Heterocyclic azo dyes derived from 2-(6-chloro-1,3-benzothiazol-2-yl)-5-methyl-2,4-dihydro-3H-pyrazol-3-one having benzothiazole skeleton: Synthesis, structural, computational and biological studies

•Synthesis of azo dyes derived from 2-(6-chloro-1,3-benzothiazol-2-yl)-5-methyl-2,4-dihydro-3H-pyrazol-3-one having benzothiazole skeleton.•Structures of the synthesized molecules were elucidated by various experimental and theoretical spectroscopic techniques.•All the studied molecules exhibited anticancer studies. A series of novel benzothiazole based azo dyes were synthesized by diazotization of various substituted anilines coupling with 2-(6-chloro-1,3-benzothiazol-2-yl)-5-methyl-2,4-dihydro-3H-pyrazol-3-one by the diazo-coupling reaction at 0-5 °C. The structural confirmation of the synthesized molecules was carried out by spectroscopic techniques such as UV-visible, FT-IR and 1H NMR, respectively and by theoretical methods. Further, the computational studies were employed to interpret the structural properties of the azo molecules by using B3LYP program at 6-31G (d, p) basis set. Furthermore, the synthesized compounds were screened against cell lines to reveal their cytotoxic property, results revealed moderate to good cytotoxic potential of few compounds.