Formic Acid → Ethyl 1H-benzimidazole-6-carboxylate

HRID 1771113Notes

Reaction equation

HRID 1771113 reaction equation
[CH2:1]([O:3][C:4](=[O:13])[C:5]1[CH:10]=[CH:9][C:8]([NH2:11])=[C:7]([NH2:12])[CH:6]=1)[CH3:2].[CH:14](O)=O>>[CH2:1]([O:3][C:4]([C:5]1[CH:10]=[CH:9][C:8]2[N:11]=[CH:14][NH:12][C:7]=2[CH:6]=1)=[O:13])[CH3:2]

Participants

3

Reactant 2

HCID 284Formic AcidHCID 458855Ethyl 3,4-Diaminobenzoate

Product 1

HCID 13505555Ethyl 1H-benzimidazole-6-carboxylateYield 70.2%

Procedure

40 g of 3,4-diaminobenzoic acid ethyl ester (0.22 mol) and 200 mL formic acid were added to a three-necked bottle. After refluxing for 7 h, the reaction was completed. After concentration under reduced pressure, the ice water was poured into the residual solution. The resulting mixture was adjusted to pH 7 with sodium hydroxide. After sucking filtration, the filtrate was extracted with dichloromethane thrice, dried with anhydrous sodium sulfate, and decolored with active charcoal. Then the solution was concentrated under reduced pressure to get a white solid (29.6 g). Yield: 70.2%. MS: 191 (M+1)

Workup

  1. temperatureAfter refluxing for 7 h
  2. concentrationAfter concentration under reduced pressure
  3. additionthe ice water was poured into the residual solution
  4. filtrationfiltration
  5. extractionthe filtrate was extracted with dichloromethane thrice
  6. dry with materialdried with anhydrous sodium sulfate
  7. concentrationThen the solution was concentrated under reduced pressure

Sources & evidence

ORD record
ord-a16637dcbc524997aefbca1df5810515
Source dataset
uspto-grants-2016_02
Patent number
US09249106B2

Reaction notes

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