K. Kobayashi et al. / Tetrahedron 62 (2006) 3158–3161
3161
(6H, d, JZ6.6 Hz), 2.85–3.0 (2H, m), 5.02 (1H, s), 6.13
(1H, dt, JZ3.3, 1.3 Hz), 6.34 (1H, dd, JZ3.3, 2.7 Hz), 7.0–
7.15 (2H, m), 7.17 (1H, d, JZ7.3 Hz), 7.27 (1H, t, JZ
7.3 Hz), 7.41 (1H, d, JZ7.3 Hz); MS m/z 254 (MC, 7.8),
154 (100). Calcd for C17H22N2: C, 80.27; H, 8.72; N, 11.01.
Found: C, 80.15; H, 9.00; N, 11.01.
(pyrrol-1-yl)benzaldehyde (1b) (0.23 g, 1.0 mmol) in
CH2Cl2 (1 mL). The mixture was stirred at the same
temperature for 36 h. Work-up and purification were carried
out in a manner similar to those described for the
preparation of 3a to afford 3h (0.20 g, 68%) as a pale-
yellow solid; mp 160–161 8C (hexane–Et2O); IR (KBr disk)
1
1620 cmK1; H NMR d 1.35–1.45 (2H, m), 1.5–1.65 (4H,
3.4.3. 9-Morpholino-9H-pyrrolo[1,2-a]indole (3e). A
pale-yellow solid; mp 138–140 8C (hexane–Et2O); IR
m), 2.4–2.5 (4H, m), 3.91 (3H, s), 3.94 (3H, s), 4.81 (1H, s),
6.18 (1H, dt, JZ3.3, 1.0 Hz), 6.31 (1H, dd, JZ3.3, 2.6 Hz),
6.78 (1H, s), 6.98 (1H, d, JZ2.6 Hz), 7.12 (1H, s); 13C
NMR d 24.45, 26.16, 49.70, 56.30, 56.67, 64.85, 94.70,
105.39, 109.91, 110.28, 111.96, 127.08, 134.70, 135.43,
145.71, 149.46; MS m/z 298 (MC, 25), 214 (100). Calcd for
C18H22N2O2: C, 72.46; H, 7.43; N, 9.39. Found: C, 72.38;
H, 7.58; N, 9.35.
(KBr disk) 1616 cmK1 1H NMR d 2.51 (4H, t, JZ
;
5.6 Hz), 3.68 (4H, t, JZ5.6 Hz), 4.89 (1H, s), 6.23 (1H, ddd,
JZ3.3, 1.3, 1.0 Hz), 6.35 (1H, dd, JZ3.3, 3.0 Hz), 7.05
(1H, dt, JZ3.0, 1.0 Hz), 7.10 (1H, td, JZ7.6, 1.0 Hz), 7.18
(1H, d JZ7.6 Hz), 7.31 (1H, td, JZ7.6, 1.0 Hz), 7.51 (1H,
d, JZ7.6 Hz); MS m/z 240 (MC, 13), 154 (100). Calcd for
C15H16N2O: C, 74.97; H, 6.71; N, 11.66. Found: C, 75.23;
H, 6.63; N, 11.53.
Acknowledgements
3.5. Typical procedure for the preparation of 3 (Method
A at 0 8C)
Determination of MS spectra and performance of combus-
tion analyses by Mrs. Miyuki Tanmatsu of this Department
are gratefully acknowledged. This research was partially
supported by a Grant-in-Aid for Scientific Research (C)
15550092 from Japan Society for the Promotion of Science.
3.5.1. 9-Dimethylamino-6,7-dimethoxy-9H-pyrrolo[1,2-
a]indole (3f). To a stirred mixture of NaI (0.33 g,
2.2 mmol), dimethylamine hydrochloride (81 mg,
0.99 mmol), Et3N (0.20 g, 2.0 mmol), and Me3SiCl
(0.24 g, 2.2 mmol) in acetonitrile (2.2 mL) at 0 8C was
added a solution of 4,5-dimethoxy-2-(pyrrol-1-yl)benzal-
dehyde (1b) (0.22 g, 0.95 mmol) in CH2Cl2 (1 mL). The
mixture was stirred at the same temperature for 2 days.
