Synthesis and anticancer activity of some new thiopyrano[2,3-d]thiazoles incorporating pyrazole moiety

The knöevenagel condensation of 3-phenyl-4-thioxo-2-thiazolidinone (1) with 1-phenyl-3-aryl-1H-pyrazole-4-carbaldehydes 2a-d in refluxing glacial acetic acid or in polyethylene glycol-400 (PEG-400) at room temperature without catalyst, afforded the corresponding 5-hetarylmethylene derivatives 3a-d. [4+2]Cycloaddition reaction of compounds 3 with N-arylmaleimides, acrylonitrile and ethyl acrylate afforded thiopyrano[2,3-d]thiazole derivatives 5a-p. The anticancer activity of some of the newly synthesized compounds was investigated against different human cancer cell lines (MCF7 and HEPG2) and confirmed by molecular docking. Moreover, the structure for one representative example of the new products was confirmed by X-ray crystallography. The structure of all the newly synthesized compounds was established by elemental and spectral data.