Novel ketoconazole analogues based on the replacement of 2,4-dichlorophenyl group with 1,4-benzothiazine moiety: Design, synthesis, and microbiological evaluation

As a part of a program to develop novel antifungal agents, new compounds which incorporate the 1,4-benzothiazine moiety into the structure of ketoconazole (KTZ) were prepared. These compounds were computationally investigated to assess whether the 1,4-benzothiazine moiety was a suitable bioisosteric replacement for the 2,4-dichlorophenyl group of KTZ in order to obtain a more potent inhibition of CYP51 enzyme of Candida albicans. Results of preliminary microbiological studies show that the racemic cis-7 analogue has a good in vivo activity, comparable to that of KTZ, but the best activity was observed in the racemic trans-7 analogue.