Hydrofluoric Acid → methyl 3-[5-(dimethylcarbamoyl)pyrazin-2-yl]oxy-5-[(2S)-1-hydroxypropan-2-yl]oxy-benzoate

Participants

Reaction Steps

A solution of hydrogen fluoride (70% in pyridine, 3.25 mL) was added to methyl 3-[5-(dimethylcarbamoyl)pyrazin-2-yl]oxy-5-[(2S)-1-tripropan-2-ylsilyloxypropan-2-yl]oxy-benzoate in THF (300 mL) in a PTFE vessel and the resulting solution stirred for 18 hours at room temp. Further hydrogen fluoride solution (70% in pyridine, 3.25 mL) was added and the reaction stirred for an additional 66 hours. The reaction was quenched by the very careful addition of saturated aqueous sodium bicarbonate solution until the solution reached pH 8. The aqueous layer was extracted with ethyl acetate (2×500 mL) and the combined organics dried (MgSO4). The solvent was removed under reduced pressure and the residue was purified by flash column chromatography on silica eluting with 25 to 100% ethyl acetate in isohexane to afford the product (13.2 g, 98%). 1H NMR δ (CDCl3) 1.32 (3H, d), 1.93 (1H, d), 3.17 (6H, d), 3.74-3.79 (1H, m), 3.91 (3H, s), 4.54-4.60 (1H, m), 6.96 (1H, t), 7.43 (1H, d), 7.51 (1H, d), 8.36 (1H, d), 8.53 (1H, d); m/z 376 (M+H+)

Provenance & Evidence