New Macrocyclolipopeptides and Steroids from Mariana Trench-Derived Fungus Cladosporium sp.

Two unusual 13-membered macrocyclolipopeptides, cladosporiums
A
(1) and B (2), and four new steroids, cladosporisteroids
D–G (3–6), were isolated from
the Mariana Trench-derived fungus Cladosporium sp.
RCDB004. Cladosporiums A (1) and B (2) possess
an unprecedented macrocyclic skeleton formed by the condensation reaction
of fatty acids and an alanine. The planar structures of isolated compounds
were established by NMR and HRESIMS, with the stereochemical configurations
further corroborated through X-ray crystallography. Notably, cocrystals
of 1 were successfully obtained through the crystalline
mate method.