4.2.1. General procedure for the synthesis of 1-(4-(methylsulfonyl)phenyl)-2-(phenylamino)ethan-1-ones (3)
A mixture of α-bromo-4-(methylsulfonyl)acetophenone 1 (7 mmol) and 4-substituted-aniline 2 (7 mmol) in anhydrous methanol (10 ml) and in the presence of two equivalents of sodium hydrogen carbonate was stirred at room temperature for 16 hours. The reaction mixture was filtered out and washed with cold MeOH and water. The crude was used in the next step without any purification.
1-(4-(methylsulfonyl)phenyl)-2-(phenylamino)ethan-1-one (3a)
Yield, 91%; Yellow powder; mp: 156–158 oC; IR (KBr disk): νcm-1 1155, 1296 (SO2), 1700 (C = O), 3396 (NH); LC-MS (ESI) m/z: 288 ([M-H]-, 100).
2-((4-fluorophenyl)amino)-1-(4-(methylsulfonyl)phenyl)ethan-1-one (3b)
Yield, 89%; Yellow powder; mp: 166–168 oC; IR (KBr disk): νcm-1 1142, 1309 (SO2), 1692 (C = O), 3364 (NH); LC-MS (ESI) m/z: 306 ([M-H]-, 100).
2-((4-chlorophenyl)amino)-1-(4-(methylsulfonyl)phenyl)ethan-1-one (3c)
Yield, 87%; Yellow powder; mp: 171–173 oC; IR (KBr disk): νcm-1 1142, 1308 (SO2), 1692 (C = O), 3355 (NH); LC-MS (ESI) m/z: 322 ([M-H]-, 100).
1-(4-(methylsulfonyl)phenyl)-2-(p-tolylamino)ethan-1-one (3d)
Yield, 86%; Yellow powder; mp: 153–154 oC; IR (KBr disk): νcm-1 1152, 1297 (SO2), 1683 (C = O), 3390 (NH); LC-MS (ESI) m/z: 302 ([M-H]-, 100).
2-((4-methoxyphenyl)amino)-1-(4-(methylsulfonyl)phenyl)ethan-1-one (3e)
Yield, 81%; dark yellow powder; mp: 149–151 oC; IR (KBr disk): νcm-1 1154, 1297 (SO2), 1675 (C = O), 3361 (NH); LC-MS (ESI) m/z: 318 ([M-H]-, 100).
General procedure for the synthesis of 2-(4-(methylsulfonyl)phenyl)-N-phenylimidazo[1,2-a]pyridin-3-amine derivatives ( 5 )
An appropriate derivative of 3 (1.73 mmol), 2-aminopyridine derivatives (1.73 mmol), ZnI2 (0.52 mmol), 4 Å MS (850 mg), and i-PrOH (8.5 ml) were added, and the mixture was stirred at 80 oC. After completing the reaction, the mixture was cooled to room temperature and then filtered and washed with water and cool i-PrOH to obtain 20 different derivatives.
2-(4-(Methylsulfonyl)phenyl)-N-phenylimidazo[1,2-a]pyridin-3-amine (5a)
Yield, 79%; yellow powder; mp: 189 oC (decomposed); IR (KBr disk): νcm− 1 1158, 1299 (SO2), 1682 (C = N), 3404 (NH); 1H NMR (DMSO-d6): δ ppm 3.25 (s, 3H, SO2Me), 6.55–6.57 (d, 2H, J = 7.6 Hz, phenyl H2 & H6), 6.72–6.75 (t, 1H, phenyl H4), 6.89–6.92 (t, 1H, imidazopyridine H6), 6.98–7.02 (t, 2H, J = 7.6 Hz, phenyl H3 & H5), 7.24–7.27 (t, 1H, imidazopyridine H7), 7.42–7.44 (d, 1H, imidazopyridine H8), 7.64–7.66 (d, 1H, imidazopyridine H5), 7.98-8.00 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.11–8.13 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5), 8.16 (s, 1H, NH); 13C NMR (DMSO-d6): δ ppm 43.57, 113.26, 113.49, 117.67, 117.84, 119.32, 123.80, 127.25, 127.67, 127.97, 129.31, 129.44. 130.09, 140.50, 144.72, 146.77; LC-MS (ESI) m/z: 364 ([M + H]+, 100); Anal. Calcd. For C20H17N3O2S: C, 66.10; H, 4.72; N, 11.56. Found: C, 65.88; H, 4.74; N, 11.68.
