Hydrochloric Acid → 1-Cyclopropyl-7-fluoro-5-nitro-1,3-dihydro-indol-2-one

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Reaction Conditions

Reaction Steps

Crude (2,3-difluoro-5-nitrophenyl) acetic acid (2.50 g, 11.5 mmol) and cyclopropylamine (6 eq., 4.78 ml, 0.0691 mol) are mixed in DMSO (10 ml) and stirred at 50 ° C. for 20 hours. 2N Hydrochloric acid (40 ml) is added in one portion and the mixture stirred at room temperature for 2 hours. The resulting light yellow precipitate is filtered, washed with water and dried under vacuum. The residue is purified by flash column chromatography (20% Ethyl acetate/hexane) to give the title compound as a yellow solid. HPLC r.t. 4.90 min; MS for C11H9FN2O3 m/z 235.0 (M−H)−.

Provenance & Evidence