
%0 Journal Article
%A Ball, JB 
%A Craik, DJ 
%A Alewood, PF 
%A Morrison, S 
%A Andrews, PR 
%A Nicholls, IA 
%T Synthesis and Conformational Analysis of the Slime-Mold Acrasin Glorin
%J Australian Journal of Chemistry
%D 1989/12/01
%V 42
%N 12
%P 2171-2180
%K 
%R https://doi.org/10.1071/CH9892171
%U https://www.publish.csiro.au/paper/CH9892171 
%X The chemotactic dipeptide for the slime-mould Polysphondylium violaceum, glorin (N- propionyl-y-L-glutamyl-L-ornithine-&#948;-lac ethyl ester) (8), was synthesized convergently in five steps with 41% overall yield, starting from L- ornithine hydrochloride (1) and L- glutamic acid &#947;-benzyl ester (4). -1H n.m.r. spectral analysis led to the conclusion that the propionamide and the &#947;-L- glutamyl amide bonds both undergo slow cis-trans isomerism in solution at room temperature. From a Karplus-type analysis of the values of the C&#945;,C&#946; coupling constants at the lactam chiral carbon, it was concluded that the six-membered ring can adopt either a half-chair or half-boat conformation, but it is not clear which. Similar calculations for the glutamyl Ca,C&#946; coupling constants were performed and, from these, significantly different relative populations for the three staggered conformations about the Glu-Ca,C&#946; bond were suggested. Receptor binding studies showed that glorin did not bind significantly to any of the six receptors studied, including opioid, dopamine, central benzodiazepine, peripheral benzodiazepine, &#945;1-adrenoceptor and &#945;2-adrenoceptor sites. 
