HCID 178499180, compound → HCID 178499176, compound

HRID 1622424Notes

Reaction equation

HRID 1622424 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].N#N.[H][H]>[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

5

Reactant 2

HCID 178499180HCID 178499180, compoundHCID 178514468HCID 178514468, compound

Product 1

HCID 178499176HCID 178499176, compoundYield 98.9%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 702EthanolSolvent

Procedure

A 2O L, reaction vessel equipped with a digital thermometer and stirrer was charged with palladium on carbon (10% wet paste, 0.170 Kg, 0.14 wt) under nitrogen. In a separate vessel, a slurry of 4-nitro-1H-pyrazole-3-carboxylic acid methyl ester (1.210 Kg, 7.07 mol, 1 wt) in ethanol (12.10 L, 1O vol) was warmed to 30 to 35° C. to effect dissolution and the solution added to the catalyst under nitrogen. Following a nitrogen-hydrogen purge sequence an atmosphere of hydrogen was introduced and the reaction mixture maintained at 28 to 3O° C. until reaction completion (5 to 10 hours) was noted by 1H NMR analysis (d6-DMSO). Following a purge cycle, the reaction mixture under nitrogen was filtered and the liquors concentrated under reduced pressure to give 4-amino-1H-pyrazole-3-carboxylic acid methyl ester (0.987 Kg, 98.9% th).

Workup

  1. customequipped with a digital thermometer and stirrer
  2. dissolutiondissolution
  3. additionthe solution added to the catalyst under nitrogen
  4. custompurge sequence an atmosphere of hydrogen
  5. additionwas introduced
  6. temperaturethe reaction mixture maintained at 28 to 3O° C
  7. customuntil reaction completion (5 to 10 hours)
  8. filtrationthe reaction mixture under nitrogen was filtered
  9. concentrationthe liquors concentrated under reduced pressure

Sources & evidence

ORD record
ord-415941b400f74359a70fe04ac4ee9789
Source dataset
uspto-grants-2014_07
Patent number
US08778936B2

Reaction notes

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