The condensation of 3-methoxybenzenethiol (I) with 2,6-dichloro-3-nitrobenzoic acid (II) produced the (arylthio)benzoic acid (III). Intramolecular cyclization of (III) to the thioxanthenone (IV) was effected by treatment with trifluoroacetic anhydride in trifluoroacetic acid. The pentacyclic system (VI) was prepared by condensation of chloroxanthenone (IV) with 2-(diethylamino)ethyl hydrazine (V). Subsequently, the nitro group of (IV) was reduced with H2 in the presence of Pd/C to furnish amine (VII). This was alkylated with 2-bromoethylamine (VIII), yielding the ethylenediamine derivative (IX). The methyl ether group of (IX) was finally cleaved by treatment with boron tribromide.