On the Fate of Biliverdin-IIIα-dimethyl Ester Formed by Scrambling During Syntheses of Biliverdin-IXα-dimethyl Ester from Bilirubin

Article abstract of DOI:10.1007/BF00810844

In the preparations of biliverdin-IXα-dimethyl ester (2b) from bilirubin-IXα (1) the ratio of the XIIIα- and IIIα-isomers 3b and 4b, formed via intermolecular scrambling, should be unity.However, irrespective of the synthetic variant considered, the amount of 4b obtained usually is exceptionally low.This is partly ascribed to a consecutive reaction of 4b in acidic methanol affording the chiral diastereomeric bridged biliverdins 5(a and b) and 6(a and b), respectively. - Keywords: Biliverdin-IIIα; Bridged biliverdins; Bilatrienes