Synthesis and evaluation of novel imidazo[4,5-: C] pyridine derivatives as antimycobacterial agents against Mycobacterium tuberculosis

Article abstract of DOI:10.1039/c6nj02069k

The current study involves the synthesis of novel imidazo[4,5-c]pyridine derivatives (IPD) containing amide/urea/sulfonamide. The synthesized compounds were evaluated for in vitro and in vivo antimycobacterial activities against Mycobacterium tuberculosis. The pharmacological activities were determined by the objective to better understand their structure-activity relationship (SAR) for their in vitro antimycobacterial activity against M. tuberculosis. Some synthesized compounds showed significant activity against M. tuberculosis based on the agar dilution method. Among the forty-one compounds screened, compounds 21, 22 and 23 were found to be the most active compounds against M. tuberculosis. In the in vivo animal model, 21, 22 and 23 decreased the bacterial load in lung and spleen tissues at the dose of 50 mg kg^-1 body weight.

Full text of DOI:10.1039/c6nj02069k

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ARTICLE
Synthesis and evaluation of novel imidazo[4,5-c]pyridine derivatives
as antimycobacterial agents against Mycobacterium tuberculosis
Received 00th January 20xx,
Accepted 00th January 20xx
a
b,
a
c
Malavalli Madaiah, Maralekere K Prashanth, * Hosakere D Revanasiddappa, Bantal Veeresh,
The current study involves the synthesis of novel imidazo[4,5-c]pyridine derivatives (IPD) contain amide/urea/sulfonamide.
The synthesized compounds were evaluated for in vitro and in vivo antimycobacterial activities against Mycobacterium
tuberculosis. The pharmacological activities were determined by the objective to better understand their structure-activity
relationship (SAR) for their in vitro antimycobacterial activity against M. tuberculosis. Some synthesized compounds
showed significant activity against M. tuberculosis by the agar dilution method. Among forty-one compound screened,
compounds 21, 22 and 23 were found to be the most active compounds against M. tuberculosis. In the in vivo animal
model, 21, 22 and 23 decreased the bacterial load in lung and spleen tissues at the dose of 50 mg/kg body weight.
DOI: 10.1039/x0xx00000x
www.rsc.org/
The resurgence in TB is alarming due to the development of
7
Introduction
pathogenic synergy with HIV. The currently employed first-line
drugs, isoniazid, rifampin, ethambutol, and pyrazinamide for the
Mycobacterium tuberculosis is a pathogenic bacteria and the
causative agent of most cases of tuberculosis (TB). TB is one of the
most prevalent diseases and is responsible for the deaths of about
initial 2 months and rifampin and isoniazid for an additional 4
months. The need for such lengthy treatment is large because the
drugs are relatively ineffective against the persistent form of the
1
one billion people during the last two centuries. The statistics show
8
disease and second-line agents such as kanamycin, p-aminosalicylic
that around 32% of the world’s population are infected with M.
tuberculosis, the main causal agent of TB and today more people
9
acid, ciprofloxacin or cycloserine also suffer from associated side-
2
effects and poor efficacy in eradicating dormant pathogens. In the
last 50 years, only a few drugs have been approved by the Food and
Drug Administration (FDA) to treat TB, which reflects the inherent
die from tuberculosis than ever before. According to estimates
from the World Health Organization (WHO), TB is a frequently fatal
infectious disease that causes more than 1.4 million deaths annually
and there were an estimated 8.7 million new cases of TB every
1
0
difficulties in the discovery and clinical testing of new agents.
3
Hence, the discovery of fast-acting effective newer drugs to
effectively cure TB, including multidrug resistant tuberculosis, is
imperative.
year.
TB is an airborne infectious disease that often remains in its
latent form, it is very different from that for other bacterial
infections. The organism has a long generation time and a capacity
for dormancy when its low metabolic activity makes it a difficult
Drugs such as necopidem, saripidem, alpidem, zolpidem, and
olprinone contain nitrogen-containing bicyclic, condensed-
1
1-13
4
imidazopyridines as bioactive scaffolds
and ironically bears
therapeutic target. In addition, M. tuberculosis may be located in
strong structural similarity to the imidazopyridine antitubercular
agents (Fig. 1). With its bioisosterimidazo ring (Fig. 1). Further, the
3D structural similarity and Low r.m.s.d. (root mean square
distance) value suggested the good 3D structural similarity between
the designed molecule and zolpidem. This prompted us to
synthesize a series of imidazo[4,5-c]pyridine derivatives and check
their antimycobacterial potential we discovered to have
outstanding in vitro potency against both replicating Mtb H37Rv
pulmonary cavities, empyemapus, or solid caseous material, where
penetration of antibiotics is difficult or the pH is sufficiently low to
5
inhibit the activity of most antibiotics. Despite the fact that the
present chemotherapy has a cure rate of up to 95%, because of
poor patient compliance arising from prolonged therapy, the
disease has been spreading at a steady rate. This leads to the
evolution of multidrug-resistant (MDR-TB) and extensively drug-
6
resistant TB causing a major impediment in treating the disease.
Cl
N
N
N
N
O
N
N
O
N
N
Cl
N
NH
O
R
Cl
*
E-mail address: prashanthmk87@gmail.com
IPD 11-50
Zolpidem
Alpidem
Tel.: +91-9449939656
This journal is © The Royal Society of Chemistry 20xx
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Journal Name
Cl
Fig. 1 Structures of IPD, Alpidemand Zolpidem
a
b
N+
Cl
Cl
N
Cl
Cl
-
Cl
N
Cl
Results and discussion
O
1
2
(72.2 %)
3 (73.03%)
c
A general route for the synthesis of the title compounds
imidazo[4,5-c]pyridine derivatives (11-51) is depicted in Scheme 1.
A variety of combinatorial approaches has described by which
pharmacophoric groups were attached to such relatively rigid
scaffold. The synthesis begins with chlorination of 2,6-
dichloropyridine using trifluoroacetic acid, hydrogen peroxide, and
2
O N
NHCH
3
NCH3
Cl
NHCH
N
3
NO
2
e
d
+
Cl
N
Cl
Cl
N
Cl
Cl
N
NHCH
3
Cl
Cl
6
(97.5%)
5 (78.5 %)
4 (51.53 %)
f
POCl . The Chloro - amine coupling was done using methylamine
3
1
4
and ethanol solvent. The nitration was done using fuming nitric
acid and sulfuric acid. The reduction was carried using iron powder,
ammonium chloride, and methanol; water solvent. Construction of
imidazole ring was made by triethylorthoformate and ethanol at
refluxed temperature. The carbon-nitrogen bond was done by
Buchwald coupling using benzophenone imine, xantphos, cesium
carbonate Tris(dibenzylideneacetone)dipalladium(0) and dioxane
solvent at refluxed temperature. Target key intermediate was
N
N
NHCH
3
N
N
N
i
N
NH
2
h
g
Cl
N
N
Cl
N
Cl
Cl
N
Cl
Cl
N
NH
10 (60.43 %)
2
Ph
Ph
8
(88.9 %)
9 (57.1 %)
7
(88.95 %)
j
N
N
1
5
accomplished by cleavage of imine bond with 1.5N HCl and
followed by basification with NaOH solution to pH-10. The aim of
the tenth step was introduced by acid chloride, isocyanate and
sulfonyl chloride to lead desired final compounds. This was
Cl
N
NH
R
O
1
1-51 (60.-75 %)
1
6,17
Scheme 1 Reagents and conditions: a) trifluoroacetic acid, 30 %
reflux, 12 h; c)
furnished by normal nucleophilic addition / elimination reaction
hydrogen peroxide, 90 °C, 12 h; b) POCl3
,
from acid chlorides/ isocyanate / sulfonyl chloride, with good yield.
1
13
methylamine, ethanol, 12 h, 40 °C; d) sulfuric acid, fuming nitric
acid, 1h, -10 °C – 0 °C; e) sulfuric acid, RT, 12 h; f) iron power,
The formation of each compound was confirmed by H NMR,
C
NMR and MS spectra.
ammonium chloride, methanol-water,
3 h, 90 °C; g) triethyl
It has been observed that in 6-chloro-1-methyl-1H-imidazo[4,5-
c]pyridine-4-amine scaffold, the amine group is a more reactive site.
However, no such increase of reactivity was required in the present
reaction system and the final compounds were done workup and
purified by column chromatography to get pure products
orthoformate, ethanol, 36 h, 105 °C; h) benzophenone imine
xantphos, cesium carbonate, Tris(dibenzylidene acetone)
dipalladium(0), dioxane, 18 h, 110 °C; i) 1.5 N HCl, NaOH, RT , 6 h; j)
sodium hydride, acid chloride/isocynate/sulfonyl chloride, DMF, RT,
-1
1
8 h.
The absence of NH2 absorption band at 1620 cm in the IR
spectra confirmed that the synthesized compounds were obtained Table 1 Chemical structure and yield of the compounds (11-51)
via condensation. The appearance of a strong absorption band at
Compound
R
Yield (%)
75
-
1
around 3435 cm is the stretching vibration due to the presence of
11
12
13
6 5
C H CO
-NH band in the synthesized compounds. The proton spectral data
2-H
3-H
4-H
3
3
3
CC
CC
CC
6
6
6
H
H
H
4
4
4
CO
CO
CO
63
agree with respect to the number of protons and their chemical
shifts with the proposed structures. The proton spectral data of the
intermediate, N-substituted imidazo[4,5-c]pyridine 10 shows
67
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
64
2- ClC
3- ClC
4- ClC
6
6
6
H
H
H
4
4
4
CO
CO
CO
61
62
2
resonance at δ 6..63 ppm (s, 2H, NH ). In all the synthesized
65
compounds, the above resonance disappeared and additional
resonances assigned to the –NH–C=O (s, 11.12–10.92 ppm), –NH–
C=O (s, 11.23 and 9.39 ppm) and–NH–S=O (s, 11.90–11.05 ppm)
were observed, which confirmed the condensation between the
amino group and carbonyl group of isocyanate and sulfonyl
compounds, respectively. The chemical formula, physical data and
yield of all the synthesized compounds are given in Table 1.
