HCID 178499180, compound → HCID 178499176, compound

HRID 1639644Notes

Reaction equation

HRID 1639644 reaction equation
[CH3:1][O:2][C:3]([C:5]1[C:9]([N+:10]([O-])=O)=[CH:8][NH:7][N:6]=1)=[O:4]>[Pd].C(O)C>[CH3:1][O:2][C:3]([C:5]1[C:9]([NH2:10])=[CH:8][NH:7][N:6]=1)=[O:4]

Participants

4

Reactant 1

HCID 178499180HCID 178499180, compound

Product 1

HCID 178499176HCID 178499176, compoundYield 98.9%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 702EthanolSolvent

Conditions

Temperature
32.5 °C

Procedure

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.

Workup

  1. temperaturewas heated to and
  2. customa vacuum/nitrogen purge cycle
  3. additionThe solution of 4-nitro-1H-pyrazole-3-carboxylic acid methyl ester in ethanol was charged to the catalyst
  4. customa vacuum/nitrogen purge cycle
  5. customA vacuum/hydrogen purge cycle
  6. filtrationThe mixture was filtered under nitrogen
  7. concentrationconcentrated under vacuum at 35 to 45° C.

Sources & evidence

ORD record
ord-d40a72c3cfe04ad79d1520d01bd8ae82
Source dataset
uspto-grants-2012_02
Patent number
US08110573B2

Reaction notes

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