HETEROCYCLES, Vol. 75, No. 1, 2008
51
(DMSO-d6): δ 21.29 (CH3), 23.87, 24.16, 31.47, 31.73, 115.00, 117.02, 128.94, 129.31, 129.83, 130.69,
145.31. Anal. Calcd for C13H17N: C, 83.37; H, 9.15; N, 7.48. Found: C, 83.57; H, 8.93; N, 7.52.
5a-Methyl-5,5a,6,7,8,9,10,10a-octahydrocyclohepta[b]indole (5b and 6b). To a solution of 3b (0.35 g,
.
1.7 mmol) in sulfolane (13 mL) was added BF3 OEt2 (0.22 mL, 1.7 mmol) and the resultant mixture was
stirred at 160-170 oC for 40 min under Ar. After cooling, water (15 L) was added and the reaction mixture
was extracted with chloroform. The organic layer was dried (MgSO4), concentrated in vacuo, and the
sulfolane was removed by column chromatography using hexane/EtOAc (9:1) as eluent. The crude
product was purified by preparative thin layer chromatography to yield 5b (93 mg, 27 %), 6b (31 mg,
9 %), and 7b (30 mg, 9 %).
Compound 5b: colorless semisolid. TLC (hexane/EtOAc 9:1): Rf = 0.51. 1H NMR ( CDCl3): δ 1.27 (s, 3H,
CH3), 1.38 (m, 1H, C7-H), 1.40 (m, 1H, C8-H), 1.42 (m, 1H, C9-H), 1.63 (m, 1H, C8-H), 1.70 (m, 1H,
C7-H), 1.74 (m, 1H, C6-H), 1.76 (m, 2H, C9-H and C10-H), 1.80 (m, 2H, C6-H and C10-H), 2.95 (dd, J = 8
and 2 Hz, 1H, C10a-H), 3.1 (br.s, 1H, NH), 6.53 (d, J = 7.8 Hz, 1H, C4-H), 6.68 (t, J = 7.4 Hz, 1H, C2-H),
13
7.00 (t, J = 7.4 Hz, 1H, C3-H), 7.01 (d, J =7.4 Hz, 1H, C1-H). C NMR (CDCl3): δ 24.65 (C-7), 28.50
(C-9), 30.81 (CH3), 31.37 (C-8), 32.33 (C-10), 40.39 (C-6), 53.96 (C-10a), 65.94 (C-5a), 108.75 (C-4),
118.07 (C-2), 124.64 (C-1), 127.38 (C-3), 133.28 (C-10b), 149.08 (C-4a). Anal. Calcd for C14H19N: C,
83.53; H, 9.51; N, 6.96. Found: C, 83.36; H, 9.27; N, 7.05.
Compound 6b: colorless semisolid. TLC (hexane/EtOAc 9:1): Rf = 0.42. 1H NMR ( CDCl3): δ 1.12 (s, 3H,
CH3), 1.37 (m,1H, C7-H), 1.52 (m, 1H, C8-H), 1.55 (m, 1H, C9-H), 1.63 (m, 1H, C10-H), 1.75 (m, 1H,
C8-H), 1.80 (m, 1H, C6-H), 1.91 (m, 2H, C6-H and C7-H), 2.00 (m, 2H, C9-H), 2.25 (m, 1H, C10-H),
3.19 (dd, J = 12.5 and 5.5 Hz, 1H, C10a-H), 3.3 (br.s, 1H, NH), 6.55 (d, J = 7.6 Hz, 1H, C4-H), 6.70(t, J =
13
7.5Hz, 1H, C2-H), 6.95 (t, J = 7.5 Hz, 1H, C3-H), 6.98 (d, J = 8 Hz, 1H, C1-H). C NMR (CDCl3): δ
20.48 (CH3), 23.55 (C-10), 25.76 (C-8), 26.05 (C-9), 27.49 (C-7), 42.58 (C-6), 48.12 (C-10a), 69.38
(C-5a), 109.02 (C-4), 118.37 (C-2), 122.75 (C-1), 126.90 (C-3), 133.32 (C-10b), 149.76 (C-4a). Anal.
Calcd for C14H19N: C, 83.53; H, 9.51; N, 6.96. Found: C, 83.42; H, 9.32; N, 6.68.
Compound 7b: yellow oil. TLC hexane/EtOAc 9:1): Rf = 0.47. 1H NMR (CDCl3): δ 1.55 (m, 1H, CH2),
1.56 (s, 3H, CH3), 1.60 (m, 3H, CH3), 1.77 (m, 1H, CH2), 1.85 (m, 1H, CH2), 2.22 (m, 1H, CH2), 2.32 (m,
1H, CH2), 2.34 (m, 1H, CH2), 2.42 (m, 1H, CH2), 3.60 (br.s, 2H, NH2), 6.68 (d, J = 8.3 Hz, 1H, ArH),
6.71 (t-d, J = 7.5 and 1 Hz, 1H, ArH), 6.90 (dd, J = 7.5 and 1 Hz, 1H, ArH, 7.02 (t-d, J = 7.5 and 1.5 Hz,
13
1H, ArH). C NMR (CDCl3): δ 22.63(CH3), 26.36, 27.39, 32.48, 35.09, 35.39, 114.93, 118.30, 127.03,
128.77, 131.95, 134.60, 138.15, 142.58. Anal. Calcd for C14H19N: C, 83.53; H, 9.51; N, 6.96. Found: C,
83.72; H, 9.39; N, 7.16.