2- FC
3- FC
4- FC
6
6
6
H
H
H
4
4
4
CO
CO
CO
66
63
64
2- F
3- F
4- F
3
3
3
CC
CC
CC
6
H
4
4
4
CO
CO
CO
62
6
H
H
63
6
63
3- NCC
4- NCC
6
H
4
4
CO
CO
66
6
H
66
C
C
6
6
H
H
5
4
NCO
CH NCO
73
2
65
2-H
3-H
4-H
3
3
3
CC
CC
CC
6
H
4
H
4
H
4
NCO
NCO
NCO
68
6
65
6
67
2- ClC
6
H
4
NCO
66
2
| J. Name., 2012, 00, 1-3
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3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
3- ClC
4- ClC
6
H
H
4
NCO
NCO
64
62
70
72
71
66
70
71
66
64
62
60
61
63
60
67
65
63
60
66
17
18
19
20
12.5±0.08
6.25±0.12
6.25±0.26
6.25±0.19
0.25±0.04
0.25±0.16
0.25±0.11
25±0.34
25±0.08
25±0.15
25±0.17
25±0.24
25±0.29
12.5±0.03
12.5±0.18
12.5±0.13
25±0.21
6.5±0.07
6.5±0.14
6.5±0.26
>25
6
4
2- FC
3- FC
4- FC
6
6
6
H
H
H
4
4
4
NCO
NCO
NCO
2
2
2
2
2
2
2
2
2
3
3
3
3
3
1
2
3
4
5
6
7
8
9
0
1
2
3
4
3- NCC
4- NCC
6
H
4
4
NCO
NCO
6
H
C
C
6
H
H
5
SO
CH
2
6
4
2
SO
2
2-H
3-H
3
3
CC
CC
6
H
H
4
4
SO
SO
2
6
2
2-ClC
3-ClC
4-ClC
6
6
6
H
4
4
4
SO
2
SO
2
SO
2
H
H
6 4 2
3-BrC H SO
2-FC
3-FC
4-FC
6
6
6
H
H
H
4
4
4
SO
SO
SO
2
2
2
3-NCC
4-NCC
6
H
H
4
4
SO
SO
2
35
6
2
3
3
6
7
The compounds were screened for their in vitro
antimycobacterial activity against M. tuberculosis by the agar
1
8
38
>25
dilution method for the determination of MIC in triplicates. The
MIC is defined as the minimum concentration of compound
required to inhibit 99% of bacterial growth, and the MIC values of
the synthesized compounds along with the standard drugs for
comparison are presented in Table 2. As evident from the Table 2,
as do many compounds belonging to sulfonamide series show
indeed moderate antimycobacterial activity (MIC >25-6.25 μM), in
sharp contrast to amide series, wherein most others displayed good
activity, suggesting that electronegative atom like fluorine
3
4
4
4
4
4
4
4
4
4
4
5
5
9
0
1
2
3
4
5
6
7
8
9
0
1
>25
>25
>25
25±0.32
25±0.21
12.5±0.29
25±0.17
12.5±0.14
6.5±0.11
6.5±0.05
12.5±0.18
>25
(lipophilic group) in all amide, urea, and sulfonamide, is a key
structural element for antimycobacterial activity.
It was also gratifying to note that many compounds of the
amide, urea, and sulfonamide respectively, showed enhanced
activity against M. tuberculosis with MIC ranging from 0.25 to
>25
Rifampicin
Isoniazid
0.12±0.03
0.36±0.12
4.71±0.07
7.64±0.15
>
25.00 μM. Eight compounds, 18, 19, 20, 34, 35, 36, 47 and 48 were
more potent than the standard drug ethambutol (MIC: 7.64 μM),
while three compounds, 21, 22 and 23 were more potent than the
standard drug isoniazid (MIC: 0.36 μM), Compounds 21, 22 and 23
with a MIC value of 0.25 μM, were found to be the most potent in
the library, being 1.4, 18.8 and 30.6 times more active than
isoniazid, ciprofloxacin, and ethambutol, respectively. However, all
the compounds were less active than rifampicin (MIC: 0.12 μM).
Table 2 In vitro antimycobacterial activity of the Compounds (11-51)
against MTB H37Rv
Ciprofloxacin
Ethambutol
a
mycobacterium tuberculosis H37Rv
To improve antimycobacterial potency and explore the
structure-activity relationships, the authors has synthesized a series
of 40 new N-substituted imidazo[4,5-c]pyridine derivatives having
different groups at phenyl ring. However, the authors have
performed the biological activity on three series of compounds like
amide, urea, and sulfonamide in that, the results demonstrated that
the antimycobacterial activity was in the order: amide >urea >
sulfonamide. On the basis of the above, six compounds in the
amide series (18, 19, 20, 21, 22 and 23), three in series urea (34, 35
and 36), and two in series sulfonamide (47 and 48) were more
active against M. tuberculosis. Among these compounds from the
series amide, urea, and sulfonamide, compounds 21, 22 and 23
a
MTB
Compound
(
MIC) (μM)
1
1
1
1
1
1
1
2
3
4
5
6
>25
>25
>25
>25
25±0.13
25±0.17
(
MIC: 0.25 μM) were found to be more active. This was due to
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amide bond the electron-withdrawing nature of the carbonyl group
where the lone pair of electrons on the nitrogen is delocalized by
resonance, and in urea the more electronegative oxygen atom pulls
electrons away from the carbon forming a greater electron density
around the oxygen, giving the oxygen a partial negative charge and
forming a polar bond. In the sulfonamide, the electron-withdrawing
nature of the sulfur group where the lone pair of electrons on the
nitrogen is delocalized by resonance.
23
162.07
Isoniazid
>455.78
Some compounds were further examined for toxicity (IC50) in a
2
2
mammalian Vero cell line. The IC50 values of compounds 21, 22
and 23 were found to be 169.07, 183.35 and 162.07 µM,
respectively (Table 3). In this study, interpretation of the in vitro
assay (MIC) data assisted in the selection of compounds for further
testing in vivo. In this regard, three compounds (21, 22 and 23)
along with isoniazid (INH) as reference compound were selected for
in vivo antimycobacterial efficacy against M. tuberculosis at a dose
Further, to increase structure-activity relationship, the authors
have introduced the different substituents at different positions of
aryl rings like simple phenyl ring, electron donating methyl group,
moderated electronegative atom chlorine, strong electronegative
fluorine and trifluoromethyl groups and electron withdrawing
cyano groups were examined. The results demonstrated that the
simple phenyl ring bearing compounds 11, 26, 27, 39 and 40 were
less active (MIC:>25-25 μM). The electron donating (hydrophobic)
methyl group at different positions ortho, meta and para on the
phenyl ring bearing compounds 12, 13, 14, 28, 29, 30, 41 and 42
showed moderate activity (MIC: >25-12.5 μM). Similarly, the
moderate electronegative chlorine atom at different positions
ortho, meta and para on the phenyl ring bearing compounds 16, 17,
23
of 50 mg/kg (Table 4) in CD-1 mice. Compound 23 decreased the
bacterial load in lung and spleen tissues with 2.47 and 3.68 log 10
reductions, while compound 21 (2.43 and 3.56) and 22 (1.81 and
2
.62) showed, log 10 reductions in lungs and spleen, respectively.
All these compounds (21, 22 and 23) were considered to be
promising in reducing bacterial count in lung and spleen tissues. As
can be seen in Table 4, the compounds 21 and 23 demonstrated
efficacy comparable to INH in mice lungs, while 22 was less
efficacious. Generally, the compounds were more effective in lungs.
When compared with isoniazid at the same dose level, 23
decreased the bacterial load with 0.28 and 0.50 log10 protections in
lung and spleen tissues, respectively, while that of compound 21
with 0.24 and 0.62 and compound 22 with 0.38 and 1.56. These
data together suggest that imidazopyridine derivatives may
represent promising lead candidates against TB that are worthy of
further investigation.
31, 32, 33, 43, 44 and 45 showed good activity (MIC: 25-12.5 μM).
In this series, the more electronegative element (lipophilic groups)
fluorine and trifluoromethyl groups at different positions ortho,
meta and para on the phenyl ring bearing compounds 18, 19, 20,
3
4, 35, 36, 47, 48 and 21, 22, 23 display maximum potent
1
9-21
antimycobacterial activity (MIC: 12.5-6.5 μM) (MIC: 0.25 μM).
Table 4 In vivo activity data of 21, 22, 23 and isoniazid against MTB
The influence of electron withdrawing group (cyano group) at
ATCC 35801 in mice
different positions on the phenyl ring bearing compounds 24, 25,
Compound
Lungs
Spleen
37, 38, 50 and 51, markedly decreased the antimycobacterial
(
log CFU ± SEM) (log CFU ± SEM)
activity (MIC: >25-25 μM).
Control
7.92 ± 0.13
5.49 ± 0.01
6.11 ± 0.17
5.45 ± 0.09
5.73 ± 0.03
8.97 ± 0.10
5.41 ± 0.18
6.35 ± 0.13
5.29 ± 0.16
4.79 ± 0.18
Synthesis and antimycobacterial activity of certain novel
imidazo[4,5-c]pyridine derivatives have been carried out. Some of
the synthesized compounds showed significant activity against M.
tuberculosis. Further studies on the synthesis and examination of
structure-activity relationships of a wide range of heterocyclic
compounds with various substituents at phenyl ring and N atom of
the imidazopyridine moiety suggest that the more electronegative
21 (50 mg/kg)
22 (50 mg/kg)
23 (50 mg/kg)
Isoniazid (25 mg/kg)
Conclusions
The compounds (21, 22 and 23) containing trifluoro methyl group
showed potent activity similar to that of standard drugs acting. The
antioxidant activity of synthesized molecules was evaluated by
DPPH method. The compounds with electron donating moiety
(lipophilic groups) group like fluorine (18, 19, 20, 34, 35, 36, 47 and
48) and trifluoromethyl groups (21, 22 and 23) on phenyl ring
compounds increases the activity to display good in vitro
antimycobacterial activity against M. tuberculosis, among which
three compounds (21, 22 and 23) were more potent than the
standard first-line drugs isoniazid, ciprofloxacin, and ethambutol.
And, the result shows that the antimycobacterial activity was in the
(
methyl) seem to give good results. The compounds 21, 22 and 23
were more potent than the standard first-line drugs isoniazid,
ciprofloxacin, and ethambutol. In comparison with the antibiotics
commonly used in the therapy, these data together suggest that
imidazopyridine derivatives may represent promising lead
candidates against TB that are worthy of further investigation.
Additional studies are planned to further assess the in vivo efficacy
of compounds 21, 22 and 23 in the standard mouse model of TB.
The synthesized compounds were screened in vitro for their
antimicrobial activities and showed variable activities.
order: amide >urea
> sulfonamide. In comparison with the
antibiotics commonly used in the therapy, test compounds were
found significantly potent.