8-Methyl-2-(4-(methylsulfonyl)phenyl)-N-phenylimidazo[1,2-a]pyridin-3-amine (5b)
Yield, 71%; yellow powder; mp:261–263 oC; IR (KBr disk): νcm− 1 1158, 1269 (SO2), 1631 (C = N), 3373 (NH); 1H NMR (CDCl3): δ ppm 2.62 (s, 3H, CH3), 2.96 (s, 3H, SO2Me), 5.61 (s, 1H, NH), 6.52–6.54 (d, 2H, J = 7.6 Hz, phenyl H2 & H6), 6.65–6.69 (t, 1H, J = 6.8 Hz phenyl H4), 6.80–6.84 (t, 1H, J = 7.2 Hz, imidazopyridine H6), 7.00-7.02 (d, 1H, J = 6.8 Hz, imidazopyridine H7), 7.13–7.17 (t, 2H, J = 7.6 Hz, phenyl H3 & H5), 7.67–7.68 (d, 1H, J = 6.8 Hz, imidazopyridine H5), 7.83–7.85 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.17–8.19 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (DMSO-d6): δ ppm 16.65, 43.99, 113.20, 113.48, 119.25, 121.29, 121.56, 124.76, 127.23, 127.40, 127.72, 130.07, 135.61, 139.18, 139.57, 142.85, 145.71; LC-MS (ESI) m/z: 378 ([M + H]+, 100); Anal. Calcd. For C21H19N3O2S: C, 66.82; H, 5.07; N, 11.13. Found: C, 66.76; H, 4.96; N, 11.24.
7-Methyl-2-(4-(methylsulfonyl)phenyl)-N-phenylimidazo[1,2-a]pyridin-3-amine (5c)
Yield, 78%; yellow powder; mp: 239–241 oC; IR (KBr disk): νcm− 1 1162, 1317 (SO2), 1661 (C = N), 3235 (NH); 1H NMR (DMSO-d6): δ ppm 2.38 (s, 3H, CH3), 3.20 (s, 3H, SO2Me), 6.50–6.52 (d, 2H, J = 7.6 Hz, phenyl H2 & H6), 6.72–6.75 (t, 1H, J = 7.2 Hz, phenyl H4), 6.79–6.8 (d, 1H, J = 6.8 Hz, imidazopyridine H6), 7.12–7.16 (t, 2H, J = 7.6 Hz, phenyl H3 & H5), 7.43 (s, 1H, imidazopyridine H8), 7.85–7.87 (d, 1H, J = 6.8 Hz imidazopyridine H5), 7.92–7.94 (d, 2H, J = 8.0 Hz, methylsulfonylphenyl H2 & H6), 8.27–8.29 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5), 8.32 (s, 1H, NH); 13C NMR (DMSO-d6): δ ppm 21.32, 43.99, 113.45, 115.70, 116.10, 119.23, 120.59, 123.05, 127.14, 127.69, 130.06, 135.72, 136.89, 139.23, 139.50, 142.96, 145.75; LC-MS (ESI) m/z: 378 ([M + H]+, 100); Anal. Calcd. For C21H19N3O2S: C, 66.82; H, 5.07; N, 11.13. Found: C, 66. 69; H, 5.11; N, 11.19.
