Base-Induced One-Pot Preparation of N- or P-Substituted Alkynes
1H NMR (400 MHz, CDCl3): δ = 8.07 (s, 1 H), 7.84 (dd, J = 5.9, 2-(4-Methylphenyl)-1-(2-phenylethynyl)-1H-benzimidazole (2q):
2.9 Hz, 1 H), 7.77 (dd, J = 8.7, 3.0 Hz, 2 H), 7.70 (d, J = 1.1 Hz,
1 H), 7.67 (dd, J = 6.1, 2.9 Hz, 1 H), 7.64–7.58 (m, 2 H), 7.43–7.35
(m, 2 H), 7.21 (dd, J = 8.9, 2.5 Hz, 1 H), 7.15 (d, J = 2.3 Hz, 1 H),
6.62 (dd, J = 3.5, 1.7 Hz, 1 H), 3.95 (s, 3 H) ppm. 13C NMR
Yield 131 mg (85 %); off-white solid; m.p. 80–81 °C. 1H NMR
(400 MHz, [D6]DMSO): δ = 8.12 (d, J = 8.0 Hz, 2 H), 7.78 (d, J
= 7.6 Hz, 1 H), 7.72 (d, J = 7.7 Hz, 1 H), 7.64–7.57 (m, 2 H), 7.47–
7.35 (m, 7 H), 2.37 (s, 3 H) ppm. 13C NMR (100 MHz, [D6]-
(100 MHz, CDCl3): δ = 158.8, 145.1, 144.7, 143.8, 142.2, 135.9, DMSO): δ = 152.2, 141.7, 141.0, 136.0, 131.3, 129.4, 129.2, 128.9,
134.7, 132.0, 129.5, 129.0, 128.6, 127.3, 124.7, 124.6, 120.6, 119.9, 128.4, 125.6, 124.6, 124.5, 120.9, 119.9, 111.1, 77.6, 75.2, 21.1 ppm.
116.2, 113.3, 112.1, 111.0, 106.0, 77.4, 76.5, 55.5 ppm. IR (neat): ν IR (neat): ν = 3035, 2910, 2257, 1716, 1697, 1683, 1652, 1647, 1558,
˜
˜
= 3056, 2937, 2248, 1629, 1602, 1515, 1489, 1456, 1436, 1391, 1314,
1541, 1507, 1489, 1521, 1473, 1456, 1397, 741, 689 cm–1. MS (EI):
1266, 1256, 1222, 1202, 1118, 1029, 1018, 925, 885, 852, 757, m/z (%) = 89.1 (3), 91.1 (2), 190.1 (6), 293.1 (35), 308.2 (100) [M+].
741 cm–1. MS (EI): m/z (%) = 76.1 (6), 126.1 (7), 182.1 (11), 267.1 HRMS (EI): m/z calcd. for [C22H16N2]+ 308.1313; found 308.1308.
(4), 292.1 (47), 305.1 (13), 321.1 (37), 335.1 (33), 349.1 (18), 364.1
2-(4-Methoxyphenyl)-1-(phenylethynyl)-1H-benzimidazole (2r):
Yield 141 mg (87%); off-white solid; m.p. 100–101 °C. 1H NMR
(400 MHz, [D6]DMSO): δ = 8.23 (d, J = 7.8 Hz, 2 H), 7.75 (dd, J
= 16.9, 7.6 Hz, 2 H), 7.67–7.60 (m, 2 H), 7.46 (s, 3 H), 7.40 (dd, J
= 15.4, 7.8 Hz, 2 H), 7.17 (d, J = 7.8 Hz, 2 H), 3.85 (s, 3 H) ppm.
13C NMR (100 MHz, [D6]DMSO): δ = 161.4, 152.0, 141.7, 136.0,
131.3, 130.1, 129.1, 128.9, 124.5, 124.3, 120.9, 120.6, 119.7, 114.3,
(100) [M+]. HRMS (EI): m/z calcd. for [C24H16O2N2]+ 364.1212;
found 364.1206.
2-(2-Furanyl)-1-(2-thiophenylethynyl)-1H-benzimidazole (2m): Yield
122 mg (84 %); off-white solid; m.p. 123–124 °C. 1H NMR
(400 MHz, CDCl3): δ = 7.82 (dd, J = 6.1, 3.0 Hz, 1 H), 7.67 (d, J
= 1.5 Hz, 1 H), 7.60 (dd, J = 6.2, 3.0 Hz, 1 H), 7.49 (d, J = 3.5 Hz,
1 H), 7.45–7.41 (m, 2 H), 7.41–7.34 (m, 2 H), 7.11–7.07 (m, 1 H),
6.60 (dd, J = 3.4, 1.6 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 145.2, 144.8, 143.6, 142.1, 135.8, 133.9, 129.1, 127.5, 124.8,
124.8, 121.3, 120.6, 113.5, 112.1, 111.0, 80.5, 69.6 ppm. IR (neat):
111.0, 77.7, 75.2, 55.5 ppm. IR (neat): ν = 2931, 2829, 2256, 1716,
˜
1683, 1653, 1647, 1558, 1541, 1521, 1507, 1473, 1456, 1418, 1398,
1254, 1175, 756, 742 cm–1. MS (EI): m/z (%) = 77 (6), 89 (3), 140
(13), 164 (10), 224 (2), 281 (59), 293 (17), 309 (36), 324 (100) [M+].