Table 3 Cytotoxicity of 21, 22, 23 and isoniazid in a mammalian
Vero cell line
Compound
IC50 (µM)
169.19
2
2
1
2
183.35
4
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C H Cl N O : C, 32.46; H, 2.27; N, 18.93, Found: C, 32.41; H, 2.20; N,
Experimental
6
5
2
3
2
1
8.98.
General: Melting points were determined in one end open capillary
tubes on a Buchi 530 melting point apparatus and are uncorrected.
1
13
The H and C NMR spectra were recorded on Bruker Avance-400
2
,6-dichloro-N-methyl-3-nitro pyridine-4-amine (6)
MHz NMR instrument using TMS as an internal solvent and DMSO- A mixture of 2,6-dichloro-N-methyl-N-nitropyridine-4-amine (16 g,
d /CDCl as a solvent. Chemical shift is given in part per million (δ- 0.07 mol) in sulfuric acid (40 mL) was stirred at room temperature
6
3
for 12 h. Completion of the reaction was checked by TLC, then the
reaction mixture was poured in to crushed ice, extracted with
scale) and coupling constant is given in Hertz. Mass spectra were
recorded on Perkin–Elmer LC-MS PE Sciex API/65
Spectrophotometer. IR spectra were recorded using KBr on 8400S
CH
2 2 2 4
Cl (3 x 160 mL), dried over anhydrous Na SO and concentrated
in vacuo to get the yellow colored solid. Yellow solid; (15.6 g,
-1
Shimadzu Fourier Transform Spectrophotometer
(
max in cm ).
1
9
6
7.5%); H NMR 400 MHz, [D
6
]DMSO: δ=7.76 (d, J = 4.00 Hz, 1H),
+
Column chromatography was performed using Merck 7734 silica gel
.99 (s, 1H), 2.84 (d, J = 4.80 Hz, 3H); MS: m/z 222.1 (M ), 223
(
60-120 mesh) and Merck made pre-coated TLC plates were used. (M+1); Anal. calcd for C H Cl N O : C, 32.46; H, 2.27; N, 18.93,
6 5 2 3 2
Elemental analysis (C, H, and N) was undertaken with Perkin-Elmer Found: C, 32.40; H, 2.21; N, 18.95.
2
,6-dichloro-N-4-methylpyridine-3,4-diamine (7). A mixture of 2,6-
model 240C analyzer.
dichloro-N-methyl-3-nitropyridine-4-amine (15.6 g, 0.07 mol), iron
powder (23.54 g, 0.4215 mol ), ammonium chloride ( 30.06 g, 0.56
mol) and methanol; water (78 mL) was heated on a oil bath with
stirring at 90 °C for 3 h. After completion of the reaction (TLC), the
Synthesis
N-oxide 2,6-dichloropyridine (2). 2,6-Dichloropyridine (50 g, 0.34
mol), trifluoroacetic acid (TFA) (300 mL, 3.38 mol) and hydrogen
peroxide 30% in water (75 mL) were mixed slowly, then it was
stirred at 90 °C for 12 h. After completion of the reaction (TLC),
TFA was removed under vacuum and the reaction mixture was
neutralized with the Na
mL) and dried over anhydrous Na SO . The resulting precipitate was
concentrated in vacuo to give the crude product which was
recrystallized from hexane to get a cream colored pure solid. Cream
reaction mixture was filtered through celite, extracted with CH
3 x 150 mL), dried over Na SO and concentrated in vacuo to give
the brown colored solid. Brown solid; (12 g, 88.95 %); H NMR 400
MHz, [D ] DMSO: δ=6.32 (t, J = 4.00 Hz, 2H), 4.90 (s, 2H), 2.78 (d, J =
2 2
Cl
(
2
4
1
2 3 2 2
CO solution, extracted with CH Cl (3 x 500
6
2
4
+
4
C
.80 Hz, 3H)), MS: m/z 192 (M ), 193 (M+1); Anal. calcd for
Cl : C, 37.52; H, 3.67; N, 21.88, Found: C, 37.48; H, 3.61; N,
6
H
7
2 3
N
1
21.82.
4,6-dichloro-1-methyl-1H-imidazo [4,5-c]pyridine (8). Mixture of
,6-dichloro-N-4-methylpyridine-3,4-diamine (12 g, 0.06 mol) and
triethylorthoformate (48 mL) in ethanol (60 mL) were heated on a
oil bath with stirring at 105 °C for 36 h. After completion of the
color solid; (40 g, 72.2 %); H NMR (400 MHz, CDCl
3
): δ=7.12 (t, J =
+
8
(
.00 Hz, 1H), 7.45 (d, J = 8.40 Hz, 2H ppm; MS: m/z 163.99 (M ), 165
M+1); Anal. calcd for C Cl NO: C, 36.62; H, 1.84; N, 8.54, Found:
C, 36.64; H, 1.82; N, 8.56.
,4,6-trichloropyridine (3)
Mixture of N–oxide-2,6-dichloropyridine (40 g, 0.24 mol) and POCl3
79.57 mL, 0.85 mol), were refluxed for 12 h. After completion of
the reaction (TLC), POCl3 was removed under vacuum and the
reaction mixture was neutralized with Na CO solution, extracted
with CH Cl2 (3 x 400 mL), dried over anhydrous Na SO and
2
5
H
3
2
2
reaction (TLC), the reaction mixture was concentrated in vacuo to
give the crude product which was recrystallized from ethyl acetate:
(
hexane mixture (50:50) to get brown colored solid. Brown solid;
1
(
(
C
10.5 g, 88.9 %); H NMR 400 MHz, [D
6
]DMSO: δ=8.48 (s, 1H), 7.92
2
3
+
s, 1H), 3.87 (s, 3H); MS: m/z 202 (M ), 203 (M+1); Anal. calcd for
Cl : C, 41.61; H, 2.49; N, 20.80, Found: C, 41.58; H, 2.45; N,
20.86.
2
2
4
7
H
5
2 3
N
concentrated in vacuo to give crude product as black liquid. Light
black liquid; (32.5g, 73.03%); H NMR (400 MHz, CDCl ): δ=7.28 (d, J
1
3
+
6-chloro-1-methyl-N-(diphenylmethylene)-1H-imidazo[4,5-c]
pyridine-4-amine (9)
A mixture of 4,6-dichloro-1-methyl-1H-imidazo[4,5-c]pyridine (10.5
g, 0.34 mol), benzophenone imine (15.1 g, 0.08 mol) xanthphose
=
7.60 Hz, 2H) ppm; MS: m/z 182.4 (M ), 183.4 (M+1); Anal. calcd
5 2 3
for C H Cl N: C, 32.92; H, 1.10; N, 7.68, Found: C, 32.94; H, 1.12; N,
7.70.
2,6-dichloro-N-methylpyridine-4-amine (4)
(
1.60 g, 0.002 mol ), cesium carbonate (36.22 g ,0.11 mol) and
Mixture of 2,4,6-trichloropyridine (32.5 g, 0.18 mol) and
methylamine (130 mL, 30 % solution) in ethanol (33 mL) were
heated on a oil bath with stirring at 40 °C for 12 h. After completion
of the reaction (TLC), reaction mixture was filtered. The crude
Tris(dibenzylideneacetone) dipalladium(0) (3.19 g, 0.005 mol) in
dioxane (110 mL) was degassed using argon, Then it was stirred at
1
10 °C for 18 h. After completion of the reaction (TLC), dioxane was
removed under vacuum, extracted with ethyl acetate (3 x 100 mL)
dried over Na SO and concentrated in vacuo to give the crude
product was recrystallized from diethyl ether to get white colored
.
2
4
1
solid. White solid; (16.25 g, 51.53 %); H NMR 400 MHz, [D ]DMSO:
6
product, which was purified by column chromatography on silica
employing ethyl acetate – hexane (1:4 v/v) as an eluent to obtain
δ=7.34 (d, J = 4.80 Hz, 1H), 6.53 (s, 2H), 2.73 (d, J = 4.80 Hz, 3H)
+
ppm; MS: m/z 177 (M ), 178 (M+1); Anal. calcd for C H Cl N : C,
6
6
2 2
pure
6-chloro-1-methyl-N-(diphenylmethylene)-1H-imidazo[4,5-
4
2
2
0.71; H, 3.42; N, 15.82, Found: C, 40.72; H, 3.44; N, 15.81.
,6-dichloro-N-methyl-N-nitro pyridine-4-amine (5). A mixture of
,6-dichloro-N-methylpyridine-4-amine (16.25 g, 0.09 mol) in
c]pyridine-4-amine brown colored solid. Brown solid; (11g, 57.1 %);
1
H NMR 400 MHz, [D
s, 1H), 7.15-7.24 (m, 5H), 3.74 (s, 3H); MS: m/z 346.81 (M ), 348
M+1); Anal. calcd for C20 : C, 69.26; H, 4.36; N, 16.15, Found:
6
]DMSO: δ=8.16 (s, 1H), 7.52-7.71 (m, 5H), 7.36
+
(
(
sulfuric acid (40.6 mL) was cooled to -10 °C then fuming nitric acid
was added slowly, Then it was stirred at 0 °C for 1h. After
completion of the reaction (TLC), the reaction mixture was poured
into crushed ice , extracted with CH Cl (3 x 160 mL), dried over
H
15ClN
4
C, 69.20; H, 4.31; N, 16.11.
