Phosphorus oxychloride → HCID 178526482, compound

HRID 1886047Notes

Reaction equation

HRID 1886047 reaction equation
O[C:2]1[NH:6][C:5]2[CH:7]=[CH:8][C:9]([N+:11]([O-:13])=[O:12])=[CH:10][C:4]=2[N:3]=1.P(Cl)(Cl)([Cl:16])=O>>[Cl:16][C:2]1[NH:6][C:5]2[CH:7]=[CH:8][C:9]([N+:11]([O-:13])=[O:12])=[CH:10][C:4]=2[N:3]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178526487HCID 178526487, compound

Product 1

HCID 178526482HCID 178526482, compoundYield 40%

Procedure

According to the procedure of A. T. James, et al., J. Chem. Soc., 1515 (1950), a mixture of 2-hydroxy-5-nitro-1H-benzimidazole (10.0 g, 0.0558 mol) and phosphoryl chloride (100 mL) was heated under reflux for 3 hours. The mixture was cooled, concentrated, and ice water was added. The resulting precipitate was collected by filtration. NMR analysis showed the material to be a 1:1 mixture of starting material and product. (Note: Longer heating does not improve the conversion.) Purification by flash chromatography (material preadsorbed onto silica; eluent 40% EtOAc/hexane) gave 4.4 g (40%) of the off-white solid product m.p. 215°-217° C.

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 3 hours
  3. temperatureThe mixture was cooled
  4. concentrationconcentrated
  5. additionice water was added
  6. filtrationThe resulting precipitate was collected by filtration
  7. additiona 1:1 mixture of starting material and product
  8. temperature(Note: Longer heating
  9. custom) Purification by flash chromatography (material preadsorbed onto silica; eluent 40% EtOAc/hexane)

Sources & evidence

ORD record
ord-a96d99a05afe44fca30e4b3973f0279b
Source dataset
uspto-grants-1992_09
Patent number
US05149700

Reaction notes

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