2-Amino-4-Bromophenol → 5-Bromo-1,3-benzoxazole-2-thiol

HRID 2116702Notes

Reaction equation

HRID 2116702 reaction equation
O(CC)[C:2]([S-])=[S:3].[K+].[NH2:8][C:9]1[CH:14]=[C:13]([Br:15])[CH:12]=[CH:11][C:10]=1[OH:16]>CCO>[Br:15][C:13]1[CH:12]=[CH:11][C:10]2[O:16][C:2](=[S:3])[NH:8][C:9]=2[CH:14]=1

Participants

4

Reactant 2

HCID 3518402-Amino-4-BromophenolHCID 2735045Potassium ethylxanthate

Product 1

HCID 106331975-Bromo-1,3-benzoxazole-2-thiolYield 90.3%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Potassium ethyl xanthate (416 mg, 2.60 mmol) was added to a solution of 2-amino-4-bromophenol (244 mg, 1.30 mmol) in EtOH (3.24 mL). The reaction mixture was heated at reflux for 4 h. Upon cooling to RT the mixture was concentrated and the resulting residue was dissolved in water. Acetic acid was added until pH=5 and a white solid precipitated from the solution. The solid was filtered, washed with water and dried to afford 270 mg (90%) of a tan powder which was used without further purification: 1H NMR (d6-DMSO, 400 MHz) δ 14.02 (s, 1H), 7.47-7.38 (m, 3H); 13C (d6-DMSO, 400 MHz) δ 181.4, 148.1, 133.7, 127.1, 117.8, 118.8, 112.2; MS (Cl) m/z 229.8 (M−1); HPLC retention time=4.34 min.

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureat reflux for 4 h
  3. concentrationwas concentrated
  4. dissolutionthe resulting residue was dissolved in water
  5. additionAcetic acid was added until pH=5
  6. customa white solid precipitated from the solution
  7. filtrationThe solid was filtered
  8. washwashed with water
  9. customdried

Sources & evidence

ORD record
ord-980f9ce5cfe2419f9f4616f985618ba0
Source dataset
uspto-grants-2008_10
Patent number
US07439236B2

Reaction notes

Loading…