-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-amine (10)
mixture of 6-chloro-1-methyl-N-(diphenylmethylene)-1H-
6
A
2
2
Na SO4 and concentrated in vacuo to give the product which was
2
imidazo[4,5-c] pyridine-4-amine (11 g, 0.03 mol) in 1.5 N HCl (100
mL) was stirred at room temperature for 6 h. After completion of
the reaction (TLC), the reaction mixture was neutralized with NaOH
solution to pH-10, extracted with CH Cl (3 x 100 mL), dried over
recrystallized from hexane to get yellow colored solid. Yellow solid;
1
(
3
16 g, 78.5 %); H NMR (400 MHz, CDCl ): δ=7.29 (d, J = 8.20 Hz, 2H),
3
+
.75 (s, 3H) ppm; MS: m/z 222 (M ), 223 (M+1); Anal. calcd for
2
2
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2016, 00, 1-3 | 5
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New Journal of Chemistry
Page 6 of 11
View Article Online
DOI: 10.1039/C6NJ02069K
ARTICLE
Journal Name
Na SO4 and concentrated in vacuo to give the crude product. The 2-chloro-N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)
2
formed product was purified by column chromatography on silica benzamide (15). White solid; (108 mg, 61 %): Rf
=
0.61
1
employing methanol–CH Cl (1:4 v/v) as an eluent to obtain pure 6- (CHCl /MeOH, 9:1); mp: 183-185 °C; H NMR (400 MHz, [D ]DMSO):
2
2
3
6
chloro-1-methyl- -1H-imidazo[4,5-c]pyridine-4-amine colorless δ=11.00 (s, 1H), 8.33 (s, 1H), 7.69 (d, J = 2.00 Hz, 2H), 7.42-7.58 (m,
1
13
solid. White solid; (3.5 g, 60.43 %); H NMR 400 MHz, [D ]DMSO: 4H), 3.84 (s, 3H) ppm; C NMR (400 MHz, [D ]DMSO): δ=164.61,
6
6
δ=8.02 (s, 1H), 6.84 (s, 1H), 6.64 (s, 2H), 3.72 (s, 3H); MS: m/z 182.6 161.51, 142.98, 140.89, 140.88, 134.42, 132.41, 132.23, 129.98,
+
(
M ), 183.6 (M+1); Anal. calcd for C H ClN C, 46.04; H, 3.86; N, 128.87, 127.30, 126.32, 94.51, 30.86 ppm; IR (KBr): ṽ = 3424, 1669
7
7
4
-
1
+
3
0.68, Found, C, 46.08; H, 3.90; N, 30.72.
2 4
cm ; MS: m/z 321.1 (M ), 322 (M+1); Anal. calcd for C14H10Cl N O C,
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl) amide (11- 52.36; H, 3.14; N, 17.45, found, C, 52.32; H, 3.12; N, 17.41.
5)
2
3
-chloro-N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-
A mixture of sodium hydride (26.28 mg, 1.09 mmol), 6-chloro-1-
methyl-1H-imidazo[4,5-c]pyridine-4-amine (100 mg, 0.54 mmol),
acid chloride (0.65 mmol) in dimethylformamide (6 mL), was stirred
at room temperature for 18 h. After completion of the reaction
yl)benzamide (16). White solid; (109 mg, 62 %): Rf
=
0.64
1
(
CHCl
δ=11.06 (s, 1H), 8.33 (s, 1H), 7.56-8.07 (m, 6H), 3.86 (s, 3H) ppm;
NMR (400 MHz, [D ]DMSO): δ=164.66, 161.59, 142.96, 140.87,
40.86, 135.31, 134.47, 132.41, 129.94, 128.82, 126.31, 125.67,
3
/MeOH, 9:1); mp: 181-183 °C; H NMR (400 MHz, [D ]DMSO):
6
13
C
6
(TLC), it was quenched with saturated NH Cl solution, extracted
4
1
9
3
with ethyl acetate (3 x 4 mL), dried over anhydrous Na
concentrated in vacuo to give the crude product, which was
purified by column chromatography on silica employing
CHCl
2
SO
4
and
-1
+
4.52, 30.83 ppm; IR (KBr): ṽ = 3428, 1671 cm ; MS: m/z 321.1 (M ),
22 (M+1); Anal. calcd for C14 O C, 52.36; H, 3.14; N, 17.45,
2 4
H10Cl N
found, C, 52.32; H, 3.12; N, 17.41.
3
/MeOH (100:0!90:10) as an eluent to obtain pure solid.
4
-chloro-N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)benzamide (11)
yl)benzamide (17). White solid; (114 mg, 65 %): Rf
(CHCl /MeOH, 9:1); mp: 184-186 °C; H NMR (400 MHz, [D ]DMSO):
δ=11.01 (s, 1H), 8.32 (s, 1H), 8.05 (t, J = 6.64 Hz, 2H), 7.76 (d, J =
0.84 Hz, 1H), 7.63 (t, J = 6.64 Hz, 2H), 3.87 (s, 3H) ppm; C NMR
(400 MHz, [D
1
=
0.66
White solid; (118 mg, 75 %): Rf = 0.77 (CHCl /MeOH, 9:1); mp:166-
]DMSO: δ=10.90 (s, 1H), 8.32 (s, 1H),
.04 (d, J = 1.48 Hz, 2H), 7.76 (s, 1H), 7.62 (d, J = 7.40 Hz, 1H), 7.55
3
1
1
3
6
1
68°C; H NMR 400 MHz, [D
6
8
13
-
1
(
t, J = 7.24 Hz, 2H), 3.87 (s, 3H) ppm; IR (KBr): ṽ = 3415, 1655 cm ;
1
3
6
]DMSO): δ=164.62, 161.55, 142.99, 140.87, 140.85,
6
C NMR (400 MHz, [D ]DMSO): δ=164.46, 161.28, 142.92, 140.73,
37.34, 133.41, 129.96, 129.94, 128.67, 128.65, 126.31, 94.52,
1
40.71, 134.12, 132.21, 128.94, 128.92, 127.14, 127.12, 125.54,
-1
+
+
30.83 ppm; IR (KBr): ṽ = 3423, 1668 cm ; MS: m/z 321.1 (M ), 322
M+1); Anal. calcd for C14 O C, 52.36; H, 3.14; N, 17.45,
found, C, 52.32; H, 3.12; N, 17.41.
94.42, 30.85 ppm; MS: m/z 286.7 (M ), 287.7 (M+1); Anal. calcd for
(
2 4
H10Cl N
14 4
C H11ClN O C, 58.65; H, 3.87; N, 19.54, found, C, 58.61; H, 3.82; N,
19.50.
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-2-fluoro
benzamide (18). White solid; (110 mg, 66 %): Rf
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-2-
methylbenzamide (12). White solid; (115 mg, 63 %): Rf = 0.79
=
0.53
1
1
(CHCl
3
/MeOH, 9:1); mp: 189-191 °C; H NMR (400 MHz, [D
6
]DMSO):
(
CHCl
]DMSO): δ=10.72 (s, 1H), 8.33 (s, 1H), 7.72 (s, 1H), 7.52 (d, J =
.32 Hz, 1H), 7.39 (t, J = 7.12 Hz, 1H), 7.26-7.28 (m, 2H), 3.86 (s, 3H),
3
/MeOH, 9:1); mp: 169-171 °C
;
H NMR (400 MHz,
δ=10.83 (s, 1H), 8.33 (d, J = 9.40 Hz, 1H), 7.71 (t, J = 5.08 Hz, 2H),
[D
6
13
7
.53-7.61 (m, 1H), 7.32 (t, J = 8.64 Hz, 2H), 3.85 (s, 3H) ppm;
C
7
2
1
1
1
3
NMR (400 MHz, [D ]DMSO): δ=164.72, 161.71, 157.82, 142.96,
6
6
.48 (s, 3H) ppm; C NMR (400 MHz, [D ]DMSO): δ=164.51, 161.21,
42.96, 140.74, 140.72, 137.19, 135.19, 132.26, 128.96, 128.94,
26.12, 125.56, 94.41, 30.85, 24.38 ppm; IR (KBr): ṽ = 3418, 1660
1
9
40.85, 140.83, 134.12, 129.98, 126.30, 125.23, 124.87, 116.08,
-1
4.51, 30.86 ppm; IR (KBr): ṽ = 3433, 1672 cm ; MS: m/z 304.7
+
-
1
+
(M ), 306 (M+1); Anal. calcd for C14
H
10ClFN
4
O C, 55.18; H, 3.31; N,
cm ; MS: m/z 300.7 (M ), 302 (M+1); Anal. calcd for C15
4
H13ClN O C,
1
8.39, found, C, 55.14; H, 3.35; N, 18.34.
59.91; H, 4.36; N, 18.63, found, C, 59.96; H, 4.32; N, 18.59.
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-fluoro
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-methyl
benzamide (13). White solid; (110 mg, 67 %): Rf
benzamide (19). White solid; (105 mg, 63 %): Rf
=
0.51
=
0.76
]DMSO):
δ=10.82 (s, 1H), 8.32 (s, 1H), 7.83-7.83 (m, 2H), 7.75 (s, 1H), 7.43 (d,
1
1
(CHCl
3
/MeOH, 9:1); mp: 188-190 °C; H NMR (400 MHz, [D
6
]DMSO):
3 6
(CHCl /MeOH, 9:1); mp: 171-173 °C ; H NMR (400 MHz, [D
δ=11.01 (s, 1H), 8.32 (s, 1H), 7.87-7.89 (m, 1H), 7.80-7.83 (m, 1H),
7.76 (s, 1H), 7.57-7.62 (m, 1H), 7.46-7.50 (m, 1H), 3.86 (s, 3H) ppm;
1
3
J = 5.92 Hz, 2H), 3.07 (s, 3H), 2.41 (s, 3H) ppm; C NMR (400 MHz, 13
C NMR (400 MHz, [D
6
]DMSO): δ=164.76, 162.76, 161.74, 142.95,
[D
6
]DMSO): δ=164.48, 161.19, 142.92, 140.75, 140.73, 137.16,
1
40.82, 140.81, 135.31, 130.47, 126.35, 123.23, 118.92, 112.56,
1
35.14, 132.21, 128.92, 128.90, 126.15, 125.52, 94.46, 30.81, 24.02
-1
+
-1
+
94.56, 30.81 ppm; IR (KBr): ṽ = 3435, 1675 cm ; MS: m/z 304.7 (M ),
06 (M+1); Anal. calcd for C14 10ClFN O C, 55.18; H, 3.31; N, 18.39,
found, C, 55.14; H, 3.35; N, 18.34.
ppm; IR (KBr): ṽ = 3421, 1663 cm ; MS: m/z 300.7 (M ), 302(M+1);
Anal. calcd for C15 O C, 59.91; H, 4.36; N, 18.63, found, C,
9.96; H, 4.32; N, 18.59.