HRMS (EI): m/z calcd. for [C22H16ON2]+ 324.1263; found
324.1257.
ν = 3103, 2248, 1621, 1516, 1458, 1444, 1399, 1386, 1314, 1312,
˜
1255, 1229, 1174, 1124, 1106, 1016, 927, 852, 758, 741, 705,
591 cm–1. MS (EI): m/z (%) = 76 (11), 196 (5), 207 (4), 236 (6), 261
(97), 290 (100) [M+]. HRMS (EI): m/z calcd. for [C17H10ON2S]+
290.0514; found 290.0508.
2-(3,4-Methylenedioxyphenyl)-1-(phenylethynyl)-1H-benzimidazole
(2s): Yield 139 mg (82 %); off-white solid; m.p. 117–118 °C. 1H
NMR (400 MHz, [D6]DMSO): δ = 7.84 (d, J = 7.6 Hz, 1 H), 7.76
(d, J = 7.5 Hz, 1 H), 7.72 (d, J = 7.3 Hz, 2 H), 7.62 (s, 2 H), 7.46
(d, J = 2.0 Hz, 3 H), 7.43–7.35 (m, 2 H), 7.16 (d, J = 8.1 Hz, 1 H),
6.15 (s, 2 H) ppm. 13C NMR (100 MHz, [D6]DMSO): δ = 151.8,
149.6, 147.7, 141.5, 136.0, 131.3, 129.2, 128.9, 124.52, 124.48,
123.3, 122.0, 120.8, 119.8, 111.1, 108.6, 108.3, 101.9, 77.6,
2-(2-Furanyl)-1-(3,3-dimethyl-1-butyn-1-yl)-1H-benzimidazole (2n):
Yield 112 mg (85 %); off-white solid; m.p. 92–94 °C. 1H NMR
(400 MHz, CDCl3): δ = 7.78 (dd, J = 6.3, 2.7 Hz, 1 H), 7.65 (d, J
= 1.6 Hz, 1 H), 7.49 (dd, J = 5.2, 2.9 Hz, 2 H), 7.33–7.35 (m, 2 H),
6.60 (dd, J = 3.5, 1.7 Hz, 1 H), 1.44 (s, 9 H) ppm. 13C NMR
(100 MHz, CDCl3): δ = 144.8, 144.7, 144.0, 142.0, 136.1, 124.33,
124.31, 120.4, 112.8, 111.8, 110.7, 84.1, 68.1, 31.1, 28.0 ppm. IR
75.4 ppm. IR (neat): ν = 3056, 2898, 2256, 1540, 1521, 1506, 1498,
˜
1473, 1457, 1404, 1308, 1271, 1256, 1235, 1039, 989, 741 cm–1. MS
(EI): m/z (%) = 77 (7), 89 (3), 105 (5), 140 (18), 163 (6), 279 (63),
292 (2), 308 (31), 338 (100) [M+]. HRMS (EI): m/z calcd. for
[C22H14O2N2]+ 338.1055; found 338.1050.
(neat): ν = 2964, 2376, 1868, 1772, 1716, 1697, 1653, 1647, 1558,
˜
1541, 1521, 1516, 1507, 1473, 1457, 1436, 1418, 1339, 744 cm–1.
MS (EI): m/z (%) = 77 (11), 117 (53), 128 (3), 140 (8), 208 (29),
221 (22), 234(10), 249 (51), 264 (100) [M+]. HRMS (EI): m/z calcd.
for [C17H16ON2]+ 264.1263; found 264.1257.
