Water → 1-acetyl-3,3-dimethyl-5-(methyloxy)-6-nitro-2,3-dihydro-1H-indole

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Reaction Conditions

Reaction Steps

A solution of 1-acetyl-3,3-dimethyl-5-(methyloxy)-2,3-dihydro-1H-indole (2.44 g, 11.13 mmol, see PCT Int. Appl. (2001), WO 2001023374 A1 20010405) in trifluoroacetic acid (50 mL) was stirred at 0° C. and potassium nitrate (1.181 g, 11.68 mmol) was added in one portion. The reaction was maintained at 0° C. for 3 hours and poured into water. The solids were collected via filtration to afford 1-acetyl-3,3-dimethyl-5-(methyloxy)-6-nitro-2,3-dihydro-1H-indole (2.545 g, 87% yield) as a yellow solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 8.41 (s, 1 H), 7.34 (s, 1 H), 3.91 (s, 3 H), 2.15 (s, 2 H), 1.36 (s, 6 H). Note: proton resonance corresponding to acetyl was extremely broad and/or not evident for a variety of lots.

Provenance & Evidence