazine Moiety as Potential Antitumor Agents

Article abstract of DOI:10.1002/jhet.3662

In an endeavor to develop antitumor agents, we made a credible survey regarding synthesis, structure, and pharmacological assay of novel pyridazine derivatives, so that 2-((6-(4-chloro-3-methylphenyl)pyridazin-3-yl)oxy)acetohydrazide 3 was utilized as sca

Full text of DOI:10.1002/jhet.3662

Month 2019
Design, Synthesis, and Pharmacological Assay of Novel Compounds
Based on Pyridazine Moiety as Potential Antitumor Agents
*
Yasmeen M. Ali, Mahmoud F. Ismail,
Fatma S. M. Abu El-Azm,
and Magda I. Marzouk
Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt
*E-mail: fawzy2010@sci.asu.edu.eg
Received March 3, 2019
DOI 10.1002/jhet.3662
Published online 00 Month 2019 in Wiley Online Library (wileyonlinelibrary.com).
In an endeavor to develop antitumor agents, we made a credible survey regarding synthesis, structure, and
pharmacological assay of novel pyridazine derivatives, so that 2-((6-(4-chloro-3-methylphenyl)pyridazin-3-
yl)oxy)acetohydrazide 3 was utilized as scaffold to build novel compounds 4–19 by reaction with various
electrophilic reagents, followed by determination and explanation atropisomerism phenomena and
tauomerism ratio such as keto-enol and lactam–lactim tautomers for some synthesized compounds. In vitro,
these compounds were screened for antitumor efficacy versus two cell lines, namely, hepatocellular carci-
noma and mammary gland breast cancer, by using MTT assay. Among the examined compounds, compound
16 was exhibited promising potent activity (IC50 = 8.67 0.7 μM) versus HepG2 cell line. Meanwhile, com-
pounds 3 and 16 were manifested the very highest efficacy (IC50 = 5.68 0.6 and 9.41 0.9 μM) versus
MCF-7 cell line.
J. Heterocyclic Chem., 00, 00 (2019).
INTRODUCTION
Indeed, during our literature survey, it is clearly
noticeable that, pyridazine nucleus constructed by variant
methods [18,20,22–25], one of them involving reaction
of β-aroyl acrylic acid and/or β-aroyl propionic acid
with hydrazine monohydrate, which has been previously
prepared in our lab [26,27].
Over the last decades, pyridazine core [1] is considered
as crucial structure in medicinal chemistry as
pharmaceuticals [2,3], agrochemistry [4–6] as herbicides
[7], material science [6,8,9], and supermolecular
chemistry [10], where it has a vast variety of biological
activities, for example, antidepressant, antifungal,
antibacterial [11,12], antituberculosis [13], antiviral,
anticancer [14], antihypertensive [15], anti-inflammatory
[16], cardiovascular disorders [17], vasorelaxant activities
[18,19], SGLT2 inhibitors [20], and anti-HRV [21] (Fig. 1).
As
a part of our studies on incorporating of
acetohydrazide to pyridazine moiety to exploit the
nucleophlicity of the nitrogen atom of hydrazide group
to attack on various electrophilic centers to build novel
compounds in order to assay their particular biological
potentials.
© 2019 Wiley Periodicals, Inc.

Y. M. Ali, M. F. Ismail, F. S. M. Abu El-Azm, and M. I. Marzouk
Vol 000
Figure 1. Pharmaceuticals containing pyridazine nucleus.
RESULTS AND DISCUSSION
The predictable structure of compound 4 was explicated
by H NMR spectrum that emerged only one singlet peak
1
As a continuation of our efforts to study the reactivity
of acetohydrazide which connecting with pyridazine
ring as a scaffold to develop new pharmacologically
active compounds. In this article, the targeted pyridazine
synthesized according to the common manners
as exemplified in Scheme 1. Thus, 2-((6-(4-chloro-3-
methylphenyl)pyridazin-3-yl)oxy) acetohydrazide 3 [28]
was formed from the reaction of 6-(4-chloro-3-
(exchangeable with D2O) at δ = 11.59 ppm compatible
with one NH proton, two doublet peaks at δ = 8.17 and
8.12 ppm compatible with Hb, a singlet peak at
δ = 7.98 ppm compatible with methine proton He, a
doublet peak at δ = 7.90 ppm compatible with Hc′, two
doublet peaks at δ = 7.75 and 7.72 ppm compatible with
Hc, a doublet peak at δ = 7.65 ppm compatible with 2Hg,
two doublet peaks at δ = 7.53 and 7.48 ppm compatible
with Hd, a doublet peak at δ = 7.12 ppm compatible with
Ha, a doublet peak at δ = 7.00 ppm compatible with 2Hf,
a singlet peak at δ = 5.28 ppm compatible with CH2, a
singlet peak at δ = 3.80 ppm compatible with OCH3, and
two singlet peaks at δ = 2.39 and 2.37 ppm compatible
with CH3. The appearance of extra signals which
indicated the existence of 4 in two conformations 4A and
4B (as atropisomers), because of hindered rotation of the
methylphenyl)pyridazin-3(2H)-one
1 [26] with ethyl
chloroacetate in dry acetone as a solvent in the presence of
anhydrous K2CO3 to afford 2, followed by hydrazinolysis.
At the outset, some obvious trends will be observed
in this article to exploit the acetohydrazide 3 as a precursor
to construct novel compounds based on pyridazine
moiety. Therefore, condensation of 3 with p-anisaldehyde
in dioxane afforded the Schiff base derivative 4 (Scheme 2).
Scheme 1. The strategy for synthesis of compound 3.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2019
Design, Synthesis, and Pharmacological Assay of Novel Compounds Based on
Pyridazine Moiety as Potential Antitumor Agents
Scheme 2. Synthesis of Schiff base derivatives 4–6.
Figure 2. The atropisomerism phenomena for compound 7.
aryl ring about the pyridazine moiety through pivot bond
as designed in the succeeding text in Figure 2.
form stabilized by the formation of intramolecular H-
bonding chelated in six-membered ring (Fig. 3).
Similarly, condensation of 3 with isatin is easily to afford
2-((6-(4-chloro-3-methylphenyl)pyridazin-3-yl)oxy)-N′-
(2-oxoindolin-3-ylidene) acetohydrazide 5 (Scheme 2).
