(5a) cis-Isomer with partial 1D 1 H NMR spectra. Far right, is the simplified spectrum after H1 decoupling to reveal 3 J2,3. (5b) trans-Isomer and simplified part of the spectrum on the far right after H4 decoupling to reveal 3 J2,3. {H1} denotes H1 decoupling and {H4} denotes H4 decoupling. 

13C chemical shifts of compound 8a (N-analogue) and compound 8b (O-analogue).