1,6,11(2H)-Naphthacenetrione, 3,4-dihydro-2,5,7-trihydroxy-3-methoxy-2-methyl- 3-Methoxy-2-methyl-2,5,7-trihydroxy-3,4-dihydro-1,6,11(2H)-naphthacenetrione 68178-51-8 Antibiotic SM 173B BRN 5639838 SM-173B