Regioselective Reactions, Spectroscopic Characterization, and Cytotoxic Evaluation of Spiro‐pyrrolidine Thiophene

Spiro‐oxo‐indole/pyrrolidine‐thiophene base possessed significant pharmacological activity. The [3 + 2] cycloaddition reactions of thia‐methine ylide respected through multi‐component reaction affording regioselective and stereoselective spiroindoline‐3,2′‐tetrahydrothiophene derivative 3. Reaction of such compound with different electrophilic and nucleophilic reagents afforded bioactive heterocyclic compounds 4–16. Biological evaluation showed that these synthesized spiro‐pyrrolidine exhibited moderate to good cytotoxic activity. Among them, compounds 7 and 14 displayed the best cytotoxic activity against MCF‐7 and Wl‐38 cells with the IC50 values of 7.02 ± 0.6 and 8.97 ± 0.9 μm (very strong), respectively. Compounds 4, 5, and 12 exhibited strong cytotoxicity's with IC50 16.28 ± 1.7, 11.16 ± 1.1, and 19.14 ± 1.7 μm, respectively, against MCF‐7 mammary gland cell line. All compound structures were supported by spectroscopic data and elemental analysis.