[Potentially CNS-active tricyclic compounds with a bridged central ring. 3. Synthesis of partially hydrogenated...

The synthesis of 9,10-epithio-9,10-dihydroanthracenes is presented. Since the direct synthesis from benzo[c]thiophene and dehydrobenzene was not possible, benzo[c]thiophene and 1,4-benzoquinone were reacted by means of Diels-Alder cyclization to 9,10-epithio-1,4,9,10-tetrahydro-1,4-dioxoanthracene, which we intended to convert into 9,10-epithio-9,10-dihydroanthracene after intermediate transfer to suitable derivatives. The configurations at the connection points 4a and 9a of the partly or completely hydrogenated derivatives in one ring were ascertained, as were those in positions 1 and 4, Sp2-hybridisation of both the C-atoms 4a and 9a resulted in the elimination of the sulphur atom.