3
H
4
H
13ClN
4
5
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-4-fluoro
benzamide (20). White solid; (107 mg, 64 %): Rf
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-4-methyl
benzamide (14). White solid; (106 mg, 64 %): Rf
=
0.57
=
0.77
]DMSO):
δ=10.80 (s, 1H), 8.31 (s, 1H), 7.95 (d, J = 8.12 Hz, 2H), 7.74 (s, 1H),
1
1
(CHCl
3
/MeOH, 9:1); mp: 190-192 °C; H NMR (400 MHz, [D
6
]DMSO):
3 6
(CHCl /MeOH, 9:1); mp: 168-170 °C; H NMR (400 MHz, [D
δ=10.93 (s, 1H), 8.30 (s, 1H), 8.08-8.12 (m, 2H), 7.74 (s, 1H), 7.35-
13
1
3
7.39 (m, 2H), 3.85 (s, 3H) ppm; C NMR (400 MHz, [D
δ=164.77, 164.70, 161.75, 142.99, 140.87, 140.85, 129.84, 129.23,
29.21, 126.31, 116.87, 116.85, 94.52, 30.85 ppm; IR (KBr): ṽ =3431,
6
]DMSO):
7
(
1
3
3
.35 (d, J = 8.08 Hz, 2H), 3.89 (s, 3H), 2.41 (s, 3H) ppm; C NMR
400 MHz, [D ]DMSO): δ=164.51, 161.26, 142.91, 140.75, 140.74,
37.08, 135.14, 132.19, 128.88, 128.86, 126.18, 125.51, 94.41,
6
1
-1
+
-1
+
1671 cm ; MS: m/z 304.7 (M ), 306 (M+1); Anal. calcd for
0.83, 24.10 ppm; IR (KBr): ṽ = 3419, 1662 cm ; MS: m/z 300.7 (M ),
02 (M+1); Anal. calcd for C15 O C, 59.91; H, 4.36; N, 18.63,
C
14
H
10ClFN
4
O C, 55.18; H, 3.31; N, 18.39, Found, C, 55.14; H, 3.35; N,
H13ClN
4
1
8.34.
found, C, 59.96; H, 4.32; N, 18.59.
6
| J. Name., 2012, 00, 1-3
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Page 7 of 11
NP lee wa s eJ od uo r nn oa tl aod fj uC s ht em ma ri sg it nr sy
View Article Online
DOI: 10.1039/C6NJ02069K
Journal Name
ARTICLE
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-2-(trifluoro
was purified by column chromatography on silica employing
/MeOH (100:0!90:10) as an eluent to obtain pure solid.
methyl)benzamide (21). White solid; (120 mg, 62 %): Rf = 0.42 CHCl
3
1
(
CHCl /MeOH, 9:1); mp: 195-197 °C; H NMR (400 MHz, [D ]DMSO):
3
6
1
-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridin-4-yl)-3-phenylurea
(26). White solid; (120 mg, 73 %): Rf = 0.72 (CHCl /MeOH, 9:1);
mp:213-215 °C; H NMR (400 MHz, [D ]DMSO): δ=11.30 (s, 1H),
δ=11.12 (s, 1H), 8.34 (s, 1H), 7.84 (d, J = 7.64 Hz, 1H), 7.66-7.78 (m,
1
3
3
4
H), 3.86 (s, 3H) ppm; C NMR (400 MHz, [D ]DMSO): δ=164.82,
1
6
6
1
1
3
61.74, 142.86, 140.78, 140.76, 132.61, 132.53, 131.42, 127.98,
9
.43 (s, 1H), 8.34 (s, 1H), 7.54 (d, J = 7.32 Hz, 3H), 7.36 (t, J = 8.12
26.87, 126.36, 125.30, 117.89, 94.56, 30.82 ppm; IR (KBr): ṽ =
13
-
1
+
Hz, 2H), 7.06 (t, J = 7.40 Hz, 1H), 3.84 (s, 3H) ppm; C NMR (400
MHz, [D ]DMSO): δ=162.72, 156.36, 142.91, 140.76, 140.75, 136.06,
29.56, 129.54, 126.59, 125.41, 122.62, 122.61, 94.51, 30.72 ppm;
438, 1678 cm ; MS: m/z 354.7 (M ), 356 (M+1); Anal. calcd for
6
C15H10ClF N O C, 50.79; H, 2.84; N, 15.79, found, C, 50.72; H, 2.81;
3
4
1
N, 15.75.
-1
+
IR (KBr): ṽ = 3426, 1662 cm ; MS: m/z 301.7 (M ), 303 (M+1);
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-(trifluoro
Anal.calcd for C14H12ClN O C, 55.73; H, 4.01; N, 23.21, found, C,
5
methyl)benzamide (22). White solid; (122 mg, 63 %): Rf = 0.45 55.72; H, 4.03; N, 23.19.
1
(
CHCl /MeOH, 9:1); mp: 194-196 °C; H NMR (400 MHz, [D ]DMSO):
3
6
1
-benzyl-3-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)urea
δ=11.23 (s, 1H), 8.33 (t, J = 7.60 Hz, 3H), 8.00 (d, J = 7.24 Hz, 1H),
1
3
(27). White solid; (112 mg, 65 %): Rf = 0.76 (CHCl /MeOH, 9:1); mp:
2
1
7.27-7.27 (m, 1H), 4.51 (d, J = 5.72 Hz, 2H), 3.83 (s, 3H) ppm;
NMR (400 MHz, [D
1
9
3
7
.79 (t, J = 11.16 Hz, 2H), 3.86 (s, 3H) ppm; C NMR (400 MHz,
]DMSO): δ=164.85, 161.77, 142.82, 140.77, 140.75, 134.81,
32.03, 131.22, 129.87, 128.24, 126.41, 124.30, 124.32, 94.52,
1
22-224 °C; H NMR (400 MHz, [D ]DMSO): δ=11.30 (s, 1H), 9.31 (s,
6
[D
6
H), 8.99 (s, 1H), 8.30 (s, 1H), 7.46 (s, 1H), 7.37 (d, J = 3.72 Hz, 3H),
1
3
13
-1
+
C
0.85 ppm; IR (KBr): ṽ = 3435, 1675 cm ; MS: m/z 354.7 (M ), 356
O: C 50.79, H 2.84, N 15.79,
6
]DMSO): δ=162.76, 156.42, 142.93, 140.78,
(M+1); Anal. calcd for C15
3 4
H10ClF N
40.77, 140.24, 129.16, 129.14, 128.46, 128.46, 127.61, 126.54,
found: C 50.72, H 2.81, N 15.75.
-1
4.59, 47.82, 30.75 ppm; IR (KBr): ṽ = 3423, 1658 cm ; MS:m/z
+
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-4-(trifluoro
315.7 (M ), 317 (M+1); Anal. calcd for C15
H14ClN
5
O C, 57.06; H, 4.47;
methyl)benzamide (23). White solid; (122 mg, 63 %): Rf = 0.41 N, 22.18, found, C, 57.02; H, 4.44; N, 22.15.
1
(
CHCl
3 6
/MeOH, 9:1); mp: 197-199 °C; H NMR (400 MHz, [D ]DMSO):
1
-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-o-tolylurea
(28). White solid; (118 mg, 68 %); Rf = 0.79 (CHCl /MeOH, 9:1); mp:
]DMSO): δ=11.24 (s, 1H), 9.39 (s,
H), 8.36 (s, 1H), 7.56 (s, 1H), 7.39 (s, 1H), 7.22-7.24 (m, 3H), 6.89
δ=11.23 (s, 1H), 8.34 (s, 1H), 8.06 (t, J = 6.68 Hz, 2H), 7.76 (d, J =
13
3
2
.86Hz, 1H), 7.65 (t, J = 6.68 Hz, 2H), 3.87 (s, 3H) ppm; C NMR (400
MHz, [D ]DMSO): δ=164.89, 161.78, 142.85, 140.79, 140.77, 140.75,
34.98, 130.26, 130.24, 127.65, 127.62, 126.41, 124.38, 94.52,
1
2
1
18-220 °C; H NMR (400 MHz, [D
6
6
1
3
13
-
1
+
(d, J = 8.04 Hz, 1H), 3.85 (s, 3H), 2.32 (s, 3H) ppm; C NMR (400
MHz, [D ]DMSO): δ=162.81, 156.62, 142.86, 140.63, 140.60, 135.06,
35.02, 129.56, 126.54, 126.62, 124.52, 122.32, 94.51, 30.72, 24.48
0.85 ppm; IR (KBr): ṽ = 3435, 1675 cm ; MS: m/z 354.7 (M ), 356
O C, 50.79; H, 2.84; N, 15.79,
6
(M+1); Anal. calcd for C15
3 4
H10ClF N
1
found, C, 50.76; H, 2.85; N, 15.76.
-1
+
ppm; IR (KBr): ṽ = 3420, 1659 cm ; MS: m/z 315.7 (M ), 317 (M+1);
Anal. calcd for C15 O C, 57.06; H, 4.47; N, 22.18, found, C,
0.35 57.02; H, 4.41; N, 22.13.
]DMSO):
δ=11.16 (s, 1H), 8.44 (s, 1H), 8.31 (t, J = 7.92 Hz, 2H), 8.10 (d, J =
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-cyano
benzamide (24). White solid; (112 mg, 66 %): Rf
H14ClN
5
=
1
(
3 6
CHCl /MeOH, 9:1); mp: 204-206 °C; H NMR (400 MHz, [D
1
-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-m-tolylurea
(29). White solid; (113 mg, 65 %); Rf = 0.73 (CHCl /MeOH, 9:1); mp:
]DMSO): δ=11.23 (s, 1H), 9.39 (s,
H), 8.34 (s, 1H), 7.54 (s, 1H), 7.38 (s, 1H), 7.22-7.23 (m, 2H), 6.88
1
3
3
7
(
1
9
3
.64 Hz, 1H), 7.76 (t, J = 8.64 Hz, 2H), 3.86 (s, 3H) ppm; C NMR
400 MHz, [D ]DMSO): δ=164.66, 161.59, 142.94, 140.87, 140.86,
35.81, 134.97, 131.41, 129.94, 129.96, 128.81, 126.35, 116.21,
1
2
1
19-221 °C; H NMR (400 MHz, [D
6
6
13
-1
+
(d, J = 7.52 Hz, 1H), 3.84 (s, 3H), 2.31 (s, 3H) ppm; C NMR (400
MHz, [D ]DMSO): δ=162.86, 156.59, 142.96, 140.78, 140.76, 138.98,
35.86, 129.56, 126.68, 124.54, 124.52, 120.32, 94.65, 30.67, 24.16
4.52, 30.83 ppm; IR (KBr): ṽ = 3439, 1682 cm ; MS: m/z 311.7 (M ),
12.7 (M+1); Anal. calcd for C15 O C, 57.79; H, 3.23; N, 22.47,
6
H10ClN
5
1
found, C, 57.75; H, 3.21; N, 22.45.
