Hydrogen Bromide → 6-Chloro-3,3-dimethyl-benzo[1,4]oxathiin-2-one

Participants

Reaction Steps

To 2-(5-chloro-2-methoxy-phenylsulfanyl)-2-methyl-propionic acid methyl ester (prepared from 5-chloro-2-methoxy-benzenesulfonyl chloride: Syn. Comm., (2001), 31, 505–510) (0.25 g, 0.9 mmol) was added 48% hydrobromic acid (5 ml). The reaction was heated to reflux for 24 hours at which time the solvent was removed by evaporation. To the crude acid phenol was added toluene (5 ml) and catalytic pyridinium p-toluenesulfonate. After 12 hours of heating at reflux the reaction was concentrated and the title compound was isolated by chromatography on silica gel (0.27 g).

Provenance & Evidence