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and 1k was achieved from NOE experiments. Compound identified
as 1-chloro-3-(4-chloro-1H-triazolo[4,5-g]quinolin-1-yl)propan-2-
one (1k) showed a negative NOE effect on H-9 when the singlet
at 6.01 ppm was irradiated. No NOE effect was instead observed
for the other compound when the methylene at 6.31 ppm was
irradiated, according to the structure of 1-chloro-3-(4-chloro-3H-
triazolo[4,5-g]quinolin-3-yl)propan-2-one (1l). Mixture 1,3-bis-
(4-chloro-1H(3H)-triazolo[4,5-g]quinoline)propan-2-one in 1:1
ratio (1m) was not resolved by chromatography. Compound (1i)
taken up with diethyl ether was crystallized by ethanol.16
282 (M+H). Anal. Calcd for (C16H10ClN3): C, 68.70; H, 3.60; Cl,
12.67; N, 15.02. Found: C, 69.04; H, 3.38; Cl, 12.29; N, 15.31.
5.1.7.3. 2-(4-Chlorophenyl)-3H-imidazo[4,5-g]quinoline (2f).
Solvent ethanol. Time of reaction 8 h. Yield 71%. Mp >300 °C. 1H
NMR (CDCl3 + DMSO-d6): d 8.83 (dd, 1H, J = 4.1 and 1.6 Hz, H-6),
8.39 (d, 1H, J = 8.0 Hz, H-8), 8.32–8.25 (m, 2H), 8.21 (s, 1H, H-9),
8.10 (s, 1H, H-4), 7.60–7.30 (m, 3H). LC/MS: 282 (M+H). Anal. Calcd
for (C16H10ClN3): C, 68.70; H, 3.60; Cl, 12.67; N, 15.02. Found: C,
68.41; H, 3.83; Cl, 12.31; N, 14.78.
5.1.5.1. 1-Chloro-3-(4-chloro-3H-triazolo[4,5-g]quinolin-3-yl)
propan-2-one (1l).
5.1.7.4. 2-(4-Nitrophenyl)-3H-imidazo[4,5-g]quinoline (2g).
Solvent ethanol. Time of reaction 8 h. Yield 32%. Mp >300 °C. 1H
NMR (CDCl3 + DMSO-d6): d 9.09 (dd, 1H, J = 4.0 and 1.6 Hz, H-6),
8.93 (d, 1H, J = 8.4 Hz, H-8), 8.61–8.45 (m, 6H), 8.30 (s, 1H, H-4),
8.10 (s, 1H, H-9), 7.74 (dd, 1H, J = 8.2 and 4.0 Hz, H-7). LC/MS:
293 (M+H). Anal. Calcd for (C16H10N4O2): C, 66.20; H, 3.47; N,
19.30. Found: C, 66.52; H, 3.18; N, 19.76.
Mp >300 °C. 1H NMR (CDCl3 + DMSO-d6):
d 9.13 (dd, 1H, J = 4.0 and 1.4 Hz, H-6), 8.64 (s, 1H, H-9), 8.52 (dd,
1H, J = 8.6 and 1.4 Hz, H-8), 7.53 (dd, 1H, J = 8.6 and 4.0 Hz, H-7),
6.31 (s, 2H, N–CH2), 4.59 (s, 2H, Cl–CH2). LC/MS: 295 (M+H). Anal.
Calcd for (C12H8Cl2N4O): C, 48.84; H, 2.73; N, 18.98; Cl, 24.03.
Found: C, 48.51; H, 2.98; N, 18.79; Cl, 24.31.
5.1.5.2. 1-Chloro-3-(4-chloro-1H-triazolo[4,5-g]quinolin-1-yl)
propan-2-one (1k).
5.1.7.5. 4-Chloro-2-(4-nitrophenyl)-3H-imidazo[4,5-g]quinoline
Mp >300 °C. 1H NMR (CDCl3 + DMSO-
(2h).
