One-pot synthesis, structural study, in silico and in vitro anticancer evaluation of spiropyrrolidine oxindoles obtained by the 3-CR of isatin, benzyl amine and a thiazolo[3,2-a]indole derivative

•One-pot stereoselective synthesis of spiropyrrolidine oxindole molecular hybrids via three component reactions is described.•Spiro heterocycles are formed with excellent yield and are isolated by chromatography free method.•Non-covalent S∙∙∙O chalcogen bond interaction was observed in the single crystals of the molecule (4 representatives were studied) and was confirmed by QTAIM and LOL plots.•In silico analysis of selected derivatives revealed the potential for the molecules to be explored as anticancer agents.•In vitro studies showed that compound 4s exhibited cell viability less than 80% with an effective dose of 25 µg/mL.•The S∙∙∙O chalcogen bond interaction is known to help in conformational locking of the molecules thereby influencing binding affinities to the biological targets. Stereoselective green synthesis of spiropyrrolidine oxindoles, in excellent yields, by the three-component reaction of isatins, benzyl amines and a thiazolo[3,2-a]indole derivative is reported here. In silico molecular docking studies of selected compounds in order to evaluate the MDM2 inhibition potential suggested that compound 4s was the best fit and further in vitro evaluation proved that 4s exhibited cell viability less than 80% with an effective dose of 25 µg/mL. Analysis of the single crystals of four derivatives showed that the S∙∙∙O chalcogen bond was a common feature which might be the reason for conformational locking and influence in the molecule's binding affinities to the biological target. QTAIM analysis revealed that two different modes of S∙∙∙O chalcogen bonds were present and Localized-Orbital Locator (LOL) plots suggested that the lone pairs on oxygen are oriented towards the sulphur atom supporting the S∙∙∙O interaction as a chalcogen bond of n→σ* type. [Display omitted]