4-Bromo-5-chloroimidazole synthesis

Yield:17487-98-8 65.4%

Reaction Conditions:

Stage #1: 4-bromo-1 H-imidazolewith sodium chlorine monoxide;sodium hydroxide in water monomer at 20; for 1.33333 h;
Stage #2: with pyrographite in water monomer; for 1 h;

Steps:

Synthesis of 4-bromo-5-chloroimidazole (HBrClIm):

For the synthesis of 4-bromo-5-chloroimidazole 4, first, the imidazole 1 was reacted with bromide using sodium acetate as the base and acetic acid as a solvent to obtain the 2,4,5-tribromoimidazole 2 with a yield of 52%. Next, precursor 2 was reacted with sodium sulfite under reflux for 4 h to yield the 4-bromoimidazole 3 as a white solid with a 72% yield. Finally, compound 3 (5.0 g, 34 mmol), sodium hydroxide (1.36 g, 34 mmol) in water (35 mL) were combined in a 100 mL flask. Then, a sodium hypochlorite (Clorox 8.25%) solution was added, and the reaction mixture was left under stirring for 80 min at room temperature. Next, carbon (1.0 g) was added to the solution, and the mixture was stirred vigorously. After 60 min, the mixture was filtered and washed with water (100 mL). The solution obtained was adjusted at pH 6-7 with concentrated hydrochloride acid. The white precipitate was filtered, washed with water (100 mL), and dried under vacuum to yield 4.04 g (65.4%) of white solid (Scheme 1), mp 196-198 °C; ¹H-NMR (700 MHz, DMSO-d6): d 13.19 (bs, 1H, NH), 7.77 (s, 1H, CH); ¹³C-NMR (176 MHz, DMSO-d6): d 136.0, 123.1, 100.2. HRMS (ESI⁺) calcd for C₃H₃BrClN₂ [M+H]⁺ 180.9168, found 180.9149

References:

Davila-Guzman, Nancy E.;Fonseca-García, Abril;Garza-Navarro, M. A.;Hernández-Fernández, Eugenio;Juárez-Ramírez, Isaías;Michaelis, David J.;Raziel álvarez, J.;Rico-Barragan, Alan;Rodríguez-Hernández, Joelis;Tiempos-Flores, Norma [Polyhedron,2022,vol. 217,art. no. 115736] Location in patent:supporting information