[NH:1]=[C:2]1[N:6]([CH2:7][CH2:8]O)[C:5]2[CH:10]=[CH:11][CH:12]=[CH:13][C:4]=2[N:3]1[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1.[BrH:20].S(Cl)(Cl)=O>C(Cl)(Cl)Cl.C(O)(C)C>[C:14]1([N:3]2[C:4]3[CH:13]=[CH:12][CH:11]=[CH:10][C:5]=3[N:6]3[CH2:7][CH2:8][N:1]=[C:2]23)[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1.[BrH:20]A solution of 2,3-dihydro-2-imino-3-phenyl-1H-benzimidazole-1-ethanol [prepared by basification of the hydrobromide (2.23 g.)]and thionyl chloride (1.5 ml.) in chloroform (20 ml.) was heated under reflux for 2 hours. After removal of the solvent the oily residue was dissolved in ethanol (50 ml.), 10N aqueous sodium hydroxide solution (2ml.) added and the solution heated under reflux for 5 hours. After removal of the ethanol the residue was taken up in chloroform, washed twice with water and dried over magnesium sulphate. Removal of the chloroform gave an oil which was taken up in isopropanol and acidified with conc. hydrobromic acid. The isopropanol was evaporated and the residue crystallised from acetone. The product (0.862 g., m.p. 223°-225°C.) was recrystallised from ethanol/ether to give the title compound as its hydrobromide (0.765 g., m.p. 225°-228° C).
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