Sodium Hydroxide → 2,5,6-Trichloro-1H-benzimidazole

HRID 919358Notes

Reaction equation

HRID 919358 reaction equation
[Cl:1][C:2]1[C:11]([Cl:12])=[CH:10][C:5]2[NH:6][C:7](=O)[NH:8][C:4]=2[CH:3]=1.[OH-].[Na+].O=P(Cl)(Cl)[Cl:17]>>[Cl:17][C:7]1[NH:6][C:5]2[CH:10]=[C:11]([Cl:12])[C:2]([Cl:1])=[CH:3][C:4]=2[N:8]=1

Participants

4

Reactant 3

HCID 14798Sodium HydroxideHCID 24813Phosphorus oxychlorideHCID 98991485,6-Dichloro-1,3-Dihydro-2H-Benzimidazol-2-One

Product 1

HCID 2860092,5,6-Trichloro-1H-benzimidazoleYield 90%

Procedure

Thoroughly dried 5,6-dichloro-1,3-dihydro-benzoimidazol-2-one (28.4 g, 0.14 mol) was suspended in POCl3 (75 mL). The reaction solution was heated to reflux temperature for 3 hours and cooled to room temperature. The solution was poured into crushed ice/water (1.5 L) slowly with sufficient stirring. The solution was neutralized to pH=7.0 with NaOH. The precipitated solid was collected by filtration, washed with water, and dried to afford the title compound (27.9 g, 90%). The crude product was used in the following reaction without further purification.

Workup

  1. temperatureThe reaction solution was heated
  2. temperatureto reflux temperature for 3 hours
  3. additionThe solution was poured
  4. filtrationThe precipitated solid was collected by filtration
  5. washwashed with water
  6. customdried

Sources & evidence

ORD record
ord-1ea956d96d8a47559c88e583115df21f
Source dataset
uspto-grants-2016_03
Patent number
US09273034B2

Reaction notes

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