Sodium hydride → (S)-methyl 5-chloro-3-methyl-1-((quinuclidin-3-ylamino)methyl)-1H-indole-7-carboxylate

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Reaction Steps

To a stirred suspension of (S)-(−)-3-aminoquinuclidine dihydrochloride (621 mg, 3.1 mmol) in methylene chloride (20 mL) was added sodium hydride (250 mg, 6.2 mmol) in portions and the mixture was stirred for 1 h. Acetic acid (0.6 mL) was added dropwise and then methyl 5-chloro-3-methyl-1-(2-oxoethyl)-1H-indole-7-carboxylate (690 mg, 2.6 mmol) from Step D above was added and the mixture continued to stir at room temperature for 2 h. Sodium triacetoxyborohydride (2.2 g, 10.4 mmol) was added in one portion and stirring was continued overnight at room temperature. The solvent was removed under reduced pressure and the crude material was purified by column chromatography (silica gel, 90:10:1 methylene chloride/methanol/concentrated ammonium hydroxide) to afford (S)-methyl 5-chloro-3-methyl-1-((quinuclidin-3-ylamino)methyl)-1H-indole-7-carboxylate (1.0 g, quantitative yield) as a light yellow solid: 1H NMR (500 MHz, CD3OD) δ 7.69 (d, J=1.0 Hz, 1H), 7.56 (d, J=1.0 Hz, 1H), 7.14 (s, 1H), 3.02-2.97 (m, 1H), 2.84-2.62 (m, 8H), 3.00-2.97 (m, 1H), 2.85-2.58 (m, 7H), 2.32 (s, 3H), 2.23-2.19 (dq, J=10.0, 2.0 Hz, 1H), 1.72-1.61 (m, 3H), 1.47-1.45 (m, 1H), 1.47-1.45 (m, 1H); MS (ESI+) m/z 362 (M+H).

Provenance & Evidence