Solvent DMF. Time of reaction 4 h. Yield 76%. Mp
d6): d 9.11 (dd, 1H, J = 4.2 and 1.6 Hz, H-6), 8.35 (dd, 1H, J = 8.6
and 1.6 Hz, H-8), 7.93 (s, 1H, H-9), 7.54 (dd, 1H, J = 8.6 and
4.2 Hz, H-7), 6.01 (s, 2H, N–CH2), 4.44 (s, 2H, Cl–CH2). LC/MS:
295 (M+H). Anal. Calcd for (C12H8Cl2N4O): C, 48.84; H, 2.73; N,
18.98; Cl, 24.03. Found: C, 49.07; H, 3.01; N, 19.30; Cl, 23.80.
>300 °C. 1H NMR (CDCl3 + DMSO-d6): d 8.97 (d, 1H, J = 4.0 Hz, H-
6), 8.67 (d, 2H, J = 8.0 Hz, H-30,50), 8.42 (d, 2H, J = 8.0 Hz, H-20,60),
8.10 (d, 1H, J = 8.2 Hz, H-8), 8.02 (s, 1H, H-9), 7.49 (dd, 1H, J = 8.2
and 4.0 Hz, H-7). LC/MS: 327 (M+H). Anal. Calcd for (C16H9ClN4O2):
C, 59.18; H, 2.79; Cl, 10.92; N, 17.25. Found: C, 59.51; H, 3.01; Cl,
11.25; N, 17.51.
5.1.5.3. Mixture 1,3-bis-(4-chloro-1H(3H)-triazolo[4,5-g]quino-
line)propan-2-one in 1:1 ratio (1m).
Mp 245 °C (dec.). 1H
5.1.7.6.
(2k).
2-(2-Methoxyphenyl)-3H-imidazo[4,5-g]quinoline
Solvent ethanol. Time of reaction 8 h. Yield 69%. Mp
NMR (CDCl3 + DMSO-d6): d 9.10–8.90 (m, 4H), 8.60–8.20 (m, 8H),
7.40–7.60 (m, 4H), 6.51–6.34 (m, 8H). LC/MS: 463 (M+H). Anal.
Calcd for (C21H12Cl2N8O): C, 54.44; H, 2.61; N, 24.19; Cl, 15.31.
Found: C, 54.71; H, 2.89; N, 24.50; Cl, 15.02.
231–233 °C. 1H NMR (CDCl3 + DMSO-d6): d 9.10–9.03 (m, 2H, H-
6,8), 8.68 (s, 1H, H-4), 8.54 (s, 1H, H-9), 8.51 (d, 2H, J = 8.2 Hz, H-
60), 7.85–7.60 (m, 2H, H-40,50), 7.28–7.16 (m, 2H, H-7,30), 4.20 (s,
3H, CH3). LC/MS: 276 (M+H). Anal. Calcd for (C17H13N3O): C,
74.17; H, 4.76; N, 15.26. Found: C, 74.43; H, 5.01; N, 14.89.
5.1.6. General procedure for preparation of imidazo[4,5-g]
quinolines 2a–c
A mixture of the diamines (6a–c) (5 mmol) and formic acid
(10 g) was stirred at 100 °C for 2 h. After cooling to rt, the solution
was neutralized with 50% sodium hydroxide aqueous solution until
pH 5. The precipitate obtained was filtered off, washed with etha-
nol and dried to give the imidazo[4,5-g]quinolines 2a–c in 80–90%
yield.12,14
5.1.7.7.
(2l).
2-(3,4-Dichlorophenyl)-3H-imidazo[4,5-g]quinoline
Solvent ethanol. Time of reaction 8 h. Yield 80%. Mp
>300 °C. 1H NMR (CDCl3 + DMSO-d6): d 8.94 (dd, 1H, J = 4.2 and
1.8 Hz, H-6), 8.66 (dd, 1H, J = 8.2 and 1.8 Hz, H-60), 8.52 (d, 1H,
J = 1.8 Hz, H-20), 8.37 (s, 1H, H-4), 8.16 (dd, 1H, J = 8.2 and 1.8 Hz,
H-8), 7.91 (s, 1H, H-9), 7.73 (d, 2H, J = 8.2 Hz, H-50), 7.56 (dd, 1H,
J = 8.2 and 4.2 Hz, H-7). LC/MS: 318 (M+H). Anal. Calcd for
(C16H9Cl2N3 + 0.5H2O): C, 59.46; H, 3.12; Cl, 21.94; N, 13.0. Found:
C, 59.81; H, 3.12; Cl, 22.31; N, 13.09.
