Simple Procedure for Preparing Bilirubin XIII α

Abstract

Bilirubin is a waste product of heme catabolism in vertebrates¹. It is higlhy toxic to tissues especially to parts of the central nervous system in human neonate², and the phototherapy method³ for reducing jaudice in newborn infants owes its success to the elimination of photobilirubin (a mixture of geometric isomers of bilirubin)⁴. A structural peculiarity of natural bilirubin (commonly called IXα)⁵ is the unsymmetrical distribution of the substituents at the β-position of the end rings of the molecule in relation bridge. Thus, bilirubin reactivity and spectroscopic behaviour (e. g. NMR.) result from the sum or interaction of two different sets of properties, each due to one pyrromethenone moiety⁶. For this reason this reason, to gain insight into bilirubin chemistry and photochemistry model compounds should be easily available in which the a,cbiladiene skeleton is formed by two identical pyrromethenone units, as, in (2) and (3).