反应详情

To a stirred solution of 5-hydroxy-2H-pyrazole-3-carboxylic acid methyl ester (1.30 g, 9.15 mmol) and (5-methyl-3-phenyl-isoxazol-4-yl)-methanol (1.73 g, 9.15 mmol) in THF (80 mL) at 5° C. under argon was added triphenylphosphine (3.12 g, 11.9 mmol), then diethyl azodicarboxylate (2.07 g, 11.9 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, heptane:ethyl acetate=1:1 then dichloromethane:methanol=9:1) gave a colorless oil (800 mg) which was triturated with diisopropylether and further purified 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 to afford the title compound (250 mg, 9%) as a white solid. MS: m/e=328.3 [M+H]+.

1. customThe reaction mixture was then evaporated
2. customPurification by chromatography (silica, heptane