Benzenesulfonyl chloride → Ethyl 5-(4-fluorophenyl)-1-(phenylsulfonyl)-1H-pyrrole-3-carboxylate

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Reaction Steps

Using 4-fluorophenacyl bromide instead of phenacyl bromide, a procedure as in Reference Example 1 was performed to synthesize ethyl 2-cyano-4-(4-fluorophenyl)-4-oxobutanoate, and procedures as in Reference Examples 2 and 3 were performed to synthesize ethyl 5-(4-fluorophenyl)-1H-pyrrole-3-carboxylate. Sodium hydride (60% in oil, 0.32 g) was added to a solution (20 mL) of ethyl 5-(4-fluorophenyl)-1H-pyrrole-3-carboxylate (1.56 g) in N,N-dimethylformamide under ice-cooling. The mixture was stirred at the same temperature for 15 min, added benzenesulfonyl chloride (1.41 g), and the mixture was stirred at room temperature for 18 hr. Water was added to the reaction mixture, and the mixture was extracted with diethyl ether. The extract was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: hexane-ethyl acetate=4:1→7:2) to give the title compound as crystals (yield 1.70 g, 68%).

Provenance & Evidence