AN UNEQUIVOCAL H-1-NMR STRUCTURAL ASSIGNMENT OF TOX8 AND TOX9, THE 2 MOST ABUNDANT TOXAPHENE CONGENERS IN MARINE MAMMALS

The structure of the two most abundant toxaphene congeners has unequivocally been established by 500 MHz H-1 NMR spectroscopy as 2-endo,3-exo,5-endo, 6-exo,8,8,9,10,10-nonachlorobornane (TOX9) and as 2-endo,3-exo,5-endo,6-exo,8,8,10,10-otachlorobornane (TOX8). Semiempirical calculations (AM1 and PM3-MNDO) were carried out for both structures. The distance information found by nuclear Overhauser enhancement (NOE) for the protons is in agreement with the energy minimized AM1 and PM3-MNDO structures. For these definitively established NMR data for TOX8 and TOX9, together with literature data for other toxaphene isolates, a set of rules has been derived for H-1 chemical shifts in polychlorinated bornane structures. A set of rules is also proposed for assigning systematical nomenclature to NMR-derived polychloro bornane structures.