Lewis Acid Mediated Aminobenzannulation Reactions of δ-Ketoalkynes
3-Phenyl-1-thien-2-ylprop-2-yn-1-ol (9c):[34] Eluent for chromatog-
raphy: n-hexane/EtOAc, 95:5. Yield: 639 mg, 60%. Dark-yellow so-
90:10. Yield: 562 mg, 79%. Dark-yellow solid. M.p. 167–169 °C.
1
IR (KBr): ν = 2921, 1736, 1636, 1517 cm–1. H NMR (200 MHz,
˜
3
lid. M.p. 56–58 °C. IR (KBr): ν = 3436, 3099, 2228, 1630, CDCl3): δ = 2.72 (s, 3 H, CH3), 6.43 (s, 1 H, Csp3-H), 6.93 (dd, J
˜
1
1489 cm–1. H NMR (200 MHz, CDCl3): δ = 2.45 (d, J = 5.9 Hz, = 5.1, 3.7 Hz, 1 H, arom.), 7.08–7.49 (m, 10 H, arom.), 7.98 (d, 3J =
1 H, OH), 5.89 (d, J = 5.9 Hz, 1 H, Csp3-H), 6.99–7.03 (m, 1 H, 8.0 Hz, 1 H, arom.), 8.96 (s, 1 H, NH) ppm. 13C NMR (50.3 MHz,
arom.), 7.24–7.37 (m, 5 H, arom.), 7.45–7.52 (m, 2 H, arom.) ppm.
CDCl3): δ = 29.2 (CH3), 30.4 (Csp3-H), 83.9, 89.0 (CϵC), 112.4,
13C NMR (50.3 MHz, CDCl3): δ = 61.0 (Csp3-H), 86.3, 88.4 (CϵC), 121.0, 123.1, 124.9, 125.4, 126.7, 127.0, 128.5, 128.6, 131.9 (Csp2
-
125.9, 126.4, 127.1, 128.6, 129.1, 132.1 (Csp2-H), 122.4, 145.0 (quat.
H), 121.2, 123.3, 127.0, 131.4, 136.4, 144.9 (quat. Csp2), 190.7
Csp2) ppm. MS (ESI+): m/z (%) = 197 (100) [M – OH]+.
(C=O) ppm. MS (ESI–): m/z (%) = 354 (100) [M – H]–. C23H17NOS
(355.45): calcd. C 77.72, H 4.82, N 3.94; found C 77.48, H 4.65, N
3.60.
1-(4-Methoxyphenyl)-3-phenylprop-2-yn-1-ol (9d):[34,35] Eluent for
chromatography: n-hexane/EtOAc, 90:10. Yield: 1035 mg, 87%.
Yellow solid. M.p. 68–70 °C. IR (KBr): ν = 3379, 2962, 2229, 1883,
1-{3-[1-(4-Methoxyphenyl)-3-phenylprop-2-ynyl]-1H-indol-2-
yl}ethanone (5d): Reaction time: 2.5 h. Eluent for chromatography:
n-hexane/EtOAc, 90:10. Yield: 713 mg, 94 %. Yellow solid. M.p.
˜
1614, 1517 cm–1. 1H NMR (200 MHz, CDCl3): δ = 2.22 (d, J =
6.2 Hz, 1 H, OH), 3.83 (s, 3 H, OCH3), 5.65 (d, J = 6.2 Hz, 1 H,
C
sp3-H), 6.90–6.97 (m, 2 H, arom.), 7.29–7.36 (m, 3 H, arom.), 74–77 °C. IR (KBr): ν = 2928, 1888, 1650, 1508 cm–1. 1H NMR
˜
7.43–7.59 (m, 4 H, arom.) ppm. 13C NMR (50.3 MHz, CDCl3): δ
= 55.6 (OCH3), 64.9 (Csp3-H), 86.7, 89.3 (CϵC), 114.3, 128.5,
128.6, 128.8, 132.0 (Csp2-H), 122.8, 133.3, 159.9 (quat. Csp2) ppm.
MS (ESI+): m/z (%) = 239 (60) [M + H]+, 221 (100) [M – OH]+.
(200 MHz, CDCl3): δ = 2.68 (s, 3 H, CH3), 3.78 (s, 3 H, OCH3),
3
6.22 (s, 1 H, Csp
3
-H), 6.84 (d, J = 8.8 Hz, 2 H, arom.), 7.07 (m, 1
H, arom.), 7.26–7.48 (m, 7 H, arom.), 7.84 (d, 3J = 8.5 Hz, 1 H,
arom.), 8.96 (s, 1 H, NH) ppm. 13C NMR (50.3 MHz, CDCl3): δ
= 29.3 (CH3), 33.5 (Csp3-H), 55.5 (OCH3), 84.5, 90.0 (CϵC), 112.5,
114.2, 120.9, 123.3, 126.7, 128.4, 128.6, 128.8, 131.9 (Csp2-H),
122.2, 123.6, 127.3, 131.7, 132.5, 136.7, 158.8 (quat. Csp2), 191.1
(C=O) ppm. MS (ESI–): m/z (%) = 378 (100) [M – H]–. C26H21NO2
(379.45): calcd. C 82.30, H 5.58, N 3.69; found C 82.21, H 5.56, N
3.48.
