Citridones, new potentiators of antifungal miconazole activity, produced by Penicillium sp FKH938-II.: Structure elucidation

The structures of citridones A, B, B' and C, new potentiators of miconazole activity against Candida albicans produced by Penicillium sp. FKI-1938, were elucidated by various spectroscopic analyses including UV, NMR, and MS and degradation experiments. Although citridones B and B' were isolated as a mixture, each structure was also elucidated, indicating that they exist in equilibrium of hemiacetal epimerization. Citridones A, B and B' have a similar phenylfuropyridone moiety.