Methyl iodide → 3-(N-Acetyl-n-methylamino)-2-benzoyl-6-chloroindole

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Reaction Steps

To a solution of 3-acetylamino-2-benzoyl-6-chloro-1-(ethoxycarbonyl)indole (Example 2, step 1, 900 mg, 2.34 mmol) in dimethylformamide (10 ml) was added sodium hydride (60% w/w dispersion in mineral oil, 94 mg, 2.34 mmol). The mixture was stirred for 0.5 h and then iodomethane (0.22 ml, 3.51 mmol) was added dropwise, and stirring continued for 19 h. The reaction mixture was poured into water (50 ml) and extracted with diethyl ether (100 ml×2). The extracts were washed consecutively with water (50 ml) and brine (50 ml), dried (MgSO4) and solvent removed by evaporation. The residual oil was dissolved in ethanol/water (1:1, 20 ml) and KOH (85% pellets, 264 mg, 4.0 mmol) added. After stirring for 3 h, the mixture was concentrated and the residue partitioned between water (100 ml) and diethyl ether (100 ml). The organic layer was separated and washed consecutively with water (100 ml) and brine (100 m), dried (MgSO4) and solvent removed by evaporation. The residual solids were recrystallized from dichloromethane/hexane to afford 165 mg (63%) of the title compound as a yellow powder. m.p.: 232-235° C.

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