Water → Benzo[b]thiophene-5-methanamine, N-methyl-

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Reaction Steps

Benzo[b]thiophene-5-carbaldehyde (276 mg, 1.70 mmol) was dissolved in anhydrous methanol (8.0 mL). Methylamine (0.68 mL of 33% solution in ethanol, 5.46 mmol) was added and the reaction was stirred for 3 h. The solution was concentrated to a white solid and then dissolved in anhydrous methanol (10 mL). Sodium borohydride (66.0 mg, 1.75 mmol) was added and the mixture was stirred overnight at room temperature. Water (8.0 mL) was added and the solution was concentrated. Sodium hydroxide (10 mL, 1N) was added and the aqueous layer was extracted with ethyl acetate (3×20 mL). Combined organic layers were dried over MgSO4, filtered and concentrated to afford benzo[b]thiophen-5-yl-N-methylmethanamine (269 mg, 89%) as a yellow oil: 1H NMR (300 MHz, DMSO-d6) δ 7.90 (d, J=8.7 Hz, 1H), 7.79 (s, 1H), 7.71 (d, J=5.7 Hz, 1H), 7.40 (d, J=5.4 Hz, 1H), 7.32 (d, J=8.1 Hz, 1H), 3.73 (s, 2H), 2.26 (s, 3H).

Provenance & Evidence