Heterocyclic bismuth carboxylates based on a diphenyl sulfone scaffold: synthesis and antifungal activity against Saccharomyces cerevisiae.

A series of heterocyclic organobismuth(III) carboxylates 4 and 5 [RCO2Bi(C6H4-2-SO2C6H4-1'-)] derived from diphenyl sulfone was synthesized to determine the influence of the carboxylate ligand structure on the lipophilicity and antifungal activity against the yeast Saccharomyces cerevisiae. In contrast to the clear structure-activity relationship between the size of the inhibition zone and the value of ClogP for specific substitution on diphenyl sulfone scaffold 1 [ClBi(5-RC6H3-2-SO2C6H4-1'-)], scaffolds 4 and 5 showed similar inhibition activities irrespective of the ClogP value. This suggests that these molecules function inside the yeast cell by separating into the cationic heterocyclic bismuth scaffold and the anionic carboxylate moiety, and that the bismuth scaffold plays an important role in the inhibition activity.

Bismuth heterocycles based on a diphenyl sulfone scaffold: synthesis and substituent effect on the antifungal activity against Saccharomyces cerevisiae.

A series of heterocyclic organobismuth(III) compounds 2 [ClBi(5-R-C6H(3)-2-SO2C6H(4)-1'-): R=Me, Ph, MeO, Cl, H, t-Bu, CF3, F, Me2N] was synthesized in order to study the relative importance of structure and specific substitutions in relation to their lipophilicity and antifungal activity against the yeast Saccharomyces cerevisiae. A clear structure-activity relationship between the size of the inhibition zone and the value of ClogP was found for 2. These results suggest that the higher the lipophilicity, the lower the antifungal activity.