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Am. Chem. Soc. 2005, 127, 4592–4593.
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We also thank Dr. M. Baruah of the Department of
Chemistry, Molecular and Nanomaterials, Katholieke
Universiteit Leuven, Celestijnenaan 200F, Belgium for
recording high resolution NMR spectra of some of
our samples.
References and notes
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28. In a typical procedure, a mixture of gallium powder (3
mmol, 0.207 g), allyl bromide (6 mmol, 0.730 g), Bu4NBr
(1 mmol, 0.322 g) and indole (3 mmol, 0.354 g) were taken
up in DMF–H2O (15 ml; 3:1) in a 100 ml round-bottom
flask and the mixture stirred at room temperature until the
completion of the reaction (TLC). After completion (4–
10 h), the reaction mixture was quenched with a concen-
trated solution of NH4Cl, followed by extraction with
ether (3 · 20 ml). The combined ether extracts were
washed with brine, dried over anhydrous sodium sulfate
and the residue obtained on evaporation of the solvent
was purified by chromatography using ethyl acetate–
hexane (1:9) to afford the pure allylated product 3a in 80%
yield. 3-Allylindole 3a: 1H NMR (200 MHz, CDCl3) d
3.30 (dd, J = 1.8, 10.4 Hz, 2H), 5.25–5.55 (m, 2H), 5.85
(m, 1H), 6.65 (d, J = 2.2 Hz, 1H), 7.10–7.22 (m, 2H), 7.32
(d, J = 8.3 Hz, 1H), 7.62 (d, J = 8.3 Hz, 1H), 7.95 (br, 1H,
NH). IR (KBr) 3400, 2920, 1460 cmÀ1. EIMS m/z 157
M+Å. Anal Calcd for C11H11N: C, 84.08; H, 7.01; N, 8.91.
Found: C, 84.16; H, 7.11; N, 8.86. Similarly, other indoles,
and pyrroles were reacted with allylgallium reagent to give
the corresponding 3-allylated products in high yields. The
reactions are generally clean and no trace of side products
could be detected in the NMR spectra of the crude
1
products. Compound 3c: H NMR (100 MHz, CDCl3) d
2.46 (t, J = 2.2 Hz, 1H), 3.18 (dd, J = 2.2, 6.3 Hz, 2H),
6.76 (d, J = 2.2 Hz, 1H), 6.98–7.12 (m, 2H), 7.28 (d,
J = 8.1 Hz, 1H), 7.56 (d, J = 8.1 Hz, 1H), 8.02 (br, 1H,
NH). Anal Calcd for C11H9N: C, 85.16; H, 5.80; N, 9.03.
Found: C, 85.10; H, 5.72; N, 9.11. Compound 3g: 1H
NMR (200 MHz, CDCl3) d 3.90 (br, d, J = 6.4 Hz, 2H),
5.02–5.18 (m, 2H), 6.12–6.28 (m, 1H), 6.96 (d, J = 7.8 Hz,
1H), 7.06 (br, s, 1H), 7.24 (d, J = 7.2 Hz, 1H), 7.32 (d,
J = 7.2 Hz, 1H), 8.12 (br, 1H, NH). IR (KBr) 3420, 1615,
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17. Yadav, J. S.; Reddy, B. V. S.; Reddy, P. M.; Srinivas, C.
Tetrahedron Lett. 2002, 43, 5185–5187.
.
1425 cmÀ1 EIMS m/z 236 M+Å. Anal Calcd for