Sulfuric Acid → Ethyl 1-(3-fluoro-5-iodo-4-methoxyphenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate

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Reaction Steps

Sulfuric acid (3 mL) was added into a cold (ice bath) mixture of ethyl 1-(3-fluoro-4-methoxyphenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate (500 mg, 1.505 mmol) and NIS (339 mg, 1.505 mmol) in acetic acid (10 mL). The resulting mixture was stirred in an ice bath and was allowed to warm to ambient temperature overnight. The reaction was then heated in a 55° C. oil bath for 5 hrs. The crude mixture was combined with the reaction crude from an identical probe reaction (32 mg scale). The combined crude was poured into an ice/water mixture and extracted with EtOAc. The separated organic phase was dried over Na2SO4, filtered and evaporated to afford a dark mixture. This dark mixture was purified by flash chromatography (SiO2, Biotage SNAP Cartridge, silica gel, KP-Sil, 100 g cartridge). The column was eluted by an EtOAc/hexanes mixture (0% to 30%). Related fractions were pooled and evaporated to afford a colorless oil as the titled compound. LCMS calc.=457.98. found=459.06 (M+H)+.

Provenance & Evidence