COMPLETE ASSIGNMENT OF THE H-1 AND C-13 NMR-SPECTRA AND SOLUTION CONFORMATION OF THE ANTITUMOR ANTIBIOTIC, ACLACINOMYCIN-A

As a prelude to the study of the molecular recognition of DNA by anthracycline antibiotics, and as a basis for comparison with synthetic analogues the proton and carbon-13 NMR spectra of Aclacinomycin A in chloroform have been fully assigned and the likely solution conformation determined using COSY, HMQC and 1-D TOCSY and 1-D ROESY techniques. The D-ring of the fused tetracyclic ring system adopts a half-chair conformation and the sugar residues are shown to lie essentially in chair conformations with the glycosidic links diaxial. This imposes considerable restriction in the rotation about the glycosidic links.