Manifestly, the condensed structure of 5 was ascertained
from the IR spectrum that obtained two absorption bands
at 1727 and 1696 cmÀ1 compatible with two carbonyl
groups. As a clue for the proposed structure of 5, 1H
NMR spectrum of compound 5 emerged the existence of
two singlet peaks at 12.68 and 11.26 ppm corresponding
to two NH protons beside the appearance of extra
four aromatic protons in aromatic region corresponding
to indolinone moiety. Lactam–lactim tautomerism in
ratio 72:28, the higher ratio of the lactam tautomer
compared with the lactim tautomer is due to their relative
thermodynamic stabilities in DMSO, whereas lactam
In the context, refluxing of compound
3 with
cyclohexanone in mixture of dioxane and
a
dimethylformamide (DMF) awarded the condensed
product 6 as the sole product in moderate yield
1
(Scheme 2). At analyzing H NMR of Schiff base 6 in
CHCl3 as a solvent, it manifested a singlet peak at
δ = 9.08 ppm compatible with deshielded one NH proton
and the peak of NH2 protons was absent. Additionally,
1H NMR displayed the presence of two multiplet peaks at
δ 2.36–2.24 and 1.71–1.62 ppm corresponding to five
CH2 protons of cyclohexylidene ring.
Heterocyclization of compound 3 with acetyl acetone
awarded the pyrazole derivative 7 [28] (Scheme 3). In
particular, 1H NMR spectrum of 7 exhibited a singlet
peak at δ = 6.45 ppm compatible with olefinic proton of
Figure 3. The lactam–lactim tautomers of compound 5.
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Y. M. Ali, M. F. Ismail, F. S. M. Abu El-Azm, and M. I. Marzouk
Vol 000
Scheme 3. Synthetic pathway to compounds 7–11.
pyrazole ring beside two singlet peaks at 2.01 and 1.74 ppm
compatible with CH3a and CH3a′ protons of pyrazole ring,
respectively.
protons for lactam tautomer and two singlet peaks at
δ = 4.90 ppm (for lactam tautomer) and δ = 4.84 ppm
(for lactim tautomer) corresponding to four OCH2
protons. The tremendous ratio of the lactim tautomer is
due to its higher stability because of its more conjugated
pattern as shown in Figure 4.
We envisioned that the structure of compound 10 was
constructed through the succeeding mechanistic scenario
(Scheme 4).
The structure of compound 10 and its mechanism were
also elucidated laboratory by detection of 5-methyl-2,4-
dihydro-3H-pyrazol-3-one as the side product in the
resulting mixture by thin-layer chromatography (TLC)
after separation of the unexpected product 10.
Indeed, reaction of hydrazide 3 with β-ketoester such as
ethyl acetoacetate in dry pyridine awarded 2-((6-(4-chloro-
3-methylphenyl) pyridazin-3-yl)oxy)-N′-(2-((6-(4-chloro-
3-methylphenyl)pyridazin-3-yl)oxy)acetyl) acetohydrazide
10 instead of 8 and 9 [29] (Scheme 3). As evidence for
the unexpected structure 10, 1H NMR spectrum (in
DMSO) canceled the conception of formation of
compounds 8 and/or 9 due to the lack of the singlet
signals of CH2 protons and olefinic proton of 5-
1
pyrazolinone and pyrazole rings, respectively. While H
NMR spectrum emerged broad singlet peak at
δ = 9.68 ppm (exchangeable with D2O) compatible with
two NH protons, five peaks at δ = 8.11–7.05 ppm
compatible with 10 aromatic protons, and a singlet peak
at δ = 2.36 ppm compatible with two CH3 protons.
Furthermore, the compound 10 existed as lactam–lactim
tautomers in the ratio 13:87 (Fig. 4), due to the
Refluxing a mixture of carbohydrazide 3 with 2-((1,3-
diphenyl-1H-pyrazol-4-yl)methylene)malononitrile
in
dioxane including small amount of piperidine as a base
catalyzed afforded pyrazole derivative 11 (Scheme 3).
The foreseeable structure of 11 was unequivocally
ascertained from spectroscopic and elemental analyses.
In DMSO solution, the 1H NMR spectrum of 11 displayed
a singlet peak at δ = 5.02 ppm compatible with Hf proton,
beside two signals at 8.66, 3.44 ppm compatible with
NH and NH2 protons (both exchangeable with D2O),
appearance of broad singlet peak at
δ = 10.35
(exchangeable with D2O) corresponding to two OH
1
respectively. Moreover, the H NMR of 11 emerged that
its comprising of a diasteromeric mixture of keto-enol
tautomers in the ratio of 74:26 (Fig. 5). The intramolecular
chelation of H-bonding in six-membered ring explained
Figure 4. The lactam–lactim tautomers of compound 10.
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Month 2019
Design, Synthesis, and Pharmacological Assay of Novel Compounds Based on
Pyridazine Moiety as Potential Antitumor Agents
Scheme 4. A plausible mechanistic pathway to compound 10.
up a singlet peak at δ = 4.12 ppm characteristic to CH2
protons, that coming from incorporation of chloroacetyl
group via tetrahedral mechanism.
Refluxing of acetohydrazide derivative 3 in formic
acid for 12 h afforded the hydrolyzed acetic acid
derivative 14 (Scheme 5). Firstly, compound 14 was
elucidated by IR spectrum, while it remarked a band at
1
1710 cmÀ1 compatible with C═O of acid. Secondly, H
NMR spectrum exhibited the existence of peak at
13.13 ppm (exchangeable with D2O) corresponding to OH
proton of acid.
Incredibly, when 3 was subjected to reflux with triethyl
orthoformate, furnished the 1,3,4-oxadiazole derivative
16 (Scheme 5). The undesired structure of 16 was
conspicuously ascertained by elemental analysis and
1
different spectroscopic techniques. H NMR spectrum of
16 showed at δ = 10.03 and 8.38 ppm two peaks
exchangeable with D2O compatible with two NH protons,
at δ = 8.10–7.05 ppm a multiplet peak compatible with
10 aromatic protons, at δ = 5.09–4.78 ppm a multiplet
peak compatible with two CH2 protons, and at δ = 2.37
and 2.27 ppm two singlet peaks compatible with two
CH3 protons.
Mechanistically, the formation of 16 initiated from
attacking of NH2 of hydrazide that prompted as a
nucleophile on the electrophilic carbon center of triethyl
orthoformate to form ethyl formohydrazonate derivative
15 as an intermediate, followed by attacking of another
molecule of carbohydrazide 3 and then finished by
oxidation after intramolecular 1,5-endo-trig cyclization as
shown in Scheme 6.
