Ethoxalyl chloride → HCID 70818356, compound

Participants

Reaction Conditions

Reaction Steps

Under nitrogen, isopropyl magnesium chloride 2M in tetrahydrofuran (0.47 mL, 0.94 mmol) was dropwise added to a solution of 4-bromo-1-cyclohexyl-5-(3,4-dihydro-2H-1-benzopyran-6-yl)-3-(trifluoromethyl)-1H-pyrazole (54b) (134 mg, 0.31 mmol) in anhydrous tetrahydrofuran (1.0 mL), previously cooled to −20° C. After 90 minutes stirring at the same temperature, ethyl chlorooxoacetate (70 μL, 0.62 mmol) was added dropwise. The mixture was stirred at −20° C. for 40 minutes before being poured in water (2 mL). The mixture was extracted with ethyl acetate (2×3 mL) and the organic layer was dried over sodium sulfate and concentrated in vacuo. The residue was purified by preparative TLC (cyclohexane/ethyl acetate 75/25) to provide the desired keto-ester (54c) (104 mg, 0.23 mmol, 74%).

Provenance & Evidence