Water → Benzimidazole

HRID 2351298Notes

Reaction equation

HRID 2351298 reaction equation
Br[CH2:2][C:3]([C:5]1C=C(OC)C=CN=1)=[O:4].Cl[C:14]1[NH:15][C:16]2[CH:22]=[CH:21][CH:20]=[CH:19][C:17]=2[N:18]=1.C([O-])([O-])=O.[K+].[K+].O>CN(C)C=O>[CH3:2][CH:3]([OH:4])[CH3:5].[CH:3]([O:4][CH:22]([CH3:21])[CH3:16])([CH3:5])[CH3:2].[N:15]1[C:16]2[CH:22]=[CH:21][CH:20]=[CH:19][C:17]=2[NH:18][CH:14]=1

Participants

7

Reactant 4

HCID 962WaterHCID 11430Potassium CarbonateHCID 785722-ChlorobenzimidazoleHCID 198461142-Bromo-1-(4-methoxypyridin-2-yl)ethanone

Product 2

HCID 5798BenzimidazoleYield 243.8%HCID 21202047Isopropyl alcohol isopropyl ether

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
2 °C

Procedure

2-Bromoacetyl-4-methoxypyridine (11.5 g, 0.05) and 2-chlorobenzimidazole (7.5 g, 0.05 mole) were dissolved in dimethylformamide (75 ml) and cooled to 2° C. K2CO3 (12 g, 0.08 mole) was added and the temperature rose to 9° C. as the suspension was stirred for 1/2 hour. The mixture was added to H2O (200 ml) giving a solid which was removed by filtration. The mother liquors were extracted with ethyl acetate and the solid was dissolved in the extracts. The organic solution was washed (brine) and dried (MgSO4) and purified by passage down a silica column and evaporated to dryness to give a sticky solid. Trituration with propan-2-ol/di-isopropyl ether gave 2-chloro-1-[2-[4-methoxypyridyl])-2-oxoethyl]-benzimidazole (7.2 g).

Workup

  1. customrose to 9° C. as the suspension
  2. customgiving a solid which
  3. customwas removed by filtration
  4. extractionThe mother liquors were extracted with ethyl acetate
  5. dissolutionthe solid was dissolved in the extracts
  6. washThe organic solution was washed (brine)
  7. dry with materialdried (MgSO4)
  8. custompurified by passage down a silica column
  9. customevaporated to dryness
  10. customto give a sticky solid

Sources & evidence

ORD record
ord-3c1425412cfe4134add47683767f40d3
Source dataset
uspto-grants-1989_10
Patent number
US04873237

Reaction notes

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