Fifty-seven entomopathogenic microorganisms were screened against human pathogens and subjected to mass spectrometry molecular networking based dereplication. BSNB-1250, shown to produce potentially novel biologically active metabolites, was grown on a large scale on potato dextrose agar, and paecilosetin () and five new analogues (-) were subsequently isolated. The structures of the new compounds were elucidated using 1D and 2D NMR. The absolute configurations of compounds - were determined using Mosher ester derivatives (, , ), comparison of experimental and calculated ECD spectra (- and ), and single-crystal X-ray diffraction analysis (). Compounds and exhibited strong antibacterial activity against MSSA and MRSA with MIC values of 1-2 μg/mL.
