Dimethylformamide → 1-(4-Fluorophenyl)-4-formyl-5-methyl-2-(4-methylsulfonylphenyl)pyrrole

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-(4-fluorophenyl)-2-methyl-5-[4-(methylsulfonyl)phenyl]-1H-pyrrole (Example 1) (1.55 g, 4.71 mmol) in dimethylformamide (3.65 ml, 47 mmol) and toluene (20 ml), phosphorous oxychloride (3.5 ml, 37.7 mmol) was added. After stirring for 20 minutes, the reaction mixture was heated at 70° C. for 5 hours. The reaction mixture was cooled, poured into aqueous sodium acetate solution and extracted with ethyl acetate. The organic fractions were washed with 10% aqueous potassium carbonate and water. After drying (Na2SO4), filtration and concentration, the crude yellowish liquid (2.06 g) was purified by chromatography (silica gel, hexane/ethyl acetate, 6/4) to give 1-(4-fluorophenyl)-2-methyl-5-[4-(methylsulfonyl)phenyl]-1H-pyrrole-3-carboxaldehyde (1.2 g, 71%): mp (DSC) 155° C. Anal Calc'd. for C19H16NSFO3 : C, 63.85; H, 4.51; N, 3.92. Found: C, 63.50; H, 4.66; N, 3.85.

Provenance & Evidence