Chlorinated Thiazole‐Containing Polyketide‐Peptides from the Caribbean Sponge Smenospongia conulosa: Structure Elucidation on Microgram Scale

Studies of non‐ribosomal peptide/polyketide (NRP/PK) hybrid compounds in the holobiome of the Caribbean marine sponge Smenospongia conulosa led to the isolation of two new chlorinated thiazole‐containing metabolites, conulothiazoles A (5) and B (6), along with four NRP/PK hybrids previously isolated from a different Smenospongia species. Structural elucidation was accomplished on a few micrograms of pure compounds using extensive NMR and MS studies, whereas determination of the absolute configuration of the amino acid moiety was achieved by degradation and by high‐resolution LC‐Ms analysis using only 4 µg of each compound.