Water → 2,6-Dithia-s-indacene-4,8-dione

Participants

Reaction Steps

48.5 g (68.5 millimoles) of 2,3,5,6-tetra-(benzoylthiomethyl)-p-benzoquinone were suspended in 450 ml of ethylene glycol, and 32.8 g (411 millimoles) of 50% strength sodium hydroxide solution were added, while stirring thoroughly. A strong jet of compressed air was then passed through the reaction mixture, and the latter was slowly heated up. At an internal temperature of 70° C., the dark mixture became homogeneous. The internal temperature was increased to 90°-100° C., and thorough stirring was continued at this temperature for 5 hours, while compressed air was continuously passed through. The mixture was cooled, 700 ml of water were added and stirring was continued for a further 0.5 hour, while cooling with ice. The solid material was filtered off under suction and washed with a large amount of water. 11.0 g (73%) of 4,8-dihydrobenzo[1,2-c:4,5-c']dithiophene-4,8-dione of melting point 340° C. were isolated.

Provenance & Evidence