1494
RAMESH et al.
4-[3-(4-Chlorobenzoyl)-3H-imidazo[4,5-b]pyridin-
J = 8.12 Hz), 8.87 d (2H, J = 8.23 Hz), 8.96 d (2H, J =
8.23 Hz). 13C NMR spectrum, δ, ppm: 13.7, 16.7, 110.8,
115.6, 119.7, 121.7, 128.6, 129.7, 130.7, 131.4, 133.3, 134.5,
135.2, 135.8, 136.7, 136.9, 145.9, 152.4, 153.8, 154.9, 162.6,
165.9. MS (ESI): 447 [M + H]+.
2-yl]phenyl(3,5-dimethyl-1H-1-pyrazolyl)methanone
1
(10d). Yield 96%, mp 325–327°C. H NMR spectrum,
δ, ppm: 2.38 s (3H), 3.40 s (3H), 6.23 s (1H), 7.50 d (2H,
J = 8.16 Hz), 7.68 t (1H), 7.80–7.85 m (3H), 8.67 d (1H,
J = 8.12 Hz), 8.86 d (2H, J = 8.22 Hz), 8.95 d (2H, J =
8.22 Hz). 13C NMR spectrum, δ, ppm: 13.7, 16.7, 110.6,
121.8, 129.5, 130.4, 130.6, 130.9, 131.5, 131.9, 133.5,
134.2, 135.6, 136.8, 138.4, 145.8, 152.3, 153.8, 154.7,
161.8, 165.6. MS (ESI): 456 [M + H]+.
(3,5-Dimethyl-1H-1-pyrazolyl)4-[3-(4-methyl-
benzoyl)-3H-imidazo[4,5-b]pyridin-2-yl]phenyl-
methanone (10i). Yield 78%, mp 309–311°C. 1H NMR
spectrum, δ, ppm: 2.30 s (3H), 2.38 s (3H), 3.40 s (3H),
6.23 s (1H), 7.49 d (2H, J = 8.18 Hz), 7.68 t (1H), 7.76–
7.85 m (3H), 8.67 d (1H, J = 8.12 Hz), 8.85 d (2H, J =
8.20 Hz), 8.94 d (2H, J = 8.20 Hz). 13C NMR spectrum, δ,
ppm: 13.7, 16.7, 24.7, 110.7, 121.6, 127.5, 129.7, 130.5,
130.9, 131.5, 132.7, 133.4, 134.7, 135.7, 136.7, 141.8,
145.7, 152.4, 153.7, 154.7, 161.8, 164.7. MS (ESI): 436
[M + H]+.
4-[3-(4-Bromobenzoyl)-3H-imidazo[4,5-b]pyridin-
2-yl]phenyl(3,5-dimethyl-1H-1-pyrazolyl)methanone
(10e). Yield 82%, mp 320–322°C. 1H NMR spectrum, δ,
ppm: 2.38 s (3H), 3.40 s (3H), 6.23 s (1H), 7.68 t (1H),
7.81–7.87 m (3H), 7.89 d (2H, J = 8.19 Hz), 8.68 d (1H,
J = 8.13 Hz), 8.86 d (2H, J = 8.23 Hz), 8.95 d (2H, J =
8.23 Hz). 13C NMR spectrum, δ, ppm: 13.7, 16.7, 110.9,
121.7, 125.5, 129.7, 129.9, 130.5, 131.5, 133.6, 133.7,
134.6, 135.4, 135.8, 136.3, 145.8, 152.7, 153.8, 154.8,
162.3, 165.9. MS (ESI): 501 [M + H]+.
(3,5-Dimethyl-1H-1-pyrazolyl)(4-3-[4-(trifluoro-
methyl)benzoyl]-3H-imidazo[4,5-b]pyridin-2-yl-
phenyl)methanone (10j). Yield 79%, mp 314–316°C.
