1H-2-Benzopyran-3-carboxylic acid, 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-, methyl ester 27267-69-2 Collinomycin alpha-Rubromycin