HCID 178499180, compound → HCID 178499176, compound

Participants

Reaction Conditions

Reaction Steps

A suspension of 4-nitro-1H-pyrazole-3-carboxylic acid methyl ester (1.084 Kg, 6.33 mol, 1.0 wt) and ethanol (10.84 L, 10.0 vol) was heated to and maintained at 30 to 35° C. until complete dissolution occurred. 10% Palladium on carbon (10% Pd/C wet paste, 0.152 Kg, 0.14 wt) was charged to a separate flask under nitrogen and a vacuum/nitrogen purge cycle was performed three times. The solution of 4-nitro-1H-pyrazole-3-carboxylic acid methyl ester in ethanol was charged to the catalyst and a vacuum/nitrogen purge cycle was performed three times. A vacuum/hydrogen purge cycle was performed three times and the reaction was placed under an atmosphere of hydrogen. The reaction mixture was stirred at 28 to 30° C. until deemed complete by 1H NMR analysis (d6-DMSO). The mixture was filtered under nitrogen and concentrated under vacuum at 35 to 45° C. to give 4-amino-1H-pyrazole-3-carboxylic acid methyl ester (0.883 Kg, 98.9%) as a purple solid.

Provenance & Evidence