ChemInform Abstract: InBr₃‐Catalyzed Three‐Component, One‐Pot Synthesis of Imidazo[1,2‐a]pyridines.

Abstract

InBr 3 -Catalyzed Three-Component, One-Pot Synthesis of Imidazo[1,2-a]pyridines. -The simple method allows the preparation of various title compounds from both aromatic and aliphatic substrates. -(REDDY*, B. V. S.; REDDY, P. S.; REDDY, Y. J.; YADAV, J. S.; Tetrahedron Lett. 52 (2011) 44, 5789-5793, http://dx.

Efficient and “Green” Synthetic Route to Imidazo[1,2-a]pyridine by Cu(II)–Ascorbate-Catalyzed A3-Coupling in Aqueous Micellar Media

“…3-Benzyl-2-(4-isopropylphenyl)H-imidazo[1,2-a]pyridine (4d). Light grey solid; mp 100−102 °C; 1 H NMR (400 MHz, CDCl 3 ): δ (ppm) 1.27 (d,J = 6.8 Hz,6H), 2.94 (sep, J = 6.8 Hz, 1H), 4.49 (s, 2H), 6.68 (dt, J 1 = 0.8 Hz, J 2 = 6. 8 Hz,1H),3H),1H),4H), 7.67 (d,J = 7.2 Hz,1H),3H); 13 C NMR (100 MHz, CDCl 3 ): δ (ppm) 24.0, 29.9, 33.9, 112.2, 117.4, 117.5, 123.4, 124.2, 126.8, 126.9, 127.7, 128.2, 129.0, 136.9, 144.2, 144.8, and 148.5;IR (KBr) ν: 3080, 3032, 2954, 2866, 1629, 1500, 1451, 1357, 1259 3.78 (s, 3H), 4.29 (s, 2H), 6.66 (dt, J 1 = 1.2 Hz, J 2 = 6.4 Hz, 1H), 6.87−6.92 (m, 2H), 7.10−7.16 (m, 3H), 7.18−7.21 (m, 2H), 7.23−7.27 (m, 2H), and 7.66 (dt, J 1 = 1.2 Hz, J 2 = 6.8 Hz, 2H); 13 C NMR (100 MHz, CDCl 3 ): δ (ppm) 30.…”

“…Light grey solid; mp 100−102 °C; 1 H NMR (400 MHz, CDCl 3 ): δ (ppm) 1.27 (d,J = 6.8 Hz,6H), 2.94 (sep, J = 6.8 Hz, 1H), 4.49 (s, 2H), 6.68 (dt, J 1 = 0.8 Hz, J 2 = 6. 8 Hz,1H),3H),1H),4H), 7.67 (d,J = 7.2 Hz,1H),3H); 13 C NMR (100 MHz, CDCl 3 ): δ (ppm) 24.0, 29.9, 33.9, 112.2, 117.4, 117.5, 123.4, 124.2, 126.8, 126.9, 127.7, 128.2, 129.0, 136.9, 144.2, 144.8, and 148.5;IR (KBr) ν: 3080, 3032, 2954, 2866, 1629, 1500, 1451, 1357, 1259 3.78 (s, 3H), 4.29 (s, 2H), 6.66 (dt, J 1 = 1.2 Hz, J 2 = 6.4 Hz, 1H), 6.87−6.92 (m, 2H), 7.10−7.16 (m, 3H), 7.18−7.21 (m, 2H), 7.23−7.27 (m, 2H), and 7.66 (dt, J 1 = 1.2 Hz, J 2 = 6.8 Hz, 2H); 13 C NMR (100 MHz, CDCl 3 ): δ (ppm) 30. 3, 55.8, 55.9, 111.9, 112.2, 115.1, 117.0, 117.6, 119.8, 123.5, 123.6, 124.4, 126.5, 128.0, 128.7, 137.3, 141.3, 144.8, 151.2, and 153.6;IR (KBr) ν: 3058, 3020, 2940, 2836, 1583, 1505, 1356, 1275, 1212 18.1, 30.1, 112.1, 117.4, 117.6, 123.4, 124.1, 126.6, 126.8, 127.7, 127.9, 128.2, 128.6, 129.0, 129.2, 130.0, 131.7, 137.0, 137.8, 144.3, and 147.4 and 7.65 (td, J 1 = 1.2 Hz, J 2 = 6.0 Hz, 2H); 13 C NMR (100 MHz, CDCl 3 ): δ (ppm) 20.…”

“…3-Benzyl-2-(4-fluorophenyl)-5-methylH-imidazo[1,2-a]pyridine (4s). Off-yellow solid; mp 145−147 °C; 1 H NMR (400 MHz, CDCl 3 ): δ (ppm) 2.59 (s, 3H), 4.63 (s, 2H), 6.42 (d,J = 6.8 Hz,1H),5H),1H), 7.32 (t, J = 7.2 Hz, 2H), 7.54 (d, J = 9.2 Hz, 1H), and 7.60 (dt, J 1 = 2.0 Hz, J 2 = 5.6 Hz, 2H); 13 C NMR (100 MHz, CDCl 3 ): δ (ppm) 20.1,31.7,113.7,115.4,(d,J = 21.3 Hz),115.9,118.7,124.7,126.6,127.5,129.1,130.3 (d,J = 8.1 Hz),130.9 (d,J = 3.2 Hz),136.2,140.9,145.0,146.8,and 162.5 (d,J = 245.3 Hz); IR (KBr) ν: 3033, 2919, 2851, 1604, 1502, 1392, 1223, 1157, 843, and…”