Hydrochloric Acid → 5,6-Dimethoxy-2-[5-methoxy-2-(2-pyridinyl)phenylthio]-1H-benzimidazole

HRID 1199462Notes

Reaction equation

HRID 1199462 reaction equation
[CH3:1][O:2][C:3]1[C:21]([O:22][CH3:23])=[CH:20][C:6]2[NH:7][C:8]([S:10][C:11]3[CH:16]=[C:15]([O:17][CH3:18])[CH:14]=[CH:13][C:12]=3N)=[N:9][C:5]=2[CH:4]=1.Cl.N([O-])=O.[Na+].[N:29]1[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=1>O>[CH3:1][O:2][C:3]1[C:21]([O:22][CH3:23])=[CH:20][C:6]2[NH:7][C:8]([S:10][C:11]3[CH:16]=[C:15]([O:17][CH3:18])[CH:14]=[CH:13][C:12]=3[C:30]3[CH:31]=[CH:32][CH:33]=[CH:34][N:29]=3)=[N:9][C:5]=2[CH:4]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 1049PyridineHCID 198667012-[-5,6-Dimethoxy-2-1H-benzimidazolylthio]-4-methoxy benzenamineHCID 23668193Sodium Nitrite

Product 1

HCID 198666535,6-Dimethoxy-2-[5-methoxy-2-(2-pyridinyl)phenylthio]-1H-benzimidazole

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

The product of step (b) above (500 mg) was treated with concentrated hydrochloric acid (0.8 ml) and water (0.8 ml) to form a paste. The paste was stirred at 0°-10° and a solution of sodium nitrite (105 mg) in water (0.5 ml) added dropwise. After stirring for 40 minutes the resultant solution was added slowly to pyridine (5 ml) stirred at 80°. The mixture was stirred for a further 40 minutes then concentrated in vacuo. The residue was slurried with 0.880 ammonia and the mixture again concentrated in vacuo. The residue was slurried with water and extracted with ethyl acetate. The ethyl acetate was washed with water and brine, then dried and evaporated to leave a brown gum. Flash chromatography produced the required product as a pale brown solid, MS MW 393 bp 216.

Workup

  1. customto form a paste
  2. stirringstirred at 80°
  3. stirringThe mixture was stirred for a further 40 minutes
  4. concentrationthen concentrated in vacuo
  5. concentrationthe mixture again concentrated in vacuo
  6. extractionextracted with ethyl acetate
  7. washThe ethyl acetate was washed with water and brine
  8. customdried
  9. customevaporated
  10. customto leave a brown gum

Sources & evidence

ORD record
ord-49e7dcebdfce42b28d01d0b452cb9002
Source dataset
uspto-grants-1990_02
Patent number
US04900751

Reaction notes

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