Refluxing a mixture of compound 3 with phenyl
isothiocyanate in DMF as a solvent furnished 2-(2-((6-(4-
chloro-3-methylphenyl)pyridazin-3-yl)oxy)acetyl)-N-
phenylhydrazine-1-carbothioamide 17 (Scheme 7). 1H
NMR spectrum of the carbothioamide derivative 17 was
clearly exhibited the presence of three peaks at δ 10.60,
10.36, and 9.65 ppm corresponding to three deshielded
NH protons.
Figure 5. The keto-enol tautomers of compound 11.
the higher proportion of enol tautomer of compound 11
as shown in the succeeding text in Figure 6, as it
manifested a broad and a singlet peak at δ = 11.61 and
5.23 ppm compatible with OH and olefinic protons,
respectively.
The phthalimido derivative 12 was commenced by
treatment of 3 with phthalic anhydride in boiling n-butanol
as a solvent (Scheme 5). The structure of compound 12
was elaborated by their spectroscopic data and elemental
analysis. Obviously, the IR spectrum of 12 displayed
υ
(C═O) at 1790, 1736, 1708, and 1656 cmÀ1. Moreover, 1H
NMR spectrum obtained at δ = 11.10 ppm a singlet peak
compatible with one NH proton beside that the peak of
NH2 protons was lacked.
Curing a mixture of compound 3 with carbon disulfide in
dioxane as a solvent under alkaline condition (aq. KOH) to
reflux for 24 h afforded a mixture from 1,3,4-oxadiazole-2-
thiol derivative 18 and the hydrolyzed product 14
(Scheme 7). This mixture was separated by treatment
with Na2CO3 solution followed by filtration, and the
residue was considerable as 1,3,4-oxadiazole-2(3H)-thione
derivative 18, while the mother liquor was acidified to get
the hydrolyzed product 14.
Stirring of carbohydrazide 3 with chloroacetyl chloride
in DMF at ambient temperature to afford smoothly 2-
chloro-N′-(2-((6-(4-chloro-3-methylphenyl)pyridazin-3-yl)
oxy)acetyl)acetohydrazide 13 (Scheme 5). After profound
1
investigation of H NMR spectrum of 13 which showed
While 2,4-dihydro-3H-1,2,4-triazole-3-thione derivative
19 was emanated from refluxing a mixture of compound 3
with ammonium thiocyanate and concentrated HCl in
aqueous solution for 30 min (Scheme 7), the spectral and
elemental analyses for the compounds 18 and 19 are in
keeping with their chemical structures.
Figure 6. Intramolecular chelation in compound 11 (enol tautomer).
Journal of Heterocyclic Chemistry
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Y. M. Ali, M. F. Ismail, F. S. M. Abu El-Azm, and M. I. Marzouk
Vol 000
Scheme 5. Synthetic pathway to compounds 12–16.
Scheme 6. A plausible mechanistic pathway to compound 16.
Scheme 7. Synthetic pathway to compounds 17–19.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2019
Design, Synthesis, and Pharmacological Assay of Novel Compounds Based on
Pyridazine Moiety as Potential Antitumor Agents
PHARMACOLOGY
In vitro antitumor evaluation.
Evaluation of the
antitumor activity in vitro for the synthesized compounds
was employed by utilizing MTT assay [30,31] versus
hepatocellular carcinoma (HepG2) and mammary gland
breast cancer (MCF-7) as two human tumor cell lines.
Doxorubicin was chosen as the reference anticancer drug.
The inhibitory activities IC50 (μM) of compounds 3–19
are expressed in Table 1 and Figure 7.
As inspection of the data in Table 1 and Figure 7, which
revealed that compound 16 has the best potent efficacy
(IC50 < 10 μM) versus HepG2 cell line. Meanwhile,
compounds 3 and 16 were manifested promising potent
activities (IC50 < 10 μM) versus MCF-7 cell line in
comparison with doxorubicin. For HepG2 cell line, the
strong cytotoxic efficacy was remarked by compounds 3
and 6 that showed the percentage viability of IC50 at
13.91 1.1 and 19.80 1.6 μM, respectively. Meanwhile,
compounds 7, 11, 13, 17, 18, and 19 revealed moderate
activity, whereas the rest of compounds exhibited weak
activities. Meanwhile, the efficacy versus MCF-7 cell line
emerged that compounds 6 and 7 have the strong
Figure 7. Antitumor activity of some new compounds versus HepG2 and
MCF-7 cells. [Color figure can be viewed at wileyonlinelibrary.com]
Figure 8. Bioisosteric relationship between five-membered rings
heterocyclic.
percentage viability IC50 at 11.50
1.0 and
lines, namely, HepG2 and MCF-7. Unfortunately, the
incorporation of other groups or heterocyclic moieties to
pyridazine ring decreased the antitumor efficacy versus
both the HepG2 and MCF-7 cells.
18.34 1.4 μM, respectively. Meanwhile, compounds 11,
13, 18, and 19 revealed moderate activities, and the other
screened compounds emerged weak activities.
Structure–activity
relationships.
Regardless of
In an effort to manifest the structure–activity
relationships’ information, the parent carbohydrazide 3
showed more potency than other synthesized compounds
except compound 16 against HepG2, which indicated
that NH2 group of carbohydrazide 3 increased the
hydrophobicity character.
incorporation of 1,3,4-oxadiazole moiety beside
carbohydrazide group to pyridazine ring as in compound
16 improved the antitumor efficacy toward two cell
Table 1
On the basis of the structural resemblance between the
pyrazole, 1,3,4-oxadiazole, and 1,2,4-triazole rings in
compounds 7, 18, and 19, respectively, as depicted in
Figure 8, its analogues have been evaluated in vitro for
antitumor efficacy. The structure–activity relationships
within these series are approximate.
Antitumor activity of some new compounds versus HepG2 and MCF-
7cells.
