Regioselective synthesis and biological evaluation of novel dispiropyrrolidine derivatives via one-pot four-component reaction

Spirocyclization and Michael addition of 3-benzylidene succinimides: route to spirocyclopentapyrrolidine-tetraones and benzylidene N-arylpyrrolidine-diones

Reactions of 3-benzylidene succinimides with 2-substituted 2-hydroxy-indane-1,3-diones and unsaturated pyrazolones are carried out under basic conditions to afford spirocyclized derivatives and Michael adducts, respectively, with high regio- and stereo-selectivities. The most notable aspect of the reaction is the ability of highly reactive benzylidene succinimide to act as both an electrophile and a nucleophile causing spirocyclization. The reaction proceeded under mild and metal-free conditions and products were isolated in good to high yields. The current strategy utilizes simple and easily accessible precursors, and provides functionally rich products of medicinal interest with two to four contiguous stereogenic centres and complete regioselectivity with excellent diastereoselectivity.

A review of the synthetic strategies toward spirobarbiturate-fused 3- to 7-membered rings

Spiro-connected hexahydropyrimidine-2,4,6-trione heterocyclic rings have received increasing attention from the viewpoint of biological activity and synthetic methods due to the importance of the rigid heterocyclic system and unique orientation of the functional substituents. Since 1900, numerous studies have exploited the synthesis of various spirobarbiturate-fused carbo- and heterocycles by applying different strategies. Due to the importance of barbiturate-based olefins as activated alkenes, these substrates have been utilized in many reactions. In addition, the nucleophilic addition of 1,3-disubstituted barbituric acid to different electrophiles has been applied to prepare highly functionalized spirobarbiturate scaffolds. This short review highlights various strategies for synthesizing spirobarbiturate-fused 3- to 7-membered carbo- and heterocyclic rings and some catalytic diastereoselective and enantioselective chemical reactions to access chiral compounds. The sections are divided by the incorporation of 3- to 7-membered heterocyclic or carbocyclic rings into a spirobarbiturate scaffold, and are presented in different subsections depending on the mechanistic details.

Recent Advances in the Application of Barbituric Acid Derivatives in Multicomponent Reactions

Abstract:

Barbituric acid is a pyrimidine heterocyclic organic compound, which is pharmacologically active. It is important to build structures containing various medicinal activities. This compound attracts the scientific research community in organic synthesis. It can be used in the synthesis of polyheterocyclic, natural, medicinal compounds, and organic sensors. Herein, the utilization of barbituric or thiobarbituric acid in multicomponent reactions is reported from 2016-2021 in this manuscript.

Anticancer potential of spirocompounds in medicinal chemistry: A pentennial expedition

Spirocompounds constitute an important class of organic frameworks enveloping numerous pharmacological activities, among them, the promising anticancer potential of spirocompounds have enthused medicinal chemists to explore new spiro derivatives with significantly improved pharmacodynamic and pharmacokinetic profile along with their mechanism of action. The current review intends to provide a sketch of the anticancer activity of various spirocompounds like spirooxindole, spiroisoxazole, spiroindole etc, from the past five years unfolding various aspects of pharmacological activities and their structure-activity relationships (SARs). This literature analysis may provide future direction for the efficient design of novel spiromolecules with enhanced safety and efficacy.

Microwave assisted synthesis of five membered nitrogen heterocycles

Our continuously changing environment demands sensible and sustainable chemistry. Consequently, organic synthesis started to follow green chemistry principles in recent years. It is observed that microwave (MW) radiation has been widely used as a source of energy in organic synthesis in the past decade. The MW heating approach has evolved into a new green method in organic synthesis since it provides short reaction time, high yields, and high product purities along with a decrease in the rate of by-product formation. Solvent-free reaction protocols worked well under MW irradiation. All these features make MW assisted organic synthesis an environment-friendly approach. In organic synthesis, heterocycles are vital targets especially nitrogen-containing ones because of their prominent presence in natural products and widespread applications in pharmaceutical industries. Five membered nitrogen heterocycles include pyrroles, oxazoles, pyrrolidones, etc. among which pyrroles are the most important ones due to their potent biological properties. Even though there are a variety of reaction protocols for the synthesis of pyrroles, a significant development materialized in MW assisted synthesis of pyrroles in the past few years. In this review, we focus on the developments in MW assisted synthesis of pyrroles and other five-membered nitrogen heterocycles.

Three-Component Access to Functionalized Spiropyrrolidine Heterocyclic Scaffolds and Their Cholinesterase Inhibitory Activity

A novel one-pot [3+2]-cycloaddition reaction of (E)-3-arylidene-1-phenyl-succinimides, cyclic 1,2-diketones (isatin, 5-chloro-isatin and acenaphtenequinone), and diverse α-aminoacids such as 2-phenylglycine or sarcosine is reported. The reaction provides succinimide-substituted dispiropyrrolidine derivatives with high regio- and diastereoselectivities under mild reaction conditions. The stereochemistry of these N-heterocycles has been confirmed by four X-ray diffraction studies. Several synthetized compounds show higher inhibition on acetylcholinesterase (AChE) than butyrylcholinesterase (BChE). Of the 17 synthesized compounds tested, five exhibit good AChE inhibition with IC₅₀ of 11.42 to 22.21 µM. A molecular docking study has also been undertaken for compound 4n possessing the most potent AChE inhibitory activity, disclosing its binding to the peripheral anionic site of AChE enzymes.

Recent applications of ninhydrin in multicomponent reactions

Ninhydrin (1,2,3-indanetrione hydrate) has a remarkable breadth in different fields, including organic chemistry, biochemistry, analytical chemistry and the forensic sciences. For the past several years, it has been considered an important building block in organic synthesis. Therefore, there is increasing interest in ninhydrin-based multicomponent reactions to rapidly build versatile scaffolds. Most of the works described here are simple reactions with readily available starting materials that result in complex molecular architectures. Some of the synthesized compounds exhibit interesting biological activities and constitute a new hope for anticancer agents. The present review aims to highlight the multicomponent reactions of ninhydrin towards diverse organic molecules during the period from 2014 to 2019.

This article aims to review recent multicomponent reactions of ninhydrin towards diverse organic scaffolds, such as indeno-fused heterocycles, spiro-indeno heterocycles, quinoxalines, propellanes, cage-like compounds, and dispiro heterocycles.