Toluene → HCID 86623338, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-[4-fluoro-2-(trifluoromethyl)phenyl]-2,5-dimethyl-1H-pyrrole-3-carbaldehyde (1.5 g, 5.3 mmol) in acetone (150 mL) was added a 0.3 M solution of KMnO4 (150 mL). The reaction mixture was stirred 3 h at room temperature and then was charged with 10% H2O2 (5 mL). After 15 minutes the reaction mixture was filtered and the filtrate was concentrated in vacuo to remove acetone. The remaining aqueous suspension was acidified with acetic acid. The precipitates were recovered by filtration and dried under high vacuum to afford 1-(4-fluoro-2-(trifluoromethyl)phenyl]-2,5-dimethyl-1H-pyrrole-3-carboxylic acid (0.99 g, 62%) as a faintly yellow powder; 1H NMR (CDCl3): δ 7.56 (dd, J=8, 3 Hz, 1H), 7.41 (m, 1H), 7.27 (dd, J=5, 8 Hz, 1H), 6.42 (s, 1H), 2.21 (s, 3H), 1.90 (s, 3H); MS (ESI) m/z 302 [M+H]+. To a suspension of 1-(4-fluoro-2-(trifluoromethyl)phenyl]-2,5-dimethyl-1H-pyrrole-3-carboxylic acid (0.65 g, 2.16 mmol) in anhyd toluene (5.0 mL) cooled to 0-3° C. were added thionyl chloride (0.25 mL) and DMF (20 μL). The reaction mixture was allowed to warm to room temperature where it remained for 3 h and then was concentrated in vacuo. The residue was evaporated twice from 5 mL of toluene to remove thionyl chloride and then was triturated in 3 mL of hexanes. The solids were removed by filtration and the filtrate was concentrated under reduced pressure and dried under high vacuum to afford the title compound (0.44 g, 64%) as a pale brown solid; 1H NMR (CDCl3): δ 7.59 (dd, J=8, 3 Hz, 1H), 7.44 (m, 1H), 7.27 (dd, J=5, 8 Hz, 1H), 6.51 (s, 1H), 2.17 (s, 3H), 1.89 (s, 3H); MS (ESI) m/z 320 [M+H]+.

Provenance & Evidence