Abstract: The synthesis and characterization, including the stereochemistry, of a series of 3, 4-dihydropyrromethenones and 2, 3-dihydrodioxobilins are described. High-resolution'H NMR spectral analysis allows the determination of the A ring coupling constants for a series of cis and trans model compounds. From these data and correlations, the relative stereochemistry in the A ring of phycocyanin and similar bile pigment structures can be ...
