Synthesis of some new pyrazole-based 1,3-thiazoles and 1,3,4-thiadiazoles as anticancer agents

N-(4-(Pyrazol-4-yl)thiazol-2-yl)-N′-phenylthiourea derivative 2 was synthesized and then treated with variety of hydrazonoyl chlorides under basic condition at reflux to afford the corresponding 2-(4-(pyrazol-4-yl)thiazol-2-ylimino)-1,3,4-thiadiazole derivatives 6, 10a–e and 17a–e. Reaction of 2 with ethyl chloroacetate and with 3-chloro-2,4-pentanedione gave the thiazolidin-4-one 22 and 1,3-thiazole 25 derivatives, respectively. Condensation of thiazolidin-4-one 22 with aldehydes gave their 5-arylidene derivatives 23a–f. Most of the synthesized compounds were tested for anticancer activity against human hepatocelluar carcinoma HepG2, human breast cancer MCF-7 and human lung cancer A549. Their SAR was studied and variously affected by the electronic factor of electron donating and withdrawing groups. Many of the tested compounds showed moderate to high anticancer activity. [Display omitted] Several 1,3-thiazole and 1,3,4-thiadiazole derivatives have been synthesized and tested for anticancer activity against three human cancer cell lines: HepG2, MCF7 and A549. •Our manuscript reports convenient routes for the synthesis of several new pyrazole-based tri-heterocyclic systems.•The structures of the obtained new compounds are elucidated with all possible spectral data (IR, MS, 1H and 13C NMR).•After that, most of the synthesized compounds were tested for anticancer activity against HepG2, MCF7 and A549 cell lines.•Their SAR was studied and variously affected by the electronic factor of electron donating and withdrawing groups.•Some of the tested compounds showed high anticancer activity, when compared with doxorubicin.