General procedure for the synthesis of 1H-benzimidazole-2-ethylamine dihydrochloride from the compound (CAS:189560-91-6): compound 3 (3 g) was dissolved in 3N hydrochloric acid/ethyl acetate mixed solvent (50 mL/25 mL) and the reaction was stirred overnight at room temperature. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure and dried under high vacuum to afford compound 4 as a pink solid (2.4 g) in over 95% yield. Analyzed by liquid chromatography-mass spectrometry (LC/MS), the molecular ion peak (M+1) m/z of 162.4 was detected with a retention time of 0.62 min.