Journal of Medicinal Chemistry
Article
(+ve, CH), 109.3 (+ve, CH), 118.7 (+ve, CH), 122.4 (+ve, CH),
124.6 (C), 125.8 (C), 128.4 (+ve, CH), 129.4 (+ve, CH), 130.6 (+ve,
CH), 135.7 (C), 136.7 (C), 138.1 (C), 139.1 (+ve, CH), 142.1 (C),
146.6 (C), 167.2 (CO). MS (FAB) 441 (M+ + 1). Anal. Calcd for
C23H15Cl2NO4: C, 62.46; H, 3.87; N, 3.17. Found: C, 62.49; H, 3.88;
N, 3.19.
Synthesis of (4Z)-4-(4-Hydroxy-3,5-dimethoxybenzylidene)-1-(3-
chlorophenyl)-3-methyl-1H-pyrazol-5(4H)-one (4). A finely ground
mixture of syringaldehyde (100 mg, 1 mmol) and 1-(3-chlorophenyl)-
3-methyl-2-pyrazolin-5-one (137 mg, 1.2 mmol) was irradiated in a
microwave oven for 1 min. The completion of reaction was checked by
TLC. The solid mass was washed with diethyl ether to give pure
product 4. Yield: 81%. Mp 184 °C. νmax (KBr)/cm−1 3205 (OH),
1598 (CO). 1H NMR (300 MHz, DMSO-d6, δ) 2.31 (s, 3H, CH3),
3.82 (s, 3H, OCH3), 3.86 (s, 3H, OCH3), 7.19 (s, 2H, ArH), 7.45 (t,
1H, J = 8.1 Hz, ArH),7.73 (s, 1H, ArH), 7.92 (d, J = 8.4 Hz, 1H, ArH),
8.07 (s, 1H, ArH), 8.24 (s, 1H, CH), 9.76 (OH, D2O exchange).
13C NMR (normal/DEPT-135, δ) 33.6 (CH3), 56.2 (OCH3), 56.3
molecules having structural similarities with the known
antibacterial drug trimethoprim. A simple synthetic method-
ology that could be scaled up to procure tons of compounds
was employed for the synthesis of the compounds. Compounds
2 and 3 showed significant tumor growth inhibitory activities
over 60 human tumor cell lines and exhibited appreciable
interactions with DHFR, as evidenced by UV−vis and NMR
spectral studies. Compounds 2 and 3 also exhibited significant
inhibition of DHFR activity with IC80 in the micromolar range,
indicating DHFR inhibition as the probable mode of action of
these compounds. Overall, a rational modification of the
trimethoprim drug with no anticancer activity led to the
development of two new molecules showing appreciable
anticancer activities and interactions with DHFR.
EXPERIMENTAL SECTION
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(OCH3), 104.6 (CH), 112.1 (CH), 116.6 (CH), 118.4 (CH), 120.2
(C), 124.1 (CH), 125.1 (C), 129.6 (CH), 129.7 (CH), 132.1 (C),
133.6 (C), 134 (C), 139.5 (C), 147 (C), 147.3 (C), 148.3 (CH), 151.4
(C). MS (FAB) 373 (M + 1). Anal. Calcd for C19H17N2O4: C, 61.21;
H, 4.60; N, 7.51. Found: C, 61.19; H, 4.61; N, 7.49.
Chemical Synthesis. General Remarks. Melting points were
determined in capillaries and are uncorrected. 1H and 13C NMR
spectra were recorded on JEOL 300 and 75 MHz NMR spectrometers,
respectively, using CDCl3 and/or DMSO-d6 as solvent. Chemical shifts
are given in ppm with TMS as an internal reference. J values are given
in hertz. Signals are abbreviated as follows: singlet, s; doublet, d;
double−doublet, dd; triplet, t; multiplet, m. In 13C NMR spectral data,
+ve and −ve terms correspond to CH3, CH, CH2 signals in DEPT-135
NMR spectra. Chromatography was performed with silica 100−200
mesh, and reactions were monitored by thin layer chromatography
(TLC) with silica plates coated with silica gel HF-254. Elemental
analysis was performed on a Thermoelectron FLASH EA1112 CHN
analyzer. Reactions under microwaves were performed using a
microwave oven (INALSA model 1MW17EG) with microwave
power of 700 W and operating frequency of 2450 MHz. IR and UV
spectral data were recorded on FTIR 8400S Shimadzu and BioTek
PowerWave XS instruments, respectively.