5-Methyl-2-(4-(methylsulfonyl)phenyl)-N-phenylimidazo[1,2-a]pyridin-3-amine (5d)
Yield, 72%; yellow powder; mp: 210 oC (decomposed); IR (KBr disk): νcm− 1 1162, 1326 (SO2), 1668 (C = N), 3361 (NH); 1H NMR (DMSO-d6): δ ppm 2.66 (s, 3H, CH3), 3.21 (s, 3H, SO2Me), 6.65–6.67 (d, 2H, J = 6.8 Hz, phenyl H2 & H6), 6.67–6.72 (t, 1H, J = 7.6 Hz, phenyl H4), 6.80–6.82 (d, 1H, J = 6.8 Hz, imidazopyridine H6), 7.13–7.17 (t, 2H, J = 7.2 Hz, phenyl H3 & H5), 7.23–7.25 (t, 1H, J = 7.2 Hz, imidazopyridine H7), 7.49–7.51 (d, 1H, J = 8.8 Hz, imidazopyridine H8), 7.91–7.93 (d, 2H, J = 8.8 Hz, methylsulfonylphenyl H2 & H6), 7.96–7.98 (d, 1H, J = 8.8 Hz, imidazopyridine H8) 8.22 (s, 1H, NH), 8.30–8.32 (d, 2H, J = 8.8 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (DMSO-d6): δ ppm 18.25, 43.91, 113.24, 114.26, 116.09, 118.78, 121.66, 126.57, 127.38, 127.62, 130.23, 136.66, 137.77, 139.10, 139.71, 144.29, 148.15; LC-MS (ESI) m/z: 378 ([M + H]+, 100); Anal. Calcd. For C21H19N3O2S: C, 66.82; H, 5.07; N, 11.13. Found: C, 66.91; H, 5.09; N, 11.02.
N-(4-Fluorophenyl)-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5e)
Yield, 56%; cream powder; mp: 238 oC (decomposed); IR (KBr disk): νcm− 1 1170, 1330 (SO2), 1648 (C = N), 3263 (NH); 1H NMR (DMSO-d6): δ ppm 3.22 (s, 3H, SO2Me), 6.50–6.54 (m, 2H, phenyl H2 & H6), 6.95–7.02 (m, 3H, phenyl H3 & H5, imidazopyridine H6), 7.34–7.38 (t, 1H, J = 7.2 Hz, imidazopyridine H7), 7.66–7.68 (d, 1H, J = 9.2 Hz, imidazopyridine H8), 7.94–7.96 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.00-8.02 (d, 1H, J = 6.8 Hz, imidazopyridine H5), 8.29–8.31 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5), 8.36 (s, 1H, NH); 13C NMR (DMSO-d6): δ ppm 43.97, 113.26, 114.48, 114.56, 116.47, 116.70, 117.94, 121.17, 123.78, 126.36, 127.24, 127.76, 136.05, 138.99, 139.73, 142.08, 142.57, 155.17, 157.49; LC-MS (ESI) m/z: 382 ([M + H]+, 100); Anal. Calcd. For C20H16FN3O2S: C, 62.98; H, 4.23; N, 11.02. Found: C, 63.15; H, 4.21; N, 11.08.
N-(4-Fluorophenyl)-8-methyl-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5f)
Yield, 47%; white powder; mp: 224–226 oC; IR (KBr disk): νcm− 1 1144, 1308 (SO2), 1621 (C = N), 3212 (NH); 1H NMR (DMSO-d6): δ ppm 2.59 (s, 3H, CH3), 3.22 (s, 3H, SO2Me), 6.50–6.53 (m, 2H, phenyl H2 & H6), 6.86–6.89 (t, 1H, J = 6.8 Hz, imidazopyridine H6), 6.97–7.01 (t, 2H, J = 8.8 Hz, phenyl H3 & H5), 7.16–7.18 (d, 1H, J = 6.8 Hz, imidazopyridine H7), 7.84–7.86 (d, 1H, J = 6.8 Hz, imidazopyridine H5), 7.95–7.97 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.30–8.32 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5), 8.35 (s, 1H, NH); 13C NMR (DMSO): δ ppm 16.63, 44.00, 113.25, 114.47, 114.54, 116.44, 116.67, 121.54, 124.79, 127.22, 127.42, 127.75, 135.59, 139.13, 139.60, 142.17, 142.87, 155.13, 157.46; LC-MS (ESI) m/z: 396 ([M + H]+, 100); Anal. Calcd. For C21H18FN3O2S: C, 63.78; H, 4.59; N, 10.63. Found: C, 63.61; H, 4.62; N, 10.57.
