2-Arylpyrazolo[3,4-c]quinolines as AR Antagonists
J ournal of Medicinal Chemistry, 2000, Vol. 43, No. 16 3123
18: 1H NMR 6.97 (br s, 2H, NH2), 7.24-7.50 (m, 3H, ar),
7.78 (d, 2H, ar, J ) 9.0 Hz), 8.00 (d, 1H, ar, J ) 7.4 Hz), 8.16
(d, 2H, ar, J ) 8.9 Hz), 9.54 (s, 1H, H-1); IR 3470, 3310, 1650.
pentyl proton), 7.18-7.43 (m, 4H, 3 ar + NH), 7.53-7.74 (m,
2H, ar), 7.93-8.09 (m, 3H, ar), 9.54 (s, 1H, H-1); IR 3440.
29: 4.84 (d, 2H, CH2, J ) 6.2 Hz), 7.22-7.67 (m, 11H, ar),
7.98-8.02 (m, 4H, 3 ar + NH), 9.50 (s, 1H, H-1); IR 3430.
30: 1H NMR 3.07 (t, 2H, CH2, J ) 7.7 Hz), 3.80-3.87 (m,
2H, CH2), 7.21-7.69 (m, 12H, 11 ar + NH), 8.01 (d, 1H, ar, J
) 7.6 Hz), 8.11 (d, 2H, ar, J ) 7.6 Hz), 9.50 (s, 1H, H-1); IR
3410.
Gen er a l P r oced u r e for th e Syn th esis of 4-N-Aceta -
m id o-2-p h en yl-2H-p yr a zolo[3,4-c]qu in olin e (31) a n d 4-N-
Ben za m id o-2-p h en yl-2H-p yr a zolo[3,4-c]qu in olin e (32). A
solution of acetyl chloride or benzoyl chloride (4 mmol) in
anhydrous dichloromethane (3 mL) was slowly added at 0 °C
to a suspension of 11 (0.520 g, 2 mmol) in anhydrous dichloro-
methane (10 mL) and anhydrous pyridine (1.61 mL, 20 mmol).
The mixture was stirred at room temperature for 24 h.
Evaporation at reduced pressure of the solvent yielded a
residue which was treated with ethanol/water (10 mL), col-
lected and recrystallized. The title compounds displayed the
following spectral data.
Gen er a l P r oced u r e for th e Syn th esis of 4-N-Am in o-
su bstitu ted -2-a r yl-2H-p yr a zolo[3,4-c]qu in olin es 19-30.
Meth od A (19, 20, 23, 25, 28-30). A mixture of 40-41, 45 (2
mmol) and the suitable cycloalkyl- or aralkylamine (2 mL) was
heated overnight at 120 °C in a sealed tube. The cooled mixture
was treated with diethyl ether (20 mL) affording a solid which
was eliminated. Evaporation at reduced pressure of the clear
solution gave a solid which was collected and treated with
cyclohexane to yield the crude title compounds. All crude
compounds but one (25) were directly recrystallized from
suitable solvent. Compound 25, before recrystallization, was
purified by column chromatography, eluting system chloroform/
ethyl acetate (9:1). Evaporation of the central eluates gave an
oil which became solid by treatment with petroleum ether.
Meth od B (21, 22, 24, 26, 27). A mixture of 42-44, 46 (2
mmol), the suitable cycloalkylamine (2.4 mmol) and triethyl-
amine (0.55 mL, 4 mmol) in absolute ethanol (20 mL) was
heated overnight at 120 °C in a sealed tube. Evaporation of
the solvent at reduced pressure yielded a solid which was
treated with petroleum ether, collected and washed with
water. Crude compounds 22 and 24 were directly recrystal-
lized, while crude compounds 21 and 26-27, before recrys-
tallization, were purified by column chromatography, eluting
system chloroform/ethyl acetate (9:1). Evaporation of the
central eluates gave an oil which became solid by treatment
with petroleum ether. The spectral data of the title compounds
are as follows.
31: 1H NMR 2.39 (s, 3H, CH3), 7.51-7.70 (m, 5H, ar), 7.84-
7.89 (m, 1H, ar), 8.13-8.24 (m, 3H, ar), 9.70 (s, 1H, H-1), 10.31
(br s, 1H, NH); IR 3400, 3140, 1680.
