Copper(II)-catalysed one-pot synthesis of thiazole/benzothiazole-based isoquinolin-1(2H)-ones as potential cytotoxic and VEGFR-2 inhibitors.

A facile one-pot annulation method for the synthesis of diverse bioactive thiazole/benzothiazole-based isoquinolin-1(2H)-one frameworks was accomplished. This approach involves the Ullman-type coupling of halo-substituted phenyl thiazolamides with various alkyl cyanoacetates employing copper (II) chloride as sustainable catalyst and water as co-solvent. Further, in silico studies were revealed the compound's selectivity towards kinase inhibition. Eventually, these derivatives were evaluated for their in vitro cytotoxicity against various cancer cell lines such as MCF-7, HCT-116, A549, HEPG-2, and HEK-293 (normal cell line). Among them, compound 3h has displayed significant cytotoxicity with an IC50 value of 7.75 ± 0.37 μM on HCT-116 cell line. Next, the compound 3h has also ability to induce apoptosis, which is examined through various staining assays like AO/EtBr, JC-1, and ROS. An ADP Glo kinase kit is utilised to evaluate the kinase inhibitory activity with most potent compound 3h, and showed an IC50 value of 1.94 μM, which is comparable to that of the standard drug sunitinib (IC50 of 400 nM). Finally, this straightforward one-pot annulation protocol is amenable in the generation of a library of new thiazole/benzothiazole-based heterocyclic compounds as potential cytotoxic and VEGFR-2 inhibitors in cancer drug discovery.