The Journal of Organic Chemistry
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H6′ + H-3 + H-5), 8.22 (t, J = 8.0 Hz, 1H, H-4); 13C NMR (50 MHz,
DMSO) δ 19.1, 20.9, 55.6, 107.9, 115.5, 121.4, 121.9, 128.6, 129.0,
130.4, 131.0, 140.9, 141.6, 142.0, 142.7, 149.5, 160.6. Anal. Calcd. for
C21H20BF4N3O2 (433.16): C, 58.22; H, 4.65; N, 9.70. Found: C,
57.81; H, 4.59; N, 9.46.
(2Z)-2-[1-(4-Tolyl)-2-oxo-3-phenyl-1,2,3,7a-tetrahydro-5H-
imidazo[4,5-b]pyridin-5-ylidene]-N-phenylethanamide (11a).
Starting from 8a or 8c, 11a was isolated as yellow crystals (0.26 g,
59%): mp 149−151 °C; IR (KBr) νmax 3249, 3056, 1755, 1650, 1592,
1
1553, 1497, 1437, 1301, 1249, 1167, 1141, 1017, 750 cm−1; H NMR
(400 MHz, DMSO) δ 2.35 (s, 3H, CH3′), 4.28 (s, 1H, CαH), 5.40 (dd,
J = 6.8, 1.1 Hz, 1H, H7a), 6.85 (m, 1H), 6.97 (dd, J = 9.6, 6.8 Hz, 1H,
H7), 7.13−7.34 (m, 7H), 7.46−7.62 (m, 5H), 8.11 (dd, J = 9.6, 1.1
Hz, 1H, H6), 8.95 (s, 1H, CONH); 13C NMR (100 MHz, DMSO) δ
20.6, 82.5, 83.0, 112.0, 118.4, 121.2, 122.6, 127.3, 128.3, 129.5, 129.6,
129.8, 131.0, 131.5, 133.7, 137.3, 140.8, 141.6, 144.2, 153.6, 165.2.
HRMS Calcd. for C27H22N4O2 434.1743, found 434.1756.
1,3-Bis(4-methoxyphenyl)-5-methyl-2-oxo-2,3-dihydro-1H-
[1,2,4]triazolo[1,5-a]pyridin-4-ium Tetrafluoroborate (9b). The
reaction mixture was stirred for 7 days. Colorless crystals (0.062 g,
7%): mp 235−239 °C; IR (KBr) νmax 3373, 3097, 3010, 2840, 1746,
1
1640, 1518, 1466, 1306, 1258, 1170, 1056, 840 cm−1; H NMR (200
MHz, DMSO) δ 2.19 (s, 3H, CH3), 3.87 (s, 6H, OCH3′ + OCH3″),
7.24 (m, 4H, H3′ + H5′ + H3″ + H5″), 7.51−7.80 (m, 6H, H-3 + H-5
+ H2′ + H6′ + H2″ + H6″), 8.20 (t, J = 8.0 Hz, 1H, H-4); 13C NMR
(50 MHz, DMSO) δ 19.0, 55.7, 55.8, 107.9, 115.1, 115.5, 121.5, 122.0,
125.4, 128.7, 131.4, 140.7, 141.4, 142.4, 149.4, 160.6, 161.5. Anal.
Calcd. for C21H20BF4N3O3 (449.15): C, 56.15; H, 4.49; N, 9.35.
Found: C, 55.96; H, 4.21; N, 9.48.
(2Z)-N-(4-Methoxyphenyl)-2-[3-(4-methoxyphenyl)-1-(4-
tolyl)-2-oxo-1,2,3,7a-tetrahydro-5H-imidazo[4,5-b]pyridin-5-
ylidene]ethanamide (11b). Starting from 8a or 8c, 11a was
isolated as yellow crystals (0.28 g, 57% or 0.33 g, 67%, respectively):
mp 158−164 °C; IR (KBr) νmax 3256, 3110, 3040, 2935, 2837, 1743,
1
1647, 1559, 1510, 1241, 1166, 1029, 826 cm−1; H NMR (400 MHz,
5-[(1Z,3E)-4-(Benzylthio)penta-1,3-dien-1-yl]-2-(4-chloro-
phenyl)-4-phenyl-2,4-dihydro-3H-1,2,4-triazol-3-one (10a).
