Acetic Anhydride → Methyl 2-(acetylamino)-5-nitro-4-(trifluoromethyl)benzoate

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Reaction Steps

A solution of 2.0 g (7.57 mmol) of 2-amino-5-nitro-4-trifluoromethyl-benzoic acid methyl ester in 20 ml of acetic anhydride is heated to reflux for 4 hours. The mixture is allowed to cool to room temperature and concentrated in vacuo. The residue is taken up in ethyl acetate and washed with water, aqueous saturated NaHCO3-solution and brine. The organic phase is dried over Na2SO4, filtered and concentrated in vacuo. Purification by flash chromatography (SiO2, hexane/ethyl acetate 3:1) provided 1.79 g (77%) of 2-acetylamino-5-nitro-4-trifluoromethyl-benzoic acid methyl ester as yellow crystals, m.p. 75-80° C.

Provenance & Evidence