In vitro cytotoxicity IC50 (μM)a
Compounds
DOX
3
4
5
6
7
10
11
12
13
14
16
17
18
19
HepG2
MCF-7
4.50 0.3
13.91 1.1
55.19 3.2
72.96 3.9
19.80 1.6
25.73 1.9
69.12 3.5
43.84 2.8
91.65 4.8
49.38 3.0
62.72 3.5
8.67 0.7
4.17 0.2
5.68 0.6
60.32 3.7
52.44 3.4
11.50 1.0
18.34 1.4
73.80 4.2
38.67 2.5
84.26 4.7
41.54 2.8
67.48 3.9
9.41 0.9
CONCLUSION
In summary, in order to develop efficacious antitumor
agents, we have designed, synthesized, and characterized
novel structures based on pyridazine moiety, as the
reaction of 2-((6-(4-chloro-3-methylphenyl)pyridazin-3-yl)
oxy)acetohydrazide 3 with various electrophilic reagents
such as aldehyde, ketones, β-diketone, β-ketoester,
arylidene malononitrile, phthalic anhydride, chloroacetyl
chloride, formic acid, triethyl orthoformate, phenyl
isothiocyanate, carbon disulfide, and ammonium
thiocyanate, followed by determination and explanation
83.45 4.3
28.65 2.1
36.07 2.4
75.03 4.5
31.39 2.3
22.95 1.7
DOX, doxorubicin.
aIC50 (μM): 1–10 (very strong); 11–20 (strong); 21–50 (moderate); 51–
100 (weak); and above 100 (non-cytotoxic).
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Y. M. Ali, M. F. Ismail, F. S. M. Abu El-Azm, and M. I. Marzouk
Vol 000
atropisomerism phenomena and tauomerism ratio such
as keto-enol and lactam–lactim tautomers for some
synthesized compounds. Evaluation of their antitumor
activities in vitro versus HepG2 and MCF-7 cell lines by
MTT assay. Compound 16 was exhibited promising
potent efficacy versus HepG2 cell line. Meanwhile,
compounds 3 and 16 were manifested the very highest
efficacy versus MCF-7 cell line.
for 12 h. The obtained mixture was concentrated.
The precipitated solid was separated, dried fully, and
recrystallized from ethanol/dioxane to give 4 as white
crystals; mp: 222–224°C, yield: 45%. IR (KBr, υ/cmÀ1):
3184 (NH), 2952, 2829 (CH2, CH3), 1695 (C═O), 1654
1
(C═N). H NMR (300 MHz, DMSO-d6) δ (ppm): 11.59
(s, 1H, NH, exchangeable with D2O), 8.17–8.13, 8.12–
8.08 (two d, 1H, Ar─H, Hb, J = 9.9 Hz), 7.98 (s, 1H,
N═CHe), 7.93–7.92, 7.90–7.89 (two d, 1H, Ar─H, Hc′,
Jm = 1.8 Hz), 7.81, 7.75–7.72 (two d, d, 1H, Ar─H, Hc,
Jo = 8.7 Hz, Jm = 1.8 Hz), 7.68–7.65 (d, 2H, Ar─H, Hg,
J = 6.9 Hz), 7.53–7.50, 7.48 (two d, 1H, Ar─H, Hd,
J = 8.4 Hz), 7.12–7.09 (d, 1H, Ar─H, Ha, J = 9.6 Hz),
7.01–6.98 (d, 2H, Ar─H, Hf, J = 6.6 Hz), 5.28 (s, 2H,
OCH2), 3.80 (s, 3H, OCH3), 2.39–2.37 (two s, 3H, CH3).
MS m/z (%): 410 (M+; 21.95), 260 (4.66), 232 (32.48),
177 (7.42), 162 (15.11), 150 (24.54), 76 (89.43). Anal.
Calcd for C21H19N4O3Cl (410.11): C, 61.39; H, 4.66;
N, 13.64; Cl, 18.63. Found: C, 61.47; H, 4.57; N, 13.72;
Cl, 18.53.
EXPERIMENTAL
All melting points without correction were measured on
Griffin and Geory melting point apparatus. The IR spectra
were obtained on the Nicolet iS10 FT-IR spectrometer
1
using KBr Wafer technique. H NMR spectra were made
on a Varian Gemini 300 MHz utilizing tetramethylsilane
as the reference and chemical shifts are explained in
δ-scale. EI-MS were performed on a Schimadzu-GC–MS
operating at 70 eV. Elemental analyses were proceeded
by Perkin-Elmer 2400 CHN elemental analyzer.
Biological activity was implemented at the drugs
department, Faculty of pharmacy, Mansoura University,
Egypt. The homogeneity and purity of the synthesized
compounds was controlled by TLC (using TLC aluminum
sheets silica gel F254 [Merck]).
2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)-N′-(2-
oxoindolin-3-ylidene)acetohydrazide 5.
A mixture of
compound 3 (0.5 g, 1.7 mmol) and isatin (0.25 g,
1.7 mmol) in dioxane (15 mL) was refluxed for 9 h. After
evaporation of the excess solvent, the deposited solid was
separated, dried fully, and recrystallized from
dioxane/DMF to give 5 as yellow crystals (as lactam–
lactim tautomer); mp: 178–180°C, yield: 40%. IR (KBr,
υ/cmÀ1): 3290, 3233 (NH), 2952, 2917, 2850 (CH3, CH2),
2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)
acetohydrazide 3 [28]. A mixture of ethyl 2-((6-(4-chloro-
3-methylphenyl)pyridazin-3-yl)oxy)acetate
2
(1 g,
1
3.2 mmol) and hydrazine hydrate (0.16 mL) in ethanol
(10 mL) was heated under reflux for 12 h. After cooling
the reaction mixture, the separated solid was boiled with
petroleum ether (bp 80–100°C) filtered off, dried fully,
and recrystallized from ethanol/dioxane to give 3 as
white crystals; mp: 220–222°C (Lit. mp: 210–212°C) [28],
yield: 50%. IR (KBr, υ/cmÀ1): 3318, 3252, 3120 (NH,
NH2), 2996, 2923 (CH3, CH2), 1669 (C═O), 1653 (C═N).
1H NMR (300 MHz, DMSO-d6) δ (ppm): 9.31 (s, 1H,
NH, exchangeable with D2O), 8.08–8.05 (d, 1H, Ar─H,
Hb, J = 9.9 Hz), 7.87–7.86 (d, 1H, Ar─H, Hc′,
Jm = 1.8 Hz), 7.74–7.71 (d, d, 1H, Ar─H, Hc, Jo = 8.4 Hz,
Jm = 2.1 Hz), 7.51–7.48 (d, 1H, Ar─H, Hd, J = 8.4 Hz),
7.06–7.02 (d, 1H, Ar─H, Ha, J = 9.9 Hz), 4.72 (s, 2H,
OCH2), 4.27 (s, 2H, NH2, exchangeable with D2O), 2.39
(s, 3H, CH3). MS m/z (%): 292 (M+; 14.39), 261 (100),
233 (43.29), 220 (4.78), 206 (16.99), 183 (8.53), 162
(18.08), 142 (8.41) 127 (8.87), 101 (6.88), 52 (68.58).
