
%0 Journal Article
%A Aasen, AJ 
%A Culvenor, CCJ 
%A Willing, RI 
%T Shielding of H7&#946; in pyrrolizidine derivatives
%J Australian Journal of Chemistry
%D 1971/12/01
%V 24
%N 12
%P 2575-2580
%K 
%R https://doi.org/10.1071/CH9712575
%U https://www.publish.csiro.au/paper/CH9712575 
%X The conformations of 3-oxopyrrolizidine derivatives are discussed on the basis of an analysis of the nuclear magnetic resonance spectrum of 3,5-dioxopyrrolizidine and partial data for methyl 2,3- dioxopyrrolizidine-1-carboxylate and methyl 2&#946;-hydroxy-3- oxopyrrolizidine-1a-carboxylate. In each compound, H 7&#946; is located forward into the fold of the rings and is subject to a shielding influence which is thought to be due to the C 8-C 1 single bond. 
