RSC Advances
Page 6 of 8
DOI: 10.1039/C3RA43889A
2-(4-Methoxyphenyl)imidazo[1,2-a]pyridine (3aj): yield 48%; 65 J = 9.2 Hz, 1H), 7.41 – 7.32 (m, 2H), 7.05 (dd, J = 9.2, 1.5 Hz,
1H), 2.30 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 144.59, 143.83,
133.55, 131.96, 128.81, 128.66, 127.04, 123.41, 122.62, 116.08,
108.17, 17.90.
colorless solid; mp 136ꢀ138 °C (lit.46 137ꢀ138 °C); 1H NMR (300
MHz, CDCl3) δ 8.05 (dt, J = 6.8, 1.2 Hz, 1H), 7.87 (d, J = 8.9 Hz,
2H), 7.73 (s, 1H), 7.59 (dd, J = 9.1, 0.7 Hz, 1H), 7.16 – 7.08 (m,
1H), 6.96 (d, J = 8.9 Hz, 2H), 6.71 (td, J = 6.8, 1.1 Hz, 1H), 3.83
2-(2-Bromophenyl)imidazo[1,2-a]pyridine (3as): yield 60%;
5
1
(s, 3H); 13C NMR (75 MHz, CDCl3) δ 159.58, 145.71, 145.61, 70 pale yellow solid; mp 80ꢀ81 °C; H NMR (500 MHz, CDCl3): δ
127.29, 126.50, 125.46, 124.42, 117.25, 114.14, 112.21, 107.24,
55.30.
8.28 (s, 1H), 8.17 – 8.13 (m, 2H), 7.68 – 7.62 (m, 2H), 7.41 (t, J =
7.6 Hz, 1H), 7.17 (t, J = 7.6 Hz, 2H), 6.78 (t, J = 6.7 Hz, 1H); 13
C
NMR (126 MHz, CDCl3) δ 144.53, 143.27, 134.48, 133.64,
131.68, 128.85, 127.50, 125.73, 124.72, 121.50, 117.67, 112.43,
75 111.97.
2-(4-Methoxyphenyl)-6-methylimidazo[1,2-a]pyridine (3ak):
10 yield 62%; paleꢀyellow solid; mp 179ꢀ180 °C (lit.54 179ꢀ181 °C);
1H NMR (300 MHz, CDCl3) δ 7.86 – 7.82 (m, 1H), 7.80 (d, J =
8.9 Hz, 2H), 7.63 (s, 1H), 7.46 (d, J = 9.2 Hz, 1H), 7.01 (dd, J =
9.2, 1.6 Hz, 1H), 6.96 (d, J = 8.9 Hz, 2H), 3.83 (s, 3H), 2.27 (s,
3H); 13C NMR (75 MHz, CDCl3) δ 159.46, 144.94, 144.49,
15 128.13, 127.11, 126.18, 123.31, 122.18, 115.83, 114.10, 107.19,
55.20, 17.86.
2-(2-Bromophenyl)-7-methylimidazo[1,2-a]pyridine
(3at):
1
yield 87%; colorless solid; mp 98ꢀ99 °C; H NMR (300 MHz,
CDCl3) δ 8.21 (s, 1H), 8.17 (d, J = 7.8 Hz, 1H), 8.01 (d, J = 6.9
Hz, 1H), 7.67 (d, J = 8.0 Hz, 1H), 7.49 – 7.36 (m, 2H), 7.17 (t, J =
80 7.6 Hz, 1H), 6.63 (d, J = 6.8 Hz, 1H), 2.41 (s, 3H); 13C NMR (75
MHz, CDCl3) δ 145.28, 143.27, 136.09, 134.92, 133.96, 132.01,
129.02, 127.77, 125.25, 121.82, 116.27, 115.47, 111.73, 21.58.
2-(4-Bromophenyl)imidazo[1,2-a]pyridine (3au): yield 58%;
2-(3,4-Dimethoxyphenyl)imidazo[1,2-a]pyridine (3al): yield
74%; yellow solid; mp 104ꢀ106 °C; 1H NMR (300 MHz, CDCl3)
δ 8.06 (d, J = 6.8 Hz, 1H), 7.76 (s, 1H), 7.61 (d, J = 9.1 Hz, 1H),
20 7.57 (d, J = 1.9 Hz, 1H), 7.43 (dd, J = 8.3, 2.0 Hz, 1H), 7.17 –
7.09 (m, 1H), 6.93 – 6.88 (m, 1H), 6.72 (td, J = 6.8, 0.9 Hz, 1H),
3.99 (s, 3H), 3.91 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 149.23,
149.01, 145.77, 145.56, 126.90, 125.45, 124.46, 118.47, 117.24,
112.27, 111.31, 109.25, 107.49, 56.01, 55.92.
