Hydrogen Bromide → 1-(4,5-Diaminopyrazol-1-yl)propan-2-ol hydrobromide

HRID 1181157Notes

Reaction equation

HRID 1181157 reaction equation
C([NH:8][C:9]1[N:13]([CH2:14][CH:15]([OH:17])[CH3:16])[N:12]=[C:11]([Br:18])[C:10]=1[N+:19]([O-])=O)C1C=CC=CC=1.[OH-].[Na+].Br>CCO.[Pd]>[BrH:18].[NH2:19][C:10]1[CH:11]=[N:12][N:13]([CH2:14][CH:15]([OH:17])[CH3:16])[C:9]=1[NH2:8]

Participants

6

Reactant 3

HCID 260Hydrogen BromideHCID 14798Sodium HydroxideHCID 130072301-(5-Benzylamino-3-bromo-4-nitropyrazol-1-yl)propan-2-ol

Product 1

HCID 694245171-(4,5-Diaminopyrazol-1-yl)propan-2-ol hydrobromideYield 69.3%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 702EthanolSolvent

Procedure

A mixture of 1-(5-benzylamino-3-bromo-4-nitropyrazol-1-yl)propan-2-ol (4-3) (5.0 g; 14.0 mmol) in EtOH (140 ml) containing 10% Pd/C as catalyst (Engelhard, 50% wet, 0.5 g dry weight) and NaOH (solid, 560 mg, 14 mmol) was hydrogenated in an autoclave (1 l) at 11 bar for 2 hours. The reaction mixture was filtered to remove the catalyst, under an inert atmosphere in an ethanolic solution containing HBr (47%, 9.7 ml, 78 mmol). The solvent was evaporated off under reduced pressure to give a solid. After washing with cold EtOH, the 1-(4,5-diaminopyrazol-1-yl)propan-2-ol was obtained in the form of the hydrobromide (3.47 eq HBr) as a white solid (2.3 g, 42%).

Workup

  1. filtrationThe reaction mixture was filtered
  2. customto remove the catalyst
  3. customThe solvent was evaporated off under reduced pressure
  4. customto give a solid
  5. washAfter washing with cold EtOH

Sources & evidence

ORD record
ord-e718f9c3cac041878471e23d4ac3e6fe
Source dataset
uspto-grants-2007_10
Patent number
US07285136B2

Reaction notes

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