Hydrochloric Acid → 2-chloro-1-ethyl-1H-1,3-benzodiazole

HRID 1030504Notes

Reaction equation

HRID 1030504 reaction equation
[CH2:1]([N:3]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[NH:5][C:4]1=O)[CH3:2].[ClH:13]>P(Cl)(Cl)(Cl)=O>[Cl:13][C:4]1[N:3]([CH2:1][CH3:2])[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[N:5]=1

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 823201-Ebio

Product 1

HCID 37447962-chloro-1-ethyl-1H-1,3-benzodiazoleYield 77%

Reagents, catalysts & solvents 1

HCID 24813Phosphorus oxychlorideSolvent

Procedure

1-Ethyl-2-benzimidazolinone (100 g, 0.62 mol) was dissolved in phosphorus oxychloride (475 mL) with stirring and heated to reflux temperature. Hydrogen chloride gas was passed into the refluxing solution for 4 h. Excess phosphorous oxychloride was removed on a rotary evaporator at 70° C. The residue was poured into a stirred mixture of aqueous potassium carbonate solution and methylene chloride. The mixture was basified with 50% sodium hydroxide solution and the methylene chloride layer was separated, dried (Na2SO4), concentrated, and distilled to obtain 86 g (77%) of oil, bp 110°-115° C./2-0.3 mmHg, which crystallized on standing; mp 50°-52° C.

Workup

  1. temperatureheated
  2. temperatureto reflux temperature
  3. customExcess phosphorous oxychloride was removed on a rotary evaporator at 70° C
  4. additionThe residue was poured into a stirred mixture of aqueous potassium carbonate solution and methylene chloride
  5. customthe methylene chloride layer was separated
  6. dry with materialdried (Na2SO4)
  7. concentrationconcentrated
  8. distillationdistilled

Sources & evidence

ORD record
ord-d0b33b2a66784204a8d55d8acd89aaa1
Source dataset
uspto-grants-1992_04
Patent number
US05106857

Reaction notes

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