Polycyclic biphenylenes. Part IV. Biphenylenes derived from 9,10-phenanthryne

Abstract

The amination of phenanthro[9,10-d]triazole gives mixtures of the 1-amino-1H- and 2-amino-2H-derivatives [(I; R = NH₂) and (V)], the latter predominating. In oxidations of compound (I; R = NH₂) with lead tetra-acetate, products derived from 9,10-phenanthryne (II) were obtained but the dimer of (II), tetrabenzo[a,c,g,i]biphenylene (III), was not found. ‘Crossed’ aryne couplings of (II) with benzyne and 2,3-naphthalyne gave dibenzo[a,c]- and tribenzo[a,c,h]-biphenylene; that with 1,2-naphthalyne failed. The results are discussed with regard to the stabilities of these annelated biphenylenes.