Acetic Acid → 4-bromo-2-methyl-6-nitro-1H-benzo[d]imidazole

Reaction equation

[Br:1][C:2]1[CH:7]=[C:6]([N+:8]([O-:10])=[O:9])[CH:5]=[C:4]([NH2:11])[C:3]=1[NH2:12].[C:13](O)(=O)[CH3:14]>>[Br:1][C:2]1[C:3]2[N:12]=[C:13]([CH3:14])[NH:11][C:4]=2[CH:5]=[C:6]([N+:8]([O-:10])=[O:9])[CH:7]=1

Participants

Reactant 2

HCID 176Acetic Acid

HCID 203480123-Bromo-5-nitrobenzene-1,2-diamine

Product 1

HCID 866878134-bromo-2-methyl-6-nitro-1H-benzo[d]imidazoleYield 56.6%

Procedure

A mixture of 3-bromo-5-nitrobenzene-1,2-diamine (90 g, 389 mmol) in acetic acid (800 mL) was stirred under reflux for 18 h. The solvent was removed in vacuo. The residue was purified by silica gel column chromatography (petroleum ether/ethyl acetate=1/1) to give the product (56 g, 56.6%) as a brown solid; LC/MS: MS (ES+) m/e 256 [M+H]+; 1H NMR (300 MHz, DMSO-d6) δ ppm 2.60 (s, 3H), 8.20 (d, J=1.8 Hz, 3H), 8.34 (d, J=1.8 Hz, 2H), 13.25 (s, br, 1H).

Workup

temperatureunder reflux for 18 h
customThe solvent was removed in vacuo
customThe residue was purified by silica gel column chromatography (petroleum ether/ethyl acetate=1/1)

Sources & evidence

ORD record: ord-9d893dcbf9fc41ed921e36f3dfd92431
Source dataset: uspto-grants-2014_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08778937B2

Reaction notes

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