Duocarmycins, potent antitumor antibiotics produced by Streptomyces sp. structures and chemistry

Seven novel potent antitumor antibiotics, duocarmycins A (1), C1 (2), C2 (3), D (4), B1 (5), B2 (6) and SA (7), were isolated from three independently collected Streptomyces sp. The complete structures, including absolute stereochemistry, were determined by spectral and chemical studies of those duocarmycins and several derivatives. Duocarmycins A (1) and SA (7) possess a 1,2,7,7a-tetrahydrocycloprop[1,2-c]indol-4-one subunit, a common pharmacophore with that of CC-1065 (10) found from Streptomyces zelensis.