The reaction mixture was stirred for 2 days. Yellow crystals (0.38 g,
41%): mp 176−179 °C; IR (KBr) νmax 3062, 2921, 1713, 1607, 1493,
DMSO) δ 2.32 (s, 3H, CH3′), 3.65 (s, 3H, OCH3‴), 3.80 (s, 3H,
OCH3″), 4.18 (s, 1H, CαH), 5.27 (dd, J = 7.0, 1.1 Hz, 1H, H7a), 6.72
(m, 2H, H3‴ + H5‴), 6.90 (dd, J = 9.0, 7.0 Hz, 1H, H7), 7.10 (m, 2H,
H3″ + H5″), 7.20 (m, 2H, H2′ + H6′), 7.29 (m, 2H, H3′ + H5′), 7.35
(m, 2H, H2‴ + H6‴), 7.51 (m, 2H, H2″ + H6″), 8.05 (dd, J = 9.0, 1.1
Hz, 1H, H6), 8.78 (s, 1H, CONH); 13C NMR (100 MHz, DMSO) δ
20.6 (CH3′), 55.0 (OCH3‴), 55.5 (OCH3″), 82.0 (C7a), 83.0 (Cα),
111.9 (C6), 113.5 (C3‴ + C5‴), 115.0 (C3″ + C5″), 120.0 (C2‴ +
C6‴), 122.6 (C2′ + C6′), 123.3 (C1″), 128.89 (C2″ + C6″), 129.4 (C3′
+ C5′), 131.1 (C7), 133.8 (C1′), 134.0 (C1‴), 137.2 (C4′), 142.0
(C3a), 145.0 (C5), 153.8 (C4‴), 153.9 (C2), 159.8 (C4″), 165.0
(HNCO). HRMS Calcd. for C29H26N4O4 494.1954, found 494.1942.
(2Z)-2-[1-(4-Chlorophenyl)-2-oxo-3-phenyl-1,2,3,7a-tetrahy-
dro-5H-imidazo[4,5-b]pyridin-5-ylidene]-N-phenylethanamide
(11c). Yellow crystals (0.26 g, 57%): mp 164−168 °C; IR (KBr) νmax
3293, 3126, 3095, 3064, 1754, 1647, 1560, 1497, 1437, 1253, 1184,
1092, 1015 cm−1; 1H NMR (400 MHz, DMSO) δ 4.16 (s, 1H, CαH),
5.42 (dd, J = 6.9, 1.0 Hz, 1H, H7a), 6.85 (m, 1H), 6.98 (dd, J = 9.5, 6.9
Hz, 1H, H7), 7.18 (m, 2H), 7.30−7.70 (m, 11H), 8.15 (dd, J = 9.5, 1.0
Hz, 1H, H6), 9.00 (s, 1H, CONH); 13C NMR (100 MHz, DMSO) δ
82.7, 83.5, 112.0, 118.4, 121.3, 124.1, 127.4, 128.3, 128.8, 129.7, 129.8,
131.0, 131.5, 131.7, 134.4, 140.7, 141.6, 144.1, 153.0, 165.1. HRMS
Calcd. for C26H19ClN4O2 454.1197, found 454.1210.
1
1377, 1278, 1093, 1013, 829 cm−1; H NMR (200 MHz, CDCl3) δ
2.12 (s, 3H, CH3), 4.19 (s, 2H, CH2″), 5.47 (d, J = 11.4 Hz, 1H), 6.68
(t, J = 11.4 Hz, 1H), 7.28−7.41 (m, 9H), 7.47−7.54 (m, 4H), 8.00 (m,
2H); 13C NMR (50 MHz, CDCl3) δ 18.2, 36.5, 105.6, 118.0, 119.6,
127.5, 127.6, 128.7, 128.9, 129.1, 129.2, 129.7, 130.4, 131.7, 132.4,
135.6, 136.6, 144.1, 145.1, 145.9. HRMS calcd. for C26H22ClN3OS
459.1172, found 459.1195.
