Hydrochloric Acid → Methyl 2-methyl-1H-benzimidazole-5-carboxylate
Reaktionsgleichung
Cl.[CH3:2][C:3]1[NH:4][C:5]2[CH:11]=[C:10]([C:12]([OH:14])=[O:13])[CH:9]=[CH:8][C:6]=2[N:7]=1.Cl.[CH3:16]O>>[CH3:2][C:3]1[NH:4][C:5]2[CH:11]=[C:10]([C:12]([O:14][CH3:16])=[O:13])[CH:9]=[CH:8][C:6]=2[N:7]=1Komponenten
4
Versuchsvorschrift
Mass spectrum (FAB, Pos): m/z 177 (M+ +1, as a free base). ##STR15## 2-Methylbenzimidazole-5-carboxylic acid hydrochloride, 6.6 g (32.5 mmols), was added to 200 ml of methanol and 5 ml of conc. hydrochloric acid was added to the mixture followed by heating to reflux for 8 hours. The solvent was distilled off under reduced pressure and 200 ml of water was added to the residue. After 1 N sodium hydroxide solution was added to the mixture to adjust pH to 9 to 10, the mixture was extracted with ethyl acetate. The ethyl acetate layer was dried over anhydrous magnesium sulfate and filtered. The solvent was distilled off to give 5.5 g (93.2%) of methyl 2-methyl-benzimidazole-5-carboxylate.