Reaction #11787

Reaction equation

2-(5-chloro-2-methoxy-phenylsulfanyl)-2-methyl-propionic acid methyl ester

hydrobromic acid

→

title compound

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

Conditions

Workup

1. 1
   TemperatureThe reaction was heated
2. 2
   Temperatureto reflux for 24 hours at which time the solvent
3. 3
   Otherwas removed by evaporation
4. 4
   workup.ADDITIONTo the crude acid phenol was added toluene (5 ml) and catalytic pyridinium p-toluenesulfonate
5. 5
   TemperatureAfter 12 hours of heating
6. 6
   Temperatureat reflux the reaction
7. 7
   Concentrationwas concentrated

Procedure

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).

Source