Med Chem Res
(1H, t, J = 7.2 Hz, H6), 7.83 (1H, d, J = 8.2 Hz, H8), 7.90
(1H, t, J = 7.0 Hz, H7), 8.30 (1H, d, J = 7.3 Hz, H5), 8.90
(1H, s, H2), 13.42 (1H, br s, enolic OH), 15.34 (1H, br s,
carboxylic OH); 13C-NMR (DMSO-d6, 60 MHz) δ = 105.3
(C, C-3), 119.7 (CH, C-9), 123.6 (CH, C-7), 125.6 (CH,
C-6), 125.9 (C, C-5), 133.9 (CH, C-8), 138.5 (C,
C-10), 158.9 (CH, C-2), 167.2 (C,COOH), 178.5 (C, C=O);
LC-MS (ESI) m/z 212.1 (M+Na+); Anal. Calcd. for
C10H7NO3: C, 63.49; H, 3.73; N, 7.40. Found: 63.62; H,
3.96; N, 7.69.
enolic OH, J = 4.4 Hz), 15.22 (1H, br s, carboxylic OH);
13C-NMR (DMSO-d6, 60 MHz) δ = 107.5 (C, C-3), 124.1
(CH, C-7), 124.6 (C, C-9), 125.0 (CH, C-6), 126.0 (CH,
C-4′), 128.5 (CH, C-2′), 128.8 (CH, C-6′), 129.3 (CH, C-
3′), 129.7 (CH, C-5′), 132.8 (C, C-5), 135.0 (CH, C-8),
135.5 (C, C-1′), 136.4 (C, C-10), 145.4 (CH, C-2), 166.2
(C, COOH), 178.5 (C, C=O); LC-MS (ESI) m/z 266.3
(M+H+), 288.3 (M+Na+); Anal. Calcd. for C16H11NO3: C,
72.45; H, 4.18; N, 5.28. Found: 72.69; H, 4.41; N, 5.52.
8-Benzoyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid
8-Methyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (4f)
(4i)
Starting from 3f (0.5 g); Yield (white powder): 0.2 g (50 %);
m.p. 277 °C; IR (KBr) νmax 1400–1600 (aromatic), 1717
(carbonyl), 2890–3300 (acidic OH) cm−1; 1H-NMR
(DMSO-d6, 500 MHz) δ = 2.60 (3H, s, CH3), 7.49 (1H, t,
J = 7.7 Hz, H6), 7.73 (1H, d, J = 7.1 Hz, H7), 8.14 (1H, d,
J = 8.0 Hz, H5), 8.63 (1H, d, J = 6.4 Hz, H2), 12.80 (1H, br
s, enolic OH), 15.33 (1H, br s, carboxylic OH); 13C-NMR
(DMSO-d6, 60 MHz) δ = 17.3 (CH3), 107.3 (C, C-3), 122.8
(CH, C-7), 124.4 (CH, C-9), 125.7 (CH, C-6), 128.1 (C,
C-5), 134.6 (CH, C-8), 137.9 (C, C-10), 144.3 (CH, C-2),
166.3 (C, COOH), 178.4 (C, C=O); LC-MS (ESI) m/z
226.5 (M+Na+); Anal. Calcd. for C11H9NO3: C, 65.02; H,
4.46; N, 6.89. Found: 65.22; H, 4.66; N, 6.98.
Starting from 3i (0.8 g); Yield (yellow powder): 0.3 g
(43 %); m.p. 297 °C; IR (KBr) νmax 1400–1600 (aromatic),
1720 (carbonyl), 2900–3500 (acidic OH) cm−1; 1H-NMR
(DMSO-d6, 500 MHz) δ = 7.63 (2H, t, J = 7.6 Hz, benzoyl
H3 and H5), 7.71–7.78 (2H, m, H6 and benzoyl H4), 7.84
(2H, d, J = 7.2 Hz, benzoyl H2 and H6), 8.08 (1H, d, J = 7.4
Hz, H7), 8.61 (1H, d, J = 8.0 Hz, H5), 8.82 (1H, s, H2),
12.90 (1H, br s, enolic OH), 14.97 (1H, br s, carboxylic
OH); 13C-NMR (DMSO-d6, 60 MHz) δ = 108.6 (C, C-3),
125.2 (CH, C-7), 125.5 (CH, C-9), 126.1 (CH, C-3′, C-5′),
128.8 (CH, C-5), 129.9 (CH, C-6), 130.1 (CH, C-2′, C-6′),
133.6 (CH, C-4′), 136.9 (CH, C-8), 137.4 (C, C-1′), 137.9
(C, C-10), 146.2 (C, C-2), 165.8 (C, COOH), 178.1 (C,
C=O), 195.8 (C, C=O); LC-MS (ESI) m/z 294.1 (M+H+);
Anal. Calcd. for C17H11NO4: C, 69.62; H, 3.78; N, 4.78.
