19462-98-7

5348-42-5

1438-16-0

19462-98-7

GENERAL METHOD: 4,5-Dichloro-1,2-phenylenediamine (0.065 mol) was heated to reflux with N-amino winding tannin (0.065 mol) in xylene (50 mL) for 5 hours. After completion of the reaction, it was cooled to room temperature and the precipitate was collected by filtration. The crude product was purified by thermal crystallization using aqueous ethanol (containing activated carbon). The resulting solid was further recrystallized in ethanol to give 2-mercapto-5,6-dichlorobenzimidazole.