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

Participants

Reaction Steps

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.

Provenance & Evidence