1-(4-Methylphenyl)oct-2-yn-1-ol (9e): Eluent for chromatography:
n-hexane/EtOAc, 95:5. Yield: 799 mg, 74%. Pale-yellow oil. IR
(NaCl): ν = 3360, 2956, 2869, 1903 cm–1. 1H NMR (200 MHz,
˜
CDCl3): δ = 0.85–1.75 (m, 9 H, aliph.), 2.17–2.30 (m, 2 H, aliph.),
2.03 (d, J = 5.87 Hz, 1 H, OH), 2.36 (s, 3 H, CH3), 5.42 (d, J =
5.87 Hz, 1 H, Csp3-H), 7.13–7.23 (m, 2 H, arom.), 7.41–7.45 (m, 2
H, arom.) ppm. 13C NMR (50.3 MHz, CDCl3): δ = 14.3, 21.4
(CH3), 19.1, 22.5, 28.6, 31.4 (CH2), 64.8 (Csp3-H), 80.5, 87.6
(CϵC), 126.9, 129.4 (Csp2-H), 138.1, 138.8 (quat. Csp2) ppm. MS
(ESI+): m/z (%) = 217 (40) [M + H]+, 157 (50) [M – C4H9]+, 143
(100) [M – C5H11]+.
1-{3-[1-(4-Methylphenyl)oct-2-ynyl]-1H-indol-2-yl}ethanone (5e):
Reaction time: 20 h. Eluent for chromatography: n-hexane/EtOAc,
90:10. Yield: 479 mg, 67%. Dark-yellow oil. IR (KBr): ν = 2930,
˜
1905, 1651, 1512 cm–1. 1H NMR (200 MHz, CDCl3): δ = 0.80–0.83
(m, 5 H, aliph.), 1.31–1.41 (m, 4 H, aliph.), 2.22–2.27 (m, 2 H,
aliph.), 2.30 (s, 3 H, CH3), 2.63 (s, 3 H, CH3), 5.94 (s, 1 H, Csp3
-
3-Propargyl-2-acylindoles 5a–g are new compounds and were pre-
pared as reported in ref.[25] starting from 2 mmol of 8a,b.
H), 7.01–7.10 (m, 3 H, arom.), 7.28–7.38 (m, 4 H, arom.), 7.73–
7.77 (m, 1 H, arom.), 8.91 (s, 1 H, NH) ppm. 13C NMR (50.3 MHz,
CDCl3): δ = 14.3, 29.3, 21.2 (CH3), 19.2, 22.5, 28.8, 31.4 (CH2),
33.4 (Csp3-H), 79.9, 84.9 (CϵC), 112.3, 120.5, 123.4, 126.5, 127.5,
129.3 (Csp2-H), 122.8, 127.4, 131.8, 136.5, 136.6, 137.9 (quat. Csp2),
191.0 (C=O) ppm. MS (ESI+): m/z (%) = 358 (100) [M + H]+, 315
(20) [M – CH3C=O]+, 286 (50) [M – C5H11]+. C25H27NO (357.49):
calcd. C 83.99, H 7.61, N 3.92; found C 83.65, H 7.40, N 4.06.
1-{3-[1-(4-Methylphenyl)-3-phenylprop-2-ynyl]-1H-indol-2-yl}eth-
anone (5a): Reaction time: 2 h. Eluent for chromatography: n-hex-
ane/EtOAc, 90:10. Yield: 516 mg, 71%. Yellow solid. M.p. 166–
1
168 °C (decomp.). IR (KBr): ν = 2920, 2221, 1646, 1527 cm–1. H
˜
NMR (200 MHz, CDCl3): δ = 2.32 (s, 3 H, CH3), 2.67 (s, 3 H,
CH3), 6.24 (s, 1 H, Csp3-H), 7.03–7.13 (m, 3 H, arom.), 7.25–7.50
(m, 9 H, arom.), 7.84–7.89 (m, 1 H, arom.), 9.00 (s, 1 H, NH) ppm.
13C NMR (50.3 MHz, CDCl3): δ = 21.3, 29.3 (CH3), 33.9 (Csp3-H),
84.6, 89.7 (CϵC), 112.4, 120.9, 123.3, 126.7, 127.6, 128.4, 128.6,
129.5, 131.9 (Csp2-H), 121.9, 123.6, 127.4, 131.9, 136.6, 136.8, 137.3
(quat. Csp2), 191.0 (C=O) ppm. MS (ESI–): m/z (%) = 362 (100)
[M – H]–. C26H21NO (363.45): calcd. C 85.92, H 5.82, N 3.85;
found C 85.73, H 5.71, N 3.91.
