Collinomycin

alpha-rubromycin

6-[2-(4,9-Dihydro-8-hydroxy-5,7-dimethoxy-4,9-dioxonaphtho[2,3-b]furan-2-yl)ethyl]-7,8-dihydroxy-1-oxo-1H-2-benzopyran-3-carboxylic acid methyl ester

1-Oxo-6-[2-(4,9-dioxo-5,7-dimethoxy-8-hydroxy-4,9-dihydronaphtho[2,3-b]furan-2-yl)ethyl]-7,8-dihydroxy-1H-2-benzopyran-3-carboxylic acid methyl ester