Synthesis of thianthrene derivatives linked by carbon chains

Dithianthren-1-ylmethanol and 1,1′-methylenedithianthrene were prepared and their reactions were studied. Lithiation of 1,1′- methylenedithianthrene took place on the methylene carbon rather than on the thianthrene framework, and when the lithiated derivative was allowed to react with thianthren-1-ylcarbaldehyde, sterically hindered 1,2,2-trithianthren-1- ylethanol was obtained in good yield. The structures of 1,1′- methylenedithianthrene and 1,2,2-trithianthren-1-ylethanol were confirmed by X-ray crystallography. To clarify the nature and reactivity of thianthrene derivatives, we also prepared 1,6-(thianthren-1,9-diyl)hexane-1,6-diol (5,6,7,8,9,10-hexahydro-1,14-epithiodibenzo[b,j]thiacycloundecine-5,10-diol) as a model compound in which the 1- and 9-positions of thianthrene are bridged by a carbon chain.