Identification of the Internal Axial Ligand of HO_2-Cobalt(III)-Bleomycin: ~1H{~15N} HSQC NMR Investigation of Bleomycin,Deglycobleomycin,and Their Hydroperocide-Cobalt(III) Complexes

摘要

The identity of the axial ligand contributed by the drug in hydroperoxide-Co(III)-bleomycin and hydroperoxide-Co(III)-deglycobleomycin has been in doubt With each structure a combination of ~1H{~15N} HSQC and HMBC and ~1H COSY and NOESY NMR spectroscopy was used to observe and completely assign the nonaromatic ~15N chemical shifts of natural abundance bleomycin in the two hydroperoxide-Co(III) structures Together with the ~15N chemical shifts of natural abundance bleomycin in the two hydroperoxide-Co(III) structures Together with the ~15N assignments from a published1D ~15N spectrum the results permitted the assisgnment of hte primary amine nitrogen to an axial ligand position in both structures.