HETEROCYCLES, Vol. 88, No. 1, 2014
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CH2Cl2–hexane (1:1, v/v) to give 31 (147.7 mg, 87%). 31: mp 125—135 °C (decomp., pale yellow
needles, recrystallized from CH2Cl2–hexane). IR (KBr): 3390, 1535, 1440, 1419, 1375, 1339, 1112, 758
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cm-1. H-NMR (CDCl3) ": 3.39 (1H, dd, J=15.3, 8.3 Hz), 3.42 (1H, dd, J=15.8, 5.5 Hz), 3.52 (1H, dd,
J=15.6, 4.6 Hz), 3.59 (1H, ddd, J=15.8, 8.3, 0.9 Hz), 4.96–5.03 (1H, m), 6.90–6.94 (1H, m), 7.13–7.17
(2H, m), 7.99 (1H, br s). MS m/z: 282, 280 (M+). Anal. Calcd for C11H9BrN2O2: C, 47.00; H, 3.23; N, 9.97.
Found: C, 46.72; H, 3.30; N, 9.73.
2,6-Dibromo- (32), 2,8-Dibromo- (33), 2,7-Dibromo-4-nitro-1,3,4,5-tetrahydrobenz[cd]indole (34)
from 31 — NBS (1.614 g, 9.07 mmol) and AIBN (270.7 mg, 4.22 mmol) were added to a solution of 31
(2.298 g, 8.18 mmol) in dry CHCl3 (800 mL) and the mixture was heated at reflux for 1 h with stirring.
After cooling, the whole was irradiated with 100W mercury lamp in quartz bottle for 30 min under Ar
atmosphere. After evaporation of the solvent under reduced pressure, the residue was purified repeatedly
by column-chromatography on SiO2 and HPLC (SiO2, 15 Kgf/cm2, 1.5 mL/min). In the order of elution,
33 (58.7 mg, 2%), 34 (403.8 mg, 14%), unreacted 31 (205.8 mg, 9%), and 32 (1.066 g, 36%) were
obtained. 32: mp 164—167 °C (decomp., yellow needles, recrystallized from nitro CH2Cl2–hexane). IR
(KBr): 3400, 1539, 1440, 1375, 1311, 788 cm-1. 1H-NMR (CDCl3) ": 3.38 (2H, m), 3.52 (1H, dd, J=15.5,
8.6 Hz), 3.58 (1H, dd, J=15.5, 4.9 Hz), 4.98–5.04 (1H, m), 7.04 (1H, d, J=8.6 Hz), 7.30 (1H, d, J=8.6 Hz),
8.04 (1H, br s). MS m/z: 362, 360, 358 (M+). Anal. Calcd for C11H8Br2N2O2: C, 36.70; H, 2.24; N, 7.78.
Found: C, 36.60; H, 2.08; N, 7.73. 33: mp 194—196 °C (decomp., pale yellow needles, recrystallized
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from CH2Cl2–hexane). IR (KBr): 3330, 1544, 1433, 1373, 1363, 1323, 800 cm-1. H-NMR (CDCl3) ":
3.38 (1H, dd, J=16.1, 5.7 Hz), 3.42 (1H, dd, J=15.7, 7.9 Hz), 3.48 (1H, dd, J=16.1, 4.3 Hz), 3.56 (1H, dd,
J=15.7, 8.4 Hz), 4.95–5.04 (1H, m), 6.83 (1H, d, J=7.7 Hz), 7.27 (1H, d, J=7.7 Hz), 8.10 (1H, br s). MS
m/z: 362, 360, 358 (M+). Anal. Calcd for C11H8Br2N2O2: C, 36.70; H, 2.24; N, 7.78. Found: C, 36.74; H,
2.11; N, 7.74. 34: mp 130—134 °C (decomp., pale yellow needles, recrystallized from CH2Cl2–hexane).
IR (KBr): 3400, 1621, 1542, 1438, 1370, 1320, 1063, 840 cm-1. 1H-NMR (CDCl3) ": 3.38 (1H, dd, J=16.3,
5.5 Hz), 3.42 (1H, dd, J=16.1, 8.8 Hz), 3.47 (1H, dd, J=16.3, 5.5 Hz), 3.58 (1H, dd, J=16.1, 8.8 Hz),
4.95–5.02 (1H, m), 7.08 (1H, d, J=1.1 Hz), 7.32 (1H, d, J=1.1 Hz), 8.02 (1H, br s). MS m/z: 362, 360, 358
(M+). Anal. Calcd for C11H8Br2N2O2: C, 36.70; H, 2.24; N, 7.78. Found: C, 36.70; H, 2.24; N, 7.76.
1-Acetyl-2,6-Dibromo-4-nitro-1,3,4,5-tetrahydrobenz[cd]indole (35) from 32 — Ac2O (0.5 mL) was
added to a solution of 32 (122.1 mg, 0.34 mmol) in pyridine (1 mL) and the whole was stirred at rt for 24
h. After addition of sat. aq. NH4Cl, the whole was extracted with CH2Cl2. The extract was washed with
brine, dried over Na2SO4, and evaporated under reduced pressure to leave an oil, which was subjected to
column-chromatography on SiO2 with acetone–hexane (1:5, v/v) as an eluent to give 35 (83.9 mg, 62%).
35: mp 145–147 °C (decomp., pale orange prisms, recrystallized from CH2Cl2–hexane). IR (KBr): 1705,
1540, 1435, 1368, 1290 cm-1. 1H-NMR (CDCl3) ": 2.85 (3H, s), 3.32 (1H, dd, J=16.1, 5.0 Hz), 3.39 (1H,