Work-up and purification were carried out in a manner
similar to those described for the preparation of 3a to afford
3f (0.20 g, 82%) as a pale-yellow solid; mp 157–158 8C
(hexane–Et2O); IR (KBr disk) 1622 cmK1; 1H NMR d 2.22
(6H, s), 3.90 (3H, s), 3.95 (3H, s), 4.84 (1H, s), 6.21 (1H,
ddd, JZ3.3, 1.3, 1.0 Hz), 6.32 (1H, dd, JZ3.3, 2.6 Hz),
6.80 (1H, s), 7.00 (1H, d, JZ2.6 Hz), 7.09 (1H, s); 13C
NMR d 40.70, 56.29, 56.53, 64.33, 94.79, 105.52, 109.88,
110.19, 112.09, 127.00, 134.39, 134.58, 145.81, 149.58; MS
m/z 258 (MC, 28), 214 (100). Calcd for C15H18N2O2: C,
69.74; H, 7.02; N, 10.84. Found: C, 69.52; H, 7.01; N, 11.01.
References and notes
1. Arend, M.; Risch, N. Synlett 1997, 974–976.
2. Kobayashi, K.; Nakahashi, R.; Takanohashi, A.; Kitamura, T.;
Morikawa, O.; Konishi, H. Chem. Lett. 2002, 624–625.
3. Garofalo, A.; Ragno, G.; Campiani, G.; Brizzi, A.; Nacci, V.
Tetrahedron 2000, 56, 9351–9355.
4. For previous syntheses of 9H-pyrrolo[1,2-a]indole derivatives:
(a) Defoin, A.; Fritz, H.; Geffroy, G.; Streith, J. Tetrahedron
Lett. 1986, 27, 3135–3138. (b) Padwa, A.; Fryxell, G. E.;
Gasdaska, J. R.; Venkatramanan, M. K.; Wong, G. S. K. J. Org.
Chem. 1989, 54, 644–653. (c) Kojima, H.; Ozaki, K.;
Matsumura, N.; Inoue, H. Chem. Lett. 1989, 1499–1500. (d)
Flitsch, W.; Lauterwein, J.; Micke, W. Tetrahedron Lett. 1989,
30, 1633–1636. (e) Brechert, S.; Wirth, T. Tetrahedron Lett.
1991, 32, 7237–7240. (f) Letcher, R. M.; Sin, D. W. M.;
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(g) Caddick, S.; Aboutayah, K.; West, R. L. J. Chem. Soc.,
Perkin Trans. 1 1996, 675–682. (h) Yavari, I.; Adib, M.; Sayahi,
M. H. J. Chem. Soc., Perkin Trans. 1 2002, 1517–1519.
3.5.2. 9-Diethylamino-6,7-dimethoxy-9H-pyrrolo[1,2-
a]indole (3g). A pale-yellow solid; mp 106–107 8C
(hexane–Et2O); IR (KBr disk) 1620 cmK1 1H NMR d
;
1.08 (6H, t, JZ7.3 Hz), 2.35–2.6 (4H, m), 3.91 (3H, s), 3.95
(3H, s), 5.02 (1H, s), 6.15 (1H, ddd, JZ3.3, 1.3, 1.0 Hz),
6.30 (1H, t, JZ3.0 Hz), 6.80 (1H, s), 6.99 (1H, d, JZ
2.6 Hz), 7.08 (1H, s); 13C NMR d 13.88, 44.92, 56.28, 56.59,
60.12, 94.73, 104.75, 109.79, 109.95, 112.07, 128.25,
134.56, 136.03, 145.76, 149.39; MS m/z 286 (MC, 17),
214 (100). Calcd for C17H22N2O2: C, 71.30; H, 7.74; N,
9.78. Found: C, 71.11; H, 7.76; N, 9.73.
´
5. Foggasy, K.; Kovacs, K.; Keseru, G. N.; To˜ke, L.; Faigl, F.
J. Chem. Soc., Perkin Trans. 1 2001, 1039–1043 and pertinent
references cited therein.
´
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J. C.; Robba, M.; Quermonne, M. A.; Nammathao, B.;
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939–946.
3.5.3. 6,7-Dimethoxy-9-piperidino-9H-pyrrolo[1,2-
a]indole (3h) (Method B at 0 8C). To a stirred mixture of
NaI (0.35 g, 2.3 mmol), piperidine (90 mg, 1.1 mmol), Et3N
(0.11 g, 1.1 mmol), triethylamine hydrochloride (0.15 g,
1.1 mmol), and Me3SiCl (0.26 g, 2.4 mmol) in acetonitrile
(2.3 mL) at 0 8C was added a solution of 4,5-dimethoxy-2-
7. Josey, A. D.; Jenner, E. L. J. Org. Chem. 1962, 27, 2416–2470.
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