Nitric Acid → 4-Nitro-3,5-bis(trifluoromethyl)phenol

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Reaction Steps

Fuming nitric acid (8.22 mL, 198.2 mmol) was added dropwise to a solution of 3,5-bis(trifluoromethyl)phenol (28.5 g, 123.9 mmol) in acetic acid (300 mL) at about 10° C. After being elevated to room temperature, the mixture was stirred for 43 hours. The reaction mixture was poured into ice water and the resulting solution was extracted with ethyl acetate. The organic layers were combined, washed successively with water and saturated saline, dried over anhydrous sodium sulfate, and distilled under reduced pressure to remove the solvent. The residue was purified by chromatography on a silica gel column (developing solvent; hexane:acetone=15:1→10:1) to yield a crude product. The crude product thus obtained was subjected to sublimation separation under reduced pressure (3 mmHg) at 80° C. by using an evaporator to distill off the isomer, that is, 2-nitro-3,5-bis(trifluoromethyl)phenol, whereby 10.1 g (yield: 29.7%) of 4-nitro-3,5-bis(trifluoromethyl)phenol was obtained as yellow needle-like crystals.

Provenance & Evidence