Thionyl Chloride → 2-Chloro-1,3-benzoxazol-6-OL

HRID 2119402Notes

Reaction equation

HRID 2119402 reaction equation
S[C:2]1[O:3][C:4]2[CH:10]=[C:9]([OH:11])[CH:8]=[CH:7][C:5]=2[N:6]=1.S(Cl)([Cl:14])=O>CN(C)C=O>[Cl:14][C:2]1[O:3][C:4]2[CH:10]=[C:9]([OH:11])[CH:8]=[CH:7][C:5]=2[N:6]=1

Participants

4

Reactant 2

HCID 24386Thionyl ChlorideHCID 178515778HCID 178515778, compound

Product 1

HCID 234412462-Chloro-1,3-benzoxazol-6-OL

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

2-Sulfanyl-1,3-benzoxazol-6-ol (2.08 g) [see Preparation 33] was added to thionyl chloride (12.3 ml), followed by dimethylformamide (0.93 ml). The reaction mixture was heated to reflux for 5 minutes, after which time the mixture was allowed to cool. The solvent was removed under reduced pressure, the residue azeotroped twice with xylene, and the residue then partitioned between diethyl ether and water. The organic layer was separated, dried over magnesium sulphate and the solvent removed under reduced pressure. The crude product was purified by column chromatography on silica gel eluting with a solvent gradient of 100:0 changing to 0:100, by volume, hexane:ethyl acetate in 50% increments to afford 2-chloro-1,3-benzoxazol-6-ol (1.715 g) as a white solid.

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureto reflux for 5 minutes
  3. temperatureto cool
  4. customThe solvent was removed under reduced pressure
  5. customthe residue azeotroped twice with xylene
  6. customthe residue then partitioned between diethyl ether and water
  7. customThe organic layer was separated
  8. dry with materialdried over magnesium sulphate
  9. customthe solvent removed under reduced pressure
  10. customThe crude product was purified by column chromatography on silica gel eluting with a solvent gradient of 100:0 changing to 0:100, by volume, hexane

Sources & evidence

ORD record
ord-4675d684eee54494bb951f302fb152fa
Source dataset
uspto-grants-2004_02
Patent number
US06686357B1

Reaction notes

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