1HNMR spectrum, δ, ppm: 2.38 s (3H), 3.40 s (3H), 6.23
s (1H), 7.69 t (1H), 7.78 d (1H, J = 8.16 Hz), 7.86 d (2H,
J = 8.21 Hz), 8.30 d (2H, J = 8.21 Hz), 8.68 d (1H, J =
8.13 Hz), 8.85 d (2H, J = 8.22 Hz), 8.94 d (2H, J =
8.22 Hz). 13C NMR spectrum, δ, ppm: 13.7, 16.7, 110.6,
114.8, 121.6, 127.6, 128.9, 129.6, 130.7, 131.7, 133.7, 134.8,
135.7, 135.9, 136.5, 136.8, 145.8, 152.7, 153.7, 154.8, 161.8,
164.9. MS (ESI): 490 [M + H]+.
(3,5-Dimethyl-1H-1-pyrazolyl)4-[3-(4-fluoro-
benzoyl)-3H-imidazo[4,5-b]pyridin-2-yl]phenyl-
methanone (10f). Yield 82%, mp 310–312°C. 1H NMR
spectrum, δ, ppm: 2.38 s (3H), 3.40 s (3H), 6.23 s (1H),
7.66–7.70 m (3H), 7.83 d (1H, J = 8.14 Hz), 7.86 d (2H,
J = 8.18 Hz), 8.67 d (1H, J = 8.12 Hz), 8.85 d (2H, J =
8.22 Hz), 8.94 d (2H, J = 8.22 Hz). 13C NMR spectrum,
δ, ppm: 13.7, 16.7, 110.8, 117.5, 121.4, 129.5, 129.8,
130.4, 131.5, 132.4, 133.5, 134.7, 135.2, 136.7, 145.7,
152.4, 153.7, 154.9, 158.7, 161.8, 164.9. MS (ESI): 440
[M + H]+.
MTT assay. Cytotoxic activity of the compounds was
determined using MTT assay. 1×104 Cells/well were
seeded in 200 mL of DMEM, supplemented with 10%
FBS in each well of 96-well microculture plates and
incubated for 24 h at 37°C in a CO2 incubator. Com-
pounds, diluted to the desired concentrations in the culture
medium, were added to the wells with the respective
vehicle control. After 48 h of incubation, 10 mL MTT
[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium
bromide] (5 mg/mL) was added to each well and the
plates were further incubated for 4 h. The supernatant
from each well was carefully removed, formazan crystals
were dissolved in 100 mL of DMSO and absorbance at
540 nm wavelength was recorded.
(3,5-Dimethyl-1H-1-pyrazolyl)4-[3-(4-nitro-
benzoyl)-3H-imidazo[4,5-b]pyridin-2-yl]phenylme-
1
thanone (10g). Yield 93%, mp 349–351°C. H NMR
spectrum, δ, ppm: 2.38 s (3H), 3.40 s (3H), 6.23 s (1H),
7.68 t (1H), 7.76 d (1H, J = 8.14 Hz), 8.10 d (2H, J =
8.24 Hz), 8.17 d (2H, J = 8.24 Hz), 8.67 d (1H, J =
8.12 Hz), 8.87 d (2H, J = 8.23 Hz), 8.96 d (2H, J =
8.23 Hz). 13C NMR spectrum, δ, ppm: 13.7, 16.7, 110.9,
121.8, 125.7, 128.6, 129.7, 130.7, 131.4, 133.6, 134.7,
135.7, 136.6, 142.8, 145.9, 150.6, 152.4, 153.7, 154.8,
162.4, 165.9. MS (ESI): 467 [M + H]+.
CONCLUSIONS
4-{(2-4-[(3,5-Dimethyl-1H-1-pyrazolyl)carbonyl]-
phenyl-3H-imidazo[4,5-b]pyridin-3-yl)carbonyl}-
benzonitrile (10h). Yield 94%, mp 356–358°C. 1H NMR
spectrum, δ, ppm: 2.38 s (3H), 3.40 s (3H), 6.23 s (1H),
7.69 t (1H), 7.76 d (1H, J = 8.15 Hz), 7.94 d (2H, J =
8.24 Hz), 8.09 d (2H, J = 8.24 Hz), 8.67 d (1H,
Anovel series of amide derivatives of imidazopyridine
10a–10j is synthesized and their structures are confirmed
by 1H and 13C NMR, and mass spectral data. The products
are tested for their anticancer activity against four hu-
man cancer cell lines: lung cancer (A549), breast cancer
(MCF-7), melanoma cancer (A375), and colon cancer
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 7 2019