Structural and Biological Properties of Vermistatin and Two New Vermistatin Derivatives Isolated from the Marine‐Mangrove Endophytic Fungus Guignardia sp. No. 4382

Vermistatin (=(3R)‐4,6‐dimethoxy‐3‐{4‐oxo‐6‐[(1E)‐prop‐1‐en‐1‐yl]‐4H‐pyran‐3‐yl}‐2‐benzofuran‐1(3H)‐one; 1) and two new vermistatin derivatives, compounds 2 and 3, were isolated from the fungal strain Guignardia sp. No. 4382 obtained from the South‐China Sea. Their structures were elucidated by various methods, including circular dichroism (CD), 1D‐ and 2D‐NMR, and HR‐EI‐MS. The structures of 1 and 2 were unequivocally corroborated by X‐ray crystallography, and their absolute configurations were derived by CD spectroscopy based on a literature comparison. The in vitro cytotoxic and antifungal activities of 1 and 2 were tested.