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Updated: Jun 13, 2026

Functionalized Spirocyclic Heterocycle Synthesis and Cytotoxicity Assay
Published on: February 9, 2021
Synthesis and structure-activity relationship studies of pyrazole-based heterocycles as antitumor agents
Ahmad M Farag1, Abdelrahman S Mayhoub, Taha M A Eldebss
1Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt. afarag49@yahoo.com
Abstract:
Several 4-cyano-1,5-diphenylpyrazoles attached to different heterocyclic ring systems at position 3 were synthesized starting from ethyl 4-cyano-1,5-diphenyl-1H-pyrazole-3-carboxylate 1. The newly synthesized compounds were tested in vivo for their anti-estrogenic effects and evaluated in vitro for their cytotoxic properties against estrogen-dependent tumors. 3-(5-Mercapto-1,3,4-oxadiazole-2-yl)-1,5-diphenyl-1H-pyrazole-4-carbonitrile 13 revealed the highest cytotoxic activity with a GI(50) value equal to 40 nM against the IGROVI ovarian tumor cell line. It also showed an anti-estrogen activity 1.6 more effective than the reference drug, in addition to a high tolerable dose. 3-(5-(Methylthio)-4-phenyl-4H-1,2,4-triazol-3-yl)-1,5-diphenyl-1H-pyrazole-4-carbonitrile 7 was found to have the highest anti-estrogenic activity, while 1,5-diphenyl-3-[5-(phenylamino)-1,3,4-thiadiazol-2-yl]-1H-pyrazole-4-carbonitrile 11 showed the lowest activity. The oral LD(50) values revealed that most of the tested compounds are relatively nontoxic.
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