Synthesis and in vitro anticancer evaluation of 8b-hydroxy-1-(6-substitutedbenzo[d]thiazol-2-yl)-3-(3-substitutedphenyl)-1,8b-dihydroindeno[1,2-c]pyrazol-4(3aH)-ones

•Synthesis of hydroxyindenopyrazolones was carried out in good yields.•The structures were confirmed by spectral (IR, 1H and 13CNMR, HRMS) and physical data.•Single crystal X-Ray crystallography of 3f was also performed.•Anticancer activity of hydroxyindenopyrazoles 3a‒o were assayed. A series of 1,8b-dihydroindeno[1,2-c]pyrazol-4(3aH)-ones has been efficiently synthesized on reaction of 2-(3-substitutedbenzoyl)-(1H)-indene-1,3(2H)-diones 1 and 2-hydrazinylbenzo[d]thiazole/2-hydrazinyl-6-substitutedbenzo[d]thiazoles 2 in presence of dry ethanol under reflux conditions in good yields. The structures of all the synthesized derivatives were elucidated by using different physical and spectral techniques (FTIR, 1H NMR, 13C NMR, 2D NMR and HRMS). The synthesized hydroxypyrazolones were assayed for their anticancer activity against two human cancer cell lines (i) lung carcinoma (A549) and (ii) breast carcinoma (MCF7) using MTT assay. Among all the tested compounds, 3d and 3k with IC50 values in the range of 30.68 ± 0.57 µM to 34.87 ± 0.76 µM exhibited moderate inhibitory ability against both the tested cancer cell lines in comparison to the standard drug Doxorubicin (0.95 ± 0.10 µM for A549 and 1.09 ± 0.11 µM for MCF7). The moderately active compounds of the series i.e.3d and 3k were further tested against normal human embryonic kidney cell line (HEK 293T) to examine their toxicity against normal cell lines. Selectivity Index (S.I.) of the most active compounds 3d and 3k was calculated for both the cancer cell lines which revealed that these derivatives i.e. 3d (S.I = 2.82 for A549 and 2.90 for MCF7) and 3k (S.I = 2.78 for A549 and 2.95 for MCF7) are safer anticancer agents. [Display omitted]