Abstract
Herein we describe the scalable diastereoselective and enantioselective syntheses of eight enantiomers of hydroxy metabolites of saperconazole. The in vitro antifungal activity of the eight stereoisomers (compounds 1–8) was compared against a broad panel of Candida__spp. (n=93),__ Aspergillus__spp. (n=10),__ Cryptococcus__spp. (n=19), and dermatophytes (n=27). The four 2__S __isomers 1–4 of the new agent were generally slightly more active than the four 2__R isomers 5–8. All eight isomers were tested in a model of experimental A. fumigatus infection in guinea pigs by intravenous inoculation of the fungal conidia. Treatment doses were 1.25 mg kg^−1^ and 2.5 mg kg^−1^ per day. Infection severity was measured in terms of mean survival time (MST) after infection and mean tissue burdens in brain, liver, spleen, and kidney at postmortem examination. Among the eight isomers, the 2__S diastereomers 1–4 showed a generally higher level of activity than the 2__R diastereomers 5–8, revealing compounds 1 and 4 as the most potent overall in eradicating tissue burden and MST. Compared with reference compounds itraconazole and saperconazole, the hydroxy isomers 1–8 are less potent inhibitors of the growth of A. fumigatus in vitro and of ergosterol biosynthesis in both A. fumigatus and C. albicans.