Synthesis and in vitro antimycobacterial activities of novel 6-substituted-3(2H)-pyridazinone-2-acetyl-2-(substituted/nonsubstituted acetophenone) hydrazone

Article abstract of DOI:10.3906/kim-1009-63

The difficulty in managing tuberculosis includes the prolonged duration of the treatment, the emergence of drug resistance, and coinfection with HIV/AIDS. Tuberculosis control requires new drugs that act on novel drug targets to help in combating resistan

Full text of DOI:10.3906/kim-1009-63

Turk J Chem
35 (2011) , 331 – 339.
¨
˙
c
ꢀ TUBITAK
doi:10.3906/kim-1009-63
Synthesis and in vitro antimycobacterial activities of
novel 6-substituted-3(2H)-pyridazinone-2-acetyl-2-
(substituted/nonsubstituted acetophenone)
hydrazone
2
3
4
Semra UTKU1,∗, Mehtap GOKC¸ E , Go¨nu¨l ASLAN , Gu¨l BAYRAM ,
¨
3
3
2
¨
˙
Mahmut ULGER , Gu¨rol EMEKDAS¸ , M. Fethi S¸AHIN
1Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mersin University,
33169, Mersin-TURKEY
e-mail: utkusemra@mersin.edu.tr
2Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Gazi University,
06330, Ankara-TURKEY
3Department of Medical Microbiology, Faculty of Medicine, Mersin University,
33169, Mersin-TURKEY
4Health Services Vocational School, Mersin University, 33020, Mersin-TURKEY
Received: 04.10.2010
The difficulty in managing tuberculosis includes the prolonged duration of the treatment, the emergence
of drug resistance, and coinfection with HIV/AIDS. Tuberculosis control requires new drugs that act on
novel drug targets to help in combating resistant forms of Mycobacterium tuberculosis and reduce the treat-
ment duration. For this purpose, 6-substituted-3(2H)-pyridazinone-2-acetyl-2-(substituted/nonsubstituted
acetophenone) hydrazone derivatives were synthesized and their structures were elucidated by elemental
analyses, IR, and 1 H-NMR. The in vitro antimycobacterial activities of synthesized compounds 5a-l were
determined by the agar proportion method against Mycobacterium tuberculosis H37Rv. Among the target
compounds, 5b and 5f exhibited the best antimycobacterial activity, with a MIC value of 5 μg/mL.
Key Words: 3(2H)-Pyridazinone, acetophenone hydrazone, antimycobacterial activity, antitubercular
drugs
∗Corresponding author
331

Synthesis and in vitro antimycobacterial activities of..., S. UTKU, et al.,
Introduction
Tuberculosis (TB) is a deadly disease caused by mycobacterial infection, and Mycobacterium tuberculosis is the
major pathogen for TB in humans.1 On an annual basis, active cases of TB account for 1.7 million deaths around
the world. There are about 2 billion individuals worldwide who are currently infected with M. tuberculosis, the
causative agent for TB, but most never develop the active form of the disease.2,3
The resurgence in the disease is caused by an inadequate and extended chemotherapy that relies on
drugs developed in the mid-twentieth century.4 The associated poor patient compliance and emergence of
drug resistant forms of TB, coupled with a strong epidemiological coexistence with HIV/AIDS, highlights the
fundamental need for new, more effective drugs to treat the disease.5,6
The past 20 years have seen the worldwide appearance of multidrug-resistant (MDR) TB, followed by
extensively drug-resistant (XDR) TB, and, most recently, strains that are resistant to all antituberculosis drugs.
MDR tuberculosis is caused by M. tuberculosis that is resistant to at least isoniazid (INH) and rifampicin, and
XDR tuberculosis by mycobacteria resistant to rifampicin and INH, any fluoroquinolone, and 1 of the 3 injectable
drugs, capreomycin, kanamycin, and amikacin. Drug resistance severely threatens tuberculosis control, since it
raises the possibility of a return to an era in which drugs are no longer effective.7−9
Consequently, although efficacious anti-TB drugs are available, TB is still a serious global threat to public
health, and a continued search is imperative for new antimycobacterial agents and therapeutic regimens.
