Nitric Acid → 1-Acetyl-4,6-dimethyl-5-nitroindoline

Reaction equation

[C:1]([N:4]1[C:12]2[C:7](=[C:8]([CH3:14])[CH:9]=[C:10]([CH3:13])[CH:11]=2)[CH2:6][CH2:5]1)(=[O:3])[CH3:2].[N+:15]([O-])([OH:17])=[O:16].C(=O)(O)[O-].[Na+]>C(OC(=O)C)(=O)C>[C:1]([N:4]1[C:12]2[C:7](=[C:8]([CH3:14])[C:9]([N+:15]([O-:17])=[O:16])=[C:10]([CH3:13])[CH:11]=2)[CH2:6][CH2:5]1)(=[O:3])[CH3:2]

Participants

Procedure

1-Acetyl-4,6-dimethylindoline (2.6 g) was dissolved in acetic anhydride (35 ml), and nitric acid (d=1.5, 0.92 ml) dissolved in acetic anhydride (15 ml) was added dropwise at 0° C. The mixture was stirred at room temperature for one hour and poured into ice water. Saturated aqueous sodium bicarbonate was added to neutralize the mixture, and the mixture was extracted with chloroform. The extract was washed with saturated brine and dried over sodium sulfate. The solvent was evaporated under reduced pressure. The residue was chromatographed (ISCO, hexane/EtOAc, 0-40%, 40 min) to give 2.4 g of white solids. 1H NMR (DMSO-d6, 400 MHz): δ 6.95 (s, 1H), 4.19 (t, J=8.0 Hz, 2H), 3.04 (t, J=8.0 Hz, 2H), 2.26 (s, 3H), 2.23 (s, 3H), 2.18 (s, 3H).