Diethyl Oxalate → ethyl 2-(1-methyl-1H-indazol-5-yl)-2-oxoacetate

HRID 879499Notes

Reaction equation

Br[C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[N:7]([CH3:11])[N:6]=[CH:5]2.C([Li])CCC.[C:17](OCC)(=[O:23])[C:18]([O:20][CH2:21][CH3:22])=[O:19]>C1COCC1>[CH3:11][N:7]1[C:8]2[C:4](=[CH:3][C:2]([C:17](=[O:23])[C:18]([O:20][CH2:21][CH3:22])=[O:19])=[CH:10][CH:9]=2)[CH:5]=[N:6]1

Participants

Conditions

Temperature: 25 °C

Procedure

To a solution of 5-bromo-1-methyl-1H-indazole (Aldrich, 1.06 g, 5 mmol) in THF (22 mL) at −78° C. was added n-butyllithium (2.2 mL, 2.5 M, 5.5 mmol) slowly. The mixture was stirred for 20 minutes, and the solution of diethyl oxalate (0.68 mL, 5.0 mmol) in THF (5 mL) was added over one minute period. The reaction was kept at −78° C. for 40 minutes, and was quenched with saturated ammonium chloride solution and warmed to 25° C. The mixture was extracted with ethyl acetate, and the organic phase was washed with water, brine, and dried over sodium sulfate. Concentration and purification with flash column chromatography (hexanes/EtOAc) gave ethyl 2-(1-methyl-1H-indazol-5-yl)-2-oxoacetate. LCMS-ESI+: calc'd for C12H13N2O3: 233.2 (M+H+); Found: 233.0 (M+H+).

Workup

waitThe reaction was kept at −78° C. for 40 minutes
customwas quenched with saturated ammonium chloride solution
extractionThe mixture was extracted with ethyl acetate
washthe organic phase was washed with water, brine
dry with materialdried over sodium sulfate
concentrationConcentration and purification with flash column chromatography (hexanes/EtOAc)

Sources & evidence

ORD record: ord-a3ffd794a892427bb15dbb033853e75a
Source dataset: uspto-grants-2015_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08987250B2

Reaction notes

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