Figure 2.

A) HPLC profiles for the oxidation of 5 (2 mm) in the presence of CuSO4 (0.5 mm) and ascorbate (5 mm) in 10% DMSO/0.1 m phosphate buffer pH 7. B) The same analysis as in (A) in the presence of ligand 3 (1 mm). C,D) Summary of data showing oxidative loss of 5 and 3 in the presence of different amounts of 3.