
%0 Journal Article
%A Riggs, NV 
%T <i>Ab Initio</i> Studies on Amides: Pyrrolidin-2-one (&#947;-Butyrolactam)
%J Australian Journal of Chemistry
%D 1985/11/01
%V 38
%N 11
%P 1585-1589
%K 
%R https://doi.org/10.1071/CH9851585
%U https://www.publish.csiro.au/paper/CH9851585 
%X By optimization with the 3-21G basis set, pyrrolidin-2-one is found clearly to prefer an envelope conformation with the flap bent 27.4&#176; out of the NC(=O)C reference plane. The ring may be bent or twisted through a few degrees at low energy-cost, and undergoes rapid inversion through a planar-ring structure lying only 3.3 kJ mol-1 above the preferred equilibrium structure. 
