Transformation of 4-oxoalkane-1,1,2,2-tetracarbonitriles under the action of Lawesson's reagent leads to 2,2′-disulfanediylbis(1H-pyrrole-3-carbonitriles) in good yields. The developed method allowed the synthesis of photochromic 2,2′-disulfanediylbis(4,5-bis(2,5-dimethylthiophen-3-yl)-1H-pyrrole-3-carbonitrile).
