Hydrogen Bromide → 1-(3-Bromopropyl)-5-chloro-1,3-dihydro-2H-benzimidazol-2-one

HRID 345533

Reaction equation

HRID 345533 reaction equation
[Cl:1][C:2]1[CH:15]=[CH:14][C:5]2[N:6]([CH2:10][CH2:11][CH2:12]O)[C:7](=[O:9])[NH:8][C:4]=2[CH:3]=1.[BrH:16]>O>[Br:16][CH2:12][CH2:11][CH2:10][N:6]1[C:5]2[CH:14]=[CH:15][C:2]([Cl:1])=[CH:3][C:4]=2[NH:8][C:7]1=[O:9]

Participants

4

Reactant 2

HCID 260Hydrogen BromideHCID 30173585-chloro-1,3-dihydro-1-(3-hydroxypropyl)-2H-benzimidazol-2-one

Product 1

HCID 30174131-(3-Bromopropyl)-5-chloro-1,3-dihydro-2H-benzimidazol-2-one

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A mixture of 9.3 parts of 5-chloro-1,3-dihydro-1-(3-hydroxypropyl)-2H-benzimidazol-2-one and 83 parts of a hydrobromic acid solution 48% in water was stirred and refluxed for 6 hours. The reaction mixture was cooled and allowed to crystallize overnight at room temperature. The precipitated product was filtered off and stirred a few times in 100 parts of water till the pH of the filtrate was greater than 2. The product was stirred and refluxed for 1 hour in 55 parts of chlorobenzene with 1.3 parts of activated charcoal. The latter was filtered off and the filtrate was allowed to crystallize overnight in an ice-box. The product was filtered off and recrystallized twice: first from chlorobenzene (activated charcoal) and then from methylbenzene (activated charcoal), yielding 4.9 parts of 1-(3-bromopropyl)-5-chloro-1,3-dihydro-2H-benzimidazol-2-one; mp. 161.5° C. (intermediate 29).

Workup

  1. temperaturerefluxed for 6 hours
  2. temperatureThe reaction mixture was cooled
  3. customto crystallize overnight at room temperature
  4. filtrationThe precipitated product was filtered off
  5. stirringstirred a few times in 100 parts of water till the pH of the filtrate
  6. stirringThe product was stirred
  7. temperaturerefluxed for 1 hour in 55 parts of chlorobenzene with 1.3 parts of activated charcoal
  8. filtrationThe latter was filtered off
  9. customto crystallize overnight in an ice-box
  10. filtrationThe product was filtered off
  11. customrecrystallized twice

Sources & evidence

ORD record
ord-2d9807367f624437855d276f5313be54
Source dataset
uspto-grants-1991_10
Patent number
US05057525

Linked notes

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