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

HRID 1520729Notes

Reaction equation

HRID 1520729 reaction equation
Cl[CH2:2][C:3]1[N:4]([CH3:11])[CH:5]=[C:6]([N+:8]([O-:10])=[O:9])[N:7]=1.[Li+].[Br-:13]>CC(C)=O>[Br:13][CH2:2][C:3]1[N:4]([CH3:11])[CH:5]=[C:6]([N+:8]([O-:10])=[O:9])[N:7]=1

Participants

4

Reactant 2

HCID 82050Lithium BromideHCID 141113082-(chloromethyl)-1-methyl-4-nitro-1H-imidazole

Product 1

HCID 668237632-(bromomethyl)-1-methyl-4-nitro-1H-imidazoleYield 95%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

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.

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 5 hours before all the solvent
  3. customwas removed under reduced pressure
  4. customThe residue was partitioned between ethyl acetate and water
  5. extractionThe aqueous phase was extracted with ethyl acetate twice
  6. washThe combined organic phase was washed with brine
  7. dry with materialdried over Na2SO4
  8. concentrationconcentrated in vacuo
  9. customThe crude product was recrystallised from DCM/hexane

Sources & evidence

ORD record
ord-fb7fb36245b34f0d8ef611210d4ce8ff
Source dataset
uspto-grants-2015_07
Patent number
US09073916B2

Reaction notes

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