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M. I. El-Gamal et al.
Arch. Pharm. Chem. Life Sci. 2014, 347, 635–641
1-(3-Nitrophenyl)-1H-pyrrolo[3,2-c]pyridin-4-amine
hydrochloride (5)
mixture was cooled and then partitioned between water and
ethyl acetate and the organic layer was separated. The aqueous
layer was then extracted with ethyl acetate and the combined
organic extracts were washed with brine and dried over
anhydrous Na2SO4. After evaporation of the organic solvent,
the residue was purified by column chromatography (silica gel,
hexane/ethyl acetate 1:1v/v) to yield compound 1 as a yellow
crystalline solid (5.0 mg, 16%); m.p. 130–132°C; 1H NMR (300 MHz,
DMSO-d6) d 10.85 (brs, 1H), 10.65 (brs, 1H), 8.28–8.27 (m, 1H), 8.13–
8.09 (m, 4H), 7.88–7.83 (m, 1H), 7.75 (d, J ¼ 3.3 Hz, 2H), 7.67–7.54
(m, 6H), 7.41–7.37 (m, 1H), 6.69–6.67 (m, 1H), 3.75–3.72 (m, 4H),
2.97–2.89 (m, 4H); 13C NMR (100 MHz, DMSO-d6) d 163.3, 158.2,
141.0, 139.5, 133.3, 133.1, 132.1, 129.3, 128.5, 128.1, 127.8, 127.3,
126.9, 126.1, 125.3, 124.5, 124.0, 123.5, 123.3, 123.0,121.4, 120.8,
119.6, 116.9, 114.4, 104.5, 67.4, 53.6; IR (KBr) 3418, 2919, 1607,
1496, 1323, 1121, 850, 709 cmꢁ1; MS m/z 586.2 (Mþ1)þ.
A mixture of compound 4 (230 mg, 2.0 mmol) and 3-nitroaniline
(1.38 g, 10.0 mmol) was fused at 180°C for 2–5 h with stirring. The
reaction mixture was cooled to room temperature and dissolved
in ethanol (150 mL). The resulting suspension was filtered to
remove the insoluble material, and the filtrate was evaporated
under reduced pressure. The residue was purified by column
chromatography (silica gel, ethyl acetate/methanol 10:1 v/v then
switching to ethyl acetate/methanol 5:1 v/v) to obtain the desired
purified product. Yield 9.5%; 1H NMR (300 MHz, CD3OD) d 8.33 (t,
1H, J ¼ 2.0 Hz), 8.25 (dd, 1H, J ¼ 1.1, 6.1 Hz), 7.94–7.91 (m, 1H),
7.81–7.76 (m, 1H), 7.63 (d, 1H, J ¼ 2.2 Hz), 7.45 (d, 1H, J ¼ 3.4 Hz),
6.90 (d, 1H, J ¼ 3.4 Hz), 6.85 (d, 1H, J ¼ 6.3 Hz); 13C NMR (75 MHz,
CD3OD)
d 155.1, 150.4, 144.5, 140.3, 132.2, 131.0, 127.2,
122.6, 119.7, 115.0, 113.3, 104.5, 98.6; MS m/z: 255.95 (Mþ2)þ,
254.65 (M)þ.
Biological screening
N-(1-(3-Nitrophenyl)-1H-pyrrolo[3,2-c]pyridin-4-yl)-
benzamide (6)
Cancer cell line screening at the NCI
Screening against the 15 cancer cell lines was carried out at the
National Cancer Institute (NCI), Bethesda, Maryland, USA [22]
applying the standard protocol of the NCI [24, 25].
To a stirred solution of compound 5 (0.465 g, 1.6 mmol) in
acetonitrile (25 mL) at room temperature, diisopropylamine
(0.7 mL, 4.0 mmol) was slowly added under nitrogen atmosphere.
Benzoyl chloride (0.2 mL, 1.9 mmol) was slowly added and the
reaction mixture was stirred at room temperature for 8 h. The
reaction mixture was concentrated under reduced pressure, and
then water (20 mL) and CH2Cl2 (20 mL) were added to the residue.
