Diverse Secondary Metabolites From the <i>Ligia exotica‐</i> Derived Fungus <i>Diaporthe melitensis</i> HZ‐1

One new phenolic derivative diameliresorcin (1), one new natural product N-(2'-oxopiperidin-3'-yl) picolinamide (2), one new α-pyrone derivative diameliphyone (3), and six known secondary metabolites (4-9) were isolated from the Ligia exotica-derived fungus Diaporthe melitensis HZ-1. The structures of three new compounds were identified by IR, NMR, and HR-ESI-MS, whereas their absolute configurations were validated either through single-crystal x-ray diffraction analysis or via time-dependent density functional theory (TDDFT)-electronic circular dichroism (ECD) calculations. It is noted that the absolute configuration of compound 2 was determined for the first time. Meanwhile, all the isolated compounds were evaluated for their antibacterial activities. Among them, diameliresorcin (1) exhibited weak anti-Vibrio vulnificus activity with minimum inhibitory concentration (MIC) value of 46 µg/mL.