Thalassosamide, a Siderophore Discovered from the Marine-Derived Bacterium Thalassospira profundimaris.

Here we describe the rapid identification and prioritization of novel active marine natural products using an improved dereplication strategy. During the course of our screening of marine natural product libraries, a new cyclic trihydroxamate compound, thalassosamide, was discovered from the α-proteobacterium Thalassospira profundimaris. Its structure was determined by 2D NMR and MS/MS experiments, and the absolute configuration of the lysine-derived units was established by Marfey's analysis, whereas that of C-9, 9', and 9″ was determined via the circular dichroism data of the [Rh ₂ (OCOCF ₃ ) ₄ ] complex and DFT NMR calculations. Thalassosamide showed moderate in vivo efficacy against Pseudomonas aeruginosa.