Potassium Carbonate → 2-methyl-4-(trifluoromethyl)-1H-indole

Participants

Reaction Steps

A mixture of 2-methyl-1-(phenylsulfonyl)-4-(trifluoromethyl)-1H-indole (13.5 g, 39.82 mmol; step C above) and K2CO3 (27.5 g) in MeOH/H2O (2:1, 300 mL) was heated at reflux temperature. After 14 h the mixture was cooled and concentrated in vacuo. The residue was partitioned between Et2O/H2O, the layers were separated and the aqueous layer was extracted with Et2O (×2). Combined organics were washed (H2O, brine), dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified via column chromatography (SiO2, 1:1 EtOAc/hexanes eluent), affording 11.0 g of the deprotected indole as a yellow oil: 1H NMR (400 MHz, CDCl3) δ 7.43 (d, J=8.0 Hz, 1H), 7.35 (d, J=8.0 Hz, 1H), 7.15 (t, J=8.0 Hz, 1H), 6.46 (s, 1H), 2.48 (s, 3H); MS (ES) m/z 200 (M+1).

Provenance & Evidence