Chloriolide, a 12-membered macrolide from Chloridium wirescens var. chlamydosporum (NRRL 37636)

A new 12-membered macrolide (chloriolide; 1) was obtained from solid-substrate fermentation cultures of Chloridium Virescens var. chlamydosporum that was originally isolated from decayed wood. The structure of 1 was determined by analysis of 1D NMR, 2D NMR, and MS data and confirmed by X-ray crystallographic analysis. The absolute configuration of 1 was assigned by application of the modified Mosher method using the (R)- and (S)- MTPA derivatives of a rearrangement product obtained under standard acylation conditions. The assignment made by analysis of the corresponding Delta delta values was verified by X-ray crystallographic analysis of the (S)-MTPA derivative.