Boron tribromide → Ethyl 1-(6-(2-hydroxy-5-methylphenyl)pyridin-2-yl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate

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Reaction Steps

To a cooled (0° C.) solution of the title compound from Example 8 Step A in DCM (20 mL) was added boron tribromide (11.7 mL, 1.0 M in DCM, 11.7 mmol). After 15 min, the reaction mixture was allowed to warm to ambient temperature. After an additional 2 h, the reaction mixture was cooled to 0° C., then was quenched by dropwise addition of sat. aq. NaHCO3 (gas evolution) and was extracted with DCM. The organic phase was separated and concentrated in vacuo. Purification by flash chromatography on silica gel (0 to 30% EtOAc in hexanes, then 30 to 100% EtOAc in hexanes) provided the title compound: LCMS m/z 392.6 [M+H]+; 1H NMR (500 MHz, CDCl3) δ 11.78 (s, 1H), 8.17 (s, 1H), 8.07-8.03 (m, 2H), 7.60 (d, J=1.5 Hz, 1H), 7.48 (dd, J=7.0, 1.5 Hz, 1H), 7.17 (dd, J=8.0, 2.0 Hz, 1H), 6.94 (d, J=8.0 Hz, 1H), 4.39 (q, J=7.0 Hz, 2H), 2.36 (s, 3H), 1.40 (t, J=7.0 Hz, 3H).

Provenance & Evidence