1-(4-Fluoro-5-nitroindolin-1-yl)ethan-1-one → 4-fluoro-5-nitro-2,3-dihydro-1H-indole

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Reaction Steps

A mixture of 1-(4-fluoro-5-nitro-indolin-1-yl)ethanone (0.56 g, 2.51 mmol) and concentrated hydrochloric acid (10 mL) was refluxed for 16 h. The reaction mixture was cooled to ambient temperature and partitioned between chlorofolin (100 mL) and water (100 mL). The organic layer was separated and the aqueous layer extracted with chloroform (5×30 mL). The combined organic layers were washed with water (3×20 mL), brine (3×20 mL) and dried over anhydrous sodium sulphate. Concentration in vacuo afforded 4-fluoro-5-nitro-indoline (0.35 g, 76%) as a yellow solid.

Provenance & Evidence