N-(4-Fluorophenyl)-7-methyl-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5g)
Yield, 52%; yellow powder; mp: 238–240 oC; IR (KBr disk): νcm− 1 1152, 1310 (SO2), 1645 (C = N), 3215 (NH); 1H NMR (DMSO-d6): δ ppm 2.38 (s, 3H, CH3), 3.21 (s, 3H, SO2Me), 6.48–6.52 (m, 2 H, phenyl H2 & H6), 6.80–6.81 (d, 1H, J = 6.8 Hz, imidazopyridine H6), 6.97–7.01 (t, 2H, J = 8.8 Hz, phenyl H3 & H5), 7.43 (s, 1H, imidazopyridine H8), 7.87-7,89 (d, 1H, J = 7.2 Hz, imidazopyridine H5), 7.93–7.95 (d, 2H, J = 8.8 Hz, methylsulfonylphenyl H2 & H6), 8.26–8.28 (d, 2H, J = 8.8 Hz, methylsulfonylphenyl H3 & H5), 8.30 (s, 1H, NH); 13C NMR (DMSO-d6): δ ppm 21.31, 43.99, 114.41, 114.49, 115.76, 116.11, 116.44, 116.66, 120.74, 123.02, 127.11, 127.71, 135.69, 136.93, 139.16, 139.54, 142.21, 142.96, 155.12, 157.44; LC-MS (ESI) m/z: 396 ([M + H]+, 100); Anal. Calcd. For C21H18FN3O2S: C, 63.78; H, 4.59; N, 10.63. Found: C, 63.88; H, 4.55; N, 10.66.
N-(4-Fluorophenyl)-5-methyl-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5h)
Yield, 60%; white powder; mp: 230 oC (decomposed); IR (KBr disk): νcm− 1 1153, 1315 (SO2), 1648 (C = N), 3343 (NH); 1H NMR (DMSO-d6): δ ppm 2.68 (s, 3H, CH3), 3.21 (s, 3H, SO2Me), 6.47–6.49 (m, 2H, phenyl H2 & H6), 6.85–6.87 (d, 1H, J = 6.8 Hz, imidazopyridine H6), 6.97–7.01 (t, 2H, J = 8.8 Hz, phenyl H3 & H5), 7.23–7.25 (t, 1H, J = 8.4 Hz, imidazopyridine H7), 7.50–7.52 (d, 1H, J = 8.8 Hz, imidazopyridine H8), 7.93–7.95 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.10–8.12 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5), 8.33 (s, 1H, NH); 13C NMR (DMSO-d6): δ ppm 18.83, 43.92, 114.25, 116.08, 116.56, 116.78, 121.96, 126.53, 127.37, 127.63, 130.11, 136.69, 137.72, 139.09, 139.70, 141.21, 144.28, 154.71, 157.03; LC-MS (ESI) m/z: 396 ([M + H]+, 100); Anal. Calcd. For C21H18FN3O2S: C, 63.78; H, 4.59; N, 10.63. Found: C, 63.59; H, 4.63; N, 10.71.
N-(4-Chlorophenyl)-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5i)
Yield, 55%; yellow powder; mp: 226–228 oC; IR (KBr disk): νcm− 1 1154, 1307 (SO2), 1669 (C = N), 3333 (NH); 1H NMR (DMSO-d6): δ ppm 3.22 (s, 3H, SO2Me), 6.53–6.55 (d, 2H, J = 8.4 Hz, phenyl H2 & H6), 6.96–6.99 (t, 1H, J = 6.8 Hz, imidazopyridine H6), 7.18–7.20 (d, 2H, J = 8.8 Hz phenyl H3 & H5), 7.34–7.38 (t, 1H, J = 8.4 Hz, imidazopyridine H7), 7.67–7.69 (d, 1H, J = 8.8 Hz, imidazopyridine H8), 7.95–7.97 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.00-8.02 (d, 1H, J = 6.8 Hz, imidazopyridine H5), 8.28–8.30 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5), 8.54 (s, 1H, NH); 13C NMR (DMSO-d6): δ ppm 43.97, 113.36, 115.08, 117.96, 120.47, 122.81, 123.77, 126.45, 127.25, 127.80, 129.86, 136.15, 138.90, 139.80, 142.66, 144.64; LC-MS (ESI) m/z: 398 ([M + H]+, 100), 400 (M + 3, 32%); Anal. Calcd. For C20H16ClN3O2S: C, 60.38; H, 4.05; N, 10.56. Found: C, 60.45; H, 4.01; N, 10.58.