5-[(1Z,3E)-4-(Benzylthio)penta-1,3-dien-1-yl]-2-(4-chloro-
phenyl)-4-(4-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-
one (10b). The reaction mixture was stirred for 16 h. Yellow crystals
(0.60 g, 62%): mp 204−208 °C; IR (KBr) νmax 3066, 3003, 2917,
2840, 1721, 1605, 1518, 1494, 1383, 1249, 1094, 1021, 1001, 812
cm−1; 1H NMR (300 MHz, CDCl3) δ 2.12 (s, 3H, CH3), 3.86 (s, 3H,
OCH3‴), 4.19 (s, 2H, CH2″), 5.47 (d, J = 11.4 Hz, 1H), 6.68 (t, J =
11.4 Hz, 1H), 7.03 (m, 2H), 7.24−7.39 (m, 10H), 8.01 (m, 2H); 13C
NMR (75 MHz, CDCl3) δ 18.2, 36.5, 55.6, 105.8, 115.0, 117.8, 119.6,
124.8, 127.6, 128.7, 128.8, 128.9, 129.0, 130.4, 131.6, 135.6, 136.6,
144.5, 145.8, 151.1, 160.1. Anal. Calcd. for C27H24ClN3O2S (489.13):
C, 66.18; H, 4.94; N, 8.58; S, 6.54. Found: C, 65.88; H, 5.11; N, 8.55;
S, 6.88.
5-[(1Z,3E)-4-(Benzylthio)penta-1,3-dien-1-yl]-2-(4-tolyl)-4-
phenyl-2,4-dihydro-3H-1,2,4-triazol-3-one (10c). The reaction
mixture was stirred for 6 days. Yellow crystals (0.46 g, 50%): mp
156−163 °C; IR (KBr) νmax 3054, 2920, 1710, 1605, 1512, 1376,
(2Z)-2-[1-(4-Chlorophenyl)-3-(4-methoxyphenyl)-2-oxo-
1,2,3,7a-tetrahydro-5H-imidazo[4,5-b]pyridin-5-ylidene]-N-(4-
methoxyphenyl)ethanamide (11d). Yellow crystals (0.23 g, 45%):
mp 154−158 °C; IR (KBr) νmax 3271, 3107, 2935, 2835, 1754, 1652,
1
1279, 1237, 1161, 1010, 816 cm−1; H NMR (300 MHz, DMSO) δ
1
1557, 1508, 1447, 1254, 1165, 1092, 1028, 830 cm−1; H NMR (400
2.12 (s, 3H, CH3), 2.33 (s, 3H, CH3′), 4.20 (s, 2H, CH2″), 5.48 (d, J =
11.4 Hz, 1H), 6.80 (t, J = 11.4 Hz, 1H), 7.10−7.58 (m, 13H), 7.94 (m,
2H); 13C NMR (75 MHz, DMSO) δ 18.4, 21.2, 36.8, 106.2, 118.2,
118.8, 127.7, 127.8, 127.9, 128.2, 128.9, 129.2, 129.7, 131.4, 135.3,
135.9, 144.5, 145.8, 151.1. Anal. Calcd. for C27H25N3OS (439.17): C,
73.77; H, 5.73; N, 9.56; S, 7.29. Found: C, 73.72; H, 5.99; N, 9.40; S,
7.29.
