Five unique compounds: Xyloketals from mangrove fungus Xylaria sp from theSouth China Sea coast

Five unique metabolites, xyloketals A (1), B (2), C (3), D (4), and E (5), and the known 6 were isolated from mangrove fungus Xylaria sp. (no. 2508), obtained from the South China Sea. The structures of these compounds were e lucidated by spectroscopic and X-ray diffraction experiments. Xyloketal A i s a ketal compound with a C-3 symmetry and xyloketals B-E are its analogues . It was found that xytoketal C slowly rearranged to xytoketal B in DMSO-d( 6) Solution at room temperature. Xyloketal A exhibited the activity of inhi biting acetylcholine esterase.