E. Egert, M. Noltemeyer, J. Siebers
Jul 25, 1992
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Influential Citations
23
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Journal
The Journal of antibiotics
Abstract
Tetracenomycin C (1), a new antibiotic produced by Streptomyces glaucescens (strain Tii 49) is structurally related to the anthracyclinones1'2*. It was the first example of a discrete group of antibiotics whose membersshow biological activity mainly against Gram-positive bacteria of the genus Streptomyces and a moderate cytotoxic effect on L1210 leukemia cells in vitro (IC50 1.2/zg/ml) caused by an interaction with DNA. In the meantime 1 has also been isolated by a Chinese group3). Similar antibiotics, the elloramycins4~6) and tetracenomycin X7), have been described and the first structure-activity relationships have been investigated within this group8). The constitution of tetracenomycin C, C23H2oO1 1? was established by chemical and spectroscopic methods1?2'4). In this paper we wish to report the X-ray analysis of 1 leading to the relative configuration of the three stereocenters. The application of the Helmchen method9) for secondary alcohols allowed us to establish the absolute configuration at C-4 and thus to determine the correct enantiomer. Crystals of 1 (yellow needles) were obtained from methanol. The crystal data for 1-0.5 MeOHare as follows: Orthorhombic, space group P212121, 0=1,498.2 (2), 6=2,023.6 (3), c=1,463.6 (2) ppm,