Hydrazone derivatives are a considerable pharmacophore group for antimicrobial activity.10 Many re-
searchers have synthesized these compounds as target structures and evaluated their biological activities. Hydra-
zones have been reported to possess, among others, antibacterial,11−14 antifungal,11−14 antitubercular,11,15−21
antiviral22,23 and antimalarial24,25 activities. In this context, we synthesized new 6-substituted-3(2H)-
pyridazinone-2-acetyl-2-(substituted/nonsubstituted acetophenone) hydrazone 5a-l in order to investigate their
in vitro antimycobacterial activities by using the agar proportion method against M. tuberculosis H37Rv.
Experimental
Chemistry
Materials
The fine chemicals and all solvents used in this study were purchased from Merck and Aldrich Chemical Co.
Melting points of the compounds were determined on an Electrothermal 9200 melting point apparatus
and the values given are uncorrected. The IR spectra of the compounds were recorded on a Bruker Vector 22 IR
(Opus Spectroscopic Software Version 2.0) spectrophotometer as KBr disks. Elemental analyses were performed
with a LECO 932 CHNS analyzer, and 1 H-NMR spectra were recorded in dimethylsulfoxide (DMSO-d6) on a
Varian Mercury 400 MHz FT-NMR spectrometer at the Central Laboratory of the Faculty of Pharmacy, Ankara
University, Ankara, Turkey.
General procedure for synthesis of 6-substituted-3(2H)-pyridazinone-2-acetyl-2-(substituted-/
nonsubstituted acetophenone) hydrazone derivatives 5a-l
A mixture of 6-substituted-3(2H)-pyridazinone-2-yl-acetohydrazide derivatives 4a-c (0.01 mol) and ap-
332

Synthesis and in vitro antimycobacterial activities of..., S. UTKU, et al.,
propriately substituted acetophenone (0.01 mol) was refluxed in 15 mL of ethanol for 6 h. The mixture was
then poured into ice-water. The precipitate formed was recrystallized from ethanol.
6-(4-phenylpiperazine)-3(2H)-pyridazinone-2-acetyl-2-acetophenonehydrazone (compound 5a)
Yield 61%. Mp 234-235 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.65 (s, 1H, N-H, exchangeable with D2 O),
7.70-7.67 (d, 1H, pyridazinone H5), 7.66-6.94 (m, 10H, aromatic protons), 6.84-6.81 (d, 1H, pyridazinone H4),
5.04 and 4.66 (s, s, 2H, CH2), 3.39-3.37 (t, 4H, piperazine a+a’ protons), 3.29-3.27 (t, 4H, piperazine b+b’
protons), 2.23 (s, 3H, CH3). FT-IR (KBr): υ 1705 (C=O, hydrazone), 1662 (C=O, 3(2H)-pyridazinone), 3216
(N-H). Anal. Calcd. for C24 H26 N6 O2 : C, 66.96; H, 6.09; N, 19.52. Found: C, 67.13; H, 6.30; N, 19.37.
6-(4-phenylpiperazine)-3(2H)-pyridazinone-2-acetyl-2-(4-bromoacetophenone) hydrazone (com-
pound 5b)
Yield 73%. Mp 243-244 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.67 (s, 1H, NH), 7.72-7.69 (d, 1H,
pyridazinone H5), 7.67-6.88 (m, 9H, aromatic protons), 6.80-6.77 (d, 1H, pyridazinone H4), 5.02 and 4.63 (s, s,
2H, CH2), 3.36-3.34 (t, 4H, piperazine a+a’ protons), 3.28-3.25 (t, 4H, piperazine b+b’ protons), 2.22 (s, 3H,
CH3). FT-IR (KBr): υ 1703 (C=O, hydrazone), 1666 (C=O, 3(2H)-pyridazinone), 3217 (N-H). Anal. Calcd.
for C24 H25 BrN6 O2 : C, 56.59; H, 4.95; N, 16.50. Found: C, 56.81; H, 5.05; N, 16.69.
