Acetonitrile → 5-amino-2-(1H-benzimidazol-2-yl)pyrazole

HRID 553021Notes

Reaction equation

HRID 553021 reaction equation
[CH:1](OCC)=O.[C:6](#[N:8])[CH3:7].[H-].[Na+].[NH:11]([C:13]1[NH:17][C:16]2[CH:18]=[CH:19][CH:20]=[CH:21][C:15]=2[N:14]=1)[NH2:12].[OH-].[Na+]>CCOCC.C(O)C>[NH2:8][C:6]1[CH:7]=[CH:1][N:11]([C:13]2[NH:14][C:15]3[CH:21]=[CH:20][CH:19]=[CH:18][C:16]=3[N:17]=2)[N:12]=1

Participants

8

Reactant 5

HCID 6342AcetonitrileHCID 8025Ethyl formateHCID 14798Sodium HydroxideHCID 24758Sodium hydrideHCID 957882-hydrazinyl-1H-1,3-benzodiazole

Product 1

HCID 574644725-amino-2-(1H-benzimidazol-2-yl)pyrazole

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 3283Diethyl EtherSolvent

Procedure

A mixture of ethyl formate (5 ml, 62 mmol), acetonitrile (1 g, 25 mmol) and ethanol (0.5 ml) is added dropwise to a suspension of sodium hydride (0.96 g, 40 mmol) in ether at room temperature. After stirring for 16 hours the volatiles are removed under reduced pressure. The residue is diluted with water and the pH is adjusted by addition of AcOH to 7. After addition of 2-hydrazino1-H-benzimidazole (6.6 g, 45 mmol) the mixture is allowed to stand for 5 hours. The pH is adjusted with sodium hydroxide, and the mixture extracted with chloroform. The crude title product is used without further purification. 1H-NMR (400 MHz, d6-DMSO): 12.7 (s, 1H); 7.57 (s, 1H); 7.49 (m, 2H); 7.40 (m, 2H); 7.19 (s, 2H); 6.9 (s, 2H); 5.44 (d, 1H).

Workup

  1. customare removed under reduced pressure
  2. additionThe residue is diluted with water
  3. additionthe pH is adjusted by addition of AcOH to 7
  4. waitto stand for 5 hours
  5. extractionthe mixture extracted with chloroform
  6. customThe crude title product is used without further purification

Sources & evidence

ORD record
ord-c3e9306968404e009928af5b22c3909b
Source dataset
uspto-grants-2011_05
Patent number
US07951957B2

Reaction notes

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