Hydrochloric Acid → 1-(2-Fluoropyridin-4-yl)-2-(3-trifluoromethylphenyl)ethane-1,2-dione-1-oxime

Participants

Reaction Steps

To a mixture of 2-(2-fluoropyridin-4-yl)-1-(3-trifluoromethyl-phenyl)ethanone (3) (10.80 g, 0.038 mol) in ethanol (200 mL), at −10° C., under argon, was added tert-butyl nitrite (5.0 mL, 0.042 mol) and hydrochloric acid (12.2 mL, 2.5M in ethanol, 0.031 mol) dropwise while maintaining the temperature below −5° C. Upon completion of additions, the reaction was allowed to warm to RT for 2 hrs. The reaction mixture was then concentrated in vacuo , diluted with water (100 mL), basified with saturated sodium bicarbonate (200 ml), and extracted with ethyl acetate (3×400 mL). The combined organic layers were washed with water (300 mL), dried with brine (300 mL) and anhydrous sodium sulfate, filtered and concentrated to an oil which weighed 11.4 g (95%). 1H NMR (300 MHz, CDCl3) d 8.31 (s, 1 H, Ar), 8.29 (d, J =5.3 Hz, 1 H, Pyr), 8.24 (d, J=7.8Hz, 1 H, Ar), 7.92 (d, J=8.1 Hz, 1 H, Ar), 7.71 (t, J=7.8 Hz, 1 H, Ar), 7.40 (d, J=5.1 Hz, 1 H, Pyr), 7.23 (s, 1 H, Pyr).

Provenance & Evidence