6-(4-phenylpiperazine)-3(2H)-pyridazinone-2-acetyl-2-(4-chloroacetophenone) hydrazone (com-
pound 5c)
Yield 67%. Mp 252-253 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.69 (s, 1H, NH), 7.73-7.70 (d, 1H,
pyridazinone H5), 7.68-6.91 (m, 9H, aromatic protons), 6.83-6.79 (d, 1H, pyridazinone H4), 5.06 and 4.68 (s, s,
2H, CH2), 3.36-3.34 (t, 4H, piperazine a+a’ protons), 3.28-3.24 (t, 4H, piperazine b+b’ protons), 2.23 (s, 3H,
CH3). FT-IR (KBr): υ 1706 (C=O, hydrazone), 1665 (C=O, 3(2H)-pyridazinone), 3214 (N-H). Anal. Calcd.
for C24 H25 ClN6 O2 : C, 62.00; H, 5.42; N, 18.08. Found: C, 62.07; H, 5.54; N, 17.96.
6-(4-phenylpiperazine)-3(2H)-pyridazinone-2-acetyl-2-(4-fluoroacetophenone) hydrazone (com-
pound 5d)
Yield 81%. Mp 262-263 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.70 (s, 1H, NH), 7.76-7.74 (d, 1H,
pyridazinone H5), 7.67-6.89 (m, 9H, aromatic protons), 6.82-6.80 (d, 1H, pyridazinone H4), 5.05 and 4.66 (s, s,
2H, CH2), 3.39-3.37 (t, 4H, piperazine a+a’ protons), 3.29-3.27 (t, 4H, piperazine b+b’ protons), 2.24 (s, 3H,
CH3). FT-IR (KBr): υ 1704 (C=O, hydrazone), 1668 (C=O, 3(2H)-pyridazinone), 3215 (N-H). Anal. Calcd.
for C24 H25 FN6 O2 : C, 64.27; H, 5.62; N, 18.74. Found: C, 64.14; H, 5.74; N, 18.77.
6-[4-(4-fluorophenyl)piperazine]-3(2H)-pyridazinone-2-acetyl-2-acetophenone hydrazone (com-
pound 5e)
Yield 80%. Mp 271-272 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.73 (s, 1H, NH), 7.77-7.75 (d, 1H,
pyridazinone H5), 7.72-6.96 (m, 9H, aromatic protons), 6.85-6.83 (d, 1H, pyridazinone H4), 5.07 and 4.70 (s, s,
2H, CH2), 3.39-3.37 (t, 4H, piperazine a+a’ protons), 3.30-3.28 (t, 4H, piperazine b+b’ protons), 2.21 (s, 3H,
CH3). FT-IR (KBr): υ 1705 (C=O, hydrazone), 1666 (C=O, 3(2H)-pyridazinone), 3213 (N-H). Anal. Calcd.
for C24 H25 FN6 O2 : C, 64.27; H, 5.62; N, 18.74. Found: C, 64.04; H, 5.33; N, 18.81.
333

Synthesis and in vitro antimycobacterial activities of..., S. UTKU, et al.,
6-[4-(4-fluorophenyl)piperazine]-3(2H)-pyridazinone-2-acetyl-2-(4-bromoacetophenone) hydrazone
(compound 5f)
Yield 62%. Mp 248-249 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.80 (s, 1H, NH), 7.79-7.76 (d, 1H,
pyridazinone H5), 7.70-6.95 (m, 8H, aromatic protons), 6.86-6.84 (d, 1H, pyridazinone H4), 5.07 and 4.70 (s, s,
2H, CH2), 3.40-3.38 (t, 4H, piperazine a+a’ protons), 3.30-3.28 (t, 4H, piperazine b+b’ protons), 2.23 (s, 3H,
CH3). FT-IR (KBr): υ 1705 (C=O, hydrazone), 1663 (C=O, 3(2H)-pyridazinone), 3216 (N-H). Anal. Calcd.
for C24 H24 BrFN6 O2 : C, 54.66; H, 4.59; N, 15.94. Found: C, 54.82; H, 4.48; N, 16.12.
6-[4-(4-fluorophenyl)piperazine]-3(2H)-pyridazinone-2-acetyl-2-(4-chloroacetophenone) hydrazone
(compound 5g)
Yield 50%. Mp 229-230 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.82 (s, 1H, NH), 7.77-7.75 (d, 1H,
pyridazinone H5), 7.79-6.72 (m, 8H, aromatic protons), 6.99-6.97 (d, 1H, pyridazinone H4), 5.10 and 4.80 (s, s,
2H, CH2), 3.42-3.39 (t, 4H, piperazine a+a’ protons), 3.31-3.29 (t, 4H, piperazine b+b’ protons), 2.24 (s, 3H,
CH3). FT-IR (KBr): υ 1704 (C=O, hydrazone), 1665 (C=O, 3(2H)-pyridazinone), 3214 (N-H). Anal. Calcd.
for C24 H24 Cl FN6 O2 : C, 59.69; H, 5.01; N, 17.40. Found: C, 59.81; H, 5.16; N, 17.26.
