Lithium Bromide → 2-(bromomethyl)-1-methyl-4-nitro-1H-imidazole

Participants

Reaction Steps

A mixture of 2-(chloromethyl)-1-methyl-4-nitro-1H-imidazole (485 mg, 2.76 mmol) and LiBr (4.80 g, 55.2 mmol) in acetone was heated at reflux for 5 hours before all the solvent was removed under reduced pressure. The residue was partitioned between ethyl acetate and water. The aqueous phase was extracted with ethyl acetate twice. The combined organic phase was washed with brine, dried over Na2SO4 and concentrated in vacuo. The crude product was recrystallised from DCM/hexane to give 2-(bromomethyl)-1-methyl-4-nitro-1H-imidazole (105) (576 mg, 95%) as an off-white solid, m.p. 130-132° C. 1H NMR (CDCl3, 400 MHz) δ 7.74 (s, 1H), 4.50 (s, 2H), 3.83 (s, 3H). Analysis found: C, 27.81; H, 3.27; N, 19.05. C5H6BrN3O2.0.04hexane requires: C, 28.16; H, 2.96; N, 18.80. HRMS (FAB+) found: 219.97220, 221.97018 (M+1), calcd. for C5H779/81BrN3O2: 219.97216, 221.97012.

Provenance & Evidence