Anal. Calcd for C13H13N4O2Cl (292.07): C, 53.34; H,
4.48; N, 19.14; Cl, 12.11. Found: C, 53.26; H, 4.54; N,
19.19; Cl, 12.02.
1727 (C═Oindolinone), 1696 (C═Oamide), 1655 (C═N). H
NMR (300 MHz, DMSO-d6) δ (ppm): 13.18 (br. s, 1H,
OH, exchangeable with D2O for lactim tautomer), 12.68
(s, 1H, NH, exchangeable with D2O for lactam tautomer),
11.26 (s, 1H, NH(indolinone), exchangeable with D2O),
8.15–8.11 (d, 1H, Ar─H, Hb, J = 9.9 Hz), 7.91–7.90 (d,
1H, Ar─H, Hc′, Jm = 1.8 Hz), 7.76–7.73 (d, d, 1H, Ar─H,
Hc, Jo = 8.4 Hz, Jm = 2.1 Hz), 7.58–7.54 (t, 1H, Ar─H,
Hf, J = 6.9 Hz, J = 6.9 Hz), 7.54–7.51 (d, 1H, Ar─H, Hd,
J = 8.4 Hz), 7.41–7.36 (t, 1H, Ar─H, Hg, J = 7.8 Hz,
J = 7.2 Hz), 7.16–7.13 (d, 1H, Ar─H, Ha, J = 9.9 Hz),
7.10–7.07 (d, 1H, Ar─H, Hh, J = 7.8 Hz), 6.96–6.94 (d,
1H, Ar─H, He, J = 7.5 Hz), 5.46 (s, 2H, OCH2 for lactam
tautomer), 5.11 (s, 2H, OCH2 for lactim tautomer), 2.39,
2.37 (two s, 3H, CH3). MS m/z (%): 421 (M+; 13.79), 395
(19.30), 380 (74.74), 303 (63.75), 260 (44.92), 245
(34.47), 210 (21.76), 170 (13.86). Anal. Calcd for
C21H16N5O3Cl (421.09): C, 59.79; H, 3.82; N, 16.60; Cl,
8.40. Found: C, 59.88; H, 3.86; N, 16.48; Cl, 8.31.
2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)-N′-
cyclohexylideneacetohydrazide 6. A mixture of compound
3 (0.5 g, 1.7 mmol) and cyclohexanone (0.2 mL, 1.7 mmol)
in dioxane/DMF (20 mL) was refluxed for 14 h. The
obtained mixture was concentrated and then poured into
water. The precipitated solid was separated, dried fully,
2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)-N′-(4-
methoxybenzylidene)acetohydrazide 4.
A mixture of
compound 3 (0.5 g, 1.7 mmol) and anisaldehyde
(0.19 mL, 1.6 mmol) in dioxane (15 mL) was refluxed
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2019
Design, Synthesis, and Pharmacological Assay of Novel Compounds Based on
Pyridazine Moiety as Potential Antitumor Agents
and recrystallized from ethanol to give 6 as white crystals
(as lactam–lactim tautomer); mp: 223–225°C, yield: 40%.
IR (KBr, υ/cmÀ1): 3214 (NH), 2931, 2854 (CH3, CH2),
1669 (C═O), 1591 (C═N). 1H NMR (300 MHz,
DMSO-d6) δ (ppm): 9.08 (s, 1H, NH, exchangeable
with D2O), 7.80 (d, 1H, Ar─H, Hc′, J = 1.5 Hz), 7.68–
7.65 (d, 1H, Ar─H, Hb, J = 9.9 Hz), 7.52–7.50 (d, 1H,
Ar─H, Hc, J = 5.7 Hz), 7.40–7.37 (d, 1H, Ar─H, Hd,
J = 8.1 Hz), 7.06–7.03 (d, 1H, Ar─H, Ha, J = 9.9 Hz),
5.36 (s, 2H, OCH2), 2.40 (s, 3H, CH3), 2.36–2.24 (m,
4H, N═C (CH2)2(cyclohexylidene)), 1.71–1.62 (m, 6H,
3CH2(cyclohexylidene)). MS m/z (%): 372 (M+; 38.86), 289
(16.50), 276 (31.94), 261 (55.19), 232 (45.02), 205 (5.30),
177 (3.82), 128 (7.14), 76 (73.69), 69 (86.65), 62 (100),
54 (87). Anal. Calcd for C19H21N4O2Cl (372.14): C,
61.21; H, 5.68; N, 15.03; Cl, 19.51. Found: C, 61.11; H,
5.81; N, 15.11; Cl, 19.43.
2H, Ar─H, 2Hc, Jo = 8.4 Hz, Jm = 1.8 Hz), 7.51–7.43
(two d, 2H, Ar─H, 2Hd, J = 8.4 Hz, J = 8.1 Hz), 7.113–
7.057 (two d, 2H, Ar─H, 2Ha, J = 9.9 Hz), 4.90 (s, 4H,
2OCH2 for lactam tautomer), 4.84 (s, 4H, 2OCH2 for
lactim tautomer), 2.36, 2.31 (two s, 6H, 2CH3). MS m/z
(%): 277 (M-C13H10N3O2Cl; 13.99), 276 (17.21), 262
(16.61), 186 (48.33), 156 (78.89), 68 (100). Anal. Calcd
for C26H22N6O4Cl2 (552.11): C, 56.43; H, 4.01; N, 15.19;
Cl, 12.81. Found: C, 56.36; H, 3.97; N, 15.27; Cl, 12.87.