6-[4-(4-fluorophenyl)piperazine]-3(2H)-pyridazinone-2-acetyl-2-(4-fluoroacetophenone) hydrazone
(compound 5h)
Yield 40%. Mp 241-242 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.79 (s, 1H, NH), 7.75-7.72 (d, 1H,
pyridazinone H5), 7.68-6.90 (m, 8H, aromatic protons), 6.85-6.83 (d, 1H, pyridazinone H4), 5.07 and 4.70 (s, s,
2H, CH2), 3.39-3.37 (t, 4H, piperazine a+a’ protons), 3.29-3.27 (t, 4H, piperazine b+b’ protons), 2.23 (s, 3H,
CH3). FT-IR (KBr): υ 1706 (C=O, hydrazone), 1662 (C=O, 3(2H)-pyridazinone), 3216 (N-H). Anal. Calcd.
for C24 H24 F2 N6 O2 : C, 61.79; H, 5.19; N, 18.02. Found: C, 61.51; H, 5.36; N, 17.93.
6-[4-(4-chlorophenyl)piperazine]-3(2H)-pyridazinone-2-acetyl-2-acetophenone hydrazone (com-
pound 5i)
Yield 56%. Mp 280-281 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.72 (s, 1H, NH), 7.73-7.70 (d, 1H,
pyridazinone H4), 7.67-6.90 (m, 9H, aromatic protons), 6.82-6.80 (d, 1H, pyridazinone H4), 5.05 and 4.70 (s, s,
2H, CH2), 3.37-3.35 (t, 4H, piperazine a+a’ protons), 3.27-3.25 (t, 4H, piperazine b+b’ protons), 2.22 (s, 3H,
CH3). FT-IR (KBr): υ 1706 (C=O, hydrazone), 1664 (C=O, 3(2H)-pyridazinone), 3218 (N-H). Anal. Calcd.
for C24 H25 ClN6 O2 : C, 62.00; H, 5.42; N, 18.08. Found: C, 62.17; H, 5.56; N, 17.98.
6-[4-(4-chlorophenyl)piperazine]-3(2H)-pyridazinone-2-acetyl-2-(4-bromoacetophenone)hydrazone
(compound 5j)
Yield 48%. Mp 231-232 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.70 (s, 1H, NH), 7.77-7.75 (d, 1H,
pyridazinone H4), 7.65-6.90 (m, 8H, aromatic protons), 6.80-6.79 (d, 1H, pyridazinone H4), 5.07 and 4.70 (s, s,
2H, CH2), 3.38-3.36 (t, 4H, piperazine a+a’ protons), 3.28-3.26 (t, 4H, piperazine b+b’ protons), 2.24 (s, 3H,
CH3). FT-IR (KBr): υ 1704 (C=O, hydrazone), 1663 (C=O, 3(2H)-pyridazinone), 3212 (N-H). Anal. Calcd.
for C24 H24 BrClN6 O2 : C, 53.00; H, 4.45; N, 15.45. Found: C, 53.08; H, 4.40; N, 15.35.
6-[4-(4-chlorophenyl)piperazine]-3(2H)-pyridazinone-2-acetyl-2-(4-chloroacetophenone) hydrazone
(compound 5k)
Yield 73%. Mp 237-238 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.72 (s, 1H, NH), 7.75-7.73 (d, 1H,
334

Synthesis and in vitro antimycobacterial activities of..., S. UTKU, et al.,
pyridazinone H5), 7.69-6.92 (m, 8H, aromatic protons), 6.82-6.80 (d, 1H, pyridazinone H4), 5.09 and 4.72 (s, s,
2H, CH2), 3.37-3.35 (t, 4H, piperazine a+a’ protons), 3.29-3.27 (t, 4H, piperazine b+b’ protons), 2.23 (s, 3H,
CH3). FT-IR (KBr): υ 1707 (C=O, hydrazone), 1666 (C=O, 3(2H)-pyridazinone), 3214 (N-H). Anal. Calcd.
for C24 H24 Cl2 N6 O2 : C, 57.72; H, 4.84; N, 16.83. Found: C, 57.96; H, 5.01; N, 16.59.
