Acetic Acid → 1,2-dimethyl-4-methoxy-1H-benzimidazole

HRID 636464Notes

Reaction equation

HRID 636464 reaction equation
[NH2:1][C:2]1[C:9]([O:10][CH3:11])=[CH:8][CH:7]=[CH:6][C:3]=1[NH:4][CH3:5].[C:12](O)(=O)[CH3:13]>Cl>[CH3:5][N:4]1[C:3]2[CH:6]=[CH:7][CH:8]=[C:9]([O:10][CH3:11])[C:2]=2[N:1]=[C:12]1[CH3:13]

Participants

4

Reactant 2

HCID 176Acetic AcidHCID 106069363-methoxy-N1-methylbenzene-1,2-diamine

Product 1

HCID 107024241,2-dimethyl-4-methoxy-1H-benzimidazoleYield 87.5%

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent

Procedure

A suspension of 2-amino-3-methoxy-N-methylaniline (671 mg) and acetic acid (265 mg) in 4N hydrochloric acid (3.5 ml) was refluxed for 10 hours. Insoluble material was filtered off, and the filtrate was adjusted to pH 7 with saturated sodium bicarbonate solution, and extracted with dichloromethane. The organic layers were combined, washed with brine, dried over magnesium sulfate and evaporated in vacuo. The residue was purified by silica gel flash chromatography (dichloromethane:methanol=40:1, v/v) to give 1,2-dimethyl-4-methoxy-lH-benzimidazole (680 mg). mp: 122.5-124° C.

Workup

  1. temperaturewas refluxed for 10 hours
  2. filtrationInsoluble material was filtered off
  3. extractionextracted with dichloromethane
  4. washwashed with brine
  5. dry with materialdried over magnesium sulfate
  6. customevaporated in vacuo
  7. customThe residue was purified by silica gel flash chromatography (dichloromethane

Sources & evidence

ORD record
ord-3fcd7eac702f4abfb6a34465a205367f
Source dataset
uspto-grants-2001_02
Patent number
US06194396B1

Reaction notes

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