Phosphorus oxychloride → 2-Chloro-5-iodo-1H-benzo[d]imidazole

HRID 2298853Notes

Reaction equation

HRID 2298853 reaction equation
[I:1][C:2]1[CH:11]=[CH:10][C:5]2[NH:6][C:7](=O)[NH:8][C:4]=2[CH:3]=1.P(Cl)(Cl)([Cl:14])=O>>[Cl:14][C:7]1[NH:8][C:4]2[CH:3]=[C:2]([I:1])[CH:11]=[CH:10][C:5]=2[N:6]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 120716615-IODO-1,3-DIHYDRO-BENZIMIDAZOL-2-ONE

Product 1

HCID 120716622-Chloro-5-iodo-1H-benzo[d]imidazole

Conditions

Temperature
120 °C

Procedure

5-Iodo-1,3-dihydro-2H-1,3-benzimidazol-2-one (7 g) [see Preparation 24] was added to a solution of phosphoryl chloride (135 ml). The reaction mixture was then heated to 120° C. and stirred for 2 hours, after which time the phosphoryl chloride was removed under reduced pressure and the residue diluted with water. The residual aqueous solution was neutralised with aqueous potassium hydrogen carbonate solution and the product extracted with 90:10, by volume, dichloromethane:methanol, dried over magnesium sulphate and the solvent removed under reduced pressure to afford 2-chloro-6-iodo-1H-1,3-benzimidazole (3.68 g) as a white solid.

Workup

  1. customafter which time the phosphoryl chloride was removed under reduced pressure
  2. additionthe residue diluted with water
  3. extractionthe product extracted with 90:10, by volume, dichloromethane
  4. dry with materialmethanol, dried over magnesium sulphate
  5. customthe solvent removed under reduced pressure

Sources & evidence

ORD record
ord-4ba0c5d9182f47faa794d136f56836ea
Source dataset
uspto-grants-2002_12
Patent number
US06495549B1

Reaction notes

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