6-[4-(4-chlorophenyl)piperazine]-3(2H)-pyridazinone-2-acetyl-2-(4-fluoroacetophenone) hydrazone
(compound 5l)
Yield 45%. Mp 245-246 ◦ C. 1 H-NMR (DMSO-d6): δ (ppm) 11.68 (s, 1H, NH), 7.76-7.74 (d, 1H,
pyridazinone H4), 7.67-6.90 (m, 8H, aromatic protons), 6.78-6.75 (d, 1H, pyridazinone H4), 5.06 and 4.68 (s, s,
2H, CH2), 3.36-3.34 (t, 4H, piperazine a+a’ protons), 3.28-3.26 (t, 4H, piperazine b+b’ protons), 2.23 (s, 3H,
CH3). FT-IR (KBr): υ 1704 (C=O, hydrazone), 1664 (C=O, 3(2H)-pyridazinone), 3213 (N-H). Anal. Calcd.
for C24 H24 ClFN6 O2 : C, 59.69; H, 5.01; N, 17.40. Found: C, 59.82; H, 5.18; N, 17.14.
Biological activity
Agar proportion method
The minimum inhibitory concentration (MIC) values of each synthesized compound, 5a-l, were tested by agar
dilution in duplicate as recommended by the Clinical Laboratory Standards Institute (CLSI).26,27 Positive
and negative growth controls were run in each assay. INH and ethambutol (EMB) were used as control agents.
H37Rv was used as the standard strain. Stock solutions of synthesized compounds 5a-l and reference compounds
were prepared in DMSO/H2 O (50%) at a concentration of 1000 μg/mL. These solutions were filtered through
a 0.22-μm membrane filter (Millipore, USA). Middlebrook 7H10 agar medium (Difco) was supplemented with
oleic acid-albumin-dextrose-catalase (OADC, BBLT M ). Synthesized compounds 5a-l and control agents were
added to obtain an appropriate final concentration in the medium. The final concentrations of INH and
ethambutol were 0.2-1 μg/mL and 1 μg/mL, respectively. Synthesized compounds 5a-l were prepared at
final concentrations of 2.5, 5, 10, 20, and 40 μg/mL. Agar without any references and synthesized compounds
5a-l were used as a positive growth control, and 3 mL of prepared medium was dispensed into sterile tubes.
The DMSO concentration in the final solutions was not above 1% for antimycobacterial activity.
Inoculum preparation
H37 Rv was maintained in Lowenstein-Jensen medium. A culture suspension was prepared by subculturing
in Middlebrook 7H9 broth (Difco) supplemented with 10% OADC at 37 ◦ C for 7-10 days, until a density
corresponding to 10−2 to 10−4 dilutions were obtained from McFarland standard No. 1. Then 0.1 mL of the
diluted suspension was inoculated onto the control and the other tubes with 5a-l in different concentrations.
The tubes were incubated at 37 ◦ C in an atmosphere of 5% CO2 for 3 weeks. The MIC values were defined
as the lowest concentration that inhibited more than 90% of the bacterial growth, and the results of INH and
EMB were interpreted according to the CLSI. The MIC was considered the lowest concentration that showed
no visible colonies in all dilutions.
335

Synthesis and in vitro antimycobacterial activities of..., S. UTKU, et al.,
Results and discussion
Chemistry
The synthetic route of the synthesized compounds is given in the Figure. Reaction of 3,6-dichloropyridazine with
arylpiperazines afforded 3-chloro-6-substitutedpyridazine derivatives 1a-c. The physical and spectral properties
of 3-chloro-6-substitutedpyridazines 1a-c were in accordance with the literature.28,29 Hydrolysis of compounds
1a-c was carried out upon heating in glacial acetic acid to afford 6-substituted-3(2H)-pyridazinone deriva-
tives 2a-c. Compounds 2a-c were made to react with ethyl bromoacetate to afford the ethyl 6-substituted-
3(2H)-pyridazinone-2-ylacetate derivatives 3a-c, from which the 6-substituted-3(2H)-pyridazinone-2-yl ace-
tohydrazide derivatives 4a-c were obtained by treatment with hydrazine hydrate (99%). The compounds
synthesized, 2a-c, 3a-c, and 4a-c, reported previously by us, were synthesized in this study as earlier reported.
