Bio-transformation of FXR antagonist CDRI 80/574

The bio-transformation of 3-β-hydroxy-5, 16-dien-pregnane-20-one (CDRI 80/574, 1) a novel antagonist of farnesoid X receptor (FXR) on hepatic membranes, with Aspergillus niger produced the oxidation products at C3 and / or C11 (compound 2 and 3) while the Aspergillus ochraeus promoted the oxidation at C11 and / or C15 (compound 4 and 5). The products were characterized using 2D-NMR spectroscopy.