N-(4-Chlorophenyl)-8-methyl-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5j)
Yield, 59%; creamy-yellowish powder; mp: 199–201 oC; IR (KBr disk): νcm− 1 1141, 1304 (SO2), 1670 (C = N), 3354 (NH); 1H NMR (DMSO-d6): δ ppm 2.58 (s, 3H, CH3), 3.22 (s, 3H, SO2Me), 6.51–6.53 (d, 2H, J = 8.4 Hz, phenyl H2 & H6), 6.86–6.89 (t, 1H, J = 6.8 Hz, imidazopyridine H6), 7.17–7.19 (m, 3H, imidazopyridine H7, phenyl H3 & H5), 7.84–7.86 (d, 1H, J = 6.4 Hz, imidazopyridine H5), 7.95–7.97 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.28–8.31 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5), 8.54 (s, 1H, NH); 13C NMR (DMSO-d6): δ ppm 16.64, 44.00, 113.34, 115.06, 120.85, 121.51, 122.74, 124.88, 127.23, 127.46, 127.78, 129.84, 135.68, 139.03, 139.67, 142.96, 144.73; LC-MS (ESI) m/z: 412 ([M + H]+, 100), 414 ([M + H + 2]+, 32%); Anal. Calcd. For C21H18ClN3O2S: C, 61.24; H, 4.40; N, 10.20. Found: C, 61.01; H, 4.44; N, 10.30.
N-(4-Chlorophenyl)-7-methyl-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5k)
Yield, 71%; yellow powder; mp: 238 oC (decomposed); IR (KBr disk): νcm− 1 1150, 1299 (SO2), 1670 (C = N), 3201 (NH); 1H NMR (DMSO-d6): δ ppm 2.38 (s, 3H, CH3), 3.21 (s, 3H, SO2Me), 6.50–6.52 (d, 2H, J = 8.4 Hz, phenyl H2 & H6), 6.80–6.82 (d, 1 H, J = 6.8 Hz, imidazopyridine H6), 7.17–7.19 (d, 2H, J = 8.8 Hz, phenyl H3 & H5), 7.44 (s, 1H, imidazopyridine H8), 8.87–7.89 (d, 1H, J = 6.8 Hz, imidazopyridine H5), 7.93–7.95 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.25–8.27 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5), 8.50 (s, 1H, NH); 13C NMR (DMSO-d6): δ ppm 21.31, 43.99, 115.02, 115.85, 116.13, 120.04, 122.71, 123.01, 127.12, 127.75, 129.84, 135.78, 137.04, 139.06, 139.60, 143.05, 144.77; LC-MS (ESI) m/z: 412 ([M + H]+, 414 ([M + H + 2]+, 32%); Anal. Calcd. For C21H18ClN3O2S: C, 61.24; H, 4.40; N, 10.20. Found: C, 61.20; H, 4.37; N, 10.26.
N-(4-Chlorophenyl)-5-methyl-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5l)
Yield, 73%; yellow powder; mp: 249 oC (decomposed); IR (KBr disk): νcm− 1 1148, 1316 (SO2), 1655 (C = N), 3372 (NH); 1H NMR (DMSO-d6): δ ppm 2.65 (s, 3H, CH3), 3.21 (s, 3H, SO2Me), 6.49–6.51 (d, 2H, J = 8.4 Hz, phenyl H2 & H6), 6.67–6.69 (d, 1H, J = 6.8 Hz, imidazopyridine H6), 7.18–7.26 (m, 3H, phenyl H3 & H5, imidazopyridine H7), 7.49–7.52 (d, 2 H, J = 8.8 Hz, imidazopyridine H8), 7.92–7.94 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.09–8.11 (d, 1H, J = 8.4 Hz, ), 8.27–8.29 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5), 8.40 (s, 1H, NH); 13C NMR (DMSO-d6): δ ppm 18.81, 43.90, 114.41, 116.14, 121.14, 122.28, 126.69, 127.34, 127.69, 129.35, 130.03, 136.56, 137.76, 138.92, 139.82, 144.37, 147.07; LC-MS (ESI) m/z: 412 ([M + H]+, 100), ([M + H + 2]+, 32%); Anal. Calcd. For C21H18ClN3O2S: C, 61.24; H, 4.40; N, 10.20. Found: C, 61.16; H, 4.43; N, 10.16.