IR and 1 H-NMR spectral data of these compounds were in accordance with the data reported in our previous
study.30−34
N
N
N
N
R1
R1
Cl
+
HN
N
Cl
N
N
Cl
1 a - c
R1= H, F, Cl
CH3COOH
CH2COOCH2CH3
N
N
N
NH
BrCH2COOCH2CH3
R1
R1
N
3 a - c
NH2NH2 . H2O
N
O
N
N
O
2 a - c
R2
CH3
CH2CONHN=C
O
CH
3
CH2CONHNH2
N
N
N
N
2
R1
R1
R
N
N
N
N
O
O
R2= H, F, Br, Cl
4 a - c
5 a - l
Figure. Synthetic route of the synthesized compounds.
By the reaction of 3(2H)-pyridazinone-2-yl acetohydrazides 4a-c with substituted acetophenone in
ethanol, 12 new final compounds, 5a-l, were synthesized. All of the newly synthesized compounds, 5a-l,
were identified by IR and 1 H-NMR spectra and confirmed by elemental analysis.
The elemental analysis data for each compound were in good agreement with the empirical formula
proposed. In the IR spectra, newly synthesized compounds 5a-l exhibited characteristic υ (C=O) bands at
1703-1707 and 1662-1668 cm−1 for acetyl side chains and pyridazinone rings, respectively. The υ (N—H)
stretching bands were centered at 3212-3218 cm−1
.
336

Synthesis and in vitro antimycobacterial activities of..., S. UTKU, et al.,
The 1 H-NMR spectral data of compounds 5a-l are presented in the Experimental Section. The 1 H-NMR
spectra of all complexes were consistent with their corresponding protons as chemical shift values and numbers
of hydrogen.
Antimycobacterial activity test
The literature survey on functional groups that could be considered as pharmacophores for antitubercular
activities revealed that the hydrazone moiety is common among most of the antitubercular agents.10,35 For this
purpose, a series of 6-substituted-3(2H)-pyridazinone-2-acetyl-2-(substituted/nonsubstituted acetophenone)
hydrazones, 5a-l, were tested in vitro against M. tuberculosis H37Rv, which is susceptible to INH and EMB.
The MIC was determined using the agar proportion method in Middlebrook 7H10 medium.
Table. In vitro antimycobacterial activity of 6-Substituted-3(2H)-pyridazinone-2-acetyl-2-(substituted/nonsubstituted
acetophenone) hydrazone 5a-l.
R2
CH3
CH2CONHN=C
N
N
R1
N
N
O
5 a - l
Compound R1 R2 MIC (μg/mL)*
5a
5b
5c
H
H
H
H
F
H
Br
Cl
F
20
5
40
5d
5e
20
H
20
5f
F
Br
Cl
F
5
5g
5h
5i
F
N/A
N/A
N/A
40
F
Cl
H
5j
Cl Br
Cl Cl
5k
5l
40
Cl
F
N/A
0.2
1
INH
EMB
*Compounds regarded as not active (N/A) if no inhibition was observed at 40 μg/mL.
337

Synthesis and in vitro antimycobacterial activities of..., S. UTKU, et al.,
The MIC values of synthesized compounds 5a-l and reference compounds INH and EMB are given
in the Table. Comparison of the activities of synthesized compounds 5a-l indicated that compounds 5b
and 5f, with a 4-bromoacetophenonehydrazone substituent, were the most potent compounds, with MIC
values of 5 μg/mL. Among the synthesized compounds, 5a, 5d, and 5e, bearing a nonsubstituted or 4-
fluoroacetophenonehydrazone, exhibited inhibitory effects with MIC values of 20 μg/mL. The other synthesized
compounds, 5c, 5j, and 5k, were found to be the least active compounds against M. tuberculosis H37Rv, with
MIC values of 40 μg/mL. As shown in the Table, 5g, 5h, 5i, and 5l did not seem to have antimycobacterial
activity.
