Hydrochloric Acid → HCID 20430314, compound

Participants

Reaction Steps

To a solution of 1-acetyl-6-(methyloxy)-2,3-dihydro-1H-indole (2.0 g, 10.5 mmol) in acetic anhydride (150 mL) at 0° C. was added 70% nitric acid (1.03 g, 11.5 mmol) via a dropwise addition. After stirring the reaction at 0° C. for 2 hrs, the contents were allowed to warm to rt, the precipitate was filtered and washed with water. The filtrate was neutralized with 5.0 M NaOH, extracted with ethyl acetate (2×200 mL). The organic layers were combined, adsorbeded onto silica gel and purified by column chromatography (DCM to 2% MeOH/DCM). The derived residue was subsequently dissolved in methanol (200 mL), followed by the addition of 4M HCl(29 mL, 116 mmol). After heating at 60° C. for 3 hrs, the solvent was removed by rotary evaporation, the residue redissolved in THF (300 mL), washed with saturated NaHCO3 (300 mL) and the aqueous layer was extracted with THF (200 mL). The combined organic layers were filtered through a cotton plug, concentrated under reduced pressure, and placed under high vacuum for several hours to give 6-(methyloxy)-5-nitro-2,3-dihydro-1H-indole (1.1 g, 54% over two steps). ESIMS (M+H)+=195. 1H NMR (400 MHz, DMSO-d6) δ ppm 2.90 (t, J=8.42 Hz, 2 H) 3.58 (t, J=8.52 Hz, 2 H) 3.75-3.79 (m, 3 H) 6.10 (s, 1 H) 7.14 (s, 1 H) 7.65 (s, 1H).

Provenance & Evidence