Methanol → methyl 1H-benzimidazole-5-carboxylate hydrochloride

Reaction equation

S(Cl)([Cl:3])=O.[N:5]1[C:9]2[CH:10]=[CH:11][C:12]([C:14]([OH:16])=[O:15])=[CH:13][C:8]=2[NH:7][CH:6]=1.[CH3:17]O>>[ClH:3].[N:5]1[C:9]2[CH:10]=[CH:11][C:12]([C:14]([O:16][CH3:17])=[O:15])=[CH:13][C:8]=2[NH:7][CH:6]=1

Participants

Reactant 3

HCID 887Methanol

HCID 24386Thionyl Chloride

HCID 4594565-Benzimidazolecarboxylic acid

Product 1

HCID 22710297methyl 1H-benzimidazole-5-carboxylate hydrochlorideYield 97%

Procedure

Under ice cooling, thionyl chloride (2.30 ml) was added dropwise to methanol (50 ml). Then, 5-benzimidazolecarboxylic acid (5.00 g) was added, followed by heating under reflux for 5 hours. The reaction mixture was distilled under reduced pressure. The residue was pulverized in diethyl ether, followed by collection through filtration, whereby colorless crystals (6.36 g, 97%) was obtained.