The 1H NMR spectrum displayed two ortho-coupled doublet
each for 1H, at d 6.94 and d 6.75, and a broad singlet for 1H at d
7.027, confirming the presence of a tri-substituted aromatic ring;
and two doublets, each for 1H, at d 7.56 (H-70) and 6.22 (H-80),
indicating the presence of trans-di-substituted ethylene moiety in
the molecule. The main spectroscopic data are resumed in Table 2.