Tert-butyl 6-nitroindoline-1-carboxylate → tert-Butyl 6-amino-2,3-dihydro-1H-indole-1-carboxylate
Reaction equation
[N+:1]([C:4]1[CH:12]=[C:11]2[C:7]([CH2:8][CH2:9][N:10]2[C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])=[CH:6][CH:5]=1)([O-])=O>CC(O)=O.O.[Fe]>[NH2:1][C:4]1[CH:12]=[C:11]2[C:7]([CH2:8][CH2:9][N:10]2[C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])=[CH:6][CH:5]=1Participants
4
Reactant 1
Product 1
Reagents, catalysts & solvents 2
Procedure
To a solution of tert-butyl 6-nitroindoline-1-carboxylate (270 mg, 1.02 mmol) in AcOH/H2O (2.5 mL, 10:1, v:v) was added iron powder (229 mg, 4.08 mmol) portionwise. The resulting mixture was stirred at rt. After 1.5 h, the reaction was filtered through Celite and the filtrate concentrated in vacuo. The residue was diluted with EtOAc and the resulting organic layer was washed with sat. NaHCO3 and brine. The organic layer was concentrated in vacuo to yield tert-butyl 6-aminoindoline-1-carboxylate as a grey solid. MS (ES+): m/z 235 [M+1]. 1H NMR (CDCl3, 400 MHz): δ1.55 (s, 9H), 2.96 (t, J=8.4 Hz, 2H), 3.61 (br.s, 2H), 3.93 (t, J=8.4 Hz, 2H), 6.27 (d, J=8.4 Hz, 1H), 6.89 (d, J=8.4 Hz, 1H), 7.30 (s, 1H).