Ethyl orthoformate → 5,6-Difluorobenzimidazole

HRID 1848138Notes

Reaction equation

HRID 1848138 reaction equation
[F:1][C:2]1[CH:3]=[C:4]([NH2:10])[C:5]([NH2:9])=[CH:6][C:7]=1[F:8].[CH:11](OCC)(OCC)OCC>C(O)=O>[F:1][C:2]1[C:7]([F:8])=[CH:6][C:5]2[NH:9][CH:11]=[N:10][C:4]=2[CH:3]=1

Participants

4

Reactant 2

HCID 31214Ethyl orthoformateHCID 27367551,2-Diamino-4,5-difluorobenzene

Product 1

HCID 3453755,6-Difluorobenzimidazole

Reagents, catalysts & solvents 1

HCID 284Formic AcidSolvent

Conditions

Temperature
100 °C

Procedure

A stirred mixture of 4,5-difluorobenzene-1,2-diamine (1.40 g, 9.7 mmol) from the previous step, formic acid (2.0 mL), and triethyl orthoformate (20 mL) was heated at 100° C. for 1 h. The reaction mixture was cooled to rt and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography eluting with 5% MeOH in DCM to afford 5,6-difluoro-1H-benzo[d]imidazole as (1.12 g, 75%) as a white solid. 1H NMR (300 MHz, CDCl3) δ 8.07 (s, 1H), 7.44 (m, 2H); LCMS (ESI) m/z 155 (M+H)+.

Workup

  1. temperatureThe reaction mixture was cooled to rt
  2. concentrationconcentrated under reduced pressure
  3. customThe residue was purified by silica gel flash chromatography
  4. washeluting with 5% MeOH in DCM

Sources & evidence

ORD record
ord-360d5bcb7c444ebface45b82daa633ab
Source dataset
uspto-grants-2015_02
Patent number
US08952058B2

Reaction notes

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