Formic Acid → ethyl 3-(formylamino)-1-phenyl-1H-pyrazole-4-carboxylate

HRID 2221652Notes

Reaction equation

[CH:1](O)=[O:2].C(OC(=O)C)(=O)C.[NH2:11][C:12]1[C:16]([C:17]([O:19][CH2:20][CH3:21])=[O:18])=[CH:15][N:14]([C:22]2[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=2)[N:13]=1>O1CCCC1>[CH:1]([NH:11][C:12]1[C:16]([C:17]([O:19][CH2:20][CH3:21])=[O:18])=[CH:15][N:14]([C:22]2[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=2)[N:13]=1)=[O:2]

Participants

Conditions

Temperature: 55 °C

Procedure

Under ice-cooling, 98% formic acid (12.75 g) was added to acetic anhydride (22.97 g) using an dropping funnel, the obtained mixture was stirred at 50-60° C. for 2 hrs, and cooled to room temperature. Tetrahydrofuran (25 mL) was added to the obtained mixture and a solution of ethyl 3-amino-1-phenyl-1H-pyrazole-4-carboxylate (20.00 g) in tetrahydrofuran (20 mL) was added. The obtained mixture was stirred at room temperature for 3 hrs and concentrated. The residue was recrystallized from ethyl acetate-hexane to give ethyl 3-(formylamino)-1-phenyl-1H-pyrazole-4-carboxylate as colorless needle crystals (20.89 g, yield 93%). melting point: 135-136° C.

Workup

temperatureUnder ice-cooling
temperaturecooled to room temperature
stirringThe obtained mixture was stirred at room temperature for 3 hrs
concentrationconcentrated
customThe residue was recrystallized from ethyl acetate-hexane

Sources & evidence

ORD record: ord-3acaf6f658f44acf8ae303aea4b5dce6
Source dataset: uspto-grants-2008_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07368578B2

Reaction notes

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