Benzocyclobutenes. Part 6. Reactions of substituted benzocyclobutene-1,2-diones with o-phenylenediamine

Abstract

Condensation of the 4-hydroxy-(3), 4,5-dichloro-(4), 3,6-dimethoxy-(5), and 4,5-benzo-(9) derivatives of benzocyclobutene-1,2-dione with o-phenylenediamine gave the corresponding 5,10-diazabenzo[b]biphenylenes, (13)–(16) whereas the similar condensation of the 4-methoxy-(6), 4,5-dimethoxy-(7), and 4,5-dibromo-(8) derivatives, also cyclobuta(l)phenanthrene-1,2-dione, unexpectedly gave derivatives of dibenzo[b,f][1,4]-diazocine-6,11(5H,12H)-dione (20)–(23). Treatment of the 4-hydroxy-dione (3) with 1.4 equivalents of o-phenylenediamine gave 1,2-bis-(2-aminophenylimino)benzocyclobuten-4-ol (18) and condensation of the phenanthrodione with the diamine in presence of phosphoric anhydride gave dibenz[a,c]isoindolo[2,1-a]-benzimidazol-15-one (25).