32: 1H NMR 7.42-7.90 (m, 12H, 11 ar + NH), 8.03 (d, 2H,
ar, J ) 7.5 Hz), 8.29 (d, 1H, ar, J ) 7.5 Hz), 9.80 (s, 1H, H-1);
IR 3160, 1695.
4-N-P h en ylacetam ido-2-ph en yl-2H-pyr azolo[3,4-c]qu in -
olin e (33). A mixture of 11 (0.260 g, 1 mmol), phenylacetic
acid (0.816 g, 6 mmol), 1-(3-(dimethylamino)propyl)-3-ethyl-
carbodiimide hydrochloride (1.150 g, 6 mmol), 1-hydroxyben-
zotriazole (0.810 g, 6 mmol), triethylamine (2.08 mL, 15 mmol)
and 4-(dimethylamino)pyridine (0.012 g, 0.1 mmol) in anhy-
drous DMF (5 mL) was stirred at room temperature for 2 h.
The resulting solid was collected, washed with water (10 mL)
and recrystallized. The title compound displayed the following
spectral data: 1H NMR 4.06 (s, 2H, CH2), 7.27-7.71 (m, 10H,
ar), 7.85-7.90 (m, 1H, ar), 8.12-8.23 (m, 3H, ar), 9.71 (s, 1H,
H-1), 10.57 (br s, 1H, NH); IR 3380, 3140, 1680.
4-P h e n ylu r e id o-2-p h e n yl-2H -p yr a zolo[3,4-c]q u in o-
lin e (34) a n d 4-Ben zylu r eid o-2-p h en yl-2H-p yr a zolo[3,4-
c]qu in olin e (35). The suitable isocyanate (1.7 mmol) was
added to a suspension of 11 (0.300 g, 1.15 mmol) in anhydrous
THF (20 mL). The mixture was refluxed for 2 h under nitrogen
atmosphere. The resulting solid was collected and recrystal-
lized. The title compounds displayed the following 1H NMR
data.
34: 7.12 (t, 1H, ar, J ) 8.4 Hz), 7.36-7.98 (m, 9H, ar), 8.00
(d, 1H, ar, J ) 6.2 Hz), 8.17-8.24 (m, 3H, ar), 9.68-9.73 (m,
2H, H-1 + NH), 12.73 (s, 1H, NH).
35: 4.60 (d, 2H, CH2, J ) 5.8 Hz), 7.34-7.78 (m, 11H, ar),
8.13-8.22 (m, 3H, ar), 9.22 (br s, 1H, NH), 9.68 (s, 1H, H-1),
10.48 (t, 1H, NH, J ) 5.8 Hz).
(B) Bioch em istr y. A1 a n d A2A Recep tor bin d in g. Dis-
placement of [3H]CHA from A1 AR in bovine cortical mem-
branes and [3H]CGS 21680 from A2A AR in bovine striatal
membranes was performed as described.33
19: 1H NMR 1.19-2.06 (m, 10H, cyclohexyl protons), 4.23-
4.38 (m, 1H, cyclohexyl proton), 6.98 (d, 1H, NH, J ) 8.7 Hz),
7.17-7.69 (m, 6H, ar), 8.00 (d, 1H, ar, J ) 7.7 Hz), 8.13 (d,
2H, ar, J ) 7.2 Hz), 9.48 (s, 1H, H-1); IR 3430.
20: 1H NMR 1.07-2.09 (m, 10H, cyclohexyl protons), 4.15-
4.35 (m, 1H cyclohexyl proton), 7.18 (d, 1H, NH, J ) 8.3 Hz),
7.37 (dd, 1H, ar, J ) 8.7, 2.4 Hz), 7.46-7.58 (m, 2H, ar), 7.66
(t, 2H, ar, J ) 7.3 Hz), 8.07-8.17 (m, 3H, ar), 9.60 (s, 1H, H-1);
IR 3430.
21: 1H NMR 1.10-1.85 (m, 8H, cyclohexyl protons), 2.00-
2.08 (m, 2H, cyclohexyl protons), 2.45 (s, 3H, CH3), 4.18-4.35
(m, 1H, cyclohexyl proton), 6.97 (d, 1H, NH, J ) 8.1 Hz), 7.16-
7.56 (m, 5H, ar), 7.88-7.99 (m, 3H, ar), 9.45 (s, 1H, H-1); IR
3440.