Synthesis of 5-(4-Hydroxy-3,5-dimethoxybenzylidene)-1,3-dime-
thylpyrimidine-2,4,6-(1H,3H,5H)-trione (5). A finely ground mixture
of syringaldehyde (100 mg, 1 mmol) and 1,3-dimethylbarbituric acid
(103 mg, 1.2 mmol) was irradiated in a microwave oven for 1 min.
The completion of reaction was checked by TLC. The solid mass was
washed with diethyl ether to give pure product 5. Yield: 95%. Mp 237
°C. νmax (KBr)/cm−1 3425(OH), 1656 (CO). 1H NMR (300 MHz,
DMSO-d6, δ) 3.22 (s, 6H, 2× CH3), 3.83 (s, 6H, 2 × OCH3), 7.97 (s,
2H, ArH), 8.31 (s, 1H, CH), 10.03 (OH, D2O exchange). 13C NMR
(normal/DEPT-135, δ) 24.5 (CH3), 32.4 (CH3), 54.4 (2 × OCH3),
111.9 (CH), 112.2 (CH), 141.3 (C), 145.4 (C), 149.3 (CO), 156.2
(CO). MS (FAB) 321 (M + 1). Anal. Calcd for C15H16N2O6: C,
56.25; H, 5.04; N, 8.75. Found: C, 56.28; H, 5.01; N, 8.76.
Synthesis of 4-(5-Bromo-1H-indol-3-ylmethylene)-2-(3-chloro-
phenyl)-5-methyl-2,4-dihydropyrazol-3-one (6). A finely ground
mixture of 5-bromoindole-3-carboxaldehyde (100 mg, 1 mmol) and
1-(3-chlorophenyl)-3-methyl-2-pyrazolin-5-one (137 mg, 1.2 mmol)
was irradiated in a microwave oven for 1 min. The completion of
reaction was checked by TLC. The solid mass was washed with diethyl
ether to give pure product 6. Orange solid. Yield 65%. Mp >240 °C.
1H NMR (300 MHz, DMSO-d6, δ) 2.40 (s, 3H, CH3), 7.20 (d, J = 9.0
Hz, 1H, ArH), 7.43 (t, J = 9.0 Hz, 2H, ArH), 7.53 (d, J = 8.4 Hz, 1H,
ArH), 7.94 (d, J = 8.1 Hz, 1H, ArH), 8.13 (d, J = 9.0 Hz, 2H, ArH),
8.49 (s, 1H, CH), 9.70 (s, 1H, indole2-H), 12.7 (NH, D2O
exchange). 13C NMR (normal/DEPT-135) (DMSO + CDCl3, δ)
13.02 (+ve, CH3), 111.779 (C), 114.507 (+ve, CH), 115.142 (C),
115.81 (+ve, CH), 117.19 (+ve, CH), 118.61 (C), 121.23 (+ve, CH),
123.22 (+ve, CH), 125.86 (+ve, CH), 129.96 (+ve, CH), 133.29 (C),
135.13 (C), 137.29 (+ve, CH), 139.02 (+ve, CH), 139.93 (C), 151.43
(C), 162.85 (C). Anal. Calcd for C19H13BrClN3O: C, 55.03; H, 3.16;
N, 10.13. Found: C, 54.64; H, 3.19; N, 11.68.
General Procedure for the Synthesis of New Conjugates. A finely
ground mixture of aldehyde (1 mmol) and heterocycle based active
methylene component (indolinone, oxindole, barbituric acid, and 1-(3-
chlorophenyl)-3-methyl-2-pyrazolin-5-one) (1.2 mmol) on irradiating
in a microwave oven gave solid products which were washed with
diethyl ether to give pure products 2−7.
