A model for one-half bilirubin, the neurotoxic yellow-orange pigment of jaundice, 9-[2-(2- carboxyethyl) benzyl]-2, 3, 7, 8-tetramethyl-1, 10-dihydrodipyrrin (1, hemirubin) was synthesized following SnCl4-catalyzed Friedel-Crafts acylation at C (9) of 2, 3, 7, 8-1-oxo-1, 10-dihydrodipyrrin (7) with methyl o-(chlorocarbonyl) hydrocinnamate. Unlike earlier bilirubin model compounds, hemirubin is predicted and found to engage in intramolecular ...
