2-Naphthacenecarboxylic acid, 6,6a,7,10,10a,11-hexahydro-6a,10a,12,?-tetrahydroxy-3,?-dimethoxy-1-methyl-6,11,?-trioxo-, methyl ester 71135-22-3 NSC 309451 Tetracenomycin C