Abstract
Two new tetraene lactone derivatives (1 and 2), two new α-pyrone derivatives (3 and 4), three compounds reported as natural products for the first time [an α-pyrone derivative (5), an indole-diketopiperazine alkaloid (6), and a β-amino acid derivative (8)], and 11 known compounds (7, 9-18), were obtained from microorganisms isolated from hadal trench sediments in the Pacific Ocean. Their structures were determined using NMR, HRESIMS, optical rotatory dispersion (ORD) spectra, NMR calculations followed by DP4+ analysis, electronic circular dichroism (ECD) calculations, X-ray crystallography analysis, and advanced Marfey's and modified Mosher eater methods. Microbial broth dilution assay suggested that compounds 6-11 and 15 had weak antibacterial effects.