5-Bromo-1-methyl-1H-imidazole → Bis(1-methyl-1H-imidazol-5-yl)methanone

Participants

Reaction Steps

To a solution of 5-bromo-1-methyl-1H-imidazole (1.2 g, 7.45 mmol) in DCM (10 mL) was added ethyl magnesium bromide (2.5 mL, 7.45 mmol, 3.0 M in diethyl ether) dropwise over a 10 minute period. The resulting pale yellow solution was stirred at room temperature for 15 minutes, cooled in an ice bath to 0° C. and then N-methoxy-N,1-dimethyl-1H-imidazole-5-carboxamide (1.0 g, 6.21 mmol, Intermediate 55: step a) dissolved in DCM (3 mL) was added dropwise. The cold bath was removed and the reaction mixture stirred at room temperature for 48 hours. To the resulting yellow suspension was added water followed by 6 M aqueous HCl to a neutral pH (pH=6-7). The aqueous mixture was extracted with DCM (2×). The combined DCM extracts were dried over MgSO4, filtered and concentrated under reduced pressure. The product was precipitated with Et2O, filtered and dried to provide the title compound as a tan solid.

Provenance & Evidence