Formic Acid → 5-Benzimidazolecarboxylic acid

HRID 339421

Reaction equation

HRID 339421 reaction equation
[NH2:1][C:2]1[CH:3]=[C:4]([CH:8]=[CH:9][C:10]=1[NH2:11])[C:5]([OH:7])=[O:6].Cl.[CH:13](O)=O>>[NH:1]1[C:2]2[CH:3]=[C:4]([C:5]([OH:7])=[O:6])[CH:8]=[CH:9][C:10]=2[N:11]=[CH:13]1

Participants

4

Reactant 3

HCID 284Formic AcidHCID 313Hydrochloric AcidHCID 692633,4-Diaminobenzoic acid

Product 1

HCID 4594565-Benzimidazolecarboxylic acid

Procedure

3,4-Diaminobenzoic acid (20 g, 0.13 mol) was suspended in formic acid (120 ml) while cooling. After that hydrochloric acid (12 ml) was added. An obtained reaction mass was agitated for 24 hours at a room temperature. Reaction mixture was filtered through fiber glass filter. Then filter cake was dissolved in water (400 ml), pH was adjusted to 2.0 with ammonia solution and reaction mass was agitated overnight. Resulting suspension was filtered, pH of filtrate was adjusted to 3.0 with ammonia solution and reaction mass was agitated for two hours. Precipitate was filtered and dried at ˜100° C. H1NMR (Brucker Avance-300, DMSO-d6, δ, ppm): 7.695 (d, H, CHAr(7)); 7.877 (dd, H, CHAr(6)); 8.25 (d, H, CHAr(4)); 8.44 (s, H, (s, H, CHAr(2)); 12.82 (s, 2H, NH, COOH). Yield was 11.3 g (54%).

Workup

  1. temperaturewhile cooling
  2. customAn obtained reaction mass
  3. customReaction mixture
  4. filtrationwas filtered through fiber glass
  5. filtrationfilter
  6. filtrationThen filter cake
  7. dissolutionwas dissolved in water (400 ml)
  8. custompH was adjusted to 2.0 with ammonia solution and reaction mass
  9. stirringwas agitated overnight
  10. customResulting suspension
  11. filtrationwas filtered
  12. custompH of filtrate was adjusted to 3.0 with ammonia solution and reaction mass
  13. stirringwas agitated for two hours
  14. filtrationPrecipitate was filtered
  15. customdried at ˜100° C

Sources & evidence

ORD record
ord-44458fcf1f6a455f97193843b5ec03b8
Source dataset
uspto-grants-2014_11
Patent number
US08895118B2

Linked notes

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