1
offꢀwhite solid; mp 201ꢀ203 °C; H NMR (300 MHz, CDCl3) δ
85 8.09 (d, J = 6.8 Hz, 1H), 7.87 – 7.75 (m, 3H), 7.61 (d, J = 9.1 Hz,
1H), 7.54 (d, J = 8.6 Hz, 2H), 7.21 – 7.12 (m, 1H), 6.77 (td, J =
6.8, 0.9 Hz, 1H); 13C NMR (75 MHz, CDCl3) δ 145.73, 144.68,
132.76, 131.83, 127.55, 125.62, 124.95, 121.87, 117.56, 112.62,
108.22.
25 2-(3,4-Dimethoxyphenyl)-8-methylimidazo[1,2-a]pyridine
1
90 2-(4-Bromophenyl)-7-methylimidazo[1,2-a]pyridine
(3av):
(3am): yield 68%; offꢀwhite solid; mp 124ꢀ126 °C; H NMR
yield 76%; pale yellow solid; mp 210ꢀ212 °C; 1H NMR (300
MHz, CDCl3) δ 7.94 (d, J = 6.9 Hz, 1H), 7.78 (d, J = 8.5 Hz, 2H),
7.71 (s, 1H), 7.52 (d, J = 8.5 Hz, 2H), 7.35 (s, 1H), 6.59 (dd, J =
6.9, 1.5 Hz, 1H), 2.38 (s, 3H); 13C NMR (75 MHz, CDCl3) δ
95 146.20, 144.40, 135.88, 132.98, 131.75, 127.46, 124.78, 121.61,
115.89, 115.22, 107.63, 21.40.
(300 MHz, CDCl3) δ 7.93 (d, J = 6.7 Hz, 1H), 7.74 (s, 1H), 7.58
(d, J = 1.9 Hz, 1H), 7.45 (dd, J = 8.3, 2.0 Hz, 1H), 6.94 – 6.88 (m,
2H), 6.63 (t, J = 6.8 Hz, 1H), 3.99 (s, 3H), 3.91 (s, 3H), 2.65 (s,
30 3H); 13C NMR (75 MHz, CDCl3) δ 149.17, 148.88, 146.09,
145.19, 127.31, 127.26, 123.29, 123.18, 118.58, 112.22, 111.30,
109.48, 107.96, 55.96, 55.92, 17.10.
2-(3-Nitrophenyl)imidazo[1,2-a]pyridine (3aw): yield 52%;
2-(3,4-Dimethoxyphenyl)-7-methylimidazo[1,2-a]pyridine
1
1
yellow solid; mp 201ꢀ203 °C; H NMR (300 MHz, DMSOꢀd6) δ
(3an): yield 71%; yellow solid; mp 135ꢀ137 °C; H NMR (300
8.80 – 8.76 (m, 1H), 8.64 (d, J = 0.4 Hz, 1H), 8.56 (dt, J = 6.8,
100 1.2 Hz, 1H), 8.43 – 8.36 (m, 1H), 8.21 – 8.14 (m, 1H), 7.75 (t, J =
8.0 Hz, 1H), 7.64 (dd, J = 9.1, 0.7 Hz, 1H), 7.35 – 7.27 (m, 1H),
6.95 (td, J = 6.8, 1.1 Hz, 1H); 13C NMR (75 MHz, DMSOꢀd6) δ
148.86, 145.49, 142.44, 136.20, 132.17, 130.83, 127.63, 126.17,
122.64, 120.18, 117.34, 113.24, 111.05.
35 MHz, CDCl3) δ 7.84 (s, 1H), 7.68 (s, 1H), 7.56 (d, J = 1.7 Hz,
1H), 7.50 (d, J = 9.2 Hz, 1H), 7.41 (dd, J = 8.3, 1.8 Hz, 1H), 6.98
(dd, J = 9.2, 1.2 Hz, 1H), 6.90 (d, J = 8.4 Hz, 1H), 3.99 (s, 3H),
3.91 (s, 3H), 2.28 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 149.22,
148.88, 145.45, 144.62, 127.63, 127.09, 123.23, 121.87, 118.31,
40 116.52, 111.29, 109.15, 107.25, 56.01, 55.92, 18.07.
105 8-Methyl-2-(3-nitrophenyl)imidazo[1,2-a]pyridine (3ax): yield
69%; yellow solid; mp 167ꢀ169 °C; 1H NMR (300 MHz, DMSOꢀ
d6) δ 8.79 – 8.74 (m, 1H), 8.59 (s, 1H), 8.42 – 8.35 (m, 2H), 8.19
– 8.12 (m, 1H), 7.73 (t, J = 8.0 Hz, 1H), 7.16 – 7.06 (m, 1H), 6.84
(t, J = 6.8 Hz, 1H), 2.56 (s, 3H); 13C NMR (75 MHz, DMSOꢀd6) δ
110 148.78, 145.97, 141.81, 136.31, 132.12, 130.70, 126.87, 125.28,
124.45, 122.45, 120.07, 113.14, 111.46, 17.10.
