Hydrochloric Acid → 5-(5-(4-fluoro-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-3,3-dimethylbenzo[c][1,2]oxaborol-1(3H)-ol

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Reaction Steps

To a solution of (Z)-N,1-dihydroxy-3,3-dimethyl-1,3-dihydrobenzo[c][1,2]oxaborole-5-carbimidoyl chloride (522 mg, 2.18 mmol) in DMF (5 mL) was successively added 1-fluoro-2-(trifluoromethyl)-4-(3,3,3-trifluoroprop-1-en-2-yl)benzene (563 mg, 2.18 mmol) and TEA (440 mg, 4.36 mmol) below −10° C. The mixture was stirred at rt overnight, poured into 1N HCl solution and extracted with EA (30 mL×3). The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by pre-TLC eluted with PE:EA (1:1, 1% HOAc) and pre-HPLC to give the final title compound (200 mg, yield 20.0%) as white solid: 1H NMR (300 MHz, DMSO-d6): δ 9.20 (s, 1H), 8.03-8.00 (m, 1H), 7.91-7.89 (d, J=12 Hz, 1H), 7.77-7.68 (m, 4H), 4.52-4.46 (d, J=18 Hz, 1H), 4.36-4.30 (d, J=18 Hz, 1H), 1.48 (s, 6H). LC-MS: 462 [M+H]+.

Provenance & Evidence