Synthesis of 2,7‐disubstituted‐4,5,9,10‐tetraazapyrenes

Abstract 2,7‐Dimethyl‐4,5,9,10‐tetraazapyrene (VI) was synthesized by the catalytic hydrogenation of 4,4′‐dimethyl‐2,2′,6,6′‐tetranitrobiphenyl (IIa) with W‐2 Raney nickel in the presence of alkali. 4,4′‐Dicarbomethoxy‐2,2′,6,6′‐tetranitrobiphenyl (IIc) under similar conditions in neutral medium gave 4,4′‐dicarbomethoxy‐2,2′,6,6′‐tetraaminobiphenyl (IV) which on oxidation gave 2,7‐dicarbomethoxy‐4,5,9,10‐tetraazapyrene (V). 2,7‐Dimethyl‐, 2,7‐dimethoxy‐, and 2,7‐diacetamido‐4,5,9,10‐tetraazapyrene di‐ N ‐oxides (III a,b,c) were obtained by catalytic reduction of the corresponding 4,4′‐disubstituted‐2,2′,6,6′‐tetranitrobiphenyls with W‐7 Raney nickel in the presence of alkali. Compound VI on oxidation with hydrogen peroxide gave the di‐ N ‐oxide (IIIa).