Diethyl Pyrocarbonate → Ethyl 5-butyryl-1,6-dimethyl-benzimidazole-2-carboxylate

HRID 1391350Notes

Reaction equation

HRID 1391350 reaction equation
[C:1]([C:6]1[C:18]([CH3:19])=[CH:17][C:9]2[N:10]([CH3:16])[C:11]([C:13]([OH:15])=[O:14])=[N:12][C:8]=2[CH:7]=1)(=[O:5])[CH2:2][CH2:3][CH3:4].[C:20](#N)[CH3:21].C(N(CC)CC)C.C(OC(OCC)=O)(=O)OCC>C(OCC)(=O)C>[C:1]([C:6]1[C:18]([CH3:19])=[CH:17][C:9]2[N:10]([CH3:16])[C:11]([C:13]([O:15][CH2:20][CH3:21])=[O:14])=[N:12][C:8]=2[CH:7]=1)(=[O:5])[CH2:2][CH2:3][CH3:4]

Participants

6

Reactant 4

HCID 3051Diethyl PyrocarbonateHCID 6342Acetonitrile2×HCID 8471TriethylamineHCID 128066655-Butyryl-1,6-dimethyl-benzimidazole-2-carboxylic acid

Product 1

HCID 12806645Ethyl 5-butyryl-1,6-dimethyl-benzimidazole-2-carboxylate

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

6.0 g of 5-butyryl-1,6-dimethyl-benzimidazole-2-carboxylic acid are introduced, in the course of 15 minutes, into a mixture of 150 ml of acetonitrile, 15 ml of triethylamine and 18.5 g of diethyl pyrocarbonate, while stirring at room temperature. The mixture is left to stand overnight, the acetonitrile is stripped off under reduced pressure, the residue is taken up in ethyl acetate and the resulting solution is washed with water, dried over sodium sulphate and evaporated to dryness. Ethyl 5-butyryl-1,6-dimethyl-benzimidazole-2-carboxylate, which is initially obtained as an oil but soon crystallises, is filtered off. When recrystallised from ethyl acetate/cyclohexane, it melts at 106°-108°.

Workup

  1. waitThe mixture is left
  2. washthe resulting solution is washed with water
  3. dry with materialdried over sodium sulphate
  4. customevaporated to dryness

Sources & evidence

ORD record
ord-563d0c4f67c2432c8384733f136520ef
Source dataset
uspto-grants-1979_02
Patent number
US04141982

Reaction notes

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