Found: 69.42; H, 3.99; N, 5.01.
7,8-Dimethyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid
(4g)
Starting from 3g (1 g); Yield (white powder): 0.5 g (60 %);
m.p. 280 °C (decomposed); IR (KBr) νmax 1400–1600
(aromatic), 1700 (carbonyl), 2900–3500 (acidic OH) cm−1;
1H-NMR (DMSO-d6, 500 MHz) δ = 2.37, 2.40 (6H, s,
2CH3), 7.32 (1H, d, J = 8.3 Hz, H6), 7.93 (1H, d, J = 8.3
Hz, H5), 8.50 (1H, d, J = 6.8 Hz, H2), 12.69 (1H, br s,
enolic OH), 15.33 (1H, br s, carboxylic OH); 13C-NMR
(DMSO-d6, 60 MHz) δ = 13.2 (CH3), 20.5 (CH3), 106.8 (C,
C-3), 122.1 (CH, C-7), 122.8 (CH, C-6), 125.8 (CH, C-9),
128.3 (C, C-5), 137.9 (CH, C-8), 142.8 (C, C-10), 144.3
(CH, C-2), 166.4 (C, COOH), 178.4 (C, C=O); LC-MS
(ESI) m/z 240.6 (M+Na+); Anal. Calcd. for C12H11NO3: C,
66.35; H, 5.10; N, 6.45. Found: 66.54; H, 5.32; N, 6.75.
4-Oxo-1,4,7,8,9,10-hexahydrobenzo[h]quinoline-3-
carboxylic acid (4j)
Starting from 3j (1 g); Yield (white powder): 0.8 g (88 %);
m.p. 300 °C; IR (KBr) νmax 1400–1600 (aromatic), 1717
(carbonyl), 2900–3600 (acidic OH) cm−1; 1H-NMR
(DMSO-d6, 500 MHz) δ = 1.79–1.92 (4H, m, H8 and H9),
2.86–2.92 (4H, m, H7 and H10), 7.33 (1H, d, J = 8.4 Hz,
H6), 8.04 (1H, d, J = 8.3Hz, H5), 8.58 (1H, d, J = 7.0 Hz,
H2), 12.51 (1H, br s, enolic OH); 13C-NMR (DMSO-d6, 60
MHz) δ = 21.5 (CH2, C-10), 21.6 (CH2, C-11), 23.6 (CH2,
C-12), 29.6 (CH2, C-9), 104.8 (C, C-3), 118.7 (CH, C-7),
121.8 (CH, C-6), 125.8 (C, C-13), 127.8 (C, C-5), 134.0 (C,
C-14), 144.1 (C, C-8), 162.6 (CH, C-2), 165.3 (C, COOH),
178.1 (C, C=O); LC-MS (ESI) m/z 266.6 (M+Na+); Anal.
Calcd. for C14H13NO3: C, 69.12; H, 5.39; N, 5.76. Found:
69.36; H, 5.77; N, 6.01.
4-Oxo-8-phenyl-1,4-dihydroquinoline-3-carboxylic acid
(4h)
Starting from 3h (0.6 g); Yield (white powder): 0.4 g
(74 %); m.p. 236 °C; IR (KBr) νmax 1400–1600 (aromatic),
1720 (carbonyl), 3380 (OH) cm−1; 1H-NMR (DMSO-d6,
500 MHz) δ = 7.50–7.65 (5H, m, phenyl), 7.69 (1H, t, H6,
J = 7.6 Hz), 7.80 (1H, d, H7, J = 8.7 Hz), 8.38 (1H, d, H5,
J = 9.3 Hz), 8.58 (1H, d, H2, J = 7.0 Hz), 12.03 (1H, d,
4-Oxo-1,4-dihydrobenzo[h]quinoline-3-carboxylic acid
(4k)
Starting from 3k (0.5 g); Yield (white powder): 0.16 g
(40 %); m.p. 290 °C; IR (KBr) νmax 1400–1600 (aromatic),