2-(4-(Methylsulfonyl)phenyl)-N-(p-tolyl)imidazo[1,2-a]pyridin-3-amine (5m)
Yield, 63%; yellow powder; mp: 198–200 oC; IR (KBr disk): νcm− 1 1153, 1313 (SO2), 1635 (C = N), 3335 (NH); 1H NMR (DMSO-d6): δ ppm 2.15 (s, 3H, CH3), 3.21 (s, 3H, SO2Me), 6.42–6.44 (d, 2H, J = 8.0 Hz, phenyl H3 & H5), 6.93–6.97 (m, 3H, imidazopyridine H6, phenyl H2 & H6), 7.33–7.37 (t, 1H, J = 7.6 Hz, imidazopyridine H7), 7.65–7.67 (d, 1H, J = 9.2 Hz, imidazopyridine H8), 7.93–7.97 (m, 3H, methylsulfonylphenyl H2 & H6, imidazopyridine H5), 8.21 (s, 1H, NH), 8.29–8.31 (d, 1H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (DMSO-d6): δ ppm 20.55, 43.97, 113.13, 113.z51, 117.89, 121.42, 123.79, 126.25, 127.23, 127.72, 127.90, 130.51, 135.99, 139.11, 139.63, 142.48, 143.18; LC-MS (ESI) m/z: 378 ([M + H]+, 100); Anal. Calcd. For C21H19N3O2S: C, 66.82; H, 5.07; N, 11.13. Found: C, 66.98; H, 5.11; N, 11.19.
8-Methyl-2-(4-(methylsulfonyl)phenyl)-N-(p-tolyl)imidazo[1,2-a]pyridin-3-amine (5n)
Yield, 59%; dark yellow powder; mp: 200–202 oC; IR (KBr disk): νcm− 1 1156, 1315 (SO2), 1632 (C = N), 3370 (NH); 1H NMR (DMSO-d6): δ ppm 2.15 (s, 3H, 4-CH3), 2.58 (s, 3H, 8-CH3), 3.21 (s, 3H, SO2Me), 6.41–6.43 (d, 2H, J = 8.0 Hz, phenyl H3 & H5), 6.84–6.87 (t, 1H, J = 6.8 Hz, imidazopyridine H6), 6.94–6.96 (d, 2H, J = 8.0 Hz, phenyl H2 & H6), 7.14–7.16 (d, 1H, J = 6.8 Hz, imidazopyridine H7), 7.80–7.82 (d, 1H, J = 6.8 Hz, imidazopyridine H5), 7.93–7.95 (d, 1H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.20 (s, 1H, NH), 8.30–8.32 (d, 1H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (DMSO-d6): δ ppm 16.64, 20.55, 44.01, 113.10, 113.50, 121.55, 121.79, 124.68, 127.22, 127.36, 127.69, 127.83, 130.48, 135.52, 139.25, 139.49, 142.78, 143.27; LC-MS (ESI) m/z: 392 ([M + H]+, 100); Anal. Calcd. For C22H21N3O2S: C, 67.50; H, 5.41; N, 10.73. Found: C, 67.41; H, 4.39; N, 10.78.
7-Methyl-2-(4-(methylsulfonyl)phenyl)-N-(p-tolyl)imidazo[1,2-a]pyridin-3-amine (5o)
Yield, 61%; creamy powder; mp: 274 oC (decomposed); IR (KBr disk): νcm− 1 1158, 1320 (SO2), 1648 (C = N), 3224 (NH); 1H NMR (DMSO-d6): δ ppm 2.16 (s, 3H, 4-CH3), 2.38 (s, 3H, 7-CH3), 3.20 (s, 3H, SO2Me), 6.40–6.42 (d, 2H, J = 8.0 Hz, phenyl H3 & H5), 6.78–6.80 (d, 1H, J = 6.8 Hz, imidazopyridine H6), 6.94–6.96 (d, 2H, J = 8.4 Hz, phenyl H2 & H6), 7.42 (s, 1H, imidazopyridine H8), 7.83–7.84 (d, 1H, J = 6.8 Hz, imidazopyridine H5), 7.91–7.93 (d, 1H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.15 (s, 1H, NH), 8.26–8.28 (d, 2H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (DMSO-d6): δ ppm 19.47, 20.23, 42.91, 112.38, 114.53, 114.99, 119.91, 121.95, 126.02, 126.58, 126.73, 129.39, 134.53, 135.71, 138.21, 138.35, 141.80, 142.23; LC-MS (ESI) m/z: 392 ([M + H]+, 100); Anal. Calcd. For C22H21N3O2S: C, 67.50; H, 5.41; N, 10.73. Found: C, 67.64; H, 5.42; N, 10.66.
