In this thesis some chemical aspects of the bile pigment bilirubin have been examined. Bilirubin has been shown to exist as the bislactam tautomer, with an intranolocularly hydrogen bonded structure which is independent of the medium. Possible structures are discussed in Chapter 2. The clinical determination of bilirubin involves treatment of the pigment with diazotised sulphanilic acid (the van den Bergh reaction) when bilirubin is cleaved at the central methylene bridge to form two azopigments. The fate of the central methylene bridge carbon atom was unknown until the present work, but it had been postulated as being liberated as formaldehyde. In Chapter 3, it is shown that formaldehyde is formed during this reaction, and that it can be detected by the product of its reaction with dimedone. Some metal complexes of bilirubin formed in dipolar aprotic solvents are discussed in Chapter 4. A possible structure for the complex with Zn(II), isolated from DMF solution, is suggested. In Chapter 5, a potentially extremely useful method for the synthesis of bilirubin conjugates of defined structures is examined, using substituted aryl triazenes, under mild conditions. This method allows the esterification of a specific hydroxyl group in a polyhydroxylated mono – or oligosaccaride without protection of the other hydroxyl group present. Thus, in this work, using l – alkyl -3-p- tolyltriazenes, the hitherto unknown diethyl, diisopropyl and dibenzyl esters of bilirubin have been prepared and characterised.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:595015 |
| Date | January 1973 |
| Creators | Johnson, Brian |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/73947/ |
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