Synthesis and Biological Evaluation of (Thiophene-2-yl)-4H-Chromen-7-yl-Sulfonate Derivatives

Inspired by the significant biological activity of our previously screened natural 4H-chromen, a series of novel (Thiophen-2-yl)-4H-chromen-7-yl-sulfonate derivatives (Va–Vi) were synthesized and investigated for their in vitro free radical scavenging potential as well as cytotoxic efficacies against selected cancer cell lines. The cytotoxicity of the 4H-chromen derivatives (Va–Vi) was evaluated according to three human cancer cell lines (HepG2, A549, HeLa) by utilizing an MTT assay. Accordingly, part of the results exhibited better antitumor activities than that of the positive controls (7-hydroxy-2-phenyl-4H-chromen-4-one, 4H-chromen-4-one, and Apigenin). Among them, compounds (Vc–Ve) exhibited better training to the positive control against the three human cancer cell lines (IC50 = 10.52 ± 0.39 μM to 15.29 ± 0.35 μM). Moreover, the extract of the 4H-chromen derivatives (Va–Vi) showed better activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) in antioxidant assays compared to that of the positive control Ascorbic acid (IC50 = 12.72 ± 0.274 μg/mL, 5.0925 ± 0.209 μg/mL). Thus, it can be confirmed from the bioassay results that the overall structural design, as well as proper substitution, is crucial in delivering anticipated biological effects. In this regard, spectroscopic techniques such as 1H NMR, 13C NMR, and HRMS were also carried out to confirm the final structures.