p-Toluenesulfonic acid → N-(4-chlorophenyl)-6-methyl-2,3-dihydro-1,4-dithiine-5-carboxamide

Participants

Reaction Steps

2-Chloro-N-(4-chlorophenyl)-3-oxobutanamide (24.7 g, 0.1 mole), 1,2-ethanedithiol (9.4 g, 0.1 mole) and a small amount of p-toluenesulfonic acid were heated under reflux in benzene (150 ml), using a Dean-Stark trap to remove water (1.9 ml collected). The reaction mixture was filtered, treated with triethylamine (8 ml), and refluxed for a further 30 minutes. The mixture was then washed with water, dilute hydrochloric acid, and water. Evaporation of the benzene gave a white solid, which was recrystallized from absolute ethanol. The product melted at 115°-117° C. (24 g, 84% yield).

Provenance & Evidence