Biologically active metabolites from Xenorhabdus spp., Part 1. Dithiolopyrrolone derivatives with antibiotic activity

Five related antibiotic compounds, named xenorhabdins, were isolated from cultures of Xenorhabdus spp., bacteria symbiotically associated with insect-pathogenic nematodes. Their chemical structures were elucidated by X-ray crystallography, nmr, and mass spectral analyses to be N-acyl derivatives of either 6-amino-4,5-dihydro-5-oxo-1,2-dithiolo [4,3-b] pyrrole (compounds 1-3) or 6-amino-4,5-dihydro-4-methyl-5-oxo-1,2-dithiolo[4,3-b] pyrrole (compounds 4 and 5). They are previously unreported members of the pyrrothine family of antibiotics. Antimicrobial and insectidical activities were found. These metabolites are specific to phase one Xenorhabdus.