Aqueous‐Mediated green synthesis of novel spiro[indole‐quinazoline] derivatives using kit‐6 mesoporous silica coated Fe 3 O 4 nanoparticles as catalyst

Efficient synthesis of 3-alkyl-2-(-1H-1,2,3-triazolyl)methyl)thio)-2,3-dihydroquinazolin-4(1H)-one derivative via multistep synthesis approach by novel Cu@Py-Oxa@SPION catalyst

In this pared, an efficient method is introduced for the synthesis of 3-alkyl-2-(((4-(2-oxopropyl)-1H-1,2,3-triazol-1-yl)alkyl)thio)-2,3-dihydroquinazolin-4(1H)-one derivatives. These novel products have both 1,2,3-triazole and quinazolinone in their structures. For the synthesis of these products, a novel catalyst is designed, synthesized, and characterized by the immobilization of copper onto modified magnetic iron oxide. The catalyst (denoted: Cu@Py-Oxa@SPION) was characterized by several characterization techniques. In this regard, 16 3-alkyl-2-(((4-(2-oxopropyl)-1H-1,2,3-triazol-1-yl)alkyl)thio)-2,3-dihydroquinazolin-4(1H)-one derivatives were synthesized in high isolated yields (77-86%). As an advantage, the catalyst is highly recoverable and its activity has not decreased after 7 sequential runs. The method is very efficient for the synthesis of the products in high isolated yields under mild reaction conditions in a green solvent. The scope of the method is broad and several examples were successfully synthesized using starting materials with different functional groups.

Pyromellitic acid grafted to cross-linked LDH by dendritic units: An efficient and recyclable heterogeneous catalyst for green synthesis of 2,3-dihydro quinazoline and dihydropyrimidinones derivatives

In this work, using layered double hydroxide (LDH) inorganic substrate, melamine as binding agent and dendrimer G1 and also pyromellitic acid (PMA) organic catalytic agent a heterogeneous acid catalyst was designed and prepared. After that, the prepared organic-inorganic catalyst was evaluated by various identification techniques such as FTIR, EDX, XRD, TGA, FESEM, and BET, and the results showed that the desired structure was successfully prepared. Also, in order to investigate the efficiency of the LDH@Me-PMA nanocatalyst as an efficient and heterogeneous catalyst, it was used for green and one-pot synthesis of 2,3-dihydro quinazoline and 3,4-dihydropyrimidinone-2-(1H)-ones derivatives. The use of LDH@Me-PMA catalyst led to the synthesis of the desired derivatives with higher efficiency and shorter reaction time than previously reported works. In addition, the prepared LDH@Me-PMA acid catalyst has the ability to be recycled and reused for 5 consecutive periods and has high stability, which is well consistent with the principles of green chemistry.

Recent Advances on Direct Functionalization of Indoles in Aqueous Media

Indoles and their derivatives have dominated a significant proportion of nitrogen-containing heterocyclic compounds and play an essential role in synthetic and medicinal chemistry, pesticides, and advanced materials. Compared with conventional synthetic strategies, direct functionalization of indoles provides straightforward access to construct diverse indole scaffolds. As we enter an era emphasizing green and sustainable chemistry, utilizing environment-friendly solvents represented by water demonstrates great potential in synthesizing valuable indole derivatives. This review aims to depict the critical aspects of aqueous-mediated indoles functionalization over the past decade and discusses the future challenges and prospects in this fast-growing field. For the convenience of readers, this review is classified into three parts according to the bonding modes (C-C, C-N, and C-S bonds), which focus on the diversity of indole derivatives, the prominent role of water in the chemical process, and the types of catalyst systems and mechanisms. We hope this review can promote the sustainable development of the direct functionalization of indoles and their derivatives and the discovery of novel and practical organic methods in aqueous phase.

Synthesis and evaluation of the antioxidant activity of new spiro-1,2,4-triazine derivatives applying Ag/Fe3O4/CdO@MWCNT MNCs as efficient organometallic nanocatalysts

We applied the Petasites hybridus rhizome water extract as green media so that Ag/Fe₃O₄/CdO@ multi-walled carbon nanotubes magnetic nanocomposites (Ag/Fe₃O₄/CdO@MWCNTs MNCs) could be prepared. We also evaluated its activity by using in the one-pot multicomponent reaction of acetophenones, diethyl oxalate, ammonium acetate, and activated carbonyl compounds such as ninhydrin, isatin and acenaphthylene-1,2-dione, and malononitrile and hydrazoyl chlorides in an aqueous medium at room temperature for the generation of spiro-1,2,4-triazines as new derivatives with tremendous output. Moreover, reducing organic pollutants from 4-nitrophenol (4-NP) was carried out by generating Ag/Fe₃O₄/CdO@MWCNTs in water at room temperature. The results displayed that Ag/Fe₃O₄/CdO@MWCNTs reduced pollutants of organic compounds in a short time. The synthesized spiro-1,2,4-triazines have NH and OH functional groups having acidic hydrogen with high antioxidant power. Also, the spiro-1,2,4-triazines exhibited antimicrobial ability. For this purpose, the disk diffusion method was applied and two kinds of bacteria, Gram-positive and Gram-negative, were employed for the analysis. Furthermore, we applied functional theory-based quantum chemical methods in order to better understand reaction mechanism density. To generate spiro-1,2,4-triazines, the applied process showed many properties such as reactions with short time, products with good yields, and simple extraction of catalyst from a mixture of reactions.

