Salarins D–J, seven new nitrogenous macrolides from the madagascar sponge Fascaplysinopsis sp.

Seven new nitrogenous macrolides, designated salarins D–J (4–10), closely related to salarins A–C (1–3), have been isolated from the Madagascar Fascaplysinopsis sp. sponge. The structure and relative stereochemistry of compounds 4–10 were elucidated by interpretation of MS, COSY, HSQC, HMBC, and NOESY spectra. Salarin Bʹs structure (2), based on the structure of salarin J (10), is now amended to also incorporate the C-14 to -17 THF ring system. All compounds were evaluated for their cytotoxicity against K562 and UT-7 human leukemia cells. While salarins D, E, H, and J displayed dose and time dependent inhibition of proliferation, salarins F and I were not active in these assays.