2-(4-Chlorophenyl)-1-(2-phenylethynyl)-1H-benzimidazole (2t):
Yield 135 mg (82%); off-white solid; m.p. 106–107 °C. 1H NMR
(400 MHz, [D6]DMSO): δ = 8.26 (d, J = 7.4 Hz, 2 H), 7.80 (dd, J
= 14.9, 7.8 Hz, 2 H), 7.71 (d, J = 7.5 Hz, 2 H), 7.64 (d, J = 2.2 Hz,
2 H), 7.51–7.39 (m, 5 H) ppm. 13C NMR (100 MHz, [D6]DMSO):
δ = 151.0, 141.5, 136.1, 135.9, 131.3, 130.3, 129.3, 129.1, 128.9,
127.2, 125.0, 124.7, 120.7, 120.2, 111.3, 77.3, 75.6 ppm. IR (neat):
2-Isopropyl-1-(phenylethynyl)-1H-benzimidazole (2o): Yield 119 mg
1
(91%); colorless oil. H NMR (400 MHz, CDCl3): δ = 7.74 (dd, J
= 6.4, 2.4 Hz, 1 H), 7.62–7.53 (m, 3 H), 7.45–7.38 (m, 3 H), 7.36–
7.30 (m, 2 H), 3.06 (t, J = 7.5 Hz, 2 H), 2.00 (dd, J = 15.0, 7.5 Hz,
2 H), 1.10 (t, J = 7.4 Hz, 3 H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 157.0, 141.8, 135.5, 131.8, 129.7, 129.0, 128.7, 123.9, 123.8,
121.8, 119.8, 115.7, 110.7, 76.5, 76.0, 30.0, 20.9, 14.0 ppm. IR
ν = 2962, 2919, 2849, 2258, 1653, 1647, 1535, 1558, 1521, 1507,
˜
1473, 1456, 1417, 1410, 1260, 1092, 1015, 800, 731, 687 cm–1. MS
(EI): m/z (%) =75.1 (5), 89.1 (3), 102.1 (4), 190.1 (12), 293.1 (100),
328.1 (58) [M+]. HRMS (EI): m/z calcd. for [C21H13N2Cl]+
328.0767; found 328.0762.
(neat): ν = 3056, 2962, 2931, 2872, 2256, 1683, 1616, 1541, 1521,
˜
1507, 1457, 1409, 1247, 1202, 743, 690 cm–1. MS (EI): m/z (%) =
77.0 (34), 89.0 (30), 115.0 (33), 132.1 (100), 143.0 (39), 171.0 (55),
186.1 (26), 218.1 (28), 231.1 (43), 245.1 (55), 260.1 (52) [M+].
HRMS (EI): m/z calcd. for [C18H16N2]+ 260.1313; found 260.1308.
2-(4-Nitrophenyl)-1-(phenylethynyl)-1H-benzimidazole (2u): Yield
2-Phenyl-1-(phenylethynyl)-1H-benzimidazole (2p): Yield 119 mg 132 mg (78%); colorless oil. 1H NMR (400 MHz, CDCl3): δ = 8.54
1
(81%); off-white solid; m.p. 78–80 °C. H NMR (400 MHz, [D6]-
(d, J = 8.9 Hz, 2 H), 8.40 (d, J = 8.8 Hz, 2 H), 7.88 (d, J = 7.4 Hz,
1 H), 7.71 (d, J = 7.9 Hz, 1 H), 7.56 (dd, J = 6.6, 3.0 Hz, 2 H),
DMSO): δ = 8.23 (dd, J = 5.8, 2.2 Hz, 2 H), 7.81 (d, J = 7.6 Hz,
1 H), 7.74 (d, J = 7.8 Hz, 1 H), 7.63–7.57 (m, 5 H), 7.47–7.37 (m, 7.51–7.38 (m, 5 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 150.2,
5 H) ppm. 13C NMR (100 MHz, [D6]DMSO): δ = 152.1, 141.6,
136.1, 131.3, 131.0, 129.2, 128.92, 128.88, 128.5, 128.3, 124.8, 124.0, 121.1, 121.0, 111.5, 77.4, 76.6 ppm. IR (neat): ν = 2919,
148.9, 142.2, 137.0, 135.0, 131.8, 129.6, 129.5, 128.9, 125.6, 125.1,
˜
124.6, 120.8, 120.1, 111.2, 77.5, 75.3 ppm. IR (neat): ν = 3056,
2838, 2376, 1716, 1697, 1683, 1652, 1647, 1558, 1540, 1521, 1507,
1456, 855, 733 cm–1. MS (EI): m/z (%) = 77.1 (4), 89.1 (2), 118.1
(1), 190.1 (14), 215.1 (2), 292.2 (100), 309.2 (30), 322.2 (7), 339.2
(78) [M+]. HRMS (EI): m/z calcd. for [C21H13O2N3]+ 339.1008;
found 339.1002.
˜
2258, 1683, 1653, 1540, 1521, 1507, 1488, 1474, 1457, 1444, 1404,
1307, 1275, 1140, 757, 741, 689 cm–1. MS (EI): m/z (%) = 77.1 (4),
89.1 (3), 190.1 (11), 217.1 (4), 294.2 (100) [M+]. HRMS (EI): m/z
calcd. for [C21H14N2]+ 294.1157; found 294.1152.
Eur. J. Org. Chem. 2015, 7806–7815
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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