Perchloric Acid → ethyl 2-[1-benzyl-5-(3,4-dihydro-2H-1-benzopyran-6-yl)-3-(trifluoromethyl)-1H-pyrazol-4-yl]-2-(tert-butoxy)acetate

Participants

Reaction Steps

To a solution of ethyl 2-[1-benzyl-5-(3,4-dihydro-2H-1-benzopyran-6-yl)-3-(trifluoromethyl)-1H-pyrazol-4-yl]-2-hydroxyacetate (49f) (70 mg, 0.152 mmol) in tert-butyl acetate (2.9 mL) at 0° C. was added perchloric acid (0.347 mL). The mixture was stirred for 1 hour at room temperature before being slowly quenched with a saturated solution of potassium carbonate (10 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (2×10 mL). The organic layers were dried over sodium sulfate and concentrated in vacuo. The residue was purified by preparative TLC (cyclohexane/ethyl acetate 75/25) to provide the desired ether (49g) (22 mg, 0.04 mmol, 28%) as a clear yellow oil.

Provenance & Evidence