5-Methyl-2-(4-(methylsulfonyl)phenyl)-N-(p-tolyl)imidazo[1,2-a]pyridin-3-amine (5p)
Yield, 63%; yellow powder; mp: 330 oC (decomposed); IR (KBr disk): νcm-1 1156, 1321 (SO2), 1648 (C = N), 3390 (NH); 1H NMR (DMSO-d6): δ ppm 2.15 (s, 3H, CH3), 2.66 (s, 3H, CH3), 3.20 (s, 3H, SO2Me), 6.42–6.44 (d, 2H, J = 8.0 Hz, phenyl H3 & H5), 6.64–6.66 (d, 1H, J = 6.8 Hz,imidazopyridine H6), 6.94–6.96 (d, 2H, J = 8.0 Hz, phenyl H2 & H6), 7.20–7.24 (t, 1H, J = 7.2 Hz, imidazopyridine H7), 7.48–7.50 (d, 1H, J = 9.6 Hz, imidazopyridine H8), 7.89–7.92 (d, 1H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.04 (s, 1H, NH), 8.29–8.31 (d, 1H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (DMSO-d6): δ ppm 18.82, 20.53, 43.81, 114.19, 116.06, 117.43, 122.06, 126.50, 127.23, 127.35, 127.59, 128.10, 130.67, 136.69, 137.68, 139.66, 144.26, 145.81; LC-MS (ESI) m/z: 392 ([M + H]+, 100); Anal. Calcd. For C22H21N3O2S: C, 67.50; H, 5.41; N, 10.73. Found: 67.59; H, 5.38; N, 10.75.
N-(4-Methoxyphenyl)-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5q)
Yield, 38%; dark yellow powder; mp: 103–105 oC; IR (KBr disk): νcm-1 1160, 1320 (SO2), 1639 (C = N), 33230 (NH); 1H NMR (CDCl3): δ ppm 3.22 (s, 3H, SO2Me), 3.63 (s, 3H, OCH3), 6.46–6.48 (d, 2H, J = 8.8 Hz, phenyl H3 & H5), 6.76–6.78 (d, 2H, J = 9.2 Hz, phenyl H2 & H6), 6.93–6.97 (t, 1H, J = 6.8 Hz, imidazopyridine H6), 7.32–7.36 (t, 1H, J = 8.0 Hz, imidazopyridine H7), 7.64–7.67 (d, 1H, J = 9.2 Hz, imidazopyridine H8), 7.93–7.96 (d, 1H, J = 8.8 Hz, methylsulfonylphenyl H2 & H6), 7.97–7.99 (d, 1H, J = 6.8 Hz, imidazopyridine H5), 8.07 (s, 1H, NH), 8.31–8.33 (d, 1H, J = 8.8 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (CDCl3): δ ppm 43.98, 55.67, 113.09, 114.48, 117.89, 121.89, 123.81, 126.21, 127.22, 127.71, 135.90, 139.15, 139.60, 142.42, 153.04; LC-MS (ESI) m/z: 394 ([M + H]+, 100); Anal. Calcd. For C21H19N3O3S: C, 64.11; H, 4.87; N, 10.68. Found: C, 63.93; H, 4.89; N, 10.76.
