Butyl bromide → 1,4-Dimethyl-6-pentyl-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine

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Reaction Steps

To a solution of 225 mg (1.39 mmol) of 1,4,6-trimethyl-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine in 4 mL of THF was added 1.39 mL (2.22 mmol, 1.6 M in hexanes) of n-BuLi followed by 157 μL (1.46 mmol) of 1-bromobutane at −78° C. The reaction mixture was slowly warmed to room temperature and stirred for another 16 h. The reaction mixture was quenched by the addition of 10 mL of sat aq NH4Cl at 0° C. The mixture was extracted with EtOAc. The combined organic layer was washed with brine, dried (MgSO4) and concentrated under diminished pressure. The residue was purified by flash chromatography on a silica gel column (25 3.2 cm). Elution with 10:1 hexanes/ethyl acetate gave the product as a yellow oil: yield 0.20 g (66%); silica gel TLC Rf 0.15 (8:1:1 hexanes/ethyl acetate/MeOH); 1H NMR (CDCl3) δ 0.88 (t, 3H, J=7.2 Hz), 1.30-1.36 (m, 4H), 1.66 (quint, 2H, J=7.6 Hz), 2.08 (s, 3H), 2.55 (t, 2H, J=8.0 Hz), 2.81 (t, 2H, J=8.0 Hz), 2.88 (s, 3H), 3.38 (t, 2H, J=8.0 Hz) and 6.13 (s, 1H); 13C NMR (CDCl3) δ 14.1, 18.0, 22.6, 24.4, 29.6, 31.8, 33.3, 38.0, 52.5, 112.4, 118.2, 141.1, 159.1 and 163.7; mass spectrum, m/z 218.2 (M+) (theoretical 218.3); mass spectrum (APCI), m/z 219.1864 (M+H)+ (C14H23N2 requires 219.1861).

Provenance & Evidence