Dimethyl Sulfoxide → HCID 178478697, compound

4-(3-amino-propyl)-1H-imidazol-2-ylamine 16 (0.200 g, 0.930 mmol) was dissolved in anhydrous dimethyl sulfoxide (6 mL) Bromine (0.047 mL, 0.930 mmol) was added drop-wise and the solution was stirred at room temperature for 1 h. Diethyl ether (7 mL) was added and the organics were then decanted. The residue was purified by column chromatography (MeOH sat. with NH3) to yield the desired product as its free base. Addition of concentrated hydrochloric acid to a methanol solution (8 mL) of the free base followed by evaporation under reduced pressure afforded the target compound ((Z)-isomer exclusively) (0.141 g, 67%) as a tan solid: 1H NMR (300 MHz, DMSO-d6) δ 12.10 (br s, 1H), 9.20 (br s, 2H), 8.18 (br s, 2H), 5.92 (t, 1H, J=7.8 Hz), 2.96 (m, 2H), 2.66 (m, 2H); 13C NMR (100 MHz, DMSO-d6) δ 164.13, 156.63, 130.88, 113.70, 37.57, 24.94; HRMS (FAB) calcd for C6H10N4O (MH+) 155.0933, found 155.0943.