STRUCTURE OF DUOCARMYCIN SA, A POTENT ANTITUMOR ANTIBIOTIC

Recently, we reported the structures of the duocarmycins, a unique antitumor antibiotics constituted with two structural moieties, a substituted pyrroloquinoline or its chemical equivalent cyclopropanopyrroloindole and a trimethoxyindolylcarbonyl group. In this communication we wish to report the structure of duocarmycin SA (1), a stable compound structurally related to the duocarmycin A (2). Duocarmycin SA (1) produced by an unidentified Streptomyces sp. is a novel and potent antitumor antibiotic, which is effective against murine lymphocytic leukemia P388 and murine sarcoma 180. The structure determination was accomplished by extensive 2D NMR experiments in addition to comparison of its spectra with those of duocarmycin A (2).