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

HRID 2064767Notes

Reaction equation

HRID 2064767 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-a3fc63cda01540df82fa25a92ae279d7
Source dataset
uspto-grants-2012_10
Patent number
US08288435B2

Reaction notes

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