Six-component synthesis and biological activity of novel spiropyridoindolepyrrolidine derivatives: A combined experimental and theoretical investigation

Petasites hybridus rhizome water extract was used as green media for the preparation of Ag/Fe₃O₄/CdO@multi-walled carbon nanotubes magnetic nanocomposites (Ag/Fe₃O₄/CdO@MWCNTs MNCs), and its activity was evaluated by using in the one-pot multicomponent reaction of isatins, acetyl chloride, secondary amines, vinilidene Meldrum’s acid, primary amines, and malononitrile in an aqueous medium at room temperature for the generation of spiropyridoindolepyrrolidine as new derivatives with tremendous output. In addition, organic pollutant reduction of 4-nitrophenol (4-NP) was carried out by generated Ag/Fe₃O₄/CdO@MWCNTs in water at room temperature. The results displayed that Ag/Fe₃O₄/CdO@MWCNTs were reduced as pollutants of organic compounds in a short time. The synthesized spiropyridoindolepyrrolidine has an NH₂ functional group that has acidic hydrogen and shows high antioxidant ability. Also, the spiropyridoindolepyrrolidine exhibited antimicrobial ability, and the method that is used for this purpose is the disk diffusion method, and two kinds of bacteria, Gram-positive and Gram-negative, were employed for this analysis. Also, to better understand the reaction mechanism density, functional theory-based quantum chemical methods have been applied. For the generation of spiropyridoindolepyrrolidine, the used process has many properties such as reactions with short time, product with good yields, and simple extraction of catalyst from the mixture of reaction.

Synthesis and characterization of Fe3O4@Sal@Cu as a novel, efficient and heterogeneous catalyst and its application in the synthesis of 2-amino-4H-chromenes

This research paper presents the synthesis and characterization of the magnetic nanoparticle, Fe₃O₄@Sal@Cu, [Fe₃O₄@Si-CH₂-CH₂-CH₂-NH-NH-CO-N=CH-(2-HO-C₆H₄-)@Cu] as a green and retrievable catalyst. This catalyst was characterized by FTIR, XRD, EDX and TGA analyses. In addition, the catalytic activity of this new catalyst was investigated for the synthesis of 2-amino 4H-chromenes by producing good-to-excellent yields under mild reaction conditions. The other advantages of the developed nanocatalyst are its ecofriendliness, being easy to handle, high reusability and being magnetically separable. The synthesis of some new derivatives of 2-amino-4H-chromenes in the presence of this nanocatalyst is also reported.

Recent developments in green approaches for sustainable synthesis of indole-derived scaffolds

An important issue to discover biological structures is the design of sustainable, safe, clean, cost-effective, excellent efficient synthetic reactions, and minimal energy consumption to provide structural diversity compounds with interesting biological properties. Among five-membered nitrogen-containing heterocyclic compounds, indole-containing scaffolds are heterocyclic structures found in abundance in natural products and various synthetic compounds, which have received remarkable attention in recent years due to their therapeutic and pharmaceutical properties and valuable role in the process of drug discovery. Indoles can be synthesized by various procedures although most of these procedures have their own restrictions and drawbacks such as performing the reaction in a toxic solvent, need of transition-metal catalysts, and amount of waste solvents. Due to the medicinal importance of indole and the need for green methods of drug synthesis, this review highlights the latest green synthetic methods leading to the formation of indole-containing compounds focusing on the past 4 years with typical examples. This review is divided into two sections: green solvents and green techniques that lead to the synthesis of indole-derived scaffolds.

Recent Progress in the Synthesis of Heterocycles Based on 1,3-Diketones

N,O-heterocycles containing the dicarbonyl ring play a significant role in heterocyclic and therapeutic chemistry. Since the discovery of 1,3-diketones, numerous research works have been achieved regarding the synthesis and its chemical reactivity. In this review, we have described the most relevant publications involving β-diketone compounds published during the period between 2018 to date. In addition, we include the 1,3-diketones-based heterocyclic compounds prepared by various synthetic methodologies.