Synthesis and Biological Evaluation of Substituted 3‐Isoxazolethioethers as Antileishmanial and Antibacterial Agents

The synthesis of substituted 3-isoxazolethioethers and their bioevaluation as anti-leishmanial and anti-bacterial agents are described. The DBU-catalyzed thioetherification of substituted 3-nitroisoxazoles via nucleophilic aromatic substitution (SNAr) reaction using aromatic, aliphatic and heteroaromatic thiols gave the title compounds in good yields. These 3-thioisoxazole derivatives were synthetically modified to prepare new compounds including 3-phenylbenzo[b]isoxazolo[4,3-f][1,4]thiazepin-4(5H)-ones. Four compounds displayed promising activity against amastigote stage of L. donovani whereas two compounds displayed good antibacterial effect.