| Summary: | <p>The synthesis of several fluorinated analogues of thiamine and precursors has been undertaken, all of which exhibit weak activity against <em>E.Coli</em>. A route to 3-fluoro-(<em>R</em>)-alanine has been explored.</p> <p>The first synthesis of the enantiomeric fluorosuccinic acids has been accomplished, and a stereochemical analysis has shown that synthesis <em>via</em> esterified malate precursors using diethylamino- sulphurtrifluoride gives <em>inversion</em> of configuration, whereas prep- aration <em>via</em> aspartic acid and polyhydrogen fluoride in pyridine gives <em>retention</em> of configuration. The circular dichroism spectra of the fluorosuccinic acids are anomalous, being the first example of such behaviour in a-substituted carboxylic acids and derivatives. A previously assigned configuration of a <em>Pseudomonal</em> metabolite ( + )- fluorosuccinic acid has been corrected. The fluorosuccinic acids are not substrates for malic enzyme, but are potent inhibitors of fumarase. Using (2<em>S</em>)-fluorosuccinic acid as a mechanistic probe the fumarase reaction is identified as a bimolecular E2 elimination.</p> <p>A stereochemical analysis of enzymic phosphoryl transfer reactions using CD spectroscopy has been investigated, and a new synthesis of inorganic pyrophosphate used to prepare P<sub>1</sub>=[(<em>S</em>)- <sup>16</sup>0, <sup>17</sup>0, <sup>18</sup>0]-pyrophosphate whose <sup>31</sup>P n.m.r. spectrum is discussed. The first example of 31 p- 17 o coupling as observed by 31 P n.m.r. is demonstrated.- The magnitude of the <sup>31</sup>P- <sup>18</sup>0 isotope shift is dependent on the nature of the phosphorus to oxygen bond. An elegant method for establishing the isotopic configuration of oxygen chiral phosphates by n.m.r. has been developed, requiring the synthesis of <em>D</em>-glucose-6[(<em>S</em>) - <sup>16</sup>0, <sup>17</sup>0, <sup>18</sup>0]-phosphate, adenosine-5'- [(<em>S</em>)- <sup>16</sup>0, <sup>17</sup>0, <sup>18</sup>0]-phosphate, and their six membered cyclic phosphate triesters. Chemical cyclisation of these molecules occurs both with <em>racemisation</em> and <em>inversion</em> of configuration at phosphorus.</p> <p>The chemical synthesis of adenosine-5'[ (<em>S</em>) - <sup>16</sup>0, <sup>17</sup>0, <sup>18</sup>0]- triphosphate has been achieved and exploited to demonstrate that hexokinase phosphoryl transfer proceeds with <em>inversion</em> of config- uration at phosphorus. Pyruvate kinase phosphoryl transfer from 2 [(<em>S</em>)- <sup>16</sup>0, <sup>17</sup>0, <sup>18</sup>0]-phospho- (<em>R</em>)-glycerate also proceeds with <em>inversion</em> of configuration, as does phosphofructokinase phosphoryl transfer from <em>sn</em>-glycerol-3[ (5)- <sup>16</sup>0, <sup>17</sup>0, <sup>18</sup>0]-phosphate.</p>
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