5-Amino-1-(2-((6-(4-chloro-3-methylphenyl)pyridazin-3-yl)
oxy)acetyl)-1′,3′-diphenyl-2,3-dihydro-1H,1’H-[3,4′-
bipyrazole]-4-carbonitrile 11. A mixture of compound 3
(0.5 g, 1.7 mmol) and 2-((1,3-diphenyl-1H-pyrazol-4-yl)
methylene)malononitrile (0.5 g, 1.7 mmol) in dioxane
(15 mL) containing 1 mL of piperidine as a base
was refluxed for 8 h. The obtained mixture was
concentrated and then acidified with cold dilute HCl and
the precipitated solid was separated, dried fully, and
recrystallized from benzene to give 11 as yellow crystals
(as keto-enol tautomer); mp: 198–200°C, yield: 25%. IR
(KBr, υ/cmÀ1): 3332, 3198 (NH, NH2), 2923, 2852 (CH2,
2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)-1-(3,5-
dimethyl-1H-pyrazol-1-yl)ethan-1-one 7 [28]. A mixture of
compound 3 (0.5 g, 1.7 mmol) and acetyl acetone (0.17 mL,
1.7 mmol) in dioxane (15 mL) was refluxed for 12 h. The
obtained mixture gave oil after concentration. This oil was
solidified by washing with methanol. The precipitated
solid was separated, dried fully, and recrystallized from
diethyl ether to give 7 as yellow crystals; mp: 158–160°C,
(Lit. mp: 164–166°C) [28], yield: 20%. IR (KBr, υ/cmÀ1):
1
CH3), 2200 (C≡N) 1692 (C═O), 1664 (C═N). H NMR
(300 MHz, DMSO-d6) δ (ppm): 11.61 (br. s, 1H, OH,
exchangeable with D2O for enol tautomer), 9.04 (s, 1H,
C5-H(pyrazole)), 8.66 (s, 1H, NH, exchangeable with D2O),
8.16–7.35 (m, 14H, Ar─H), 7.13–7.09 (d, 1H, Ar─H, Ha,
J = 9.9), 5.23 (s, 1H, C═CH for enol tautomer), 5.02 (s,
1H, Hf), 4.87 (s, 2H, OCH2 for keto tautomer), 3.44 (br. s,
2H, NH2, exchangeable with D2O), 2.39 (s, 3H, CH3). MS
m/z (%): 586 (M+-2; 3.46), 551 (14.53), 521 (20.73), 449
(17.95), 261 (55.84), 233 (16.24), 162 (8.48), 77 (89.06),
68 (100), 56 (14.69), 62 (100). Anal. Calcd for
C32H25N8O2Cl (588.18): C, 65.25; H, 4.28; N, 19.02; Cl,
6.02. Found: C, 65.13; H, 4.21; N, 19.00; Cl, 5.92.
1
2921, 2852 (CH2, CH3), 1657 (C═O), 1591 (C═N). H
NMR (300 MHz, DMSO-d6) δ (ppm): 8.10–8.07 (d, 1H,
Ar─H, Hb, J = 9.9 Hz), 7.88–7.87 (d, 1H, Ar─H, Hc′,
Jm = 2.1 Hz), 7.76–7.73 (d, d, 1H, Ar─H, Hc), 7.53–7.50
(d, 1H, Ar─H, Hd, J = 8.4 Hz), 7.10–7.06 (d, 1H, Ar─H,
Ha, J = 9.6 Hz), 6.45 (s, 1H, C═CH(pyrazole)), 5.12–5.07
(two d, 2H, OCHeHf, J = 12.9 Hz, J = 13.2 Hz), 2.39 (s,
3H, CH3), 2.01 (s, 3H, CH3a(pyrazole)), 1.74 (s, 3H, CH3a′
(pyrazole)). MS m/z (%): 356 (M+; 30.50), 263 (47.01), 260
(53.07), 233 (50.39), 204 (20.07), 163 (47.82), 127
(31.95), 100 (28.33), 75 (31.69), 69 (82.48), 55 (56.91).
Anal. Calcd for C18H17N4O2Cl (356.10): C, 60.59; H,
4.80; N, 15.70; Cl, 19.94. Found: C, 60.73; H, 4.89; N,
15.64; Cl, 19.86.
2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)-N-
(1,3-dioxoisoindolin-2-yl)acetamide 12.
A mixture of
compound 3 (0.5 g, 1.7 mmol) and phthalic anhydride
(0.25 g, 1.7 mmol) in n-butanol (10 mL) was heated under
reflux for 8 h. The deposited solid was separated on hot,
washed with ethanol, dried fully, and recrystallized
from dioxane to give 12 as white crystals; mp: >300°C,
yield: 20%. IR (KBr, υ/cmÀ1): 3159 (NH), 2949 (CH2,
CH3), 1790, 1736, 1708 (C═Oimide), 1656 (C═Oamide). 1H
NMR (300 MHz, DMSO-d6) δ (ppm): 11.10 (s, 1H,
NH, exchangeable with D2O), 8.09–8.06 (d, 1H, Ar─H,
Hb, J = 9.9 Hz), 7.98–7.92 (m, 5H, Ar─H), 7.88–7.87 (d,
1H, Ar─H, Hc′, Jm = 1.8 Hz), 7.76–7.73 (d, d, 1H, Ar─H,
Hc, Jo = 8.7 Hz, Jm = 1.8 Hz), 7.54–7.51 (d, 1H, Ar─H,
Hd, J = 8.1 Hz), 7.13–7.09 (d, 1H, Ar─H, Ha, J = 9.6 Hz),
5.07 (s, 2H, OCH2), 2.41 (s, 3H, CH3). MS m/z (%): 422
(M+; 29.61), 320 (40.78), 280 (35.43), 276 (77.07). Anal.
Calcd for C21H15N4O4Cl (422.08): C, 59.65; H, 3.58;
N, 13.25; Cl, 8.38. Found: C, 59.60; H, 3.56; N, 13.29;
Cl, 8.32.
2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)-N′-(2-
((6-(4-chloro-3-methylphenyl)pyridazin-3-yl)oxy)acetyl)
acetohydrazide 10.
A mixture of compound 3 (0.5 g,
1.7 mmol) and ethyl acetoacetate (0.21 mL, 1.6 mmol)
in pyridine (10 mL) was heated under reflux for 3 h.
The deposited solid was separated on hot, dried, and
recrystallized from DMF to give 10 as white crystals; mp:
>300°C, yield: 30%. IR (KBr, υ/cmÀ1): 3156 (NH), 2960
(CH2, CH3), 1675 (C═O), 1627 (C═N). 1H NMR
(300 MHz, DMSO-d6) δ (ppm): 10.35 (br. s, 2H, 2OH,
exchangeable with D2O for lactim tautomer), 9.68 (br. s,
2H, 2NH, exchangeable with D2O for lactam tautomer),
8.11–8.05 (two d, 2H, Ar─H, 2Hb, J = 9.6 Hz), 7.87–7.86
(d, 2H, Ar─H, 2Hc′, Jm = 1.8 Hz), 7.77–7.69 (two d, d,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Y. M. Ali, M. F. Ismail, F. S. M. Abu El-Azm, and M. I. Marzouk
Vol 000
2-Chloro-N′-(2-((6-(4-chloro-3-methylphenyl)pyridazin-3-
yl)oxy)acetyl)acetohydrazide 13. To a cold stirred solution
(ppm): 10.03 (s, 1H, NH, exchangeable with D2O), 8.38
(br. s, 1H, NH, exchangeable with D2O), 8.10–7.48 (m,
8H, Ar─H), 7.08–7.05 (d, 2H, Ar─H, 2Ha, J = 9.9 Hz),
5.09–4.78 (m, 4H, 2OCH2), 2.37, 2.27 (2 s, 6H, 2CH3).
