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

Participants

Reaction Steps

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.

Provenance & Evidence