D
M. Rimaz
OH
O
HO
H
2
Ar
ϪH2O
O
Ar
N
O
O
OH
N
O
N
N
O
Hϩ
5
Ar
DABCO
or
N
H
O
OH
O
ϪH2O
Hϩ
3
7
N
6
Ar
N
Pyridine
N
Path a
Path b
Path a
Ar
Angular product formed
Linear product not formed
N
H
O
O
NH2
N
1
ϪH2O
NH2NH2
Path b
N
H
ϪH2O
O
O
Ar
8
N
N
H
N
9
Scheme 4. Suggested mechanism for regioselective formation of 3-arylpyridazino[4,3-c]quinolin-5(6H)-ones.
3-(4-Chlorophenyl)pyridazino[4,3-c]quinolin-
5(6H)-one (1c)
8.61 (d, J 8.7, 2H, Ar), 8.88 (d, J 8.1, 1H, Ar), 12.19 (s, 1H, NH).
dC 116.7, 116.9, 121.8, 123.7, 124.2, 124.6, 128.7, 133.1, 138.8,
141.7, 142.1, 148.8, 153.9, 158.8, 160.3. nmax (KBr)/cmꢂ1 3198,
3104, 2900, 2873, 1656, 1602, 1517, 1343, 757. Found: C 64.18,
H 3.18, N 17.82. C17H10N4O3 requires C 64.15, H 3.17, N
17.60 %.
Yellow powder, mp 2818C (dec.). dH 7.43 (d, J 7.4, 2H, Ar),
7.63–7.71 (m, 3H, Ar), 8.36 (d, J 8.5, 2H, Ar), 8.74 (s, 1H, Ar),
8.88 (d, J 8.02, 1H, Ar), 12.18 (s, 1H, NH). dC 116.9, 120.6,
123.2, 123.7, 124.0, 128.6, 129.2, 129.7, 132.7, 134.8, 135.7,
138.5, 150.6, 157.0, 160.4. nmax (KBr)/cmꢂ1 3189, 3032, 2973,
2902, 1677, 1618, 1479, 1405, 1251, 1091, 761. Found: C 66.43,
H 3.30, N 13.82. C17H10ClN3O requires C 66.35, H 3.28,
N 13.65 %.
3-(3-Bromophenyl)pyridazino[4,3-c]quinolin-
5(6H)-one (1g)
Yellow powder, mp 2688C (dec.). dH 7.38–7.44 (m, 2H, Ar),
7.56(t, J7.8,1H, Ar),7.67(t, J7.8,1H, Ar),7.76(d, J7.8,1H, Ar),
8.32 (d, J 7.2, 1H, Ar), 8.52 (s, 1H, Ar), 8.76 (s, 1H, Ar), 8.86 (d,
J 7.8, 1H, Ar), 12.16 (s, 1H, NH). dC 116.8, 116.9, 121.1, 123.0,
123.2, 123.7, 124.1, 126.4, 129.9, 131.8, 132.8, 133.3, 138.3,
138.5, 150.7, 156.6, 160.4. nmax (KBr)/cmꢂ1 3176, 3066, 2971,
2906, 1676, 1604, 1437, 1400, 887, 757. Found: C 57.90, H 2.88,
N 12.15. C17H10BrN3O requires C 57.98, H 2.86, N 11.93 %.
3-(4-Fluorophenyl)pyridazino[4,3-c]quinolin-
5(6H)-one (1d)
Pale green powder, mp 2928C (dec.). dH 7.40–7.46 (m, 4H,
Ar), 7.66 (t, J 7.8, 1H, Ar), 8.37–8.42 (m, 2H, Ar), 8.71 (s, 1H,
Ar), 8.86 (d, J 7.5, 1H, Ar), 12.14 (s, 1H, NH). dC 116.5, 116.7,
116.8, 120.4, 123.2, 123.6, 124.0, 129.7, 129.8, 132.5, 132.6,
138.4, 150.3, 157.1, 160.4, 165.6. nmax (KBr)/cmꢂ1 3177, 3032,
2871, 2856, 1674, 1603, 1509, 1405, 1229, 1159, 848, 758.
Found: C 70.06, H 3.40, N 14.54. C17H10FN3O requires C 70.10,
H 3.46, N 14.43 %.
3-(3,4-Dimethoxyphenyl)pyridazino[4,3-c]
quinolin-5(6H)-one (1h)
Yellow powder, mp 2968C (dec.). dH 3.85 (s, 3H, OCH3),
3.92 (s, 3H, OCH3), 7.16 (d, J 8.4, 1H, Ar), 7.40–7.47 (m, 2H,
Ar), 7.65 (t, J 7.8, 1H, Ar), 7.88–7.92 (m, 2H, Ar), 8.68 (s, 1H,
Ar), 8.85 (d, J 7.8, 1H, Ar), 12.11 (s, 1H, NH). dC 56.0, 110.2,
112.5, 116.8, 117.1, 119.6, 120.4, 123.1, 123.6, 123.8, 128.4,
132.9, 137.0, 138.2, 149.7, 151.3, 158.0, 160.6. nmax
(KBr)/cmꢂ1 3431, 2924, 2882, 1680, 1605, 1518, 1404, 1263,
1151, 1022, 765. Found: C 68.54, H 4.61, N 12.80. C19H15N3O3
requires C 68.46, H 4.54, N 12.61 %.
3-(4-Methoxyphenyl)pyridazino[4,3-c]quinolin-
5(6H)-one (1e)
Yellow powder, mp 2868C (dec.). dH 3.83 (s, 3H, OCH3),
7.12 (d, J 8.1, 2H, Ar), 7.37–7.41 (m, 2H, Ar), 7.63 (t, J 7.2, 1H,
Ar), 8.24 (d, J 8.1, 2H, Ar), 8.58 (s, 1H, Ar), 8.82 (d, J 7.8, 1H,
Ar), 12.06 (s, 1H, NH). dC 55.8, 115.1, 116.8, 117.0, 119.4,
123.1, 123.7, 123.8, 128.2, 128.8, 132.4, 138.1, 149.8, 157.7,
160.6, 161.5. nmax (KBr)/cmꢂ1 3426, 3039, 2903, 2837, 1685,
1606, 1485, 1252, 1174, 763. Found: C 71.30, H 4.34, N 13.98.
C18H13N3O2 requires C 71.28, H 4.32, N 13.85 %.
3-(2,5-Dimethoxyphenyl)pyridazino[4,3-c]
quinolin-5(6H)-one (1i)
Yellow powder, mp 3208C (dec.). dH 3.58 (s, 3H, OCH3),
3.69 (s, 3H, OCH3), 6.78 (d, J 8.7, 1H, Ar), 6.89 (d, J 9, 1H, Ar),
7.00 (s, 1H, Ar), 7.27 (t, J 7.5, 2H, Ar), 7.56 (t, J 7.5, 1H, Ar),
7.94 (d, J 7.5, 1H, Ar), 8.35 (s, 1H, Ar), 12.19 (s, 1H, NH). dC
55.8, 56.3, 112.6, 115.1, 115.9, 116.3, 118.1, 123.1, 123.5,
3-(4-Nitrophenyl)pyridazino[4,3-c]quinolin-
5(6H)-one (1f)
Pale red powder, mp 2898C (dec.). dH 7.50–7.60 (m, 2H, Ar),
7.68 (t, J 7.8, 1H, Ar), 8.33 (s, 1H, Ar), 8.41 (d, J 8.7, 2H, Ar),