Reaction #1583894

Reaction equation

Sulfuric acid

7-methyl-2-propyl-3H-benzoimidazole-5-carboxylic acid

MeOH

→

Intermediate ( 7a )

Yield 92.1%

7-Methyl-2-propyl-3H-benzoimidazole-5-carboxylic acid methyl ester

Yield 92.1%

Conditions

Workup

1. 1
   TemperatureThe mixture was refluxed for 36 hours
2. 2
   Concentrationconcentrated in vacuo
3. 3
   workup.DISSOLUTIONThe recovered material was dissolved in 500 ml, EtOAc
4. 4
   Washwashed with a saturated NaHCO3 solution
5. 5
   DryingThe organic layer was dried over MgSO4
6. 6
   Concentrationconcentrated

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.

Source