Dimethylformamide → 5-(Trifluoromethyl)-1h-indole-3-carbaldehyde

Participants

Reaction Steps

Phosphorous oxychloride (7.6 mL, 83.0 mmol) was added dropwise to DMF (150 mL) at 0° C. A solution of 5 (4.5 g, 24.4 mmol) in DMF (30 mL) was added after 15 min. and the reaction mixture was allowed to warm to room temperature for 2 h. The mixture was poured on ice-water (300 g), made alkaline (pH 7-8) with 2 N aq. NaOH, extracted with EtOAc, the extracts were washed with brine, dried (MgSO4), and concentrated. The crude product was purified by flash chromatography on silica gel using 10% MeOH/CHCl3 as eluent. Recrystallization by dissolving yellow solid in hot MeOH and pouring onto cold water afforded 1 (3.9 g, 75% yield) as a white solid. Mp 242-243° C. 1H NMR (300 MHz, MeOH-d4): δ 9.95 (s, 1H), 8.48 (bs, 1H), 8.22 (s, 1H), 7.63 (d, 8.5 Hz, 1H), 7.53 (dd, 8.5, 1.7 Hz, 1H). MS m/z: 212 (M−1). Analysis calcd. for C10H6NOF3; C, 56.35; H, 2.84, N, 6.57; found, C, 56.60; H, 2.92; N, 6.55.

Provenance & Evidence