Sodium hydride → ethyl 1-(2-tert-butoxy-2-oxoethyl)-1H-pyrazole-4-carboxylate

HRID 1257419Notes

Reaction equation

[NH:1]1[CH:5]=[C:4]([C:6]([O:8][CH2:9][CH3:10])=[O:7])[CH:3]=[N:2]1.[H-].[Na+].Br[CH2:14][C:15]([O:17][C:18]([CH3:21])([CH3:20])[CH3:19])=[O:16]>CN(C)C=O>[C:18]([O:17][C:15](=[O:16])[CH2:14][N:1]1[CH:5]=[C:4]([C:6]([O:8][CH2:9][CH3:10])=[O:7])[CH:3]=[N:2]1)([CH3:21])([CH3:20])[CH3:19]

Participants

Conditions

Temperature: 50 °C

Procedure

Ethyl 1H-pyrazole-4-carboxylate (20.0 g) was dissolved in N,N-dimethylformamide (200 mL), and sodium hydride (60% in mineral oil, 8.6 g) was added by small portions under cooling in an ice bath. The reaction mixture was stirred at the same temperature for 30 min, and tert-butyl 2-bromoacetate (33 g) was added dropwise. The mixture was stirred at room temperature for 10 min, heated at 50° C. overnight. The reaction mixture was poured into ice water, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was separated, washed with saturated brine, dried over sodium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (carrier: silica gel, eluent: hexane-petroleum ether) to give the title compound (17.6 g) as a colorless solid.

Workup

temperatureunder cooling in an ice bath
stirringThe mixture was stirred at room temperature for 10 min
extractionthe mixture was extracted with ethyl acetate
customThe ethyl acetate layer was separated
washwashed with saturated brine
dry with materialdried over sodium sulfate
concentrationconcentrated under reduced pressure
customThe residue was purified by column chromatography (carrier: silica gel, eluent: hexane-petroleum ether)

Sources & evidence

ORD record: ord-80379723a38d448d95b5d6ca803f3fc8
Source dataset: uspto-grants-2013_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08461348B2

Reaction notes

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