Xylariaides A and B, novel cytochalasans with a unique 5/6/5/3 ring system from a soil fungus Xylaria sp. Y01

Abstract

Two new cytochalasans, xylariaides A (1) and B (2), were isolated and identified from a soil fungus Xylaria sp. Y01. Their structures were unambiguously determined by extensive spectroscopic methods including high resolution electrospray ionization mass spectrometry, ultraviolet radiation, infrared spectroscopy, and 1D/2D NMR, as well as in-depth quantum chemical calculations of gauge-including atomic orbital (GIAO) ¹³C NMR chemical shifts, electronic circular dichroism (ECD), and spin–spin coupling constants. The unprecedented core structure with a 5/6/5/3 fused tetracyclic ring system further enriches the scaffold types of cytochalasans.

Graphical Abstract