[CH3:1][C:2](/[CH:4]=[N:5]/[OH:6])=O.[F:7][C:8]([F:18])([F:17])[C:9]1[CH:14]=[CH:13][C:12]([NH:15][NH2:16])=[CH:11][CH:10]=1.C(OCC)(=O)C>C(OCC)C.O.O.O.O.O.O.S([O-])([O-])(=O)=O.[Cu+2]>[CH3:1][C:2]1[CH:4]=[N+:5]([O-:6])[N:15]([C:12]2[CH:13]=[CH:14][C:9]([C:8]([F:7])([F:18])[F:17])=[CH:10][CH:11]=2)[N:16]=1
To a stirred solution of anti-pyruvic aldehyde 1-oxime (2.67 g, 30.7 mmol) in diethyl ether (50 mL) was added 4-(trifluoromethyl)phenylhydrazine (5.40 g, 30.7 mmol). The reaction mixture was stirred at 23° C. for 2 h, then concentrated under reduced pressure. The crude residue was dissolved in 15% aqueous pyridine (150 mL). A solution of copper(II) sulfate pentahydrate (15.31 g, 61.3 mmol) in water (75 mL) was added at once. The resulting mixture was stirred at reflux for 17 h, then cooled to 0° C. Ethyl acetate (100 mL) was added and the mixture was filtered through Celite® diatomaceaous filter aid. The layers were separated, and the aqueous layer was extracted with ethyl acetate (2×100 mL). The combined organic layers were washed with 1.0 M aqueous hydrochloric acid (3×50 mL). The organic layer was dried (MgSO4), filtered, and evaporated under reduced pressure. The residue was purified by chromatography on silica gel, eluting with 0 to 50% ethyl acetate in hexanes, to afford the title compound (5.84 g) as a colorless solid.
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