The organic layer was separated, and the aqueous layer was
extracted with CH2Cl2 (2 ꢀ 20 mL). The combined organic layer
extracts were washed with brine, 1 N HCl, and then aqueous
NaHCO3, dried over anhydrous MgSO4, and filtered. The organic
solvent was evaporated under reduced pressure, and the residue
was purified by column chromatography (silica gel, hexane/ethyl
acetate 3:1 v/v) to give the target product. Yield 15%; 1H NMR
(300 MHz, DMSO-d6) d 10.90 (brs, 1H), 8.41 (t, 1H, J ¼ 2.1 Hz), 8.30
(d, 1H, J ¼ 8.0 Hz), 8.16–8.09 (m, 4H), 7.93–7.82 (m, 2H), 7.62–7.52
(m, 4H), 6.74 (brs, 1H); MS m/z: 359.11 (Mþ1)þ, 358.24 (M)þ.
MTT assay for peritoneal macrophage cell viability
Peritoneal macrophages were plated at a density of 105 cells/well
in 96-well plates. Cytotoxicity studies were performed 24 h after
treating cells with various concentrations of the test compound 1.
Cell viabilities were determined using colorimetric MTT assays, as
described previously [26].
Evaluation of the antiproliferative activity against HS-27
fibroblasts
HS-27 fibroblasts were purchased from American Type Culture
Collection (ATCC, Rockville, MD, USA) and maintained in
Dulbecco’s modified Eagle medium (DMEM; Welgene, Daegu,
Republic of Korea) supplemented with bovine calf serum (BCS;
Welgene) and 1% penicillin/streptomycin (Welgene) in a humidi-
fied atmosphere with 5% CO2 at 37°C. HS-27 fibroblasts were
taken from culture substrate with 0.05% trypsin–0.02% EDTA and
plated at a density of 5 ꢀ 103 cells/well in 96-well plates and then
incubated at 37°C for 24 h in a humidified atmosphere with 5%
CO2 prior to treatment with various concentrations (threefold
serial dilution, 12 points) of the tested compounds. The cells were
incubated for 48 h after treatment with the test compounds. The
HS-27 cell viability was assessed by the conventional 3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) re-
duction assay. MTT assays were carried out with CellTiter 961
(Promega) according to the manufacturer’s instructions. The
absorbance at 590 nm was recorded using EnVision 2103 (Perkin
Elmer, Boston, MA, USA). The IC50 values were calculated using
GraphPad Prism 4.0 software. Triplicate testing was performed
for each test compound.
N-(1-(3-Aminophenyl)-1H-pyrrolo[3,2-c]pyridin-4-yl)-
benzamide (7)
A mixture of compound 6 (0.466 g, 1.3 mmol) and Pd/C (10%) in
anhydrous THF (20 mL) was stirred in hydrogen atmosphere at
room temperature for 2 h. The reaction mixture was filtered
through celite, and the filtrate was concentrated under reduced
pressure. The residue was purified by column chromatography
(silica gel, hexane/ethyl acetate 1:2 v/v) to give the purified
1
desired product. Yield 32%; H NMR (300 MHz, DMSO-d6) d 10.84
(brs, 1H), 8.11–8.09 (m, 3H), 7.62 (d, 2H, J ¼ 3.2 Hz), 7.54 (d, 2H,
J ¼ 7.5 Hz), 7.42 (brs, 1H), 7.22 (t, 1H, J ¼ 7.9 Hz), 6.77 (brs, 1H),
6.69–6.62 (m, 3H), 5.50 (brs, 2H); MS m/z: 330.24 (Mþ2)þ, 329.21
(Mþ1)þ.
N-(3-(4-Benzamido-1H-pyrrolo[3,2-c]pyridin-1-yl)phenyl)-
4-morpholino-3-(trifluoromethyl)benzamide (1)
This work was supported by Korea Institute of Science and Technology
(KIST), KIST Project (2E23720). We would like to thank the National
Cancer Institute (NCI), Bethesda, Maryland, USA, for performing the
anticancer testing of the target compound over 15 cancer cell lines.
A mixture of compound 7 (17.0 mg, 0.05 mmol), 3-(trifluoro-
methyl)-4-morpholinobenzoic acid (28.5 mg, 0.1 mmol), HOBt
(15.4 mg, 0.11 mmol), and EDCI (24.83 mg, 0.13 mmol) in dry
DMF (1.0 mL) was cooled to 0°C under nitrogen atmosphere. To
the reaction mixture, TEA (0.02 mL, 0.01 mmol) was added at 0°C.
The mixture was then stirred at 80°C for 12 h. The reaction
The authors have declared no conflict of interest.
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