Metal Complexes of Biologically Important Ligands, CLXXI [1]. Incorporation of the cis-Dichloroplatinum Group into Amides of 3,4-Diarylpyrrole-2,5-dicarboxylic Acids

3,4-Diarylpyrrole-2,5-dicarboxylic acids are suitable starting materials for the biomimetic synthesis of several types of marine pyrrole alkaloids, e. g. lamellarins [2], polycitrins [3], polycitones [4], and storniamides [5]. Several of these compounds exhibit interesting anticancer activities [6], and even the simple pyrrole dicarboxylic acids 1 and 2, isolated from a marine Halomonas bacterium, show remarkable antitumor-promoting properties [7]. It seemed therefore attractive to us to use pyrroledicarboxylic acids as templates for ethylenediamine ligands, which could be easily transformed into the corresponding di(platinum) complexes.