| Summary: | In this paper, we report on the chemistry of the rare South African Actinomycete <i>Kribbella speibonae</i> strain SK5, a prolific producer of hydroxamate siderophores and their congeners. Two new analogues, dehydroxylated desferrioxamines, speibonoxamine <b>1</b> and desoxy-desferrioxamine D<sub>1 </sub><b>2</b>, have been isolated, together with four known hydroxamates, desferrioxamine D<sub>1</sub> <b>3</b>, desferrioxamine B <b>4</b>, desoxy-nocardamine <b>5</b> and nocardamine <b>6</b>, and a diketopiperazine (DKP) <b>7</b>. The structures of <b>1</b>–<b>7</b> were characterized by the analysis of HRESIMS and 1D and 2D NMR data, as well as by comparison with the relevant literature. Three new dehydroxy desferrioxamine derivatives <b>8</b>–<b>10</b> were tentatively identified in the molecular network of <i>K.</i> <i>speibonae </i>strain SK5 extracts, and structures were proposed based on their MS/MS fragmentation patterns. A plausible <i>spb</i> biosynthetic pathway was proposed. To the best of our knowledge, this is the first report of the isolation of desferrioxamines from the actinobacterial genus <i>Kribbella</i>.
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