1,3-Dibromo-5,5-dimethylhydantoin → HCID 178467426, compound

To a stirred solution of 6-chloro-4-(1-cyclobutylethoxy)-3-((trans-4-methylcyclohexyl)methyl)-3H-imidazo[4,5-c]pyridine (3.5 g, 11.73 mmol) in THF (20 mL) was added 2,2,6,6-tetramethylpiperidinyl magnesium chloride lithium chloride complex (1.0 M in THF/Toluene, 29.8 mL, 29.84 mmol) at −78° C. The resulting solution was stirred 2.5 hours and then 1,3 dibromo-5,5 dimethyl hydantoin (8.5 g, 29.84 mmol) in THF (20 mL) was added dropwise at −78° C. The reaction was stirred for 30 minutes then slowly warmed to room temperature over a period of 2 hours. The reaction was quenched with saturated NH4Cl solution (50 mL) at 0° C. and extracted with EtOAc (2×20 mL). The combined organic extracts were washed with water (20 mL) and brine (20 mL), dried over anhydrous Na2SO4, filtered, and concentrated. The residue was purified by silica gel chromatography (eluting with 8-10% EtOAc/petroleum ether) to yield 2-bromo-6-chloro-4-(1-cyclobutylethoxy)-3-((trans-4-methylcyclohexyl)methyl)-3H-imidazo[4,5-c]pyridine. MS ES/APCI calc'd. for C20H27BrClN3O [M+H]+ 440. found 440.