A suspension of the nitroarene (63) (30.0 g, 82.0 mmol) and iron powder (22.8 g, 408 mmol) in AcOH (300 mL) was heated at 50° C. for 1.5 hr, and was then cooled to RT. Solid sodium carbonate was added portionwise to the reaction mixture until effervescence was no longer observed. The mixture was extracted with ethyl acetate (2×700 mL) and the combined organic extracts were washed with saturated aqueous sodium carbonate and with brine and then dried (MgSO4). Evaporation in vacuo furnished the title compound (Intermediate M) as a brown solid (25.0 g, 77%): m/z 338 (M+H)+ (ES+).
