En route to hexaaza-kekulene

As synthetic precursors of hexaaza-kekulene 1 the dibenzo[$\text{b,j}$]= [1,10] phenanthroline systems 2, 3, 4, 5 and 6 were prepared. From 6 via 7 a product was obtained for which the dodecahydrohexaaza-kekulene structure 8 is suggested on the basis of ¹H-NMR comparison with the dipyrido[3,2-$\text{c}$;=2′,3′-$\text{h}$]acridine (14) for which two syntheses are reported.