p-Toluenesulfonic acid → Ethyl (([5,5-dimethyl-2-(4-methylphenyl)-1,3-dioxan-2-yl]methyl}thio)acetate

Participants

Reaction Steps

Ethyl {[2-(4-methylphenyl)-2-oxoethyl]thio}acetate (12.2 g, 48.4 mmol) was dissolved in benzene (350 ml). 2,2-Dimethyl-1,3-propanediol (40.3 g, 0.387 mol) and p-toluene sulfonic acid (1 g) were added. The mixture was stirred at reflux in a Dean-Stark apparatus for two hours, cooled and concentrated under reduced pressure. CH2Cl2 was added and the organic phase was washed twice with brine and dried (MgSO4). Filtration and concentration under reduced pressure afforded a crude oil, which was purified by flash-chromatography (hexane:EtOAc 8:1) to afford 10.0 g (61%) of the title compound as a clear oil.

Provenance & Evidence