MS m/z (%): 590 (M+-2; 2.29), 578 (9.44), 302 (100),
261 (15.81), 233 (8.95), 204 (9.13), 192 (12.29), 163
(8.03) 150 (10.36), 126 (20.48), 68 (33.47), 57 (43.01),
44 (78.74). Anal. Calcd for C27H22N8O4Cl2 (592.11): C,
54.65; H, 3.74; N, 18.88; Cl, 11.95. Found: C, 54.71; H,
3.77; N, 18.83; Cl, 11.89.
of compound 3 (0.5 g, 1.7 mmol) in DMF (10 mL),
chloroacetyl chloride (0.13 mL, 1.6 mmol) was added
dropwise, and the obtained mixture was stirred at room
temperature for 4 h and then left overnight and poured
into water. The precipitated solid was separated, dried
fully, and recrystallized from ethanol/dioxane to give 13
as white crystals; mp: 258–260°C, yield: 20%. IR (KBr,
υ/cmÀ1): 3176 (NH), 1678, 1658 (C═O), 1614 (C═N),
1
2920, 2853 (CH2, CH3). H NMR (300 MHz, DMSO-d6)
2-(2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)
δ (ppm): 10.41 (s, 2H, 2NH, exchangeable with D2O),
8.09–8.06 (d, 1H, Ar─H, Hb, J = 9.9 Hz), 7.89 (d, 1H,
Ar─H, Hc′, Jm = 1.8 Hz), 7.75–7.72 (d, d, 1H, Ar─H,
Hc, Jo = 8.7 Hz, Jm = 1.8 Hz), 7.53–7.51 (d, 1H, Ar─H,
Hd, J = 8.4 Hz), 7.11–7.07 (d, 1H, Ar─H, Ha,
J = 9.6 Hz), 4.85 (s, 2H, OCH2), 4.12 (s, 2H, CH2Cl),
2.40 (s, 3H, CH3). MS m/z (%): 368 (M+; 21.76), 331
(86.69), 302 (73.50), 296 (27.70), 277 (77.40), 260
(26.32), 234 (69.81). Anal. Calcd for C15H14N4O3Cl2
(368.04): C, 48.80; H, 3.82; N, 15.18; Cl, 19.20. Found:
C, 48.81; H, 3.87; N, 15.13; Cl, 19.27.
acetyl)-N-phenylhydrazine-1-carbothioamide
17.
A
mixture of compound 3 (0.5 g, 1.7 mmol) and phenyl
isothiocyanate (0.3 mL, 1.7 mmol) in DMF (15 mL) was
refluxed for 20 h. The precipitated solid on hot was
separated, washed well with diethyl ether, and dried fully
to give 17 as white crystals; mp: 248–250°C, yield:
20%. IR (KBr, υ/cmÀ1): 3158 (NH), 2959, 2835
1
(CH2, CH3), 1671 (C═O), 1628 (C═N), 1163 (C═S). H
NMR (300 MHz, DMSO-d6)
δ (ppm): 10.60 (s,
NHPh, exchangeable with D2O), 10.36 (s, 1H, NHCS,
exchangeable with D2O), 9.65 (s, 1H, CONH,
exchangeable with D2O), 8.08–8.05 (d, 1H, Ar─H, Hb,
J = 9.3 Hz), 7.93 (s, 1H, Ar─H, Hc′), 7.72–7.69 (d, 1H,
Ar─H, Hc, Jo = 8.7 Hz), 7.61–7.33 (m, 6H, Ar─H,
Ph + Hd), 7.09–7.06 (d, 1H, Ar─H, Ha, J = 9.6 Hz), 4.84
(s, 2H, OCH2), 2.36 (s, 3H, CH3). MS m/z (%): 427 (M+;
23.60), 426 (27.34), 290 (30.09), 261 (23.55), 260
(27.76), 235 (100), 178 (45.55), 151 (31.46), 143 (27.53),
101 (24.49), 76 (72.84), 63 (92.80), 50 (81.12). Anal.
Calcd for C20H18N5O2ClS (427.09): C, 56.14; H, 4.24; N,
16.37; Cl, 8.28; S, 7.49. Found: C, 56.21; H, 4.29; N,
16.39; Cl, 8.22; S, 7.56.
2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)acetic
acid 14. A solution of compound 3 (0.5 g, 1.7 mmol) in
formic acid (10 mL) was heated under reflux for 12 h.
The obtained mixture was concentrated. The deposited
solid was separated, washed well with diethyl ether, dried
fully, and recrystallized from ethanol to give 14 as white
crystals; mp: 218–220°C, yield: 55%. IR (KBr, υ/cmÀ1):
3435–2485 (br.) (OH), 2992, 2920, 2836 (CH2, CH3),
1711 (C═Oacid), 1649 (C═N), 1629 (C═C). 1H NMR
(300 MHz, DMSO-d6) δ (ppm): 13.13 (br. s, 1H, OH,
exchangeable with D2O), 8.14–8.08 (two d, 1H, Ar─H,
Hb, J = 9.9 Hz), 7.90, 7.89–7.88 (two d, 1H, Ar─H, Hc′,
Jm = 2.1 Hz), 7.71 (two d, d, 1H, Ar─H, Hc,
Jo = 8.4 Hz, Jm = 2.1 Hz), 7.54–7.51, 7.53 (two d, 1H,
Ar─H, Hd, J = 8.1 Hz), 7.12–7.08 (two d, 1H, Ar─H,
Ha, J = 9.9 Hz), 4.84 (s, 2H, OCH2), 2.39, 2.37 (s, 3H,
CH3). MS m/z (%): 278 (M+; 18.53), 234 (48.96), 233
(25.91), 208 (32.18), 206 (90.93), 190 (2.77), 163 (100),
128 (57.85) 127 (48.70), 102 (24.15), 77 (36.27), 63
(50.58). Anal. Calcd for C13H11N2O3Cl (278.05): C,
56.03; H, 3.96; N, 10.05; Cl, 12.72. Found: C, 56.07; H,
3.98; N, 10.01; Cl, 12.68.
5-(((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)
methyl)-1,3,4-oxadiazole-2-thiol 18.
