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, while determination of the absolute configuration of the amino acid moiety was achieved by degradation and by high-resolution LC-Ms analysis using of only 4 micrograms of each compound.