Synthesis of Aza[]phenacenes ( = 4-6) via Photocyclodehydrochlorination of 2-Chloro--aryl-1-naphthamides.

A novel methodology for the synthesis of aza[]phenacenes was successfully developed utilizing photocyclodehydrochlorination reaction of 2-chloro--aryl-1-naphthamides. In these key intermediates, the factors influencing the photoreaction were studied. The target aza[]phenacenes were obtained by triflation or chlorination from prepared phenanthridinones, followed by hydrogenation. The introduction of a nitrogen atom into a phenacene skeleton induced changes in the physicochemical properties. The important properties of prepared aza[]phenacenes ( = 4-6) were studied experimentally and by density functional theory calculations and were compared to those of their carbo analogues. Furthermore, some important features of the crystalline aza[]phenacenes were investigated, including intermolecular interaction in the crystal lattice and the increased solubility or decreased melting points.