In this thesis the in vivo cleavage of the phosphorus-carbon bond of 2-aminoethyl phosphoric acid (AEP) is discussed, and attempts to achieve a similar cleavage in vitro investigated. Diazotisation of AEP failed to cause P-C bond rupture but led instead to 2-hydroxyethyl phosphonic acid, which itself was unexpectedly labile, undergoing fragmentation to ethylene and inorganic phosphate. A mechanism involving a 4-membered phosphorus containing ring is proposed to explain this lability. An improved synthetic route to amino-phosphonic acids has been developed and is discussed. The rearrangement of phosphoenol pyruvate to 3-phosphono pyruvate as a step in the biosynthesis of AEP has been studied in the general context of 4-centre rearrangements. The evidence for these rearrangements in phosphorus chemistry, together with analogous observations in carbon chemistry, is reviewed and discussed. Evidence for the rearrangement of enol phosphates to B-keto phosphonates, although in very low yields, is presented and the significance of this observation discussed. The relationship between enol phosphates and B-keto phosphonates in the Perkow reaction has stimulated some work directed towards an understandings of the mechanism of the reaction. Whilst the results of experiments with acyclic phosphates and halocarbonyl compounds can be adequately explained by existing theories of the Perkow reaction mechanism, other studies have necessitated a reappraisal of the route to enol phosphates in certain cases. Chloral was found to react with cyclic phosphates to form relatively stable intermediates. These intermediates were characterised and shown to contain pentacovalent phosphorus. Thermal decomposition has been shown to yield enol phosphates. On the basis of these results, a mechanism has been proposed for the course of the reaction between cyclic phosphites and [?]-halocarbonyl compounds. Scanty evidence has been obtained for similar intermediates in "normal" Perkow reactions. A parallel has been drawn between the Perkow reaction and the reaction of other activated carbonyl compounds with phosphites.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:594889 |
| Date | January 1969 |
| Creators | Place, Brian Deason |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/61762/ |
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