Butyric Acid → 4-Methyl-2-propyl-1H-benzimidazole

HRID 1977827Notes

Reaction equation

HRID 1977827 reaction equation
[NH2:1][C:2]1[C:7]([NH2:8])=[CH:6][CH:5]=[CH:4][C:3]=1[CH3:9].[C:10](O)(=O)[CH2:11][CH2:12][CH3:13].[H-].[Na+].C(=O)([O-])[O-].[Na+].[Na+].C(=O)=O>O>[CH3:9][C:3]1[C:2]2[N:1]=[C:10]([CH2:11][CH2:12][CH3:13])[NH:8][C:7]=2[CH:6]=[CH:5][CH:4]=1

Participants

7

Reactant 5

HCID 264Butyric AcidHCID 280Carbon DioxideHCID 10340Sodium CarbonateHCID 175932,3-DiaminotolueneHCID 24758Sodium hydride

Product 1

HCID 219956454-Methyl-2-propyl-1H-benzimidazole

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

5.00 g (41 mmol) of 2,3-diamino-toluene and 3.7 ml (41 mmol) of butyric acid are stirred in 41 ml of polyphosphoric acid at 120° C. for 3 hours, and the mixture is poured into 410 ml of water and brought to pH=9 with solid sodium hydride. Thereafter, sodium carbonate is added until the evolution of carbon dioxide has ended, the mixture is extracted five times with 100 ml of ethyl acetate each time, the combined organic phases are dried with anhydrous sodium sulphate and the solution is evaporated—finally under a high vacuum; crude weight: 5.89 g. The product is purified by chromatography over silica gel 60 (Merck/40-63 μm/methylene chloride:methanol=100:1); yield: 2.45 (34%). Rf=0.16 (methylene chloride:methanol=20:1)

Workup

  1. extractionthe mixture is extracted five times with 100 ml of ethyl acetate each time
  2. dry with materialthe combined organic phases are dried with anhydrous sodium sulphate
  3. customthe solution is evaporated—finally under a high vacuum
  4. customThe product is purified by chromatography over silica gel 60 (Merck/40-63 μm/methylene chloride:methanol=100:1)

Sources & evidence

ORD record
ord-201323a010e24d32aa29cc9a4b2b9ce3
Source dataset
uspto-grants-2001_05
Patent number
US06235770B1

Reaction notes

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