Ethyl Acetate → 5-(5-(3-chloro-4-fluorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-3,3-dimethylbenzo[c][1,2]oxaborol-1(3H)-ol

Participants

Reaction Steps

To a solution of (Z)—N,1-dihydroxy-3,3-dimethyl-1,3-dihydrobenzo[c][1,2]oxaborole-5-carbimidoyl chloride (239 mg, 1.0 mmol) and 2-chloro-1-fluoro-4-(3,3,3-trifluoroprop-1-en-2-yl)benzene (240 mg, 1.07 mmol) in DMF (5 mL) at rt was added TEA (108 mg, 1.07 mmol). The reaction mixture was stirred at rt for 18 h, poured into ice-water and extracted with EA (20 mL). The organic layer was washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel eluted with PE:EA (6:1) to give the final title compound 5-(5-(3-chloro-4-fluorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-3,3-dimethylbenzo[c][1,2]oxaborol-1(3H)-ol (140 mg; yield 30.6%) as a white solid. 1H NMR (400 MHz, DMSO-d6): δ 9.21 (s, 1H), 7.80-7.70 (m, 4H), 7.64-7.60 (m, 2H), 4.43 (d, J=18.4 Hz, 1H), 4.27 (d, J=18.4 Hz, 1H), 1.48 (s,6H) ppm; HPLC purity: 96.0% at 220 nm and 96.4% at 254 nm; MS: m/z=428.1 (M+, ESI+).

Provenance & Evidence