Trifluoromethanesulfonic acid → Ethyl 5-[o-(chloromethyl)benzoyl]-3-ethoxycarbonyl-4-hydroxy-1-methylpyrrole-2-acetate

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Reaction Steps

Ethyl 3-ethoxycarbonyl-4-hydroxy-1-methylpyrrole-2-acetate (510 mg, 2.0 mmol) is mixed with o-(chloromethyl)benzoyl chloride (565 μl, 4.0 mmol) under nitrogen, and 2.0 ml anhydrous trifluoromethanesulfonic acid is added. The reaction mixture is stirred at room temperature for one hour followed by dilution with methylene chloride (50 ml), and then water (30 ml). Solid sodium bicarbonate is slowly added until the acid is neutralized. The organic layer is separated and the aqueous layer is washed with methylene chloride (50 ml). The combined organic layers are washed with water (20 ml) and saturated brine (50 ml). Subsequently, the washed layers are dried with sodium sulfate and the solvent is removed in vacuo to give a red solid which is recrystallized from ethanol to give 525 mg (64.5%) of ethyl 5-[o-(chloromethyl)benzoyl]-3-ethoxycarbonyl-4-hydroxy-1-methylpyrrole-2-acetate.

Provenance & Evidence