Abstract
Two approaches to the synthesis of 2-(2-oxo-5-aryl-1,2-dihydro-3H-pyrrol-3-ylidene)malononitriles (DCAA-pyrroles 1) were implemented. The first one was based on the transformation of 4-oxobutane-1,1,2,2-tetracarbonitriles 2 by the action of morpholine. The second approach was based on the reaction between protected form of 4-oxobutane-1,1,2,2-tetracarbonitriles 2 namely 2,7-dioxabicyclo[3.2.1]octane-4,4,5-tricarbonitriles 3 and morpholine. This approach involving sequential furan and pyran ring-opening of the 2,7-dioxabicyclo[3.2.1]octane moiety with further pyrrole ring-closure, resulted in a smoother formation of DCAA-pyrroles 1. The optical absorption properties of DCAA-pyrroles 1 were studied for the first time. The absorption maxima were observed in the range of 506–545 nm showing positive solvatochromism and dependence on the substituent in aryl moiety.