Hydrochloric Acid → 2-[p-Carboxyphenyl]-5,6-diaminobenzimidazole hydrochloride

HRID 1414376Notes

Reaction equation

HRID 1414376 reaction equation
[C:1]([C:4]1[CH:9]=[CH:8][C:7]([C:10]2[NH:11][C:12]3[C:18]([N+:19]([O-])=O)=[C:17]([N+:22]([O-])=O)[CH:16]=[CH:15][C:13]=3[N:14]=2)=[CH:6][CH:5]=1)([OH:3])=[O:2].[ClH:25].[H][H]>CO.[Pd]>[ClH:25].[C:1]([C:4]1[CH:9]=[CH:8][C:7]([C:10]2[NH:11][C:15]3[CH:16]=[C:17]([NH2:22])[C:18]([NH2:19])=[CH:12][C:13]=3[N:14]=2)=[CH:6][CH:5]=1)([OH:3])=[O:2]

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 178418361HCID 178418361, compoundHCID 178524232HCID 178524232, compound

Product 1

HCID 214872132-[p-Carboxyphenyl]-5,6-diaminobenzimidazole hydrochlorideYield 82%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 887MethanolSolvent

Procedure

A solution of 5 g (16.7 mmole) of 2-[p-carboxyphenyl]-5,6-dinitrobenzimidazole (as prepared in Example I) in 200 ml of methanol at 0° C was thoroughly purged with nitrogen. To this was added 500 mg of 10% palladium on charcoal, and 30 ml of concentrated HCl. The hydrogenation flask was then pressurized with 55 lbs/in2 of hydrogen, and the flask was shaken at room temperature for 8 hours. After the reaction period had elapsed, the solution was filtered by suction, and the filtrate evaporated to dryness in vacuo. The residual yellow solid was redissolved in a minimum amount of boiling methanol (which contained a trace of HCl), and the filtered solution added to 50 ml of concentrated HCl. Removal of the methanol from the solution in vacuo and subsequent cooling in ice yielded 4.2 g (82%) of 2-[p-carboxyphenyl]-5,6-diaminobenzimidazole hydrochloride as fluffy yellow needles.

Workup

  1. customAfter the reaction period
  2. filtrationthe solution was filtered by suction
  3. customthe filtrate evaporated to dryness in vacuo
  4. dissolutionThe residual yellow solid was redissolved in a minimum amount of boiling methanol (which
  5. additionadded to 50 ml of concentrated HCl
  6. customRemoval of the methanol from the solution in vacuo
  7. temperaturesubsequent cooling in ice

Sources & evidence

ORD record
ord-b0d247dfd38644deaceefc02493dc571
Source dataset
uspto-grants-1977_01
Patent number
US04001268

Reaction notes

Loading…