N-(4-Methoxyphenyl)-8-methyl-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5r)
Yield, 41%; white-creamy powder; mp: 229–231 oC; IR (KBr disk): νcm-1 1151, 1314 (SO2), 1627 (C = N), 3252 (NH); 1H NMR (DMSO-d6): δ ppm 2.57 (s, 3H, CH3), 3.21 (s, 3H, SO2Me), 3.62 (s, 3H, OCH3), 6.45–6.48 (d, 2H, J = 8.8 Hz, phenyl H3 & H5), 6.75–6.77 (d, 2H, J = 8.8 Hz, phenyl H2 & H6), 6.84–6.87 (t, 1H, J = 7.2 Hz, imidazopyridine H6), 7.14–7.16 (d, 1H, J = 6.8 Hz, imidazopyridine H7), 7.82–7.84 (d, 1H, J = 6.8 Hz, imidazopyridine H8), 7.94–7.96 (d, 1H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.07 (s, 1H, NH), 8.32–8.34 (d, 1H, J = 8.8 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (DMSO-d6): δ ppm 16.64, 44.01, 55.67, 113.07, 114.47, 115.54, 121.57, 122.27, 124.64, 127.21, 127.70, 135.43, 139.28, 139.46, 142,73, 153.00; LC-MS (ESI) m/z: 408 ([M + H]+, 100); Anal. Calcd. For C22H21N3O3S: C, 64.85; H, 5.19; N, 10.31. Found: C, 65.01; H, 5.15; N, 10.25.
N-(4-Methoxyphenyl)-7-methyl-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5s)
Yield, 44%; white powder; mp: 138–140 oC; IR (KBr disk): νcm-1 1155, 1307 (SO2), 1648 (C = N), 3227 (NH); 1H NMR (DMSO-d6): δ ppm 2.37 (s, 1H, CH3), 3.21 (s, 3H, SO2Me), 3.63 (s, 3H, OCH3), 6.44–6.47 (d, 2H, J = 8.8 Hz, phenyl H3 & H5), 6.75–6.77 (m, 3H, phenyl H2 & H6, imidazopyridine H6), 7.41 (s, 1H, imidazopyridine H8), 7.84–7.86 (d, 1H, J = 7.2 Hz, imidazopyridine H8), 7.92–7.94 (d, 1H, J = 8.4 Hz, methylsulfonylphenyl H2 & H6), 8.03 (s, 1H, NH), 8.28–8.30 (d, 1H, J = 8.4 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (DMSO-d6): δ ppm 21.31, 44.00, 55.67, 114.42, 115.55, 116.06, 121.47, 123.05, 127.10, 127.67, 135.54, 136.75, 139.33, 139.40, 142.83, 152.99; LC-MS (ESI) m/z: 408 ([M + H]+, 100); Anal. Calcd. For C22H21N3O3S: C, 64.85; H, 5.19; N, 10.31. Found: C, 64.98; H, 5.14; N, 10.24.
N-(4-Methoxyphenyl)-5-methyl-2-(4-(methylsulfonyl)phenyl)imidazo[1,2-a]pyridin-3-amine (5t)
Yield, 50%; yellow-orange powder; mp: 156 oC (decomposed); IR (KBr disk): νcm-1 1152, 1313 (SO2), 1641 (C = N), 3365 (NH); 1H NMR (DMSO-d6): δ ppm 2.68 (s, 1H, CH3), 3.21 (s, 3H, SO2Me), 3.62 (s, 3H, OCH3), 6.37–6.39 (d, 2H, J = 8.4 Hz, phenyl H3 & H5), 6.64–6.65 (d, 1H, J = 6.8 Hz, imidazopyridine H6), 6.76–6.78 (d, 2H, J = 8.4 Hz, phenyl H2 & H6), 7.20–7.23 (t, 1H, J = 7.2 Hz, imidazopyridine H7), 7.47–7.49 (d, 1H, J = 8.8 Hz, imidazopyridine H8), 7.90–7.92 (m, 3H, methylsulfonylphenyl H2 & H6, NH), 8.31–8.33 (d, 1H, J = 8.0 Hz, methylsulfonylphenyl H3 & H5); 13C NMR (DMSO-d6): δ ppm 18.86, 43.93, 55.61, 114.03, 114.15, 114.92, 115.70, 116.06, 122.48, 126.47, 127.36, 127.59, 136.72, 137.66, 139.20, 139.62, 141.93, 144.18, 152.50; LC-MS (ESI) m/z: 408 ([M + H]+, 100); Anal. Calcd. For C22H21N3O3S: C, 64.85; H, 5.19; N, 10.31. Found: C, 64.76; H, 5.22; N, 10.35.