2-Bromopropane → methyl 6-bromo-1-isopropyl-1H-indole-4-carboxylate

Participants

Reaction Steps

To a cooled (0° C.) solution of methyl 6-bromo-1H-indole-4-carboxylate (1.0 g, 3.94 mmol) solid in N,N-dimethylformamide (25 mL) was added sodium hydride (0.173 g, 4.33 mmol). The reaction was stirred for 15 min, at which time 2-bromopropane (0.554 mL, 5.90 mmol) was added. The reaction was then allowed to warm to RT and was maintained overnight. LCMS showed about 25% starting material remaining The reaction was heated at 45° C. for 4 h, but no further conversion was noted. The reaction vessel was put back into an ice bath and stirred for 15 min. Then excess NaH (60%) was added, stirred for 10 min, and then 2-bromopropane (excess) was added. The ice bath was removed and the reaction stirred for 1 h. Approximately half of the reaction volume was removed in vacuo and poured into saturated NH4Cl (200 mL). This was extracted with ether (2×) and the combined organics were washed with brine, dried (MgSO4), and concentrated. Purification by column chromatography (80 g Isco silica column; Gradient B: 5-25%, A: hexane, B: ethyl acetate) gave methyl 6-bromo-1-(1-methylethyl)-1H-indole-4-carboxylate (0.53 g, 1.718 mmol, 43.7% yield).

Provenance & Evidence