Trimethyl orthoformate → 1,3-Benzoxazole-7-carboxylic acid

HRID 560306Notes

Reaction equation

HRID 560306 reaction equation
[NH2:1][C:2]1[C:3]([OH:11])=[C:4]([CH:8]=[CH:9][CH:10]=1)[C:5]([OH:7])=[O:6].[CH:12](OC)(OC)OC>>[O:11]1[C:3]2[C:4]([C:5]([OH:7])=[O:6])=[CH:8][CH:9]=[CH:10][C:2]=2[N:1]=[CH:12]1

Participants

3

Reactant 2

HCID 9005Trimethyl orthoformateHCID 684433-Aminosalicylic acid

Product 1

HCID 183553101,3-Benzoxazole-7-carboxylic acid

Procedure

A solution of 3-amino-2-hydroxy-benzoic acid (12.5 mmol) in trimethyl orthoformate (19.2 mL) is heated to reflux for 20 h and concentrated in vacuo. The residue is washed three times with hot MeOH, the filtrates are combined and the solvent is removed in vacuo to give the desired product which is used without further purification. 1H-NMR (DMSO-d6): δ=13.4 (bs, 1H); 8.87 (s, 1H); 8.08 (d, J=8.0 Hz, 1H); 7.96 (d, J=7.5 Hz, 1H); 7.52 (t, J=7.9 Hz, 1H).

Workup

  1. temperatureto reflux for 20 h
  2. concentrationconcentrated in vacuo
  3. washThe residue is washed three times with hot MeOH
  4. customthe solvent is removed in vacuo

Sources & evidence

ORD record
ord-eb43d318344b4462a94fa34419a801f6
Source dataset
uspto-grants-2011_11
Patent number
US08063099B2

Reaction notes

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