Formic Acid → 1,3-Benzoxazole-4-carboxylic acid

HRID 382350Notes

Reaction equation

HRID 382350 reaction equation
[NH2:1][C:2]1[C:10](N)=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].[CH:12](O)=[O:13]>Cl>[O:13]1[C:10]2=[CH:9][CH:8]=[CH:7][C:3]([C:4]([OH:6])=[O:5])=[C:2]2[N:1]=[CH:12]1

Participants

4

Reactant 2

HCID 284Formic AcidHCID 1980692,3-Diaminobenzoic acid

Product 1

HCID 183546021,3-Benzoxazole-4-carboxylic acidYield 77%

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent

Procedure

A mixture of 2,3-diaminobenzoic acid (0.5 g, 3.29 mmol) and formic acid (405 μl, 9.87 mmol) in hydrochloric acid (4M, 10 ml) was heated under reflux for one hour. The precipitate which formed on cooling was collected, redissolved in boiling methanol, and decolorised with activated charcoal. Evaporation of the solvent gave benzoxazole-4-carboxylic acid as a white powder (407.9 mg, 77%) Found: C, 46.11; H, 3.63; N, 13.27. C8H6N2O2.HCl.0.5 H2O requires C, 46.28; H, 3.88; N, 13.49%; δH (d6-DMSO, 200 MHz) 7.7-7.8; (1H, t, Ar-5H), 8.2-8.3 (2H, dd, Ar-4/6H), 9.65 (1H, s, imidazole-2H).

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for one hour
  3. customThe precipitate which formed
  4. temperatureon cooling
  5. customwas collected
  6. dissolutionredissolved
  7. customEvaporation of the solvent

Sources & evidence

ORD record
ord-3eee5a06d86045f5a2db757251c83abd
Source dataset
uspto-grants-2001_10
Patent number
US06310082B1

Reaction notes

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