3-Hydroxyanthranilic Acid → 2-Oxo-2,3-dihydro-1,3-benzoxazole-4-carboxylic acid

HRID 1505202Notes

Reaction equation

HRID 1505202 reaction equation
[NH2:1][C:2]1[C:10]([OH:11])=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].C1N=CN([C:17](N2C=NC=C2)=[O:18])C=1>C1COCC1>[O:18]=[C:17]1[NH:1][C:2]2=[C:3]([C:4]([OH:6])=[O:5])[CH:7]=[CH:8][CH:9]=[C:10]2[O:11]1

Participants

4

Reactant 2

HCID 863-Hydroxyanthranilic AcidHCID 682631,1'-Carbonyldiimidazole

Product 1

HCID 109210912-Oxo-2,3-dihydro-1,3-benzoxazole-4-carboxylic acidYield 37.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
80 °C

Procedure

2-amino-3-hydroxybenzoic acid (1.2 g, 7.8 mmol) was suspended in 20 ml of THF and at 0° C. CDI (1.9 g, 1.5 equiv.) was added. The mixture was warmed at 80° C. for 5 hours. The solvent was evaporated and the crude was dissolved in AcOEt (30 ml) and washed with water (1×20 ml) and brine. The organic phase was dried over sodium sulfate and concentrated under vacuum. The purification of the crude residue by crystallization from EtOAc/ether gave 520 mg of an orange solid. Yield=37% 1HNMR (DMSO, 200 MHz) δ 7.45 (3H, m), 10.40 (1H, bs), 12.00 (1H, bs)

Workup

  1. customThe solvent was evaporated
  2. dissolutionthe crude was dissolved in AcOEt (30 ml)
  3. washwashed with water (1×20 ml) and brine
  4. dry with materialThe organic phase was dried over sodium sulfate
  5. concentrationconcentrated under vacuum
  6. customThe purification of the crude residue
  7. customby crystallization from EtOAc/ether

Sources & evidence

ORD record
ord-b9e4e97d1e594ff3b3292481197f5500
Source dataset
uspto-grants-2015_12
Patent number
US09216975B2

Reaction notes

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