September 2011
One-Pot-One-Step, Microwave-Assisted Fischer Indole Synthesis
1101
Table 5
Reaction of phenylhydrazines 1a–d and isobutyrophenone 2g.
125.5 (d), 126.5 (d), 135.0 (s), 135.7 (s), 144.1 (s), 147.7 (s),
154.5 (s).
8-Methoxy-6,11-dihydro-5H-benzo[a]carbazole (6f). Pale
orange needles from hexane/benzene: m.p. 166ꢀC (lit.[40] m.p.
Entries
1
Power (W) Time (min) Product Yielda (%)
1
167–168ꢀC); IR (KBr): 3400 cmꢂ1 (NAH); H NMR (CDCl3):
1b
2b
3b
4c
1a
1b
1c
1d
600
80
3
7
7
4
3g
4g
5g
6g
54
78
75
69
d 2.92–2.97 (m, 2H), 3.03–3.07 (m, 2H), 3.86 (s, 3H), 6.84
(dd, J ¼ 7.5 Hz, 1.5 Hz, 1H), 6.99 (d, J ¼ 1.5 Hz, 1H), 7.18
(dd, J ¼ 7.5 Hz, 7.5 Hz, 1H), 7.22–7.29 (m, 3H), 7.31 (d, J ¼
7.5 Hz, 1H), 8.08 (br s, 1H); 13C NMR (CDCl3): d 19.7 (t),
29.5 (t), 55.9 (q), 100.6 (d), 111.8 (d), 112.3 (s), 112.4 (d),
119.7 (d), 126.5 (d), 126.6 (d), 127.8 (s), 128.4 (d), 128.9 (s),
132.1 (s), 133.9 (s), 136.4 (s), 154.3 (s).
80
80
a Isolated yield.
b 2: 2.0 mmol.
c 2: 3.0 mmol.
5-Methoxy-3,3-dimethyl-2-phenyl-3H-indole (6g). Orange
liquid [41]: IR (neat): 2956 cmꢂ1 (CAH); 1H NMR (CDCl3):
d 1.58 (s, 6H), 3.87 (s, 3H), 6.86–6.92 (m, 2H), 7.43–7.51 (m,
3H), 7.60 (d, J ¼ 7.5 Hz, 1H), 8.11 (dd, J ¼ 7.5 Hz, 7.5 Hz,
2H); 13C NMR (CDCl3): d 24.8 (q), 53.7 (s), 55.7 (q), 107.5
(d), 112.4 (d), 121.2 (d), 127.9 (d), 128.5 (d), 130.1 (d), 133.4
(s), 146.8 (s), 149.3 (s), 158.5 (s), 181.2 (s).
7.5 Hz, 1H), 8.12 (dd, J ¼ 7.5 Hz, 7.5 Hz, 2H); 13C NMR
(CDCl3): d 24.6 (q), 53.9 (s), 121.7 (d), 127.9 (d), 128.2 (s),
128.3 (d), 128.6 (d), 130.7 (d), 131.5 (d), 132.9 (s), 149.3 (s),
151.6 (s), 183.5 (s).
5-Methoxy-3-methyl-2-phenylindole (6a). Colorless crystals
from hexane: m.p. 114–116ꢀC (lit.[10,37] m.p. 116ꢀC); IR
Acknowledgments. ECC thanks the Japan Society for the Pro-
motion of Science (JSPS) for the research grant at Niigata Univer-
sity, Japan.
1
(KBr): 3408 cmꢂ1 (NAH); H NMR (CDCl3): d 2.44 (s, 3H),
3.89 (s, 3H), 6.87 (dd, J ¼ 7.5 Hz, 1.5 Hz, 1H), 7.04 (d, J ¼
1.5 Hz, 1H), 7.26 (d, J ¼ 7.5 Hz, 1H), 7.34 (t, J ¼ 7.5 Hz,
1H), 7.47 (dd, J ¼ 7.5 Hz, 7.5 Hz, 2H), 7.57 (d, J ¼ 7.5 Hz,
2H), 7.90 (br s, 1H); 13C NMR (CDCl3): d 9.7 (q), 55.9 (q),
100.8 (d), 108.4 (s), 111.5 (d), 112.4 (d), 127.2 (d), 127.6 (d),
128.7 (d), 130.4 (s), 131.0 (s), 133.3 (s), 135.0 (s), 154.1 (s).
