PAPER
Oxidation of Deoxybenzoins and Synthesis of Quinoxalines
395
2,3-Bis(4-methoxyphenyl)quinoxaline (4ia)18e
HRMS: m/z calcd for C15H11N3O2: 265.0851; found: 265.0843.
White solid; mp 149–150 °C.
2-Butyl-3-phenylquinoxaline (4pa)19g
Yellow oil.
IR (KBr): 3060, 2934, 2836, 1607, 1512, 1463, 1342, 1296, 1250,
1176, 1029, 834, 764 cm–1.
IR (KBr): 3060, 2958, 2930, 2866, 1558, 1476, 1453, 1344, 1217,
1174, 1078, 1009, 763, 701 cm–1.
1H NMR (400 MHz, CDCl3): d = 0.84 (t, J = 7.6 Hz, 3 H), 1.26–
1.36 (m, 2 H), 1.68–1.76 (m, 2 H), 3.04 (t, J = 8.0 Hz, 2 H), 7.46–
7.54 (m, 3 H), 7.60–7.62 (m, 2 H), 7.67–7.73 (m, 2 H), 8.08–8.12
(m, 2 H).
1H NMR (400 MHz, CDCl3): d = 3.82 (s, 6 H), 6.87 (d, J = 8.8 Hz,
4 H), 7.49 (d, J = 8.8 Hz, 4 H), 7.70–7.72 (m, 2 H), 8.11–8.13 (m,
2 H).
13C NMR (100 MHz, CDCl3): d = 55.3, 113.8, 129.0, 129.5, 131.2,
131.7, 141.1, 153.0, 160.2.
MS (70 eV): m/z (%) = 342 [M]+ (100), 311, 255, 209, 166, 133,
103, 76.
13C NMR (100 MHz, CDCl3): d = 13.8, 22.6, 31.1, 35.8, 128.5,
128.8, 129.1, 129.2, 129.6, 139.2, 140.7, 141.5, 155.0, 156.3.
2-(4-Methoxyphenyl)-3-methylquinoxaline (4ka)
MS (70 eV): m/z (%) = 262 [M]+, 219 (100), 178, 109, 77.
White solid; mp 99–100 °C.
6-Nitro-2,3-diphenylquinoxaline (4ab)18d
Yellow solid; mp 188–189 °C.
IR (KBr): 3060, 2999, 2959, 2837, 1608, 1513, 1478, 1395, 1341,
1292, 1250, 1178, 1031, 998, 840, 764 cm–1.
IR (KBr): 3062, 1564, 1482, 1434, 1341, 1219, 1126, 1069, 816,
762 cm–1.
1H NMR (400 MHz, CDCl3): d = 7.38–7.47 (m, 6 H), 7.57–7.60 (m,
4 H), 8.32 (d, J = 9.2 Hz, 1 H), 8.53–8.56 (m, 1 H), 9.10 (s, 1 H).
13C NMR (100 MHz, CDCl3): d = 123.3, 125.6, 128.4, 129.6, 129.7,
129.8, 129.9, 130.7, 138.0, 138.1, 140.0, 143.6, 147.9, 155.7, 156.3.
1H NMR (400 MHz, CDCl3): d = 2.80 (s, 3 H), 3.88 (s, 3 H), 7.03–
7.06 (m, 2 H), 7.63–7.65 (m, 2 H), 7.68–7.71 (m, 2 H), 8.04–8.12
(m, 2 H).
13C NMR (100 MHz, CDCl3): d = 24.6, 55.4, 114.0, 128.2, 129.1,
129.4, 130.5, 131.4, 141.0, 141.1, 152.6, 154.5, 160.3.
MS (70 eV): m/z (%) = 250 [M]+, 249 (100), 219, 166, 117, 90, 76.
MS (70 eV): m/z (%) = 327 [M]+, 281, 178, 141, 104, 75 (100).
HRMS: m/z calcd for C16H14N2O: 250.1106; found: 250.1089.
6-Chloro-2,3-diphenylquinoxaline (4ac)18d
White solid; mp 122–123 °C.
2-(4-Fluorophenyl)-3-methylquinoxaline (4la)29
White solid; mp 78–79 °C.
IR (KBr): 3059, 1600, 1546, 1470, 1445, 1341, 1243, 1189, 1069,
1026, 977, 922, 833, 766, 698 cm–1.
1H NMR (400 MHz, CDCl3): d = 7.31–7.37 (m, 6 H), 7.50 (d,
J = 6.8 Hz, 4 H), 7.67–7.70 (m, 1 H), 8.09 (d, J = 8.8 Hz, 1 H), 8.16
(d, J = 2.4 Hz, 1 H).