2-(4-Fluorophenyl)imidazo[1,2-a]pyridine (3ao): yield 63%;
colorless solid; mp 161ꢀ163 °C (lit.55 164ꢀ165 °C); 1H NMR (300
MHz, CDCl3) δ 8.05 (dt, J = 6.8, 1.1 Hz, 1H), 7.95 – 7.85 (m,
2H), 7.75 (s, 1H), 7.60 (dd, J = 9.1, 0.6 Hz, 1H), 7.19 – 7.05 (m,
45 3H), 6.73 (td, J = 6.8, 1.0 Hz, 1H); 13C NMR (75 MHz, CDCl3) δ
164.32, 161.05, 145.67, 144.90, 130.05, 130.00, 127.73, 127.62,
125.57, 124.75, 117.43, 115.76, 115.48, 112.44, 107.79.
6-Methyl-2-(3-nitrophenyl)imidazo[1,2-a]pyridine (3ay): yield
60%; yellow solid; mp 159ꢀ161 °C; 1H NMR (300 MHz, CDCl3)
δ 8.72 (t, J = 1.9 Hz, 1H), 8.32 – 8.26 (m, 1H), 8.17 – 8.10 (m,
115 1H), 7.91 (s, 1H), 7.87 (s, 1H), 7.64 – 7.46 (m, 2H), 7.06 (dd, J =
9.2, 1.5 Hz, 1H), 2.33 (s, 3H); 13C NMR (75 MHz, CDCl3) δ
148.69, 144.97, 143.08, 135.89, 131.65, 129.60, 128.65, 123.47,
122.70, 122.24, 120.57, 117.00, 108.77, 18.11.
2-(4-Nitrophenyl)imidazo[1,2-a]pyridine (3az): yield 86%;
120 yellow solid; 1H NMR (300 MHz, DMSOꢀd6) δ 8.65 (s, 1H), 8.58
(d, J = 6.8 Hz, 1H), 8.31 (d, J = 9.0 Hz, 2H), 8.23 (d, J = 9.0 Hz,
2H), 7.63 (d, J = 9.1 Hz, 1H), 7.37 – 7.27 (m, 1H), 6.96 (td, J =
6.8, 0.9 Hz, 1H); 13C NMR (75 MHz, DMSOꢀd6) δ 146.94,
145.72, 142.45, 140.97, 127.72, 126.76, 126.40, 124.65, 117.45,
125 113.39, 112.15.
2-(4-Fluorophenyl)-7-methylimidazo[1,2-a]pyridine
(3ap):
yield 58%; offꢀwhite solid; mp 138ꢀ139 °C; 1H NMR (300 MHz,
50 CDCl3) δ 7.94 (d, J = 6.9 Hz, 1H), 7.92 – 7.85 (m, 2H), 7.68 (s,
1H), 7.35 (d, J = 0.6 Hz, 1H), 7.15 – 7.04 (m, 2H), 6.58 (dd, J =
6.9, 1.6 Hz, 1H), 2.38 (s, 3H); 13C NMR (75 MHz, CDCl3) δ
164.22, 160.95, 146.16, 144.64, 135.71, 130.22, 130.18, 127.63,
127.53, 124.75, 115.81, 115.70, 115.41, 115.07, 107.18, 21.36.
55 2-(4-Chlorophenyl)imidazo[1,2-a]pyridine (3aq): yield 62%;
colorless solid; mp 201ꢀ202 °C (lit.55 201ꢀ202 °C); 1H NMR (300
MHz, CDCl3) δ 8.09 (d, J = 6.8 Hz, 1H), 7.86 – 7.78 (m, 3H),
7.58 (d, J = 9.1 Hz, 1H), 7.42 – 7.35 (m, 2H), 7.26 – 7.15 (m,
1H), 6.79 (t, J = 6.8 Hz, 1H); 13C NMR (75 MHz, CDCl3) δ
60 145.58, 144.20, 133.74, 131.87, 128.87, 127.18, 125.72, 125.43,
116.89, 112.83, 108.44.
7-Methyl-2-(4-nitrophenyl)imidazo[1,2-a]pyridine (3ba): yield
92%; yellow solid; mp 214ꢀ216 °C; 1H NMR (300 MHz, DMSOꢀ
d6) δ 8.55 (s, 1H), 8.45 (d, J = 7.0 Hz, 1H), 8.29 (d, J = 9.1 Hz,
2H), 8.20 (d, J = 9.1 Hz, 2H), 7.39 (s, 1H), 6.80 (dd, J = 6.9, 1.6
2-(4-Chlorophenyl)-6-methylimidazo[1,2-a]pyridine
(3ar):
1
yield 56%; colorless solid; mp 210ꢀ212 °C; H NMR (300 MHz,
CDCl3) δ 7.86 (s, 1H), 7.82 – 7.74 (m, 2H), 7.71 (s, 1H), 7.47 (d,
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