1-(3-{1-(4-Methylphenyl)-2-Phenyl-3-[3-(trifluoromethyl)phenyl]-
prop-2-ynyl}-1H-indol-2-yl)ethanone (5f): Reaction time: 18 h. Elu-
ent for chromatography: n-hexane/EtOAc, 98:2. Yield: 640 mg,
63%. Dark-yellow solid. M.p. 108–111 °C. IR (KBr): ν = 3072,
˜
2255, 1696 cm–1. 1H NMR (200 MHz, CDCl3): δ = 2.31 (s, 3 H,
2
CH3), 4.24 (d, 2J = 16.1 Hz, 1 H, CH2), 4.35 (d, J = 16.1 Hz, 1
H, CH2), 6.39 (s, 1 H, Csp3-H), 7.04–7.86 (m, 17 H, arom.), 8.87 (s,
1 H, NH) ppm. 13C NMR (50.3 MHz, CDCl3): δ = 21.3 (CH3),
1-(3-{1-(4-Methylphenyl)-3-[3-(trifluoromethyl)phenyl]prop-2-ynyl}-
1H-indol-2-yl)ethanone (5b): Reaction time: 1.5 h. Eluent for
chromatography: n-hexane/EtOAc, 90:10. Yield: 578 mg, 67 %.
33.9 (Csp -H), 47.8 (CH2), 83.1, 91.7 (CϵC), 112.6, 121.1, 123.0,
3
126.8, 127.5 (2 C), 129.0, 129.1, 129.6, 129.8, 135.1 (Csp -H), 122.2,
2
Dark-yellow oil. IR (KBr): ν = 2921, 2225, 1651, 1529 cm–1. 1H
2
˜
124.6, 127.2, 131.2, 134.0, 136.8, 136.9, 137.0 (quat. Csp ), 124.0 (q,
1
3
NMR (200 MHz, CDCl3): δ = 2.32 (s, 3 H, CH3), 2.67 (s, 3 H,
CH3), 6.28 (s, 1 H, Csp3-H), 7.04–7.85 (m, 12 H, arom.), 8.94 (s, 1
H, NH) ppm. 13C NMR (50.3 MHz, CDCl3): δ = 21.3, 29.3 (CH3),
33.9 (Csp3-H), 83.0, 91.6 (CϵC), 112.5, 121.0, 123.2, 126.7, 127.5,
129.1, 129.6, 135.1 (Csp2-H), 121.5, 124.6, 127.3, 131.8, 136.6,
2
JC,F = 270.8 Hz CF3), 124.8 (q, JC,F = 3.7 Hz, Csp -H), 128.7 (q,
3
2
JC,F = 3.9 Hz, Csp -H), 131.1 (q, JC,F = 32.6 Hz, quat. Csp ), 191.2
2
2
(C=O) ppm. MS (ESI–): m/z (%) = 506 (100) [M – H]– .
C33H24F3NO (507.54): calcd. C 78.09, H 4.77, N 2.76; found C
77.78, H 4.54, N 2.95.
1
136.9, 137.0 (quat. Csp2), 124.0 (q, JC,F = 272.4 Hz, CF3), 124.9
2-Phenyl-1-[3-(3-phenyl-1-thien-2-ylprop-2-ynyl)-1H-indol-2-yl]eth-
anone (5g): Reaction time: 2.5 h. Eluent for chromatography: n-
hexane/EtOAc, 97:3. Yield: 509 mg, 59%. Dark-yellow solid. M.p.
(q, 3JC,F = 3.8 Hz, Csp2-H), 128.7 (q, 3JC,F = 4.2 Hz, Csp2-H), 131.1
(q, 2JC,F = 32.8 Hz, quat. Csp2), 190.9 (C=O) ppm. MS (ESI+): m/z
(%) = 432 (100) [M + H]+. C27H20F3NO (431.45): calcd. C 75.16,
H 4.67, N 3.25; found C 74.92, H 4.50, N 3.62.
105–107 °C. IR (KBr): ν = 3350, 2877, 1649 cm–1
.
1H NMR
˜
2
(200 MHz, CDCl3): δ = 4.27 (d, J = 16.1 Hz, 1 H, CH2) 4.39 (d,
1-[3-(3-Phenyl-1-thien-2-ylprop-2-ynyl)-1H-indol-2-yl]ethanone (5c): 2J = 16.1 Hz, 1 H, CH2), 6.56 (s, 1 H, Csp3-H), 6.91 (dd, J = 4.9,
3
Reaction time: 2.5 h. Eluent for chromatography: n-hexane/EtOAc,
3.5 Hz, 1 H, arom.), 7.07–7.48 (m, 15 H, arom.), 8.01 (d, 3J =
Eur. J. Org. Chem. 2009, 2872–2882
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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