The newly synthesized compounds derived from 4-bromoacetophenone hydrazone, 5b and 5f, were found
to be more active than the other acetophenone hydrazone compounds. This finding is consistent with the
data reported in the literature, of a hydrazone analog with derived substituted benzaldehyde. 10,17,35 In the
literature, it was also reported that the aryl ring with electron-withdrawing substituents enhanced the activity,
especially the bromo substituent, and with electron-donating substituents/properties, activity decreased.36−38
In conclusion, 6-substituted-3(2H)-pyridazinone-2-acetyl-2-(substituted/nonsubstituted acetophenone) hydra-
zone derivatives 5b and 5f seem to have the potential to be used as antimycobacterial agents, but further in
vitro and in vivo experiments are required to verify their antimycobacterial activities.
References
1. Tripathi, R. P.; Tewari, N.; Diwivedi, N.; Tivari, V. K. Med. Res. Rev. 2005, 25, 93-131.
2. Arcus, V. L.; Lott, J. S.; Johnston, J. M.; Baker, E. N. Drug Discov. Today 2006, 11, 28-35.
3. Umesiri, F. E.; Sanki, A. K.; Boucau, J.; Ronning, D. R.; Sucheck, S. J. Med. Res. Rev. 2010, 30, 290-326.
4. Haydel, S. E. Pharmaceuticals 2010, 3, 2268-2290.
5. Toossi, Z. J. Infect. Dis. 2003, 188, 1146-1155.
6. Kranzer, K.; Houben, R. M.; Glynn, J. R.; Bekker, L. G.; Wood, R.; Lawn, S. D. Lancet Infect. Dis. 2010, 10,
93-102.
7. Logu, A. D.; Onnis, V.; Saddi, B.; Congiu, C.; Schivo, M. L.; Cocco, M. T. J. Antimicrob. Chemoth. 2002, 49,
275-282.
8. Takahashi, K.; Hasegawa, Y.; Abe, T.; Yamamoto, T.; Nakashima, K.; Imaizumi, K.; Shimokata, K. Tuberculosis
2008, 88, 52-57.
9. Caminero, J. A.; Sotgiu, G.; Zumla, A.; Migliori, G. B. Lancet Infect. Dis. 2010, 10, 621-629.
10. Rollas, S.; Ku¨¸cu¨kgu¨zel, S. G. Molecules 2007, 12, 1910-1939.
¨
11. Ku¨¸cu¨kgu¨zel, S. G.; Mazi, A.; S¸ahin, F.; Oztu¨rk, S.; Stables, J. Eur. J. Med. Chem. 2003, 38, 1005-1013.
¨
12. Ozkay, Y.; Tunalı, Y.; Karaca, H.; I¸sıkdag˘, I. Eur. J. Med. Chem. 2010, 45, 3293-3298.
˙
13. Ajani, O. O.; Obafemi, C. A.; Nwinyi, O. C.; Akinpelu, D. A. Bioorg. Med. Chem. 2010, 18, 214-221.
14. Salgın-Go¨k¸sen, U.; G¨okhan-Kelek¸ci, N.; G¨okta¸s, O.; K¨oysal, Y.; Kılıc¸, E.; I¸sık, S.; Aktay, G.; Ozalp, M. Bioorg.
Med. Chem. 2007, 15, 5738-5751.
338

Synthesis and in vitro antimycobacterial activities of..., S. UTKU, et al.,
15. Sriram, D.; Yogeeswari, P.; Madhu, K. Bioorg. Med. Chem. Lett. 2005, 15, 4502-4505.
16. Maccari, R.; Ottan´a, R.; Vigorita, M. G. Bioorg. Med. Chem. Lett. 2005, 15, 2509-2513.
17. Sriram, D.; Yogeeswari, P.; Devakaram, R. V. Bioorg. Med. Chem. 2006, 14, 3113-3118.
18. Ko¸cyi˘git-Kaymak¸cıo˘glu, B.; Oru¸c, E.; Unsalan, S.; Kandemirli, F.; Shvets, N.; Rollas, S.; Anatholy, D. Eur. J.
Med. Chem. 2006, 41, 1253-1261.
