Dysidealactams and Dysidealactones: Sesquiterpene Glycinyl-Lactams, Imides, and Lactones from a Dysidea sp. Marine Sponge Collected in Southern Australia.

A GNPS molecular networking approach mapped a library of 960 southern Australian marine sponges and prioritized Dysidea sp. (CMB-01171) for chemical investigation. Although the published natural products literature on Australian Dysidea sponges extends back over half a century and suffers from the perception of being near exhausted, fractionation of Dysidea sp. (CMB-01171) led to the discovery of a family of 10 new biosynthetically and chemically related sesquiterpenes. Detailed spectroscopic analysis guided structure elucidation identified dysidealactams A-F (1-6), dysidealactones A and B (7 and 8), and two solvolysis artifacts, 9 and 10. The dysidealactams A-D (1-4) incorporate a rare glycinyl-lactam functionality, while dysidealactam E (5) is particularly noteworthy in incorporating an unprecedented glycinyl-imide moiety. In addition to expanding knowledge of Dysidea natural products, this study demonstrates the value of applying GNPS molecular networking to map chemical diversity and prioritize the selection of marine sponge extracts for more detailed chemical analysis.