MHz, DMSO) δ 3.68 (s, 3H, OCH3″), 3.82 (s, 3H, OCH3‴), 4.11 (s,
1H, CαH), 5.32 (dd, J = 6.6, 1.0 Hz, 1H, H7a), 6.76 (m, 2H), 6.94 (dd,
J = 9.7, 6.6 Hz, 1H, H7), 7.13−7.65 (m, 10H), 8.12 (dd, J = 9.7, 1.0
Hz, 1H, H6), 8.85 (s, 1H, CONH); 13C NMR (100 MHz, DMSO) δ
55.0, 55.5, 82.3, 83.5, 111.9, 113.5, 115.0, 120.0, 123.3, 124.1, 128.8,
129.0, 131.2, 131.6, 133.9, 134.4, 142.0, 143.9, 153.2, 154.0, 159.9,
164.9. HRMS Calcd. for C28H23ClN4O4 514.1408, found 514.1420.
Reaction of 1-(4-Methoxyphenyl)-5-methyl-3-(4-tolyl)-2-
oxo-2,3-dihydro-1H-[1,2,4]triazolo[1,5-a]pyridin-4-ium chlor-
ide (9a) with 4-Methoxyphenyl Isocyanate and Phenyl
Isocyanate in the Presence of DBU. A mixture of 1-(4-
methoxyphenyl)-5-methyl-3-(4-tolyl)-2-oxo-2,3-dihydro-1H-[1,2,4]-
triazolo[1,5-a]pyridin-4-ium chloride (9a, 100 mg, 0.26 mmol), DBU
(31 mg, 0.26 mmol), 4-methoxyphenyl isocyanate (60 mg, 0.4 mmol),
and absolute acetonitrile (8 mL) was stirred at room temperature for
10 min. The precipitated yellow crystals were filtered off and washed
with diethyl ether to give (2Z)-N-(4-methoxyphenyl)-2-[3-(4-
methoxyphenyl)-1-(4-tolyl)-2-oxo-1,2,3,7a-tetrahydro-5H-imidazo-
[4,5-b]pyridin-5-ylidene]ethanamide (11b) (115 mg, 90%).
5-[(1Z,3E)-4-(Benzylthio)penta-1,3-dien-1-yl]-2-(4-methoxy-
phenyl)-4-phenyl-2,4-dihydro-3H-1,2,4-triazol-3-one (10d).
The reaction mixture was stirred for 7 days. Yellow crystals (0.06 g,
13%): mp 140−154 °C; IR (KBr) νmax 3054, 2913, 2836, 1710, 1604,
1513, 1380, 1252, 1161, 1031, 829 cm−1 1H NMR (200 MHz,
;
CDCl3) δ 2.11 (s, 3H, CH3), 3.78 (s, 3H, OCH3′), 4.19 (s, 2H, CH2″),
5.49 (d, J = 11.4 Hz, 1H), 6.65 (t, J = 11.4 Hz, 1H), 6.87 (m, 2H),
7.25−7.53 (m, 11H), 7.94 (m, 2H); 13C NMR (50 MHz, CDCl3) δ
18.1, 36.6, 55.5, 106.1, 114.2, 118.2, 120.3, 127.5, 127.6, 128.7, 128.9,
129.6, 131.0, 131.5, 132.7, 135.8, 143.6, 144.5, 145.1, 150.8, 157.2.
HRMS calcd. for C27H25N3O2S 455.1667, found 455.1668.
General Procedure for the Synthesis of Imidazo[4,5-
b]pyridinones (11a−d). A mixture of the appropriate 2-arylthio-6-
methylpyridinium imides (8a−d) (1 mmol) and aryl isocyanate (3
mmol) in dichloromethane (22 mL) was stirred at room temperature
for 15 min. The obtained precipitate was filtered off and washed with
diethyl ether.
(2Z)-2-[1-(4-Tolyl)-3-(4-methoxyphenyl)-2-oxo-1,2,3,7a-tet-
rahydro-5H-imidazo[4,5-b]pyridin-5-ylidene]-N-phenylethana-
mide (11e). This compound was prepared from 9a (100 mg, 0.26
mmol), DBU (31 mg, 0.26 mmol), phenyl isocyanate (48 mg, 0.4
mmol), and absolute acetonitrile (8 mL), which was stirred at room
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dx.doi.org/10.1021/jo201645t|J. Org. Chem. 2011, 76, 9362−9369