Reaction of 2,2′-Di(4-chlorophenyl)-1,1′,3,3′-tetraoxo-2,2′,3,3′-tetrahydro-1H,1′H-6,6′-di(benzo[de]isoquinoline)-7,7′-dicarboxylic Acid with Thiourea Dioxide in Water-Alkaline Solution

The stoichiometric mechanism of the reductive cyclization of 2,2′-di(4-chlorophenyl)-1,1′,3,3′-tetraoxo-2,2′,3,3′-tetrahydro-1H,1′H-6,6′-di(benzo[de]isoquinoline)-7,7′-dicarboxylic acid potassium salt under the action of thiourea dioxide in an aqueous-alkaline solution was studied. The reduction products of two or four oxo groups in 3,4,9,10-perylenetetracarboxylic acid N,N′-di(4-chlorophenyl)diimide were obtained, as well as the cyclization product of an unknown composition. It is shown that the composition and quantity of intermediate and final products of the cyclization depend on the concentration of the reducing agent and the presence of air oxygen in the solution, which is due to the formation of various reducing intermediates from the reducing agent molecules. A stepwise stoichiometric mechanism of reductive cyclization reaction was proposed.