Über die Reaktion substituierter Thioxanthenoxide mit Säuren

9-[(N-Methyl-3′-piperidyl)-methyl]-thioxanthene-10-oxide (I) on treatment with boiling concentrated hydrochloric acid gives mainly 9-[(N-methyl-3′-piperidyl)-methylene]-thioxanthene (IV) together with small amounts of 9-[(N-methyl-3′-piperidyl)-chloro-methylene]-thioxanthene(II), 9-hydroxy-9-[(N-methyl-3′-piperidyl)-methyl]-thioxanthene (III) and 9-[(N-methyl-3′-piperidyl)-methyl]-thioxanthene (V). Treatment of I with acetic anhydride yields only IV.