13C NMR (100 MHz, CDCl3): d = 128.1, 128.3, 129.0, 129.1, 129.8,
130.4, 130.9, 135.6, 138.7, 139.7, 141.5, 153.6, 154.3.
IR (KBr): 3061, 2966, 2926, 1602, 1559, 1511, 1481, 1341, 1229,
1160, 1004, 845, 763 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.77 (s, 3 H), 7.20 (t, J = 8.4 Hz,
2 H), 7.64–7.67 (m, 2 H), 7.70–7.76 (m, 2 H), 8.04–8.10 (m, 2 H).
13C NMR (100 MHz, CDCl3): d = 24.4, 115.6, 128.3, 129.2, 129.8,
130.9, 135.1, 140.9, 141.2, 152.3, 153.8, 163.3.
MS (70 eV): m/z (%) = 238 [M]+, 237 (100), 197, 170, 117, 76.
MS (70 eV): m/z (%) = 316 [M]+ (100), 280, 239, 213, 178, 151,
110, 75.
2-(3-Methoxyphenyl)-3-methylquinoxaline (4na)
Yellow oil.
6-Methyl-2,3-diphenylquinoxaline (4ad)18d
White solid; mp 116–117 °C.
IR (KBr): 3061, 2931, 2837, 1590, 1484, 1460, 1341, 1254, 1171,
1125, 1049, 1020, 857, 763 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.78 (s, 3 H), 3.88 (s, 3 H), 7.02–
7.05 (m, 1 H), 7.18–7.22 (m, 2 H), 7.43 (t, J = 7.6 Hz, 1 H), 7.70–
7.76 (m, 2 H), 8.05–8.13 (m, 2 H).
13C NMR (100 MHz, CDCl3): d = 24.3, 55.4, 114.5, 114.8, 121.2,
128.3, 129.2, 129.6, 129.7, 140.3, 140.9, 141.2, 152.5, 154.5, 159.7.
IR (KBr): 3057, 2092, 1550, 1487, 1344, 1246, 1060, 1025, 829,
770, 698 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.64 (s, 3 H), 7.34–7.38 (m, 6 H),
7.52–7.55 (m, 4 H), 7.62–7.64 (m, 1 H), 7.98 (s, 1 H), 8.09 (d,
J = 8.8 Hz, 1 H).
13C NMR (100 MHz, CDCl3): d = 21.9, 128.0, 128.2, 128.6, 128.7,
129.8, 132.3, 139.3, 139.7, 140.4, 141.3, 152.6, 153.3.
MS (70 eV): m/z (%) = 250 [M]+, 249 (100), 219, 166, 117, 90, 76.
MS (70 eV): m/z (%) = 296 [M]+ (100), 281, 219, 192, 165, 140, 89.
HRMS: m/z calcd for C16H14N2O: 250.1106; found: 250.1097.
6,7-Dimethyl-2,3-diphenylquinoxaline (4ae)18f
White solid; mp 174–175 °C.
2-Methyl-3-(4-nitrophenyl)quinoxaline (4oa)
Yellow solid; mp 137–138 °C.
IR (KBr): 3070, 2967, 2852, 1598, 1518, 1480, 1345, 1112, 1001,
858, 759, 714 cm–1.
IR (KBr): 3058, 2921, 1560, 1446, 1341, 1200, 1094, 1021, 802,
766, 695 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.79 (s, 3 H), 7.75–7.82 (m, 2 H),
7.87 (d, J = 8.4 Hz, 2 H), 8.10 (t, J = 9.6 Hz, 2 H), 8.39 (d,
J = 8.0 Hz, 2 H).
13C NMR (100 MHz, CDCl3): d = 24.2, 123.7, 128.5, 129.3, 129.7,
130.2, 130.6, 140.8, 141.6, 145.3, 148.1, 151.6, 152.4.
1H NMR (400 MHz, CDCl3): d = 2.51 (s, 3 H), 2.78 (s, 3 H), 7.30–
7.32 (m, 6 H), 7.51–7.58 (m, 5 H), 7.90 (d, J = 8.8 Hz, 1 H).
13C NMR (100 MHz, CDCl3): d = 13.0, 20.6, 125.9, 128.1, 128.2,
128.5, 129.8, 130.2, 132.9, 134.6, 137.7, 139.5, 139.6, 139.7, 140.2,
151.5, 151.7.
MS (70 eV): m/z (%) = 265 [M]+, 218 (100), 178, 151, 117, 90, 76.
MS (70 eV): m/z (%) = 310 [M]+ (100), 295, 233, 206, 165, 103, 77.
Synthesis 2011, No. 3, 387–396 © Thieme Stuttgart · New York