-1
+
ppm; IR (KBr): ṽ = 3428, 1668 cm ; MS: m/z 315.7 (M ), 317 (M+1);
Anal. calcd for C15 O C, 57.06; H, 4.47; N, 22.18, found, C,
0.31 57.02; H, 4.41; N, 22.13.
]DMSO):
δ=11.18 (s, 1H), 8.47 (s, 1H), 8.31 (t, J = 7.92 Hz, 2H), 8.10 (d, J =
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-4-cyano
benzamide (25). White solid; (112 mg, 66 %): Rf
H14ClN
5
=
1
(
3 6
CHCl /MeOH, 9:1); mp: 206-208 °C; H NMR (400 MHz, [D
1
-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-p-tolylurea
(30). White solid; (115 mg, 67 %); Rf = 0.77 (CHCl /MeOH, 9:1); mp:
]DMSO): δ=11.23 (s, 1H), 9.35 (s,
H), 8.33 (s, 1H), 7.53 (s, 1H), 7.43 (d, J = 8.36 Hz, 2H), 7.24 (d, J =
1
3
3
7
(
1
9
3
.64 Hz, 1H), 7.76 (t, J = 8.64 Hz, 2H), 3.82 (s, 3H) ppm; C NMR
400 MHz, [D ]DMSO): δ=164.68, 161.55, 142.96, 140.84, 140.82,
38.40, 132.98, 132.96, 128.94, 128.92, 126.28, 126.32, 115.96,
1
2
1
23-225 °C; H NMR (400 MHz, [D
6
6
13
-1
+
9.12 Hz, 2H), 3.84 (s, 3H), 2.27 (s, 3H) ppm; C NMR (400 MHz,
]DMSO): δ=162.78, 156.67, 142.92, 140.67, 140.65, 135.26,
34.86, 129.78, 129.75, 126.56, 121.66, 121.62, 94.56, 30.81, 24.32
4.55, 30.88 ppm; IR (KBr): ṽ = 3439, 1682 cm ; MS: m/z 311.7 (M ),
12.7 (M+1); Anal. calcd for C15 O C, 57.79; H, 3.23; N, 22.47,
[D
6
H10ClN
5
1
found, C, 57.72; H, 3.20; N, 22.41.
-1
+
ppm; IR (KBr): ṽ = 3433, 1672 cm ; MS: m/z 315.7 (M ), 317 (M+1);
-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-urea (26- Anal. calcd for C15H14ClN O C, 57.06; H, 4.47; N, 22.18, found, C,
1
3
5
8)
57.02; H, 4.41; N, 22.13.
A mixture of sodium hydride (26.28 mg 1.09 mmol), 6-chloro-1-
methyl-1H-imidazo[4,5-c]pyridine-4-amine (100 mg, 0.54 mmol)
and isocyanate (0.65 mmol) in dimethyl formamide (6 mL), was
stirred at room temperature for 18 h. After completion of the
1
-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-(2-
chlorophenyl)urea (31). White solid; (122 mg, 66 %); Rf = 0.63
1
(
3 6
CHCl /MeOH, 9:1); mp: 227-229 °C; H NMR (400 MHz, [D ]DMSO):
δ=11.66 (s, 1H), 9.64 (s, 1H), 8.35-8.39 (m, 2H), 7.51-7.56 (m, 2H),
7
reaction (TLC) , it was quenched with saturated NH Cl solution,
4
13
.33-7.37 (m, 1H), 7.07-7.12 (m, 1H), 3.84 (s, 3H) ppm; C NMR
extracted with ethyl acetate (3 x 4 mL), dried over anhydrous
(
400 MHz, [D ]DMSO): δ=162.86, 156.65, 142.81, 140.76, 140.74,
6
Na SO and concentrated in vacuo to give the crude product which
2
4
1
35.12, 134.09, 129.22, 126.19, 126.17, 126.65, 124.08, 94.62,
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2016, 00, 1-3 | 7
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New Journal of Chemistry
Page 8 of 11
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DOI: 10.1039/C6NJ02069K
ARTICLE
Journal Name
-
1
+
3
0.76 ppm; IR (KBr): ṽ = 3431, 1669 cm ; MS: m/z 335.1 (M ), 336.1 140.81, 128.02, 127.99, 127.97, 126.62, 126.59, 120.49, 116.25,
-1
(M+1); Anal. calcd for C14
H
11Cl
2
N
5
O C, 50.02; H, 3.30; N, 20.83, 94.51, 30.72 ppm; IR (KBr): ṽ = 3436, 1669 cm ; MS: m/z
+
found, C, 50.06; H, 3.33; N, 20.78.
326.74(M ), 328 (M+1); Anal. calcd for C15H11ClN O C, 55.14; H,
6
3
.39; N, 25.72, Found, C, 55.12; H, 3.36; N, 25.71.
1
-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-(3-chloro
phenyl)urea (32). White solid; (117 mg, 64 %); Rf 0.65 1-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-(3-
]DMSO): cyanophenyl)urea (38). White solid; (126 mg, 70 %); Rf = 0.38
=
1
(CHCl
3 6
/MeOH, 9:1); mp: 225-227 °C; H NMR (400 MHz, [D
1
δ=11.33 (s, 1H), 9.63 (s, 1H), 8.34 (s, 1H), 7.81 (t, J = 2.00 Hz, 1H), (CHCl /MeOH, 9:1); mp: 239-241 °C; H NMR (400 MHz, [D ]DMSO):
3
6
7
.55 (s, 1H), 7.30-7.40 (m, 2H), 7.10-7.13 (m, 1H), 3.84 (s, 3H) ppm; δ=11.48 (s, 1H), 9.78 (s, 1H), 8.35 (s, 1H), 7.82 (d, J = 8.68 Hz, 2H),
1
3
13
C NMR (400 MHz, [D ]DMSO): δ=162.72, 156.71, 142.85, 140.82, 7.48 (d, J = 8.96 Hz, 2H), 7.57 (s, 1H), 3.86 (s, 3H) ppm; C NMR
6
1
9
3
2
40.80, 140.79, 134.66, 130.22, 126.73, 125.70, 121.69, 121.65, (400 MHz, [D
4.68, 30.69 ppm; IR (KBr): ṽ = 3429, 1663cm ; MS: m/z 335.1 (M ), 140.71, 134.65, 134.62, 126.65, 124.19, 124.15, 120.21, 116.52,
6
]DMSO): δ=162.81, 156.56, 142.86, 140.76, 140.73,
-1
+
-1
36.1 (M+1); Anal. calcd for C14
0.83, Found, C, 50.06; H, 3.33; N, 20.78.
H
11Cl
2
N
5
O C, 50.02; H, 3.30; N, 94.66, 30.82 ppm; IR (KBr): ṽ = 3432, 1664 cm ; MS: m/z
+
326.74(M ), 328 (M+1); Anal. calcd for C15H11ClN O C, 55.14; H,
6
3
.39; N, 25.72, Found, C, 55.11; H, 3.37; N, 25.70.
1
-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-(4-chloro
0.69 N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl) sulfonamide
]DMSO): (39-51). A mixture of sodium hydride (26.28 mg 1.09 mmol), 6-
δ=11.32 (s, 1H), 9.56 (s, 1H), 8.34 (s, 1H), 7.56 (t, J = 4.16 Hz, 3H), chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-amine (100 mg, 0.54
phenyl)urea (33). White solid; (114 mg, 62 %); Rf
=
1
3 6
(CHCl /MeOH, 9:1); mp: 228-230 °C; H NMR (400 MHz, [D
13
7
.41 (d, J = 8.68 Hz, 2H), 3.84 (s, 3H) ppm; C NMR (400 MHz, mmol) and sulfonyl chloride (0.65 mmol) in dimethyl formamide (6
]DMSO): δ=162.79, 156.69, 142.91, 140.79, 140.75, 138.88, mL), was stirred at room temperature for 18 h. After completion of
29.88, 129.85, 129.82, 126.75, 124.24, 124.21, 94.59, 30.71 ppm; the reaction (TLC) , it was quenched with saturated NH Cl solution,
IR (KBr): ṽ = 3434, 1668 cm ; MS: m/z 335.1 (M ), 336.1 (M+1); extracted with ethyl acetate (3 x 4 mL), dried over anhydrous
Anal. calcd for C14
O C, 50.02; H, 3.30; N, 20.83, Found, C, Na SO and concentrated in vacuo to give the crude product, which
was purified by column chromatography on silica employing
CHCl /MeOH (100:0!90:10) as an eluent to obtain pure solid.
[D
6
1
4
-1
+
H11Cl
2
N
5
2
4
50.06; H, 3.33; N, 20.78.
3
1-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-(2-fluoro
phenyl)urea (34). White solid; (119 mg, 70 %); Rf
=
0.57 N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-
3 6
/MeOH, 9:1); mp: 232-234 °C; H NMR (400 MHz, [D
]DMSO): yl)benzenesulfonamide (39). White solid; (126 mg,71 %); Rf = 0.72
1
(CHCl
1
δ=11.70 (s, 1H), 9.70 (s, 1H), 8.35 (s, 1H), 8.28-8.28 (m, 1H), 7.55 (s, (CHCl
3
/MeOH, 9:1); mp: 227-229 °C; H NMR (400 MHz, [D
6
]DMSO):
1
1
1
1
H), 7.31 (q, J = 8.28 Hz, 1H), 7.19 (t, J = 7.72 Hz, 1H), 7.05-7.07 (m, δ=11.50 (s, 1H), 8.28 (s, 1H), 8.07 (d, J = 1.48 Hz, 2H), 7.56-7.57 (m,
1
3
13
H), 3.85 (s, 3H) ppm; C NMR (400 MHz, [D
6
]DMSO): δ=162.83, 3H), 7.42 (s, 1H), 3.77 (s, 1H) ppm; C NMR (400 MHz, [D
6
]DMSO):
62.81, 156.58, 142.88, 140.77, 140.74, 126.65, 125.63, 124.09, δ=162.51, 142.96, 140.89, 140.87, 140.85, 132.41, 129.98, 129.95,
24.06, 121.18, 121.15, 94.67, 30.81 ppm; IR (KBr): ṽ = 3432, 1664 127.30, 127.27, 126.29, 94.51, 30.82 ppm; IR (KBr): ṽ = 3424, 1372
-
1
+
-1
+
cm ; MS: m/z 319.7 (M ), 321 (M+1); Anal. calcd for C14
H
11ClFN
5
O
4 2
cm ; MS: m/z 322.77 (M ), 324 (M+1); Anal. calcd for C13H11ClN O S
C, 52.59; H, 3.47; N, 21.90, Found, C, 52.54; H, 3.43; N, 21.86.
