FeCl 3 ‐Catalyzed [3+2] Cycloaddition Reaction: A Mild Synthetic Approach to Spirooxindolo‐2‐iminothiazolidine Scaffolds

Dithiocarbamation of spiro-aziridine oxindoles: a facile access to C3-functionalised 3-thiooxindoles as apoptosis inducing agents

Herein, we report the first dithiocarbamation of spiro-aziridine oxindoles involving regiospecific ring-opening by using in situ generated nucleophilic dithiocarbamates as an instant source of sulfur. This approach afforded C3-functionalised-3-thiooxindoles in good to excellent yields with a wide substrate scope under catalyst-free and mild reaction conditions. These compounds were screened for their anticancer activity against a panel of human cancer cell lines, wherein compound 3u exhibited significant cytotoxic activity against human lung cancer cells with an IC50 value of 4.31 ± 1.88 μM. Phase contrast microscopy as well as different staining assays such as acridine orange/ethidium bromide (AO/EB), DAPI and DCFDA demonstrated the induction of apoptosis in A549 lung cancer cells after treatment with compound 3u. In addition, the clonogenic assay and migration assay demonstrated the ability of compound 3u to inhibit colony formation and cell migration, respectively, in A549 cells in a dose-dependent manner.

Transition metal-catalyzed synthesis of spirooxindoles

Spirooxindole is a principal bioactive agent and is observed in several natural products including alkaloids. They are broadly studied in the pharmaceutical field and have a significant role in the evolution of drugs such as anti-viral, anti-cancer, anti-microbial etc. In organic chemistry, an indispensable role is presented by transition metal catalysts. An effective synthetic perspective to spirooxindoles is the use of transition metals as the catalyst. This review discusses the synthesis of spirooxindoles catalyzed by transition metals and covers literature up to 2020.

Recent advances in multi-component reactions and their mechanistic insights: a triennium review

This review summarizes the recent developments in MCRs, incorporating different strategies along with their mechanistic aspects.

Sequential one-pot synthesis of N-sulfonyl spiroaziridine oxindoles from spiroepoxy oxindoles

The N-sulfonyl spiroaziridine oxindole is a recently developed versatile precursor in the synthesis of a wide range of 3,3-disubstituted spirooxindoles. It is usually prepared in three steps from isatin and needs costly and hardly available sulfinimides and hazardous peracid. A sequential and one-pot direct strategy for the synthesis of terminal N-sulfonyl spiroaziridine oxindoles has been developed under ambient conditions with excellent yields (up to 95%) from easily accessible spiroepoxy oxindoles by regioselective amination with aqueous ammonia and a subsequent ring enclosure reaction of the resulting 1,2-amino alcohol using easily available sulfonyl chloride and a base. Other salient features of the protocol include inexpensive substrate requirement and the ease of isolation of the desired product by performing single column chromatographic purification after two consecutive steps.

Base-mediated 1,3-dipolar cycloaddition of pyridinium bromides with bromoallyl sulfones: a facile access to indolizine scaffolds

An expedient and transition-metal-free synthetic strategy has been developed for the construction of substituted indolizines from a unique combination of pyridinium salts and 2-bromoallyl sulfones. This approach does not compromise with the diverse substitutions on both the pyridinium salts and 2-bromoallyl sulfones. Wide substrate scope, operational simplicity, milder reaction conditions and good to moderate yields are the merits associated with the current approach. Moreover, this method provides two products which are amenable for the generation of a library of key indolizine building blocks.

Syntheses and reactivity of spiro-epoxy/aziridine oxindole cores: developments in the past decade

This review highlights various reactions to afford spiro-epoxy/aziridine oxindoles and their potential synthetic transformations.