Synthesis of 3-(4-Hydroxy-3,5-dimethoxybenzylidene)-1,3-dihy-
droindol-2-one (2). A finely ground mixture of syringaldehyde (100
mg, 1 mmol) and oxindole (84.34 mg, 1.2 mmol) was irradiated in a
microwave oven for 1 min. The completion of the reaction was
checked by TLC. The solid mass was washed with diethyl ether to give
pure product 2. Yield 80%. Yellow solid. Mp 200 °C. νmax (KBr, cm−1):
3401 (NH), 3205 (OH), 1598 (CO). 1H NMR (300 MHz, DMSO-
d6, δ) 3.79 (s, 3H, OCH3), 3.82 (s, 3H, OCH3), 6.80−6.98 (m, 2H,
ArH), 7.05 (s, 1H, ArH), 7.13−7.22 (m, 1H, ArH), 7.54−7.82 (m, 2H,
ArH), 8.07 (s, 1H, CH), 9.16, 9.30 (NH, D2O exchange), 10.53
(OH, D2O exchange). 13C NMR (normal/DEPT-135) (CDCl3, δ)
56.4 (+ve, OCH3), 109.3 (+ve, CH), 109.9 (+ve, CH), 110.1 (+ve,
CH), 118.7 (+ve, CH), 121.6 (C), 121.9 (+ve, CH), 122.8 (C), 125.8
(+ve, CH), 128.1 (C), 129.5 (C), 136.5 (C), 138.2 (+ve, CH), 138.6
(C), 141.2 (C), 146.5 (C), 170.1 (CO). MS (FAB) 298 (M+ + 1).
Anal. Calcd for C17H15NO4: C, 68.68; H, 5.09; N, 4.71. Found: C,
68.69, H, 5.08, N, 4.79.
Synthesis of (Z)-1-(2,6-Dichlorophenyl)-3-((pyridin-2-yl)-
methylene)indolin-2-one (7). A finely ground mixture of pyridine-2-
carboxaldehyde (100 mg, 1 mmol) and indolinone (137 mg, 1.2
mmol) was irradiated in a microwave oven for 1 min. The completion
of reaction was checked by TLC. The solid mass was washed with
diethyl ether to give pure product 7. Shiny yellow solid. Yield 86%. Mp
Synthesis of 1-(2,6-Dichlorophenyl)-3-(4-hydroxy-3,5-dimethox-
ybenzylidene)-1,3-dihydroindol-2-one (3). A finely ground mixture of
syringaldehyde (100 mg, 1 mmol) and indolinone (84.34 mg, 1.2
mmol) was irradiated in a microwave oven for 1 min. The completion
of reaction was checked by TLC. The solid mass was washed with
diethyl ether to give pure product 3. Yield 82%. Yellow solid. Mp 150
1
188 °C. νmax (KBr): 1668 (CO). H NMR (300 MHz, DMSO-d6,
δ) 6.45 (d, J = 7.8 Hz, 1H, ArH), 7.16 (t, J = 7.5 Hz, 1H, ArH), 7.33 (t,
J = 7.5 Hz, 1H, ArH), 7.50−7.54 (m, 1H, ArH), 7.65 (d, J = 7.8 Hz,
1H, ArH), 7.78 (d, J = 8.4 Hz, 3H, ArH), 7.98 (s, 2H, ArH), 8.94 (d, J
= 7.5 Hz, 1H, ArH). 9.22 (d, J = 7.5 Hz, 1H, ArH). 13C NMR
(normal/DEPT-135) (CDCl3, δ) 109.2 (+ve, CH), 122.4 (+ve, CH),
123.2 (+ve, CH), 123.7 (+ve, CH), 124.4 (C), 127.7 (+ve, CH), 128.8
(+ve, CH), 128.91 (+ve, CH), 128.94 (+ve, CH), 129.7 (+ve, CH),
130.6 (+ve, CH), 135.71 (C), 135.73 (C), 135.9 (C), 136.9 (+ve,
CH), 141.5 (C), 144.8 (+ve, CH), 167.1(C). FAB mass m/z 366 (M+)
1
°C. νmax (KBr, cm−1): 3215 (OH), 1612 (CO). H NMR (300
MHz, DMSO-d6, δ) 3.81 (s, 3H, OCH3), 3.82 (s, 3H, OCH3), 6.39−
6.46 (m, 1H, ArH), 7.08−7.24 (m, 3H, ArH), 7.62 (t, J = 8.1 Hz,1H,
ArH), 7.76 (d, J = 8.7 Hz, 1H, ArH), 7.78−7.99 (m, 2H, ArH), 7.99−
8.06 (m, 2H, ArH), 9.76 (OH, D2O exchange). 13C NMR (normal/
DEPT-135) (CDCl3, δ) 56.5 (+ve, OCH3), 106.7 (+ve, CH), 108.7
G
dx.doi.org/10.1021/jm300644g | J. Med. Chem. XXXX, XXX, XXX−XXX