5.1.7. General procedure for preparation of imidazo[4,5-g]
quinolines 2d–h,k–p
Compounds in title were synthesized by condensation of the
diaminoquinolines 6a–c (1–3 mmol) with an equimolar amount
of the suitable activated aldehyde (Bertagnini’s salt), in refluxed
ethanol (10–30 mL) for 8 h or in DMF (dimethylformamide) at
130 °C for 4 h. On cooling, a small amount of inorganic compound
was filtered off and the ethanol mother liquors were evaporated to
dryness in vacuo. The solid residues, colored from orange to dark
red, were purified by recrystallization from ethanol in good yields.
5.1.7.8. 2-(Biphenyl-4-yl)-3H-imidazo[4,5-g]quinoline (2m).
Solvent ethanol. Time of reaction 8 h. Yield 75%. Mp 179–
181 °C. 1H NMR (CDCl3 + DMSO-d6): d 9.03 (d, 1H, J = 4.1 Hz, H-
6), 8.94 (d, 1H, J = 8.0 Hz, H-8), 8.59 (s, 1H, H-4), 8.46 (d, 2H,
J = 8.6 Hz, H-20,60), 7.41 (s, 1H, H-9), 7.84 (d, 2H, J = 8.6 Hz, H-
30,60), 7.75–7.60 (m, 2H), 7.55–7.40 (m, 3H). LC/MS: 322 (M+H).
Anal. Calcd for (C22H15N3): C, 82.22; H, 4.70; N, 13.08. Found: C,
82.60; H, 4.45; N, 13.39.
5.1.7.1. 2-Phenyl-3H-imidazo[4,5-g]quinoline (2d).
Solvent
ethanol. Time of reaction 8 h. Yield 60%. Mp 162–164 °C. 1H NMR
(CDCl3 + DMSO-d6): d 9.01 (d, 1H, J = 4.0 Hz, H-6), 8.85 (d, 1H,
J = 8.0 Hz, H-8), 8.47 (s, 1H, H-4), 8.40–8.30 (m, 3H), 7.60–7.50
(m, 4H). LC/MS: 246 (M+H). Anal. Calcd for (C16H11N3): C, 78.35;
H, 4.52; N, 17.13. Found: C, 78.61; H, 4.32; N, 17.40.
5.1.7.9. 2-(4-Nitronaphthalen-1-yl)-3H-imidazo[4,5-g]quinoline
(2n).
Solvent ethanol. Time of reaction 8 h. Yield 70%. Mp
1
>300 °C. H NMR (CDCl3 + DMSO-d6): d 9.28 (m, 1H, H-50), 9.01–
8.84 (m, 2H, H-6,80), 7.60–8.20 (m, 5H), 7.90–7.80 (m, 2H), 7.50
(dd, 1H, J = 8.0 and 4.0 Hz, H-7). LC/MS: 341 (M+H). Anal. Calcd
for (C20H12N4O2): C, 70.58; H, 3.55; N, 16.46. Found: C, 70.23; H,
3.86; N, 16.28.
5.1.7.2. 4-Chloro-2-phenyl-3H-imidazo[4,5-g]quinoline (2e).
Solvent ethanol. Time of reaction 8 h. Yield 82%. Mp 185–187 °C.
1H NMR (CDCl3 + DMSO-d6): d 8.96 (dd, 1H, J = 4.0 and 1.8 Hz, H-6),
8.47 (d, 1H, J = 8.0 Hz, H-8), 8.40–8.32 (m, 2H), 8.06 (s, 1H, H-9),
7.60–7.56 (m, 3H), 7.45 (1H, dd, J = 8.1 and 4.0 Hz, H-7). LC/MS:
5.1.7.10.
(2o).
4-Chloro-2-cyclohexyl-3H-imidazo[4,5-g]quinoline
Solvent ethanol. Time of reaction 8 h. Yield 95%. Mp
146–148 °C. 1H NMR (CDCl3 + DMSO-d6): d 8.96 (dd, 1H, J = 4.0