22: 1H NMR 1.10-1.83 (m, 8H, cyclohexyl protons), 2.00-
2.10 (m, 2H, cyclohexyl protons), 2.42 (s, 3H, CH3), 4.18-4.48
(m, 1H, cyclohexyl proton), 6.94 (d, 1H, NH, J ) 7.9 Hz), 7.21
(t, 1H, ar, J ) 7.4 Hz), 7.33-7.56 (m, 4H, ar), 7.96-8.04 (m,
3H, ar), 9.45 (s, 1H, H-1); IR 3440.
23: 1H NMR 1.10-2.02 (m, 10H, cyclohexyl protons), 4.22-
4.34 (m, 1H, cyclohexyl proton), 7.06 (d, 1H, NH, J ) 8.6 Hz),
7.17-7.45 (m, 3H, ar), 7.52-7.75 (m, 2H, ar), 7.92-8.09 (m,
3H, ar), 9.55 (s, 1H, H-1); IR 3440.
24: 1H NMR 1.10-1.81 (m, 8H, cyclohexyl protons), 2.00-
2.01 (m, 2H, cyclohexyl protons), 4.20-4.29 (m, 1H, cyclohexyl
proton), 7.01 (d, 1H, NH, J ) 8.9 Hz), 7.17-7.55 (m, 3H, ar),
7.72 (d, 2H, ar, J ) 8.9 Hz), 7.95 (d, 1H, ar, J ) 7.0 Hz), 8.16
(d, 2H, ar, J ) 8.9 Hz), 9.50 (s, 1H, H-1); IR 3440.
A3 Recep tor bin d in g. The displacement of [125I]AB-MECA
in membranes prepared from CHO cells stably expressing the
human A3 receptor was performed as described.34 The assay
medium consisted of a buffer containing 50 mM Tris-HCl, 10
mM MgCl2, and 1 mM EDTA at pH 8.12. The glass incubation
tubes, containing 20 µL of the membrane suspension (0.2 mg
of protein/mL, stored at -80 °C in the same buffer), 20 µL of
25: 1H NMR 1.60-1.74 (m, 6H, cyclopentyl protons), 2.02-
2.10 (m, 2H, cyclopentyl protons), 4.68-4.71 (m, 1H, cyclo-
pentyl proton), 7.16-7.25 (m, 2H, 1 ar + NH), 7.35-7.68 (m,
5H, ar), 7.99 (d, 1H, ar, J ) 7.7 Hz), 8.13 (d, 2H, ar, J ) 7.5
Hz), 9.49 (s, 1H, H-1); IR 3430.
[
125I]AB-MECA (final concentration 0.2 nM), and 10 µL of the
26: 1H NMR 1.50-1.88 (m, 6H, cyclopentyl protons), 1.92-
2.16 (m, 2H, cyclopentyl protons), 2.26 (s, 3H, CH3), 4.60-4.79
(m, 1H, cyclopentyl proton), 7.16-7.59 (m, 8H, 7 ar + NH),
7.98 (d, 1H, ar, J ) 7.6 Hz), 9.02 (s, 1H, H-1); IR 3360.
tested ligand, were incubated for 60 min at 25 °C in a total
volume of 100 µL. After incubation, the samples were filtered
on Whatman GF/C filters presoaked for 1 h in 0.5% poly-
(ethylenimine) followed by three washes with 5 mL of ice-cold
incubation buffer. Nonspecific binding was determined in the
presence of 200 µM NECA. Specific binding was obtained by
subtracting nonspecific binding from total binding.
27: 1H NMR 1.56-1.78 (m, 6H, cyclopentyl protons), 2.00-
2.09 (m, 2H, cyclopentyl protons), 2.51 (s, 3H, CH3), 4.58-4.76
(m, 1H, cyclopentyl proton), 7.13-7.57 (m, 6H, 5 ar + NH),
7.85-7.98 (m, 3H, ar), 9.45 (s, 1H, H-1); IR 3420.
Compounds were dissolved in DMSO (buffer/concentration
of 2%) and added to the assay mixture. Blank experiments
were carried out to determine the effect of solvent on binding.
28: 1H NMR 1.55-1.79 (m, 6H, cyclopentyl protons), 2.05-
2.09 (m, 2H, cyclopentyl protons), 4.50-4.70 (m, 1H, cyclo-