Triphenylphosphine → 1-methyl-5-(5-methyl-3-pyridin-2-yl-isoxazol-4-ylmethoxy)-1H-pyrazole-3-carboxylic acid methyl ester

Participants

Reaction Steps

To a stirred solution of 5-hydroxy-1-methyl-1H-pyrazole-3-carboxylic acid methyl ester (400 mg, 2.6 mmol) and (5-methyl-3-pyridin-2-yl-isoxazol-4-yl)-methanol (500 mg, 2.6 mmol) in THF (10 mL) at 5° C. under argon was added triphenylphosphine (862 mg, 3.3 mmol), then diethyl azodicarboxylate (573 mg, 3.3 mmol) was added dropwise. The reaction mixture was warmed to room temperature and stirred overnight. The reaction mixture was then evaporated. Purification by chromatography (silica, dichloromethane:methanol=9:1) then purification using a 5×50 cm Chiralpak AD column at room temperature using an isopropanol:heptane (2:8) mobile phase with UV detection at 220 nM afforded the title compound (400 mg, 48%) as a white solid. MS: m/e=328.3 [M+H]+.

Provenance & Evidence