Benzo r cinnolines

Reaction of (benzo[r]cinnolin-5-ium-5-yl)(A -phenylbenzimidoyl)amide with 2,3-diphenylcy-clopropenethione in refluxing benzene for 2 hours gave a 1 1 adduct 7 in 97% yield. 

Benzo[r]bcnzo[3,4]cinnolino[l,2- ]cinnoline 61 and a series of 5,6-dihydrobenzo[c]cinnoline derivatives, including compounds 62, were studied by cyclic voltammetry. The unusual shape of the voltammograms of the investigated compounds can be explained by an EiE-DISP mechanism with a slow disproportionation reaction <1996JA5020>. 

As illustrated in eqs. 1 and 2, azobenzene, azotoluene, and benzo[c]cinnoline have been found to undergo net [2+2] cycloaddition of their N=N double bond across the R C triple bond of the BPh4 salt of carbyne complex 1 [3]. These reactions represent the... 

A soln. of phthalic anhydride and 5,6-dihydrobenzo[c]cinnoline in toluene refluxed 5 min., the solvent distilled off, and treated repeatedly with boiling water to remove excess anhydride l, 4 -dioxo-l, 2, 3, 4 -tetrahydrophthalazino-[2, 3 5,6]benzo[c]cinnoline. Y 89%. F. e. s. A. Etienne and R. Piat, Bl. 1962, 292. 

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