C, 48.37; H, 3.44; N, 17.36, Found, C, 48.32; H, 3.41; N, 17.34.
1-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-(3-
6-chloro-1-methyl-N-[(phenylsulfonyl)methyl]-1H-imidazo[4,5-
fluorophenyl)ure (35). White solid; (126 mg, 72 %); Rf = 0.59 c]pyridine-4-amine (40). White solid; (121 mg, 66 %); Rf = 0.75
1
1
(CHCl
3 6
/MeOH, 9:1); mp: 235-237 °C; H NMR (400 MHz, [D
3 6
]DMSO): (CHCl /MeOH, 9:1); mp: 231-233 °C; H NMR (400 MHz, [D ]DMSO):
δ=11.40 (s, 1H), 9.60 (s, 1H), 8.34 (s, 1H), 7.57-7.58 (m, 1H), 7.39 (q, δ=11.05 (s, 1H), 8.32 (s, 1H), 7.59 (s, 1H), 7.35 (s, 5H), 5.09 (s, 2H),
1
3
J = 7.08 Hz, 1H), 7.16 (d, J = 8.08 Hz, 1H), 6.86-6.87 (m, 1H), 3.84 (s, 3.84 (s, 3H) ppm; C NMR (400 MHz, [D
6
]DMSO): δ=162.46, 142.93,
]DMSO): δ=162.79, 162.75, 156.77, 140.76, 140.74, 134.32, 129.55 129.52, 128.77, 128.73, 126.52,
6
13
1
1
1
3
3
H) ppm; C NMR (400 MHz, [D
-1
42.91, 140.88, 140.83, 140.79, 130.85, 126.74, 120.74, 120.71, 126.49, 94.68, 60.61, 30.78 ppm; IR (KBr): ṽ = 3428, 1374 cm ; MS:
-
1
+
4 2
20.68, 94.68, 30.69 ppm; IR (KBr): ṽ = 3428, 1664 cm ; MS: m/z m/z 336.8 (M ), 338 (M+1); Anal. calcd for C14H13ClN O S C, 49.93;
+
19.7 (M ), 321 (M+1); Anal. calcd for C14
H
11ClFN
5
O C, 52.59; H, H, 3.89; N, 16.64, Found, C, 49.91; H, 3.85; N, 16.62.
.47; N, 21.90, Found, C, 52.55; H, 3.44; N, 21.81.
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-2-
1
-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-(4-
methylbenzenesulfonamide (41). White solid; (118 mg, 64 %); Rf =
1
fluorophenyl)urea (36). White solid; (124 mg, 71 %); Rf = 0.58 0.78 (CHCl
CHCl /MeOH, 9:1); mp: 238-240 °C; H NMR (400 MHz, [D
3 6
]DMSO): [D
6
3
/MeOH, 9:1); mp: 233-235 °C; H NMR (400 MHz,
]DMSO): δ=11.80 (s, 1H), 8.28 (s, 1H), 8.10 (d, J = 7.92 Hz, 1H),
δ=11.27 (s, 1H), 9.47 (s, 1H), 8.33 (s, 1H), 7.53-7.55 (m, 3H), 7.20 (q, 7.48 (t, J = 6.16 Hz, 1H), 7.39 (t, J = 8.36 Hz, 2H), 7.31 (d, J = 7.56 Hz,
1
(
1
3
13
J = 2.12 Hz, 2H), 3.84 (s, 3H) ppm; C NMR (400 MHz, [D
6
6
]DMSO): 2H), 3.77 (s, 3H), 2.62 (s, 3H) ppm; C NMR (400 MHz, [D ]DMSO):
δ=162.88, 162.85, 156.65, 142.89, 140.79, 140.75, 130.63, 126.71, δ=162.65, 142.91, 140.83, 140.80, 140.78, 136.98, 129.96, 129.94,
1
3
23.24, 123.21, 119.86, 119.83, 94.71, 30.78 ppm; IR (KBr): ṽ = 127.53, 127.51, 126.38, 94.52, 30.84, 24.29 ppm; IR (KBr): ṽ = 3425,
-1
+
-
1
+
431, 1664 cm ; MS: m/z 319.7 (M ), 321 (M+1); Anal. calcd for 1372 cm ; MS: m/z 336.8 (M ), 338 (M+1); Anal. calcd for
11ClFN O C, 52.59; H, 3.47; N, 21.90, Found, C, 52.55; H, 3.45; N,
S C, 49.93; H, 3.89; N, 16.64, Found, C, 49.90; H, 3.85;
1.89.
14
C H
5
14 4 2
C H13ClN O
2
N, 16.62.
1-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-(3-
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-
cyanophenyl)urea (37). White solid; (118 mg, 66 %); Rf = 0.35 methylbenzenesulfonamide (42). White solid; (115 mg, 62 %); Rf =
1
1
(
CHCl
3
/MeOH, 9:1); mp: 236-238 °C; H NMR (400 MHz, [D
6
]DMSO): 0.71 (CHCl
]DMSO): δ=11.50 (s, 1H), 8.27 (s, 1H), 7.97 (s, 1H), 7.84 (t, J =
.68-7.69 (m, 1H), 7.51-7.51 (m, 3H), 3.85 (s, 3H) ppm; C NMR 4.52 Hz, 1H), 7.44 (q, J = 4.68 Hz, 3H), 3.77 (s, 3H), 2.39 (s, 3H) ppm;
3
/MeOH, 9:1); mp: 235-237 °C; H NMR (400 MHz,
δ=11.48 (s, 1H), 9.73 (s, 1H), 8.34 (s, 1H), 8.08 (d, J = 1.64 Hz, 1H), [D
6
1
3
7
1
3
(400 MHz, [D
6
]DMSO): δ=162.76, 156.59, 142.93, 140.85, 140.83,
C NMR (400 MHz, [D ]DMSO): δ=162.59, 142.77, 140.95, 140.92,
6
8
| J. Name., 2012, 00, 1-3
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Journal Name
NP lee wa s eJ od uo r nn oa tl aod fj uC s ht em ma ri sg it nr sy
View Article Online
DOI: 10.1039/C6NJ02069K
ARTICLE
1
40.89, 137.75, 133.74, 127.51, 127.49, 127.47, 126.53, 94.64, (M+1); Anal. calcd for C13H10ClFN O S C, 45.82; H, 2.96; N, 16.44,
4 2
-1
+
3
3
0.79, 24.31 ppm; IR (KBr): ṽ = 3426, 1338 cm ; MS: m/z 336.8 (M ), Found, C, 45.81; H, 2.95; N, 16.43.
38 (M+1); Anal. calcd for C H ClN O S C, 49.93; H, 3.89; N, 16.64,
14
13
4
2
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-4-
Found, C, 49.91; H, 3.87; N, 16.61.
fluorobenzenesulfonamide (49). White solid; (118 mg, 63 %); Rf =
1
2-chloro-N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-
0.59 (CHCl /MeOH, 9:1); mp: 239-241 °C; H NMR (400 MHz,
3
6
yl)benzenesulfonamide (43). White solid; (118 mg, 60 %); Rf = 0.63 [D ]DMSO): δ=11.68 (s, 1H), 8.27 (s, 1H), 8.10-8.11 (m, 2H), 7.40-
1
13
(
CHCl /MeOH, 9:1); mp: 223-225 °C; H NMR (400 MHz, [D ]DMSO): 7.40 (m, 3H), 3.77 (s, 3H) ppm; C NMR (400 MHz, [D ]DMSO):
3
6
6
δ=8.30 (s, 1H), 8.21 (d, J = 1.28 Hz, 1H), 7.56-7.57 (m, 3H), 7.40 (s, δ=162.72, 162.69, 142.66, 140.78, 140.75, 135.61, 128.89, 128.85,
1
3
1
1
1
H), 3.79 (s, 3H) ppm; C NMR (400 MHz, [D ]DMSO): δ=162.63, 126.56, 119.98, 119.97, 94.68, 30.85 ppm; IR (KBr): ṽ = 3432, 1374
6
-1
+
42.88, 140.68, 140.65, 140.62, 133.64, 132.11, 129.56, 128.30, cm ; MS: m/z 340.76 (M ), 342 (M+1); Anal. calcd for
28.27, 126.51, 94.63, 30.85 ppm; IR (KBr): ṽ = 3431, 1358cm ; MS: C13H10ClFN O S C, 45.82; H, 2.96; N, 16.44, Found, C, 45.81; H, 2.95;
m/z 357.2 (M ), 358 (M+1); Anal. calcd for C13
-1
4
2
+
2 4 2
H10Cl N O S C, 43.71; N, 16.43.
H, 2.82; N, 15.68 , Found, C, 43.70; H, 2.81; N, 15.66.
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-
3
-chloro-N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-
cyanobenzenesulfonamide (50). White solid; (115 mg, 60 %); Rf =
1
yl)benzenesulfonamide (44). White solid; (120 mg, 61 %); Rf = 0.68 0.34 (CHCl /MeOH, 9:1); mp: 229-231 °C; H NMR (400 MHz,
3
1
(CHCl
3 6 6
/MeOH, 9:1); mp: 226-228 °C; H NMR (400 MHz, [D ]DMSO): [D ]DMSO): δ=8.49 (s, 1H), 8.29 (d, J = 6.00 Hz, 2H), 8.09 (d, J = 7.72
1
3
δ=8.31 (s, 1H), 8.17 (s, 1H), 7.99 (d, J = 7.84 Hz, 1H), 7.72-7.72 (m, Hz, 1H), 7.78 (t, J = 7.76 Hz, 1H), 7.40 (s, 1H), 3.76 (s, 3H) ppm;
C
13
1H), 7.63 (t, J = 7.96 Hz, 1H), 7.48 (s, 1H), 3.79 (s, 3H) ppm; C NMR NMR (400 MHz, [D
6
]DMSO): δ=162.75, 142.89, 142.87, 140.83,
(
1
400 MHz, [D ]DMSO): δ=162.56, 142.94, 140.98, 140.95, 141.24, 140.81, 136.99, 131.47, 131.45, 131.41, 126.61, 118.87, 116.98,
6
-1
+
34.45, 132.67, 130.24, 126.78, 126.75, 126.74, 94.58, 30.89 ppm; 94.58, 30.81 ppm; IR (KBr): ṽ = 3437, 1378 cm ; MS:m/z 347.8(M ),
-1
+
IR (KBr): ṽ = 3433, 1362 cm ; MS: m/z 357.2 (M ), 358 (M+1); Anal. 349 (M+1); Anal. calcd for C14
calcd for C13 S C, 43.71; H, 2.82; N, 15.68, Found, C, 43.69; Found, C, 48.33; H, 2.88; N, 20.11.
