Acetic Anhydride → 1,2-Benzisoxazole, 6-bromo-3-(trifluoromethyl)-

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Reaction Steps

To a flask containing 1-(4-bromo-2-hydroxy-phenyl)-2,2,2-trifluoro-ethanone oxime (2.64 g, 9.29 mmol) was added acetic anhydride (14 mL) and the reaction mixture stirred for 18 h at rt. The reaction mixture was concentrated and taken up in toluene and again concentrated to yield the acylated intermediate. This intermediate was dissolved in pyridine (15 mL) and triethylamine (3.2 mL) and heated at 112° C. for 4.5 h. The reaction mixture was concentrated and the residue was taken up in toluene and again concentrated the residue was then partitioned between EtOAc (25 mL) and HCl (1 N aq., 25 mL). The layers were separated and the organic layer washed with HCl (1 N aq., 25 mL). The combined water layers were then extracted with EtOAc (25 mL×2) and the combined organic layers were washed with brine (15 mL), dried (Na2SO4) and concentrated. The crude material was purified (FCC) to yield the title compound (44 mg, 17%).

Provenance & Evidence