Potassium Carbonate → 2-methyl-4-(trifluoromethyl)-1H-indole
Reaction equation
[CH3:1][C:2]1[N:3](S(C2C=CC=CC=2)(=O)=O)[C:4]2[C:9]([CH:10]=1)=[C:8]([C:11]([F:14])([F:13])[F:12])[CH:7]=[CH:6][CH:5]=2.C([O-])([O-])=O.[K+].[K+]>CO.O>[CH3:1][C:2]1[NH:3][C:4]2[C:9]([CH:10]=1)=[C:8]([C:11]([F:13])([F:12])[F:14])[CH:7]=[CH:6][CH:5]=2Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
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).