p-Toluenesulfonic acid → 1-(3,4-difluorophenyl)-2-methyl-5-[4-(methylsulfonyl)phenyl]-1H-pyrrole

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Reaction Steps

A mixture of 1-(4-methylsulfonylphenyl)-1,4-pentanedione (Example 1, Step 2) (300 mg, 1.18 mmol), 3,4-difluoroaniline (0.13 ml, 1.3 mmol) and p-toluenesulfonic acid (25 mg) in toluene (80 ml) was heated to reflux for 24 hours. The reaction mixture was cooled, filtered and concentrated. The crude dark orange solid (700 mg) was purified by chromatography (silica gel, hexane/ethyl acetate, 7/3) to give 1-(3,4-difluorophenyl)-2-methyl-5-[4-(methylsulfonyl)phenyl]-1H-pyrrole (370 mg, 90%) as a white solid: mp (DSC) 151° C. Anal Calc'd. for C18H15NSO2F2 : C, 62.24; H, 4.35; N, 4.03. Found: C, 62.08; H, 4.52; N, 4.05.

Provenance & Evidence