2,5-Dichlorobenzoic acid → 2-(2,5-Dichlorophenyl)-1,3-benzoxazole

HRID 1378551Notes

Reaction equation

HRID 1378551 reaction equation
[Cl:1][C:2]1[CH:10]=[CH:9][C:8]([Cl:11])=[CH:7][C:3]=1[C:4]([OH:6])=O.[NH2:12][C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][C:14]=1O>>[Cl:1][C:2]1[CH:10]=[CH:9][C:8]([Cl:11])=[CH:7][C:3]=1[C:4]1[O:6][C:14]2[CH:15]=[CH:16][CH:17]=[CH:18][C:13]=2[N:12]=1

Participants

3

Reactant 2

HCID 57842,5-Dichlorobenzoic acidHCID 58012-Aminophenol

Product 1

HCID 145128882-(2,5-Dichlorophenyl)-1,3-benzoxazoleYield 47.2%

Procedure

2,5-Dichlorobenzoic acid (800 g, 4.2 mol), 2-aminophenol (415 g, 3.8 mol) and polyphosphoric acid (1600 g) were placed in a flask and heated at 180°-190° C. for 2 days. The viscous dark solution was poured onto ice while hot. The solid was collected by filtration and washed with water thoroughly. The solid cake was transferred into a large beaker and stirred with 2 liters of saturated aqueous sodium bicarbonate for 16 hours. The brownish suspension was filtered and washed with water and dried at 80° C. overnight to give 1 kg of crude product. The crude product was purified by recrystallization from cyclohexane twice to give 474 g of monomer as white crystals.

Workup

  1. temperatureheated at 180°-190° C. for 2 days
  2. additionThe viscous dark solution was poured onto ice while hot
  3. filtrationThe solid was collected by filtration
  4. washwashed with water thoroughly
  5. filtrationThe brownish suspension was filtered
  6. washwashed with water
  7. customdried at 80° C. overnight
  8. customto give 1 kg of crude product
  9. customThe crude product was purified by recrystallization from cyclohexane twice

Sources & evidence

ORD record
ord-1b6313b88a3e4f49a90a96a4c0135ce0
Source dataset
uspto-grants-1997_09
Patent number
US05668245

Reaction notes

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