Synthesis and Comparison of In Vitro Leishmanicidal Activity of 5-(Nitroheteroaryl)-1,3,4-Thiadiazols Containing Cyclic Amine of Piperidin-4-ol at C-2 with Acyclic Amine Analogues against Iranian Strain of Leishmania major (MRHO/IR/75/ER)

BACKGROUND: Cutaneous Leishmaniasis (CL) is endemic in many tropical and subtropical regions of the world. Due to the prolonged duration of therapy, adverse effect and resistance to current drugs in the treatment of CL, the discovery of novel, efficient, and safe leishmanicidal drugs is required. The aims of the present study was to synthesis of new compounds based on the active compounds of 5-(5-nitrofuran-2-yl)- and 5-(5-nitrothiophen-2-yl)-1,3,4-thiadiazole bearing the linear amino alcohol of 3-aminopropan-1-ol in the C-2 position of thiadiazole ring and evaluation of their activity against the promastigote and amastigote forms of Leishmania major. METHODS: Reaction between the solution of 5-(5-nitro heteroaryl)-2-chloro-1,3,4-thiadiazole and piperidin-4-ol in absolute ethanol was performed and the resulting products were evaluated against promastigotes form of L. major with MTT assay and amastigote form of L. major in murine peritoneal macrophages. In addition, the toxicity of these compounds was assessed against mouse peritoneal macrophages with MTT assay. RESULTS: New synthetic compounds 5a-b showed moderate in vitro antileishmanial activity against L. major promastigotes with IC(50) values of 68.9 and 27μM, respectively. These compounds have also demonstrated a good antiamastigote activity in terms of amastigote number per macrophage, the percentage of macrophage infectivity and infectivity index. CONCLUSION: Novel cyclic compounds 5a-b were synthesized and exhibited less antipromastigote and antiamastigote activity compared to linear analogues.