Methanol → 4-Methyl-2-propyl-1H-benzimidazole-6-carboxylic acid methyl ester

HRID 476297Notes

Reaction equation

HRID 476297 reaction equation
S(=O)(=O)(O)O.[CH3:6][C:7]1[C:12]2[N:13]=[C:14]([CH2:16][CH2:17][CH3:18])[NH:15][C:11]=2[CH:10]=[C:9]([C:19]([OH:21])=[O:20])[CH:8]=1.[CH3:22]O>>[CH3:22][O:20][C:19]([C:9]1[CH:8]=[C:7]([CH3:6])[C:12]2[N:13]=[C:14]([CH2:16][CH2:17][CH3:18])[NH:15][C:11]=2[CH:10]=1)=[O:21]

Participants

4

Reactant 3

HCID 887MethanolHCID 1118Sulfuric AcidHCID 102628317-Methyl-2-propyl-1H-benzimidazole-5-carboxylic acid

Product 1

HCID 101308354-Methyl-2-propyl-1H-benzimidazole-6-carboxylic acid methyl esterYield 92.1%

Procedure

Sulfuric acid (12 mL, 0.22 mol) was added to 7-methyl-2-propyl-3H-benzoimidazole-5-carboxylic acid (30 g, 136 mmol) dissolved in MeOH (670 mL, 16 mol). The mixture was refluxed for 36 hours and concentrated in vacuo. The recovered material was dissolved in 500 mL EtOAc and washed with a saturated NaHCO3 solution. The organic layer was dried over MgSO4 and concentrated to provide Intermediate (7a) as a brown solid (29.1 g). MS m/z: [M+H+] calcd for C13H16N2O2, 233.1. found 233.2.

Workup

  1. temperatureThe mixture was refluxed for 36 hours
  2. concentrationconcentrated in vacuo
  3. dissolutionThe recovered material was dissolved in 500 mL EtOAc
  4. washwashed with a saturated NaHCO3 solution
  5. dry with materialThe organic layer was dried over MgSO4
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-d3151f6a0ab940c19a64ed2be7828279
Source dataset
uspto-grants-2014_01
Patent number
US08637676B2

Reaction notes

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