... ORGANIC MAGNETIC RESONANCE, VOL. 17, NO. ... (C-4 and C-4') resonate at lower magnetic fields than the ortho carbons (C-6 and C-6'). In our experiment (see Table 2), four peaks at 6129.8, 127.0, 125.5 and 129.2 in 4, R=CH,, gave doublets in the SFORD spectrum. ...