A series of 2-arylamino-5-(indolyl)-1,3,4-thiadiazoles as potent cytotoxic agents

A series of 2-arylamino-5-(indolyl)-1,3,4-thiadiazoles 6a–v were prepared and studied for their anticancer activity against selected human cancer cell lines. The reaction of indolylhydrazides 3a–h with a variety of aryl isothiocyanates 4 afforded the key intermediate thiosemicarbazides 5a–v, which upon treatment with acetyl chloride produced the 2-arylamino-5-(indolyl)-1,3,4-thiadiazoles 6a–v in good yields. Most of the synthesized compounds showed selective cytotoxicity towards human breast cancer cell line (MDA-MB-231). Of the synthesized 2-arylamino-5-(indolyl)-1,3,4-thiadiazoles, compound 6f is the most potent towards tested cancer cell lines (IC50 = 0.15–1.18 μM).

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► Diverse series of novel 2-arylamino-5-(indolyl)-1,3,4-thiadiazoles were synthesized.
► All the compounds were evaluated for their in-vitro anticancer activity.
► The compounds are selective against MDA-MB-231 cancer cell line (IC50 < 1 μM).
► The most potent compound showed IC50 value of 150 nM against LnCap cancer cell line.