The structure of KS-619-1, a potent inhibitor of Ca2+ and calmodulin-dependent cyclic nucleotide phosphodiesterase, was determined to be 8, 13-dioxo-3-(2-oxopropyl)-5, 6, 8, 13-tetrahydro-l, 7, 9, 11-tetrahydroxybenz[a]naphtacene-2-carboxylicacid by spectral studies of KS-619-1 and its methyl derivative.