5-Methoxy-2,3-diphenylindole (6b). Orange crystals from
hexane: m.p. 155ꢀC (lit.[38] m.p. 155ꢀC); IR (KBr): 3404
REFERENCES AND NOTES
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1
cmꢂ1 (NAH); H NMR (CDCl3): d 3.82 (s, 3H), 6.90 (dd, J ¼
7.5 Hz, 1.5 Hz, 1H), 7.12 (d, J ¼ 1.5 Hz, 1H), 7.26–7.34 (m,
5H), 7.36–7.45 (m, 6H), 8.12 (br s, 1H); 13C NMR (CDCl3): d
55.9 (q), 101.2 (d), 111.7 (d), 113.0 (d), 114.9 (s), 126.2 (d),
127.6 (d), 128.0 (d), 128.5 (d), 128.6 (d), 129.2 (s), 130.1 (d),
131.0 (s), 132.7 (s), 134.9 (s), 135.2 (s), 154.8 (s).
[3] (a) Shiri, M.; Zolfigol, M. A.; Kruger, H. G.; Tanbakou-
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mun 2009, 104.
2-(20-Hydroxyphenyl)-5-methoxy-3-methylindole (6c). Brown-
ish liquid: IR (neat): 3328 cmꢂ1 (OAH); 1H NMR (CDCl3): d
2.28 (s, 3H), 3.88 (s, 3H), 5.68 (br s, 1H), 7.07 (dd, J ¼ 7.5 Hz,
1.5 Hz, 1H), 6.98–7.02 (m, 2H), 7.04 (d, J ¼ 1.5 Hz, 1H), 7.24
(d, J ¼ 7.5 Hz, 1H), 7.29 (dd, J ¼ 7.5 Hz, 7.5 Hz, 1H), 7.35 (d, J
¼ 7.5 Hz, 1H), 7.99 (br s, 1H); 13C NMR (CDCl3): d 9.4 (q),
55.9 (q), 108.4 (d), 110.1 (s), 111.7 (d), 112.6 (d), 112.7 (s), 115.8
(d), 119.3 (s), 120.5 (d), 129.8 (d), 130.3 (d), 130.4 (s), 131.6 (s),
153.3 (s), 154.1 (s).
[4] (a) Gribble, G. W. J Chem Soc Perkin Trans 1 2000, 1045;
(b) Treu, M.; Karner, T.; Kousek, R.; Berger, H.; Mayer, M.;
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A.; Sato, K.; Nonoyama, N.; Mase, T.; Yasuda, N. Tetrahedron Lett
2006, 47, 969.
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(b) Gilchrist, T. L. J Chem Soc Perkin Trans 1 1999, 2849; (c) Gil-
christ, T. L. J Chem Soc Perkin Trans 1 1998, 615.
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Markina, N. A.; Larock, R. C. Tetrahedron 2009, 65, 8908; (c) Bogdal,
D.; Bednarz, S.; Lukasiewicz, M. Tetrahedron 2006, 62, 9440.
6-Methoxy-1,2,3,4-tetrahydrocarbazole (6d). Pale orange
crystals from hexane: m.p. 95–97ꢀC (lit.[39] m.p. 96–97ꢀC);
IR (KBr): 3388 cmꢂ1 (NAH); 1H NMR (CDCl3) [21]: d
1.84–1.93 (m, 4H), 2.65–2.73 (m, 4H), 3.85 (s, 3H), 6.76
(dd, J ¼ 7.5 Hz, 1.5 Hz, 1H), 6.92 (d, J ¼ 1.5 Hz, 1H), 7.15
(d, J ¼ 7.5 Hz, 1H), 7.55 (br s, 1H) NH; 13C NMR
(CDCl3): d 20.9 (t), 20.9 (t), 23.2 (t), 23.3 (t), 55.9 (q),
100.2 (d), 109.9 (s), 110.4 (d), 110.9 (d), 128.1 (s), 130.7
(s), 135.1 (s), 153.8 (s).
´
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8-Methoxy-5,10-dihydroindeno[1,2-b]indole (6e). Colorless
crystals from benzene: m.p. 208ꢀC (lit.[32] m.p. 207ꢀC); IR
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1
(KBr): 3404 cmꢂ1 (NAH); H NMR (CDCl3): d 3.70 (s, 2H),
3.88 (s, 3H), 6.84 (dd, J ¼ 7.5 Hz, 1.5 Hz, 1H), 7.09 (d, J ¼
1.5 Hz, 1H), 7.21 (dd, J ¼ 7.5 Hz, 7.5 Hz, 1H), 7.28–7.34 (m,
2H), 7.44 (d, J ¼ 7.5 Hz, 1H), 7.53 (d, J ¼ 7.5 Hz, 1H), 8.17
(br s, 1H); 13C NMR (CDCl3): d 30.3 (t), 55.8 (q), 101.1 (d),
111.5 (d), 112.6 (d), 117.3 (d), 121.5 (s), 124.8 (d), 125.1 (s),
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Kaessler, A.; Apcin, Y.; Yilmaz, A.; Jose, J. Molecules 2008, 13, 736.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet