1,2-BIS-DIPYRRINON-9-YL-ETHENE - A NOVEL B-HOMO-VERDIN CHROMOPHORE - THE REACTION OF 9-METHYL-10H-DIPYRRIN-1-ONES WITH BROMINE

Upon treatment of 9-methyl-10H-dipyrrin-1-ones with bromine in dichlor omethane, red bile pigment derivatives were obtained in moderate yield s. They were structurally assigned as 1,2-bis-dipyrrinon-9-yl-ethenes, which are examples of the hitherto unknown h-homo-verdins. In additio n, the corresponding meso-biliverdins-XIII alpha could be isolated fro m the reaction mixture. The mechanistic aspects of the reaction are di scussed.