Synthesis of New 4‑Thiazolidinone‑, Pyrazoline‑, and Isatin-Based Conjugates with Promising Antitumor Activity

The synthesis and antitumor activity screening of novel 3-[2-(3,5-diaryl-4,5-dihydropyrazol-1-yl)-4-oxo-4,5-dihydro-1,3-thiazol-5-ylidene]-2,3-dihydro-1H-indol-2-ones 1–23 and 3-(3,5-diarylpyrazol-1-yl)-2,3-dihydro-1H-indol-2-ones 24–39 are performed. In vitro anticancer activity of the synthesized compounds was tested by the National Cancer Institute. Most of them displayed anticancer activity on leukemia, melanoma, lung, colon, CNS, ovarian, renal, prostate, and breast cancers cell lines. The structure–activity relationship is discussed. The most effective anticancer compound 10 was found to be active with mean GI50 and TGI values of 0.071 μM and 0.76 μM, respectively. It demonstrated the highest antiproliferative influence on the non-small-cell lung cancer cell line HOP-92 (GI50 < 0.01 μM), colon cancer line HCT-116 (GI50 = 0.018 μM), CNS cancer cell line SNB-75 (GI50 = 0.0159 μM), ovarian cancer cell line NCI/ADR-RES (GI50 = 0.0169 μM), and renal cancer cell line RXF 393 (GI50 = 0.0197 μM).