19. Imramovsky´, A.; Polanc, S.; Vinsov´a, J.; Kocevar, M.; Jamp´ılek, J.; Reckova, Z.; Kaustova´, J. Bioorg. Med. Chem.
2007, 15, 2551-2559.
¨
20. Turan-Zitouni, G.; Ozdemir, A.; Kapancıklı, Z. A.; Benkli, K.; Chevallet, P.; Akalin G. Eur. J. Med. Chem. 2008,
43, 981-985.
21. Pavan, F. R.; Maia, P. I.; Liete, S. R. A.; Deflon, V. M.; Batista, A. A.; Sato, D. N.; Franzbau, S. G.; Liete, C. Q.
F. Eur. J. Med. Chem. 2010, 45, 1898-1905.
22. Abdel-Aal, M. T.; El-Sayed, W. A; El-Ashry, E. H. Arch. Pharm. Chem. Life Sci. 2006, 339, 656-663.
23. El-Sabbagh, O. I.; Rady, H. M. Eur. J. Med. Chem. 2009, 44, 3680-3686.
24. Walcourt, A.; Loyevsky, M.; Lovejoy, D. B.; Gordeuk, V. R.; Richardson, D. R. Int. J. Biochem. Cell B 2004, 36,
401-407.
25. Gemma, S.; Kukreja, G.; Fattorusso, C.; Persico, M.; Romano, M. P.; Altarelli, M.; Savini, L.; Campiani, G.;
Fattorusso, E.; Basilico, N.; Taramelli, D.; Yardley, V.; Butini, S. Bioorg. Med. Chem. Lett. 2006, 16, 5384-5388.
26. National Committee for Clinical Laboratory Standards. Susceptibility Testing of Mycobacteria, Nocardia, and Other
Aerobic Actinomycetes:;pproved Standard NCCLS Document M24-A. Wayne, Pennsylvania, 2003.
27. Clinical and Laboratory Standards Institute (CLSI) (formerly NCCLS). Antimycobacterial Susceptibility Testing
for M. tuberculosis: Tentative Standard NCCLS Document M24-T. Villanova, Pennsylvania, 2002.
28. Boissier, J. R.; Ratouis, R.; Dumont, C. J. Med. Chem. 1963, 6, 541-544.
29. Elvio, B.; Paravicini, F.; Emilio, T. Farmaco Ed. Sci. 1969, 24, 919-929.
30. G¨ok¸ce, M.; Do˘gruer, D. S.; S¸ahin, M. F. Il Farmaco 2001, 56, 233-237.
31. S¸ahin, M. F.; Badı¸cog˘lu, B.; G¨ok¸ce, M.; Ku¨peli, E.; Ye¸silada, E. Arch. Pharm. Pharm. Med. Chem. 2004, 337,
445-452.
32. Du¨ndar, Y.; G¨ok¸ce, M.; Ku¨peli, E.; S¸ahin, M. F. Arzneim-Forsch Drug Res. 2007, 57, 777-781.
33. Yelken, G. 6-Su¨bstitu¨e-3(2H)-Piridazinon 2-il Asetohidrazit Tu¨revi Bile¸siklerin Sentezi Antibakteriyel ve Antifungal
˙
Aktivetelerinin Incelenmesi. Gazi University, Institute of Health Science, Ankara, Turkey, 2008.
34. G¨ok¸ce, M.; Utku, S.; Ku¨peli, E.;ur. J. Med. Chem. 2009, 44, 3760-3764.
35. Sriram, D.; Yogeeswari, P.; Madhu, K. Bioorg. Med. Chem. Lett. 2006, 16, 876-878.
36. Sriram, D.; Yogeeswari P.; Reddy, S. P. Bioorg. Med. Chem. Lett. 2006, 16, 2113-2116.
37. Ali, M. A.; Shaharyar, M. Bioorg. Med. Chem. 2007, 15, 1896-1902.
38. Fassihi, A; Azadpour, Z; Delbari, N.; Saghaie, L.; Memarian, H. R.; Sabet, R.; Alborzi, A.; Miri, R.; Pourabbas,
B.; Mardaneh, J.; Mousavi, P.; Moeinifard, B.; Sadeghi-aliabadi, H. Eur. J. Med. Chem. 2009, 44, 3253-3258.
339

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