H, 2.80; N, 15.65.
5 2
H10ClN O S C, 48.35; H, 2.90; N, 20.14,
H
2 4 2
10Cl N O
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-4-
4
-chloro-N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-
cyanobenzenesulfonamide (51). White solid; (126 mg, 66 %); Rf =
1
yl)benzenesulfonamide (45). White solid; (124 mg, 63 %); Rf = 0.65 0.36 (CHCl
3
/MeOH, 9:1); mp: 233-235 °C; H NMR (400 MHz,
1
(
CHCl
δ=8.29 (s, 1H), 8.05-8.06 (m, 2H), 7.67-7.68 (m, 2H), 7.44 (s, 1H), Hz, 2H), 7.42 (s, 1H), 3.78 (s, 3H) ppm; C NMR (400 MHz,
3 6 6
/MeOH, 9:1); mp: 227-229 °C; H NMR (400 MHz, [D ]DMSO): [D ]DMSO): δ=8.28 (s, 1H), 8.20 (d, J = 8.28 Hz, 2H), 8.08 (d, J = 8.24
13
1
3
3
1
1
3
2
.79 (s, 3H) ppm; C NMR (400 MHz, [D
40.87, 140.85, 138.57, 138.55, 129.98, 129.95, 128.65, 128.62, 133.57, 129.89, 129.86, 126.63, 118.52, 116.88, 94.64, 30.79 ppm;
26.56, 94.72, 30.76 ppm; IR (KBr): ṽ = 3428, 1359 cm ; MS: m/z IR (KBr): ṽ = 3434, 1375 cm ; MS: m/z 347.8(M ), 349 (M+1); Anal.
57.2 (M ), 358 (M+1); Anal. calcd for C13
6 6
]DMSO): δ=162.58, 142.92, [D ]DMSO): δ=162.59, 142.91, 142.89, 140.87, 140.85, 133.59,
-1
-1
+
+
H
10Cl
2
N
4
O
2
S C, 43.71; H, calcd for C14
5 2
H10ClN O S C, 48.35; H, 2.90; N, 20.14, Found, C, 48.33;
H, 2.88; N, 20.11.
.82; N, 15.68, Found, C, 43.68; H, 2.79; N, 15.66.
3-bromo-N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-
Anti-tubercular activity
yl)benzenesulfonamide (46). White solid; (132 mg, 60 %); Rf = 0.70
All experiments were performed in compliance with the
1
3 6
(CHCl /MeOH, 9:1); mp: 232-234 °C; H NMR (400 MHz, [D ]DMSO): relevant laws and institutional guidelines by Institutional Animal
δ=8.31 (s, 1H), 8.03 (d, J = 7.96 Hz, 1H), 7.86 (d-d, J = 0.96 Hz, 1H), Ethics Committee (IAEC). The IAEC reviewed and approved all the
1
3
7
.58 (t, J = 7.88 Hz, 1H), 7.48 (s, 1H), 3.79 (s, 1H) ppm; C NMR (400 experiments adopted. Also stated that human subject has not been
MHz, [D ]DMSO): δ=162.72, 142.67, 142.65, 140.77, 140.75, 135.61, used in this experiment.
32.89, 132.85, 132.83, 126.56, 122.97, 94.68, 30.85; ppm; IR (KBr):
All compounds were screened for their in vitro
ṽ = 3430, 1374 cm ; MS: m/z 401.67 (M ), 403 (M+1); Anal. calcd antimycobacterial activity against M. tuberculosis by an agar
6
1
-1
+
for C13
H
10BrClN
4
O
2
S C, 38.87; H, 2.51; N, 13.95, Found, C, 38.85; H, dilution method for the determination of MIC in duplicate. Ten-fold
serial dilutions of each test compound/drug were incorporated into
2.50; N, 13.92.
Middlebrook 7H11 agar medium with oleic albumin dextrose
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-2-
catalase (OADC) growth supplement (Drug concentration 12.5 to
0.78 μg/mL). An inoculum of M. tuberculosis H37Rv was prepared
from fresh Middlebrook 7H11 agar slants with OADC. A 5 μL
amount of the bacterial suspension was spotted in 7H11 agar tubes
containing 10-fold serial dilutions of drugs per mL. The tubes were
incubated at 37 °C, and final readings were recorded after 28 days.
The activity of each sample was performed in triplicate. The
minimum inhibitory concentration (MIC) is defined as the minimum
concentration of the compound required to give the complete
inhibition of bacterial growth.
fluorobenzenesulfonamide (47). White solid; (125 mg,67 %); Rf =
1
0.53 (CHCl
3
/MeOH, 9:1); mp: 234-236 °C; H NMR (400 MHz,
6
[D ]DMSO): δ=8.29 (s, 1H), 8.14 (q, J = 5.22 Hz, 2H), 7.44 (q, J = 8.88
1
3
Hz, 3H), 3.79 (s, 3H) ppm; C NMR (400 MHz, [D
6
]DMSO): δ=162.65,
1
1
60.62, 142.72, 140.64, 140.62, 133.69, 128.11, 128.08, 126.51,
-1
26.48, 115.27, 94.60, 30.83 ppm; IR (KBr): ṽ = 3433, 1375cm ; MS:
+
m/z 340.76 (M ), 342 (M+1); Anal. calcd for C13
4 2
H10ClFN O S C,
45.82; H, 2.96; N, 16.44, Found, C, 45.80; H, 2.95; N, 16.42.
N-(6-chloro-1-methyl-1H-imidazo[4,5-c]pyridine-4-yl)-3-
fluorobenzenesulfonamide (48). White solid; (121 mg, 65 %); Rf =
Cytotoxicity
1
0
.56 (CHCl
]DMSO): δ=11.81 (s, 1H), 8.31 (s, 1H), 7.90 (q, J = 7.36 Hz, 2H),
.63-7.65 (m, 1H), 7.50-7.51 (m, 1H), 7.48 (s, 1H), 3.79 (s, 3H) ppm;
3
/MeOH, 9:1); mp: 237-239 °C; H NMR (400 MHz,
Some compounds were further screened to assess toxicity (IC50
)
[D
6
in a mammalian Vero cell line. After 72 h of exposure, viability was
assessed on the basis of cellular conversion of MTT into a formazan
product using the Promega Cell Titer 96 non-radioactive cell
7
1
3
C NMR (400 MHz, [D
6
]DMSO): δ=162.68, 160.65, 142.57, 140.88,
1
3
40.85, 140.83, 130.25, 126.67, 122.56, 119.48, 119.45, 94.59,
0.72 ppm; IR (KBr): ṽ = 3435, 1388 cm ; MS:m/z 340.76 (M ), 342
24
proliferation assay.
-1
+
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2016, 00, 1-3 | 9
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New Journal of Chemistry
Page 10 of 11
View Article Online
DOI: 10.1039/C6NJ02069K
ARTICLE
Journal Name
In vivo studies
Pattoli, K. Gillooly, K. W. McIntyre, L. Chen, Z. Yang, P. H.
Marathe, D. Wang-Iverson, J. H. Dodd, M. McKinnon, J. C.
Barrish, W. J. Pitts, J. Med. Chem., 2009, 52, 1994.
Compounds 21, 22 and 23 showed good activities in the in vitro
study were tested for their efficacy against M. tuberculosis at a dose
of 40 mg/kg in CD-1 mice, six per group. In this model, the mice
were infected intravenously with M. tuberculosis (ATCC 35801).
Drug treatment by intraperitoneal route began after 10 days of
inoculation of the animal with microorganism and was continued
for 10 days. Thirty-five days post-infection, the spleens, and right
1
6 J. Kempson, J. Guo, J. Das, R. V. Moquin, S. H. Spergel, S. H.
Watterson, C. M. Langevine, A. J. Dyckman, M. Pattoli, J. R.
Burke, X. Yang, K. M. Gillooly, K. W. McIntyre, L. Chen, J. H.
Dodd, M. McKinnon, J. C. Barrish, W. J. Pitts, Bioorg. & Med.
Chem. Lett., 2009, 19, 2646.
lungs were aseptically removed and ground in
a tissue
homogenizer, and the number of viable organisms was determined
by serial 10-fold dilutions and subsequent inoculation onto 7H10
agar plates. Cultures were incubated at 37 °C in an ambient air for 4
weeks prior to counting. Bacterial counts were measured and
compared with the counts from negative controls (vehicle treated)
in lung and in the spleen.
1
1
7 V. F. Paul, G. B. Christopher, G. B. David, B. Richard, G. C.
Michael, P. D. Roger, T. H. Brian, A. H. Valerie, P. H. John, K.
Elizabeth, M. O'Gara, M. Dawn, M. Fraser, P. Christopher, W.
Robert, J. Med. Chem., 2007, 50, 2341.
8 C. S. Mel, M. H. James, J. C. Cleo, J. G. Patrick, R. T. Winters, R.
B. Mark, W. M. Charles, L. B. Stacey, M. C. Sheila, J. K. Alan, L.
D. Denise, W. V. Patrick, L. E. William, H. L. Gina, L. B. Brian, K.
D. Tawny, C. M. Terry, L. P. Robert, M. D. Annette, H. D. H.
Showalter, J. Med. Chem., 2001, 44, 1915.
Acknowledgments
The authors are grateful to G Pullareddy College of Pharmacy,
Mehdipatnam, Hyderabad, India for providing facilities to carry out
the antimycobacterial activity. One the author MM is thankful to
the University of Mysore, Mysore for providing necessary facilities.
19 C. K. Stover, P. Warrener, D. R. VanDevanter, D. R. Sherman, T.
M. Arain, M. H. Langhorne, S. W. Anderson, J. A. Towell, Y.
Yuan, D. N. McMurray, B. N. Kreiswirth, C. E. Barry, W. R.
Baker, Nature, 2000, 405, 962.
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0 | J. Name., 2012, 00, 1-3
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Page 11 of 11
New Journal of Chemistry
View Article Online
DOI: 10.1039/C6NJ02069K
Novel imidazo[4,5-c]pyridine derivatives showing cytotoxicity and decreased the bacterial load
in lung and spleen tissues in the in vivo animal model.