Polycyclic biphenylenes. Part III. Syntheses of benzo- and dibenzo-biphenylenes via aryne intermediates

Abstract

Lead tetra-acetate oxidations of 1-amino-1H-naphtho[2,3-d]triazole and 1-amino-1H-naphtho[1,2-d]triazole have given dibenzo[b,h]biphenylene and a mixture of dibenzo[a,g]- and dibenzo[a,i]-biphenylene, respectively. The hitherto unknown dibenzo[a,h]biphenylene has been obtained from a “crossed” oxidation of these two triazoles; similar “crossed” reactions with 1-amino-1H-benzotriazole provide convenient routes to the two monobenzobiphenylenes.