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

HRID 1276170Notes

Reaction equation

HRID 1276170 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-benzimidazole-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-414953190d1f4247917490e2af1e0582
Source dataset
uspto-grants-2000_12
Patent number
US06166011

Reaction notes

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