A
mixture of
compound 3 (0.5 g, 1.7 mmol) and carbon disulfide
(5 mL) in dioxane (10 mL) in the presence of aqueous
potassium hydroxide solution (0.5 g/10 mL) was refluxed
on a water bath for 24 h. The obtained mixture was
acidified with cold dilute hydrochloric acid and the
precipitated solid was separated and then later poured on
Na2CO3 solution, followed by filtration. The filtrate was
acidified by dilute HCl to get 14. While the residue
obtained was separated, dried well, and recrystallized from
ethanol to give 18 as orange crystals; mp: 192–194°C,
yield: 30%. IR (KBr, υ/cmÀ1): 2918, 2849 (CH2, CH3),
1648 (C═N), 1630 (C═C). 1H NMR (300 MHz,
DMSO-d6) δ (ppm): 13.19 (br. s, SH, exchangeable with
D2O), 8.10–8.07 (d, 1H, Ar─H, Hb, J = 9.9 Hz), 7.92 (s,
1H, Ar─H, Hc′), 7.73–7.70 (d, 1H, Ar─H, Hc,
Jo = 8.4 Hz), 7.53–7.50 (d, 1H, Ar─H, Hd, J = 8.4 Hz),
7.12–7.08 (d, 1H, Ar─H, Ha, J = 9.9 Hz), 4.84 (s, 2H,
OCH2), 2.39 (s, 3H, CH3). MS m/z (%): 334 (M+; 9.70),
304 (11.55), 260 (17.95), 234 (54.31), 163 (76.87), 162
2-((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)-N′-(5-
(((6-(4-chloro-3-methylphenyl)pyridazin-3-yl)oxy)methyl)-
1,3,4-oxadiazol-2-yl)acetohydrazide 16.
A solution of
compound 6 (0.5 g, 1.7 mmol) in triethyl orthoformate
(20 mL) was refluxed for 72 h. The obtained mixture was
concentrated. The precipitated solid was separated,
washed well with ethanol, dried fully, and recrystallized
from dioxane to give 14 as white crystals; mp: 208–
210°C, yield: 35%. IR (KBr, υ/cmÀ1): 3224 (NH), 1656
1
(C═O), 1633 (C═N). H NMR (300 MHz, DMSO-d6) δ
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2019
Design, Synthesis, and Pharmacological Assay of Novel Compounds Based on
Pyridazine Moiety as Potential Antitumor Agents
(84.35), 128 (45.40), 127 (47.73), 115 (43.70), 102 (16.66),
77 (76.15), 64 (96.12), 63 (80.40), 40 (100). Anal. Calcd for
C14H11N4O2ClS (334.03): C, 50.23; H, 3.31; N, 16.74; Cl,
10.59; S, 9.58. Found: C, 50.19; H, 3.29; N, 16.75; Cl,
10.61; S, 9.54.
cells were seeded. After incubation, the cells were treated
with variant concentrations of compounds and put in the
incubator for 24 h and then 20 μL of MTT solution at
5 mg/mL was added and incubated for 4 h. Into each well,
DMSO (100 μL) was added to dissolve the purple
formazan formed. At 570 nm absorbance, the colorimetric
assay was measured and recorded by utilizing a plate
reader (EXL 800, USA).
5-(((6-(4-Chloro-3-methylphenyl)pyridazin-3-yl)oxy)
methyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione
19.
A
mixture of compound 3 (0.5 g, 1.7 mmol), ammonium
isothiocyanate (0.13 g, 1.7 mmol) in the presence of
concentrated hydrochloric acid (1.4 mL), and water
(8.5 mL) was heated under reflux for 30 min. The
precipitated solid on hot was separated, washed well with
water, dried fully, and recrystallized from ethanol/dioxane
to give 19 as white crystals; mp: 288–290°C, yield: 25%.
IR (KBr, υ/cmÀ1): 3170 (NH), 2952, 2920 (CH2, CH3),
1649 (C═N), 1629 (C═C), 1244 (C═S). 1H NMR
Calculation of the relative cell viability (%) = (A of
treated samples/A of untreated sample) × 100.
REFERENCES AND NOTES
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https://doi.org/10.1016/S0223-5234(96)80008-0; (b) Morillo, C.;
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Chemosphere 2005, 60, 656. https://doi.org/10.1016/j.chemosphere.
2005.01.030.
(300 MHz, DMSO-d6)
δ (ppm): 10.34 (s, NH,
exchangeable with D2O), 1028 (s, NH, exchangeable with
D2O), 8.11–8.08 (d, 1H, Ar─H, Hb, J = 9.3 Hz), 7.887–
7.880 (d, 1H, Ar─H, Hc′, Jm = 2.1 Hz), 7.74–7.70 (d, d,
1H, Ar─H, Hc, Jo = 8.4 Hz, Jm = 2.4 Hz), 7.53–7.51 (d,
1H, Ar─H, Hd, J = 8.4 Hz), 7.12–7.09 (d, 1H, Ar─H, Ha,
J = 9.6 Hz), 4.84 (s, 2H, OCH2), 2.39 (s, 3H, CH3). MS
m/z (%): 333 (M+; 16.89), 307 (20.34), 274 (7.66), 260
(12.62), 233 (18.58), 207 (21.79), 205 (32.83), 190
(14.91), 169 (48.64), 127 (77.31), 115 (55.56), 80 (100),
77 (55.10), 63 (61.16), 45 (74.31). Anal. Calcd for
C14H12N5OClS (333.79): C, 50.38; H, 3.62; N, 20.98; Cl,
10.62; S, 9.60. Found: C, 50.49; H, 3.67; N, 20.93; Cl,
10.71; S, 9.54.
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C1RA00207D.
IN VITRO ANTITUMOR EVALUATION
MTT assay.
MTT assay employed for antitumor
screening of pyridazine derivatives 3–19 toward
hepatocellular carcinoma (HepG2) and mammary gland
(MCF-7) as two cell lines was from ATCC via Holding
company for biological products and vaccines
(VACSERA), Cairo, Egypt. The reagents utilized were
RPMI-1640 medium, MTT, DMSO (Sigma Co., St. Louis,
USA), and fetal bovine serum (GIBCO, UK). Doxorubicin
was utilized as the reference anticancer drug.
The two cell lines aforementioned were utilized to detect
the inhibitory effects of compounds on cell growth utilizing
the MTT assay [30,31]. This colorimetric test is depending
on the conversion of the yellow tetrazolium bromide
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SUPPORTING INFORMATION
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article.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet