Pseudo five component reaction towards densely functionalized spiro[indole-3,2'-pyrrole] by picric acid, an efficient syn-diastereoselective catalyst: insight into the diastereoselection on C(sp3)-C(sp3) axial conformation

Highly efficient, catalyst-free, one-pot sequential four-component synthesis of novel spiroindolinone-pyrazole scaffolds as anti-Alzheimer agents: in silico study and biological screening

Alzheimer's disease is a neurodegenerative disorder that impacts memory, thinking, and behavior, and currently, there is no effective cure available for its treatment. This study explored a one-pot strategy for synthesizing spiroindolinone-pyrazole derivatives through a sequential four-component condensation reaction. These derivatives were further investigated for their potential as anti-Alzheimer's disease agents. The developed synthetic procedure provides remarkable advantages, including a clean reaction profile, abundant starting materials, operational simplicity, and easy purification without traditional methods with good to excellent yields (84-96%). Next, the biological potencies of the newly synthesized spiroindolinone-pyrazole derivatives against AChE and BChE as Alzheimer's disease-related targets were determined. Also, the kinetic study and cytotoxicity of the most potent derivative were investigated. Furthermore, molecular docking and molecular dynamics evaluations were performed employing in silico tools to investigate the interaction, orientation, and conformation of the potent analog over the active site of the enzyme.

Substrate Switchable Pathway for Selective Construction of Bridged Dibenzo[b,f][1,5]diazocines and Bridged Spiromethanodibenzo[b,e]azepines

An operationally simple method for the synthesis of bridged dibenzo[b,f][1,5]diazocines and bridged spiromethanodibenzo[b,e]azepines exhibiting bridged eight-membered and seven-membered molecular architecture is reported. This unique approach is based on substrate selective mechanistic pathway, including an unprecendented aerial oxidation-driven mechanism for the synthesis of bridged spiromethanodibenzo[b,e]azepines. The reaction is highly atom economic, and in addition, it allows the construction of two rings and four bonds in a single operation under metal-free condition. The easy availability of β enaminone and ortho phathalaldehyde as starting materials and the simple operation make this approach suitable for the preparation of important dibenzo[b,f][1,5]diazocine and spiromethanodibenzo[b,e]azepine cores.

Development of spiro-3-indolin-2-one containing compounds of antiproliferative and anti-SARS-CoV-2 properties

A series of 1″-(alkylsulfonyl)-dispiro[indoline-3,2'-pyrrolidine-3',3″-piperidine]-2,4″-diones 6a‒o has been synthesized through regioselective multi-component azomethine dipolar cycloaddition reaction of 1-(alkylsulfonyl)-3,5-bis(ylidene)-piperidin-4-ones 3a‒h. X-ray diffraction studies (6b‒d,h) confirmed the structures. The majority of the synthesized analogs reveal promising antiproliferation properties against a variety of human cancer cell lines (MCF7, HCT116, A431 and PaCa2) with good selectivity index towards normal cell (RPE1). Some of the synthesized agents exhibit potent inhibitory properties against the tested cell lines with higher efficacies than the standard references (sunitinib and 5-fluorouracil). Compound 6m is the most potent. Multi-targeted inhibitory properties against EGFR and VEGFR-2 have been observed for the synthesized agents. Flow cytometry supports the antiproliferation properties and shows the tested agents as apoptosis and necrosis forming. Vero cell viral infection model demonstrates the anti-SARS-CoV-2 properties of the synthesized agents. Compound 6f is the most promising (about 3.3 and 4.8 times the potency of the standard references, chloroquine and hydroxychloroquine). QSAR models explain and support the observed biological properties.

Diastereo- and regioselective petasis aryl and allyl boration of ninhydrins towards synthesis of functionalized indene-diones and dihydrobenzoindeno-oxazin-ones

Petasis aryl and allyl borations were accomplished using substituted ninhydrins, boronic acids or 2-allyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane and 1,2-aminophenols in Hexafluoroisopropanol (HFIP) without any catalysts to synthesize different aryl and allyl derivatives of ninhydrins. The nature of substitution in the boronic acids and 1,2-amino phenols was the key factor in determining the diastereo-regioselectivity and the type of product distributions. The products were isolated and characterized by HMBC, HSQC, ¹H, ¹³C NMR experiments and X-ray single crystallographic analysis. A probable reaction pathway involves in situ formation of acyclic and cyclic ninhydrin-amino alcohol adducts, with the positioned hydroxyl group determining the stereo-regioselective outcome via tetracoordinated boron intermediates. A metal free diastereo- and regioselective Petasis aryl and allyl boration of ninhydrins.

Recent Developments on Five-Component Reactions

Multicomponent reactions (MCRs) have inherent advantages in pot, atom, and step economy (PASE). This important green synthetic approach has gained increasing attention due to high efficiency, minimal waste, saving resources, and straightforward procedures. Presented in this review article are the recent development on 5-compoment reactions (5CRs) of the following six types: (I) five different molecules A + B + C + D + E; pseudo-5CRs including (II) 2A + B + C + D, (III) 2A + 2B + C, (IV) 3A + B + C, (V) 3A + 2B, and (VI) 4A + B. 5CRs with more than five-reaction centers are also included.

Engaging Isatins in Multicomponent Reactions (MCRs) - Easy Access to Structural Diversity

Multicomponent reactions (MCRs) are a valuable tool in diversity-oriented synthesis. Its application to privileged structures is gaining relevance in the fields of organic and medicinal chemistry. Isatin, due to its unique reactivity, can undergo different MCRs, affording multiple interesting scaffolds, namely oxindole-derivatives (including spirooxindoles, bis-oxindoles and 3,3-disubstituted oxindoles) and even, under certain conditions, ring-opening reactions occur that leads to other heterocyclic compounds. Over the past few years, new methodologies have been described for the application of this important and easily available starting material in MCRs. In this review, we explore these novelties, displaying them according to the structure of the final products obtained.

Access to molecular complexity. Multicomponent reactions involving five or more components

The evaluation of the significance of a chemical transformation addresses many factors, including such important characteristics as the number of chemical bonds formed in one step, the reaction time, labour intensity, the cost of reactants and catalysts and so on. The amount of waste produced in the reaction has also gained increasing importance in recent years. Multicomponent reactions (MCRs) occupy a special place as a synthetic tool in modern organic chemistry. These reactions allow the synthesis of target products with complex structures, minimizing labour costs. This review summarizes the literature on multicomponent reactions involving five or more components. The data in the review are classified according to the number of reactants participating in the reaction and the types of reactions. It is worth noting that in some cases, these transformations can be a part of a domino process, making this classification difficult, if not impossible. The structural diversity of the reaction products greatly increases with increasing number of components involved in the MCR, which becomes virtually unlimited when using combinations of MCRs. This review highlights the main trends of past decades in the field of MCRs. The last two decades have witnessed an explosive growth in the number of publications in this area of chemistry.

The bibliography includes 309 references.