Hydrochloric Acid → 5-bromo-4-chloro-2-ethyl-1H-benzimidazole

HRID 1188492Notes

Reaction equation

HRID 1188492 reaction equation
[Br:1][C:2]1[C:3]([Cl:10])=[C:4]([NH2:9])[C:5]([NH2:8])=[CH:6][CH:7]=1.[C:11](O)(=O)[CH2:12][CH3:13].Cl>>[Br:1][C:2]1[CH:7]=[CH:6][C:5]2[NH:8][C:11]([CH2:12][CH3:13])=[N:9][C:4]=2[C:3]=1[Cl:10]

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 1032Propionic AcidHCID 578001544-Bromo-3-chlorobenzene-1,2-diamine

Product 1

HCID 578001585-bromo-4-chloro-2-ethyl-1H-benzimidazoleYield 89%

Conditions

Temperature
140 °C

Procedure

4-Bromo-3-chloro-1,2-benzenediamine (0.17 g, 0.766 mmol), propionic acid (0.17 g, 2.298 mmol), and 4 N HCl (1.724 ml, 6.894 mmol) were combined and heated to 140° C. for 3 h. Treatment with 1 N NaOH was followed by extraction with EtOAc (×3), and washing with brine. The dried (Na2SO4) organic portions were filtered, concentrated, and chromatographed (SiO2, MeOH/CH2Cl2) to obtain 0.177 g of the title compound: 1HNMR (400 MHz, CDCl3) δ 9.50 (broad s, 1H), 7.43 (d, J=8.31 Hz, 1H), 7.35 (broad s, 1H), 2.96 (q, J=7.5 Hz, 2H), 1.43 (t, J=7.5 Hz, 3H); MS (ESI) m/z 261 (M+1).

Workup

  1. extractionTreatment with 1 N NaOH was followed by extraction with EtOAc (×3)
  2. washwashing with brine
  3. dry with materialThe dried (Na2SO4) organic portions
  4. filtrationwere filtered
  5. concentrationconcentrated
  6. customchromatographed (SiO2, MeOH/CH2Cl2)

Sources & evidence

ORD record
ord-ea18b5dc1d6545018d3ace9a714eacbb
Source dataset
uspto-grants-2014_03
Patent number
US08673948B2

Reaction notes

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